DE102021004099A1 - Pumped storage power plant with a storage basin enclosed by a circular dam - Google Patents

Abstract

A power supply mainly from wind and photovoltaics requires, among other things, large short-term storage. In addition to batteries, advanced, large pumped storage power plants with a high level lift in one of the storage basins, e.g. a high lower basin 33 delimited by a closed ring dam 3 within an opencast mine residual lake 0, are possible. The invention proposes an expansion of the storage volume as a bottom hole storage space 37 into the bottom of the lake and enables an almost complete utilization of the energetic potential of the high total basin 333 through a variable and depending on the pressure level controlled interconnection of several standardized pump turbines, which are then all used in differently combined units at any time.

Description

The invention relates to a pumped storage power plant (PSKW) which has a storage basin, the storage energy of which is determined less by its altitude, but rather by its overall height.

An important application of such a high storage basin results as a lower basin enclosed by a circular dam within an abandoned open-cast mine, the remaining lake of which serves as the upper basin of the PSKW.

1. Current state of the art:

PSPs are built in such a way that a body of water can be exchanged using pump turbines between two basins, the levels of which are at different levels. Normally, the difference in level in the upper and lower basins is mainly caused by the altitude of the upper basin and less by the level difference within a basin that occurs during operation. The altitude of the upper basin results from the height profile of the landscape.

For example, the PSKW Goldisthal (/ Goldisthal /) has a reservoir as its lower basin, which is formed by the Salza river, and the upper basin was built by a wall on a mountain, the top of which was removed. The most powerful German PSP with 1.06 GW has a nominal level difference of 302 [m] and a level fluctuation of up to 20 [m] in the lower basin and up to about 24 [m] in the upper basin. The maximum height tolerance to which the pump turbines have to adapt is 44 m, which is only +/- 7.3% in relation to the nominal level difference.

However, there are also considerations to set up PSKW in a natural landscape that does not have a sufficiently large difference in height. For this purpose, for example, in the "Ringwallspeicher project" (/ Popp 2009 /), which was worked out by Mathias Popp over many years (/ Popp 2021 /), an inner high upper basin is built up as a circular wall, whereby the material from the excavation of the lower basin, which concentrically surrounds the ring wall and is characterized by its excavation depth a (Fig. 1). Ring wall storage facilities could be built on land as well as in bodies of water and also in transition zones between land and bodies of water.

• (1) Die Aufschüttung eines Staudammes, der durch sein hohes Gewicht die starke Verschiebekraft des Wasserdruckes neutralisieren muss, führt bei großen Stauhöhen zu gewaltigen Ausmaßen für die Dammbreite. Dies mag bei sehr großen Durchmessern des Ringwalles - in seinem visionären „Projekt Ringwallspeicher“ (/Popp 2021/) rechnet Popp mit einem Durchmesser von ca. 6 km und einer maximalen Höhe von H_max = 235 m - durchaus gerechtfertigt sein; aber bei Ringbecken mit deutlich kleinerem Durchmesser (z.B. nur 1 bis 2 km) wird ein aufgeschütteter Staudamm zu aufwendig. Dies gilt umso mehr, wenn gleichzeitig auch noch eine deutlich größere Höhe verlangt wird.
• (2) Der durch den Ringwall eingeschlossenen Wasserkörper, der z.B. als Oberbecken eines PSKW genutzt wird, reicht zwar bis zum Niveau des Unterbeckens herunter, aber seine große Höhe wird zu einem erheblichen Teil nur dafür genutzt, eine für den Pumpturbinensatz geeignete Mindesthöhe für die Pegeldifferenz sicherzustellen. Der Pegelhub dh0 im Oberbecken wird also von vorneherein auf einen kleinen Bereich begrenzt und beschränkt dadurch auch denjenigen Wasserkörper WK0 im Oberbecken, der tatsächlich zur Speicherarbeit herangezogen wird. Die Höhe des unteren Wasserkörpers WKu, der am Austausch der Speicherenergie nicht aktiv teilnimmt, beträgt in (/Popp 2021/) ca. 150 m, während das aktive Austauschvolumen des Wasserkörpers WK0 um die mittlere Pegeldifferenz von 200 m um +/- 35 m (also um 17,5 %) schwankt.

Die Verhältnisse werden in Bild 1, das etwas verändert aus /Popp 2021/ zusammengestellt wurde, dargestellt.However, the concept of the ring wall storage tank (Fig. 1) has two properties which, from our point of view, would be advantageous to modify:

• (1) The backfilling of a dam, which, due to its heavy weight, has to neutralize the strong displacement force of the water pressure, leads to enormous dimensions for the width of the dam in the case of high water levels. This may well be justified in the case of very large diameters of the ring wall - in his visionary “Ring wall storage project” (/ Popp 2021 /) Popp calculates a diameter of approx. 6 km and a maximum height of H _max = 235 m; But in the case of ring basins with a significantly smaller diameter (eg only 1 to 2 km), a heaped dam becomes too expensive. This is all the more true if a significantly higher amount is also required at the same time.
• (2) The water body enclosed by the ring wall, which is used, for example, as the upper basin of a PSKW, extends down to the level of the lower basin, but its high height is used to a considerable extent only to achieve a minimum height for the level difference that is suitable for the pump turbine set to ensure. The level swing dh0 in the upper basin is therefore limited from the outset to a small area and thus also restricts the water body WK0 in the upper basin that is actually used for storage work. The height of the lower body of water WKu, which does not actively participate in the exchange of storage energy, is approx. 150 m in (/ Popp 2021 /), while the active exchange volume of the body of water WK0 by the mean level difference of 200 m by +/- 35 m ( i.e. by 17.5%).

The relationships are shown in Figure 1, which has been compiled slightly changed from / Popp 2021 /.

• Die Erfinder haben sich die Aufgabe gestellt, die konzeptionelle Voraussetzungen für ein PSKW zu schaffen, das als Oberbecken einen Tagebau-Restsee nutzt, und dafür ein technisch und wirtschaftlich geeignetes Unterbecken zu konzipieren.

Aim of the invention:

• The inventors have set themselves the task of creating the conceptual prerequisites for a PSKW that uses a residual open pit lake as an upper basin, and to design a technically and economically suitable lower basin for this purpose.

With this general objective and / or with special consideration of the possibilities resulting from the expiry of the open-cast lignite mine and here in particular in the largest German open-cast mine Hambach (Rheinisches Braunkohlerevier), following the fundamental determination of DE19513817 B4 (/ Siol 1995 /) that an abandoned opencast mine is a suitable place for the construction of a PSKW, several authors put forward inventions and considerations. The state of the art up to 2019 is in the description DE 10 2019 118 725 (/ LuSchmB 2019_SeeEi1 /) in the sections "Open-cast lignite mining as a site for PSKW" and "Underground and submarine PSKW". That through our own patent applications DE 10 2019 118 725.7 (/ Lu-SchmB 2019_SeeEi1 /) and DE 10 2019 118 726.5 (/ LuSchmB 2019_SeeEi1v /) extended state of the art, which particularly concerns the construction of underwater PSKW (U.PSKW), is summarized in the chapter "state of the art" of the description of our patent application DE 10 2020 002 609 A1 (/ LuSchmB 2020_SeeEi2 /)).

The patent application DE 10 2020 002 609 A1 (/ LuSchmB 2020_SeeEi2 /) is split into two parts due to inconsistency. The main part, which was continued under the original application number, includes significant improvements to the construction and statics of underwater PSKW, in the lower basins of which storage spaces are joined together on the basis of hollow spheres as well as hollow prisms to form an overall body.

In DE10 2020 111 844 (/ LuSchmB 2020_SeeEi3 /) the idea of the modular structure of the underwater reservoir is carried out further and, in particular, optimized from the point of view of an effective and cost-effective manufacturing process. With regard to the current invention, it is important that the hexagonal, upright pressure vessels in particular are joined together to form a modular arrangement and that both the vessels and the modules are adjacent to one another via large contact walls, so that a favorable pressure guide structure is obtained for the transmission of external pressure forces .

The outsourced part of DE 10 2020 002 609 A1 (/ LuSchmB 2020_SeeEi2 /) describes the idea of a PSKW with a ring-shaped closed dam and is now presented in the current patent application in a significantly expanded form as a separate patent application.

Starting from the state of the art, one can arrive at this basic idea according to the invention in three different ways:

(1.) From the high and wide underwater basin to the circular dam

We are in DE 10 2020 002 609 A1 (/ LuSchmB 2020_SeeEi2 /) initially dealt in detail with high underwater pools. In physics, it is a popular way of thinking to mentally scale things further and to see whether new phenomena and structures arise at certain breakpoints. What happens if you make tall storage pipes without storeys ever higher and wider and wider in diameter?
When you get thicker, it becomes more and more time-consuming to put a suitable and pressure-resistant "lid" on the huge storage tubes. If the height is increased further, however, it becomes easier to make the cover pressure-resistant, since the load pressure decreases as the overlap height with seawater and / or overburden decreases. The point of interest is reached when the storage tubes rise above the surface of the lake and are all grouped together into a single large circular reservoir. What has now arisen can also be called differently: A ring-shaped closed dam wall within the rest of the lake, the interior of which represents the lower basin and the exterior of which the upper basin of a pumped storage power plant. We refer to this full-circle dam as the “ring dam” 3, which is the lower basin 33 of a PSKW.

One can ask: why is the full-circle dam not state-of-the-art for a long time? The answer is simple: this amazingly simple idea is only suitable for deep, completely closed holes and not for damming up a deep valley. So the hole must already be there and not first created by the dam from a long valley. But this is exactly the case with the opencast mine holes.

(2) From the deep shaft to the circular dam

Also in DE 10 2011 105 307 / LuSchmB 2011 -Bergei1 / a conceptually similar storage solution is addressed. However, this involves deep shafts created by mines with a separate one Upper basin, e.g. in a flowing water (see also DE 10 2014 007 184 A1 ; / LuSchmB 2014 -LangeSaar /), and not about ring dams in a lake. The walls of the storage shafts according to our "Bergei patent" DE 10 2013 019776 B3 (/ Lu-SchmB 2013 -Bergei2 /) are not surrounded by water, but by soil.

(3.) From the ring wall to the ring dam

The concept of the ring wall storage system according to M. Popp (/ Popp 2009 /) has already been explained above. The way from this concept to the circular wall storage tank according to the invention is a long one: M. Popp's ingenious trick of creating a lower basin in a flat landscape by dredging an outer circular basin and then layering the excavation to create a wall to enclose an upper basin, is not advantageous for an abandoned open pit mine, and probably not feasible at all.

The idea of the ring wall storage facility is also aimed at significantly larger PSKW storage capacities, as would be necessary for storage over many days to cover dark doldrums and periods of shortage lasting several days. On the other hand, we represent the dual storage concept, according to which a complete backup of the power supply takes place via gas power plants and the short-term storage capacity to be provided by PSKW or large battery storage only takes on the task of the amount of gas required, which is costly and with heavy losses when the energy transition is completed would have to be generated from RE, to reduce - for example to halve.
In the chapter “3.1 Comparison of circular wall storage versus circular wall storage” we show that circular wall storage and circular wall storage complement each other in their area of application for physical and technical reasons.

2. Solution

The inventors have set themselves the task of creating the conceptual prerequisites for a PSKW that uses an open pit residual lake as an upper basin, and to design a technically and economically suitable lower basin for this purpose.

The solution according to the invention relies on a PSKW, its lower basin 33 is formed by a ring-shaped closed dam within the later residual lake and the upper basin of which represents the residual lake itself. We refer to this full-circle dam as the “ring dam” 3. Figure 2 shows a cross-section of the Hambacher Loch (or a similar large open-cast mine hole), in whose deep excavation channel, ie on the natural soil, a ring-shaped dam was built. The diameter can be as large as the width of the excavation channel, including its surrounding area of the same height, for example 1 km or - if something is digged off at the edge - for example 1.5 km.

The headwater is, for example, via sufficiently large lateral access shafts 44 from Obersee 0 fed into the turbines at the foot of the ring dam; the pump water takes the same route in the opposite direction. The access shafts 44 only need to take into account the debris that has been piled up on the side 12th tower overhead and keep access to the pump turbines safe and free over the long term. So you can if necessary. also be pretty short; however, they should be generously dimensioned in width so that the flow speed of the storage water remains low and - in contrast to the conditions in many pressure pipes - the frictional resistance remains negligibly low.

Figure 3 shows the top view of the remaining lake of an opencast mine 300 with - in this example four - lower basins each formed by a circular ring dam 33 . The trace of the lower basin marks the assumed course of the deep channel. The dam walls avoid the area of the heaped or relocated soil.

Many dam walls, especially in narrow, high valleys, are designed as segments of a circle, the bulges of which protrude outward into the reservoir. With this slim type of dam, eg the so-called "arch dam", the lateral pressure of the water is not absorbed by the great weight of the thick wall as with a "weight dam", but elegantly by the curved wall on the lateral anchoring in the mountain diverted (more detailed descriptions and clear pictures can be found at Wikipedia (/ Wikipedia ## Arch dam /). A special type of dam is known as an arch weight dam (/ Wikipedia ## arch weight dam /); it is a mixture of a weight dam and an arch dam. We include with the general term " Dam “all types of that kind. Due to the ring-shaped closure of the dam, however, certain aspects that are important for the construction of barrier structures, such as the load on the valley flank, are obsolete.

In the case of the symmetrical, (more or less) circularly closed ring dam, which we have shown as a borderline case, the lateral sliding pressure of the water is canceled out for reasons of symmetry; because the water level in the Rundumsee is the same everywhere and at all times. The dam just needs to be tight and withstand the pressure difference between inside and outside. The bottom of the inner basin must - and this is no different than on the valley side of the usual dam walls - withstand the high water pressure of the "groundwater", which tries to create an "artesian well" at weak points. It is important that the lower basin as a whole has no buoyancy and therefore cannot float, because it is not surrounded from below by freely accessible and strongly flowable pressurized water. In the event of a “worst case” dam break, the lower basin may develop into a gigantic stilling basin, but it cannot float up.

The circular dam in the deep Hambacher Loch (or in another open-cast mine hole) creates a very high storage basin and it is important that a large water level rise within the lower basin is inexpensive using previous standard pump turbines 33 can be used. According to the invention, this is made possible by the existing pump turbines being interconnected to form suitable units, depending on the pending pressure head range, so that the requirements for each individual pump turbine are within their tolerance range at all times. It has been shown that this task can be achieved with units that result from the parallel connection of strings from pump turbines connected in series, the number of which results from the upcoming pressure stage. As a rule, only two classes of pump turbines are sufficient, a "standard pump turbine" with a pressure head of H _P and a "fractional pump turbine" with a pressure head of (H _P * b) and b - the power, where the product of b and the number M _b of “fractional pump turbines” must remain an integer.

This method of variable series parallel connection of pump turbines even enables a further increase in the overall height of the lower basin, which can be achieved according to the invention by properly deepening the bottom of the lower basin, depending on the geological conditions.

3. Basic properties

In the following we want to consider some basic properties of the proposed approaches according to the invention for the construction of a PSKW with a storage basin formed by a ring dam. Further additions and important detailed questions are then dealt with in Chapter 5.

3.1 Comparison of RM storage versus U.PSKW and RW storage

The following are important properties of the following three types of unconventional storage tanks
Ringwall storage facility (RW.Sp)
Circular Wall Storage (RM.Sp)
Underwater PSKW (U.PSKW)
are worked out on the basis of simple physical relationships and scales and their areas of application are weighed up against each other.

To the ring wall storage facility (RW.Sp):

oder mit einem geeigneten Proportionalitätsfaktor c_W: $$\text{s}=\text{c\_W}*\text{H}$$

Andererseits müssen Böschungen stabil gegen Rutschungen sein. Dies gewährleistet u.a. ein richtig gewählter Böschungswinkel, den man meistens durch den Quotienten aus Höhe h und Breite, also als Steigung m, $$\text{m}=\text{h}/\left(\text{s}/2\right)$$

angibt. Hierbei ist s/2 die Breite der Böschung. Ein Wall besteht aus zwei Böschungen, an jeder Seite eine, und s ist daher die gesamte Breite des Walles in der Stautiefe H. Hierbei haben wir die Dammkrone als relativ klein angesehen und daher weggelassen.Due to their sheer weight, walls defy driving forces that want to push them away or tear them apart. In the case of a retaining wall, these forces are proportional to the depth H of the standing water. Therefore the following applies to the thickness s of the dam; $$\text{s}\sim \text{H}$$

or with a suitable proportionality factor c_W: $$\text{s}=\text{c\_W}*\text{H}$$

On the other hand, embankments must be stable against landslides. This ensures, among other things, a correctly selected angle of repose, which is usually given by the quotient of height h and width, i.e. as the slope m, $$\text{m}=\text{H}/\left(\text{s}/2\right)$$

indicates. Here s / 2 is the width of the slope. A wall consists of two embankments, one on each side, and s is therefore the entire width of the wall in the storage depth H. Here we have considered the dam crest to be relatively small and therefore omitted.

was einem Böschungswinkel von 32° entspricht.In his calculations Popp (/ Popp 2009 /, / Popp 2021 /) used the value as the ring wall gradient: $$\text{m}.\text{RW}=\text{1/1}\text{, 6}=\text{62}\text{, 5\%;}$$

which corresponds to a slope angle of 32 °.

• Grundsätzlich anders verläuft die Stauhöhenabhängigkeit für die Dicke s einer Staumauer. Die Staumauer hält durch die Festigkeit des Betons zusammen. Die angreifenden Kräfte werden tangential über die seitliche Verankerung an die Auffanglager im Felsgestein weitergegeben. Bei der Ring-Staumauer gibt es keine Schiebekräfte mehr: der Ring ruht frei von Verschiebekräften im See, da die Verschiebungskräfte sich über den geschlossenen Ring gegenseitig aufheben.

To the Ringmauer-Speicher (RM.Sp) and comparison:

• The dam height dependency is fundamentally different for the thickness s of a dam. The dam holds together due to the strength of the concrete. The acting forces are passed on tangentially via the lateral anchoring to the reception camp in the rock. With the ring dam there are no longer any pushing forces: the ring rests free of shifting forces in the lake, as the shifting forces cancel each other out via the closed ring.

.wobei g =9.81 [m/s²] die Erdbeschleunigung und rho_Wasser =1000 kg/m³ die Dichte des Wassers bezeichnen.
Zulässig sind diese mechanischen Spannungen σ_t nur, wenn sie von der Festigkeit des Betons, σ_Beton, noch ausgehalten werden, also wenn für die auf den Durchmesser D des zylinderförmigen Hohlkörpers bezogene Wanddicke s gilt: $$\text{s/D}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.*\text{H}*\left(\text{g}*\text{rho\_Wasser}\right)/{\sigma }_{Beton}$$

Auf der rechten Seite von GI(4) stehen bis auf die Druckhöhe H nur allgemeine und stoffliche Konstanten, die man als c_B zusammenfassen kann: $$\text{s/D}=\text{c\_B*H}$$

The strength of a boiler-shaped structure is described by the boiler formula, which _{specifies the tangential stress σ t} in the concrete for cylindrical structures with the diameter D: $$\text{D.}/\text{s}=2*{\sigma }_{\text{t}}*1/p==2*{\sigma }_{\text{t}}/\left(\text{H}*G*\text{rho\_water}\right)$$

where g = 9.81 [m / s ² ] denotes the acceleration due to gravity and rho_Wasser = 1000 kg / m ³ denotes the density of the water.
These mechanical stresses σ _{t are} only permissible if they can still be withstood by the strength of the concrete, σ _concrete , i.e. if the following applies to the wall thickness s related to the diameter D of the cylindrical hollow body: $$\text{s / D}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.*\text{H}*\left(\text{G}*\text{rho\_water}\right)/{\sigma }_{\mathrm{B.}etOn}$$

On the right-hand side of Eq. (4) there are only general and material constants except for the pressure level H, which can be summarized as c_B: $$\text{s / D}=\text{c\_B * H}$$

lässt sich nur noch über die Betonfestigkeit σ_Beton in einem gewissen Bereich beeinflussen.The constant c_B $$\text{c\_B}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.*\left(\text{G}*\text{rho\_water}\right)/{}_{}$$

can only be influenced within a certain range via the concrete strength σ _concrete.

First of all, the boiler formula GI (3) has proven itself for boilers and also for large pressure vessels in construction engineering. For larger diameters it will probably remain valid for a while to a good approximation, but it is completely unsuitable for straight walls:

dann versteht man etwas Fundamentales:

• • Die Mauerdicke s hängt also vom Produkt (D*H) ab, und nicht mehr wie beim Ringwall allein von der Höhe H.

Das hat für große Baukörper dramatische Konsequenzen.If we write GI (5) in analogy to GI (1): $$s=\left(\text{D.}*\text{H}\right)*\text{c\_B}$$

then one understands something fundamental:

• • The wall thickness s therefore depends on the product (D * H) and no longer solely on the height H as in the case of the ring wall.

This has dramatic consequences for large structures.

• Betrachten wir nämlich in einer festgelegten Höhe H für eine kleine Scheibe der Höhe dh das Verhältnis Nutzen zu Aufwand als Quotient X von gespeicherter Energie zu dem beanspruchten Speichervolumen, , so ergibt sich für den Ringwall zunächst $$X_{Wall}=\left[\text{Pi()}*\text{D}*\left(\text{H}*\text{c\_w}\right)*\text{dh}\right]/\left[\text{Pi()}*{\text{<figure-callout id="2" label="D" filenames="DE102021004099A1\_0024.png" state="{{state}}">D</figure-callout>}}^2*\text{dh}\right]$$
  
  und nach dem Kürzen erhält man den volumenspezifischen Aufwand einer niedrigen Ringwallscheibe zu: $$X_{Wall}=\left[\text{H}*\text{c\_w}\right]/\text{D}$$
  

Aber die dazu analoge Kennziffer X_RM für die Ringmauer $$X_{RM}=\text{Pi()}*\text{D}*\left(\text{D}*\text{H}*\text{c\_B}\right)*\text{dh}/\text{Pi()}*{\text{<figure-callout id="2" label="D" filenames="DE102021004099A1\_0024.png" state="{{state}}">D</figure-callout>}}^2*\text{dH}$$

ergibt nach dem Kürzen $$X_{RM}=\text{H}*\text{c\_B}$$

und hängt gar nicht mehr von dem Durchmesser des Ringes, D, ab.Effort per storage unit:

• If we consider namely at a fixed height H for a small slice of height, ie the ratio of benefit to expenditure as the quotient X of stored energy to the required storage volume, then this results for the ring wall $$X_{\mathrm{W.}all}=\left[\text{Pi()}*\text{D.}*\left(\text{H}*\text{c\_w}\right)*\text{ie}\right]/\left[\text{Pi()}*{\text{D.}}^2*\text{ie}\right]$$
  
  and after shortening you get the volume-specific effort of a low circular wall disk: $$X_{\mathrm{W.}all}=\left[\text{H}*\text{c\_w}\right]/\text{D.}$$
  

But the analogous code number X _RM for the curtain wall $$X_{\mathrm{R.}\mathrm{M.}}=\text{Pi()}*\text{D.}*\left(\text{D.}*\text{H}*\text{c\_B}\right)*\text{ie}/\text{Pi()}*{\text{D.}}^2*\text{i.e.}$$

results after shortening $$X_{\mathrm{R.}\mathrm{M.}}=\text{H}*\text{c\_B}$$

and no longer depends on the diameter of the ring, D.

• • Bei gleichem Nutzvolumen kann man mit Ringmauern zu gleichen Kosten sowohl viele im Durchmesser kleine als auch wenige große Becken errichten, denn die Kennziffer X_RM enthält ja den Durchmesser D gar nicht mehr
• • Bei großen Durchmessern D werden die spezifischen Baukosten für Ringwälle (X_wall) immer günstiger und bei genügend Vorstellungskraft für die Ausmaße irgendwann automatisch zur preiswerteren Alternative.

Two conclusions are essential:

• • With the same usable volume, circular walls can be used to build many pools with a small diameter as well as a few large pools at the same cost, because the code number X _RM no longer includes the diameter D at all
• • In the case of large diameters D, the specific construction costs for ring walls (X _wall ) are becoming cheaper and, with enough imagination for the dimensions, they will automatically become a cheaper alternative at some point.

For this reason, for an increasingly gigantic solution, in the end, only the circular wall storage system is considered, but below that, the circular wall storage system remains as the often cheaper solution. Only a project-related cost estimate can reveal where this limit lies, and of course many other factors also play a role.

In densely populated Germany, we give the curtain wall storage facility a good chance, primarily because of its ability to be split up into smaller units at low cost. Especially in the "huge" Hambacher Loch there is a great advantage for the ring wall storage compared to the ring wall, because the excavation from the history of the open pit is in bulk and does not seem suitable, untreated, can be used as an inexpensive building material for the filling of a very high embankment to be.

But the visionary circular wall storage system, which has been known for 12 years now, may still have a great future with regard to less densely populated geographical areas, not least thanks to the rapid improvement in its economic efficiency through the technology of the "variable parallel series connection of pump turbines for exhaustion of a high storage basin ”in section 5 is addressed and is presented in more detail in the / LuSchmB 2021_SeeEi5 / submitted by us as an independent patent application at the same time.

Illustration: "Slope slope" of a dam wall

wobei wir die „Böschung“ vollständig auf nur eine Seite der Ringmauer gelegt haben.Something like an "embankment slope", with RM, can also be calculated for the ring wall wall: $$\text{m}\text{.RM}=\text{H}/\text{s}$$

where we have completely laid the "embankment" on only one side of the curtain wall.

With GI ( 5 ) we receive: $$\text{m}\text{.RM}=\text{H}/\text{s}=1/\left(\text{D.}*\text{c\_B}\right)$$

$$\text{c\_B}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.*\left(\text{g}*\text{rho\_Wasser}\right)/{\mathrm{\sigma }}_{\text{Beton}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.*\mathrm{9,81}*1000/\left(5*{10}^7\right)=\text{ca}\text{. }{10}^{-4}\left[1/\text{m}\right]$$

und wir erhalten die Steigung der Staumauer zu $$\text{m}\text{.RM}={10}^4/\text{D}$$

, was beispielweise bei D= 1000 m eine Steigung der Mauer von 10 : 1 ergibt.
Die Dicke einer derartigen Staumauer in H=400 m Höhe beträgt also $$\text{s}=\text{H}/\text{m}\text{.RM}=400\left[\text{m}\right]/10=40\text{ m}$$

Bei einem extrem hochwertigen Beton von z.B. σ_Beton = 100 MPa entspräche dies sogar nur noch einer Dicke s von 20 m.For the material constant c_B we choose a round value for a reasonably high-strength concrete:
then according to Eq. ( 6th ) $${\mathrm{\sigma }}_{\text{concrete}}=50\text{MPa}=5*{10}^{\mathrm{7th}}\left[{\text{N / m}}^2\right]$$

$$\text{c\_B}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.*\left(\text{G}*\text{rho\_water}\right)/{\mathrm{\sigma }}_{\text{concrete}}=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.*9.81*1000/\left(5*{10}^{\mathrm{7th}}\right)=\text{approx}\text{.}{10}^{-\mathrm{4th}}\left[1/\text{m}\right]$$

and we get the slope of the dam too $$\text{m}\text{.RM}={10}^{\mathrm{4th}}/\text{D.}$$

, which for example at D = 1000 m results in a wall gradient of 10: 1.
The thickness of such a dam wall at a height of H = 400 m is therefore $$\text{s}=\text{H}/\text{m}\text{.RM}=400\left[\text{m}\right]/10=40\text{m}$$

In the case of extremely high-quality concrete of, for example, σ _concrete = 100 MPa, this would even only correspond to a thickness s of 20 m.

However, this value should not be compared with the base widths of constructed dams of this height, as the compressive strength of the floor must also be taken into account for the foot that rests on the floor and a wider “shoe” is usually used for the stand area.

• Von den vorgenannten Typen (RW.Sp und RM.Sp), die beide Becken beschreiben, die nach oben offen sind, unterscheidet sich das Unterwasser-PSKW, abgekürzt „U.PSKW“, ( siehe DE 10 2019 118 725 A1 (/LuSchmB 2019_SeeEi1/), DE 10 2020 002 609 A1 (/LuSchmB 2020_SeeEi2/) und DE 10 2020 111 844 A1 (/LuSchmB 2020_SeeEi3/) ) dadurch, dass das Unterbecken ein nach allen Seiten hin abgeschlossener Hohlkörper ist. Das kann unter gewissen Blickrichtungen einen Vorteil bedeuten, allerding kann man aus anderer Sichtweise darin auch große Nachteile erkennen, nämlich:
  • Man sieht das U.PSKW von außen nicht, das Unterbecken bleibt „unsichtbar“ in der Tiefe des Obersees verborgen.

Allerdings kann andererseits eine aus dem Wasser herausragende Insel durch geschickte landschaftliche Einbindung und Ausbildung touristischer Strukturen durchaus zum Blickfang und zur Attraktion werden. Ein negativer optischer Eindruck des schwankenden Pegelstandes kann durch vorgelagerte „schwimmende Inseln“ mit geeigneter Bepflanzung und Bebauung vermieden werden.To underwater PSKW (U.PSKW):

• The underwater PSKW, abbreviated to "U.PSKW" (see DE 10 2019 118 725 A1 (/ LuSchmB 2019_SeeEi1 /), DE 10 2020 002 609 A1 (/ LuSchmB 2020_SeeEi2 /) and DE 10 2020 111 844 A1 (/ LuSchmB 2020_SeeEi3 /)) in that the lower basin is a hollow body closed on all sides. This can be an advantage from certain perspectives, but from another point of view you can also see major disadvantages, namely:
  • You cannot see the U.PSKW from the outside, the lower basin remains "invisible" hidden in the depths of the upper lake.

However, on the other hand, an island protruding from the water can become an eye-catcher and an attraction through skillful integration into the landscape and the formation of tourist structures. A negative visual impression of the fluctuating water level can be avoided by upstream "floating islands" with suitable plants and buildings.

The U.PSKW can be built with a freely selectable height, which is based, for example, on the existing relatively narrow tolerance range of the pump turbines used in conventional PSKW.
However, this has the disadvantage that the water body above remains unused for storage. This weighs particularly heavily because now, through “variable parallel series connection of pump turbines” (see Section 5 and / LuSchmB 2021_SeeEi5 /), a simple and effective method for utilizing a high storage basin with a single type of pump turbine is state of the art.

In the case of a U.PSKW with a small overall height, a depth range is used that requires a body of water with a smaller working volume per stored amount of energy than in bodies of water above it. This then results in a somewhat lower level fluctuation in the upper basin.
However: Since the total area of the Hambacher Loch is very large, the level fluctuation in the upper basin is not of central importance. Bathing on the beaches is not really hindered by the ebb and flow of the tide. In addition, one accepts a noticeable level fluctuation even in the often much smaller basins of conventional PSKW; In the Goldisthal PSP, for example, the level difference within the basin is still up to 24 or 20 [m].

• Bei U.PSKW muss man dem Problem des Auftriebes nicht nur aus technischen, sondern vor allem auch beim Sicherheitsnachweis und in der öffentlichen Diskussion des Genehmigungsverfahrens eine besondere Aufmerksamkeit widmen; vermutlich wird man um die Annahme eines worst case und daher um eine intrinsische materielle Kompensation des Auftriebes durch langfristig sicheren Einbau von Ballastmaterial nicht umhinkommen. Dadurch werden die Vorteile einer leichteren Bauweise, die sich in den oberen Bereichen aufgrund des geringeren Wasserdruckes oder bei Benutzung von Betonarten mit hoher Festigkeit ergeben, durch einen erhöhten Aufwand für sicher angebrachten Ballast teilweise wieder kompensiert.

Conversely, a serious disadvantage of the U.PSKW is avoided by the circular wall storage tank (RM.Sp):

• With U.PSKW special attention must be paid to the problem of buoyancy not only from a technical point of view, but also from the point of view of safety evidence and in the public discussion of the approval process; presumably one will not be able to avoid the assumption of a worst case and therefore an intrinsic material compensation of the buoyancy through long-term safe installation of ballast material. As a result, the advantages of a lighter construction, which result in the upper areas due to the lower water pressure or when using types of concrete with high strength, are partially compensated for by an increased effort for securely attached ballast.

Some of the advantages of the RM.Sp, which may be decisive for many purposes, are described in chapter “6. Advantages "in a nutshell.

Figure list

• Bild 1: Stand der Technik: Ringwallspeicher auf dem flachen Land mit erhöhtem Innenbekken als Oberbecken (Prinzipdarstellung in Anlehnung an (Popp 2021_A/;
• Bild 2: PSKW mit einem durch eine Ringstaumauer 3 vom Obersee 0 abgetrennten Unterbecken 33.
• Bild 3: Pumpspeicherkraftwerk bestehend aus dem Restsee 300 eines ehemaligen Tagebauloches als Obersee und einem (oder mehreren, im Bild sind es vier) Unterbecken 33.
• Bild 4: Ringmauerspeicher mit sehr tiefem Innenbecken als Unterbecken eines PSKW (Prinzipdarstellung).
• Bild 5: Variable Serien-Parallelschaltung von 12 Pumpturbinen für 4 Druckstufen
• Bild 6: Ringmauerspeicher mit tiefem Innenbecken als Unterbecken eines PSKW mit Zusatz-Wasserkörper WK2a für den Einsatz von „Halb-Pumpturbinen“ 71. (Prinzipdarstellung).
• Bild 7: Variable Serien-Parallelschaltung von 8 Standard- Pumpturbinen und 8 Halb-Pumpturbinen für 5 Druckstufen.
• Bild 8 Erweitertes Unterbecken 333 mit einem zusätzlichen Bodenloch-Speicherraum 37, hier dargestellt als ein nach Methoden des Tagebaues hergestelltes terrassiertes Loch.
• Bild 9: Bodenloch-Speicherraum 37 mit Stabilisierung einer besonders steilen Böschung durch eine Druckleitstruktur 376.
• Bild 10: Rechenmodell des erweiterten Unterbecken 333 als Kombination aus zylindrischem Ringmauer -Becken 33 und einem Kegelstumpf als Bodenloch-Speicherraum 37.
• Bild 11: Potentielle Speicherenergie des Bodenloch-Speicherraumes 37 unter den Annahmen des Rechenmodelles nach Bild 10.
• Bild 12: Anbindung eines als Unterwasser-Bunker ausgeführten, zentralen Maschinenhauses 777 zu den einzelnen Unterbecken 33 und auch zu einer Anschlussstelle am Ufer.
• Bild 13: Querschnitt durch Ringmauer-Unterbecken 33 mit inwendig angebrachtem spiralförmigem Fahrweg 53 von der Krone des Beckens bis zum Boden.
• Bild 14: Interims-Betrieb: Ringmauerspeicher mit hohem Innenbecken als Oberbecken eines PSKW während der Auffüllungsphase des Restsee.
• Bild 15: Ringmauer -Unterbecken 33 mit einer Zwischendecke und einem Kurzschlussrohr zwischen einem obersten und einem untersten Wasserkörper.

The prior art, the procedure according to the invention and examples for implementing the invention are illustrated by images which are presented here with a brief title-like description. The images are described and explained in more detail in the “Captions” chapter.

• Fig. 1: State of the art: Ring dam on the flat land with a raised inner basin as the upper basin (schematic diagram based on (Popp 2021_A /;
• Image 2: PSKW with one through a circular dam 3 from Obersee 0 separate lower basin 33 .
• Fig. 3: Pumped storage power plant consisting of the residual lake 300 of a former open pit as an upper lake and one (or more, in the picture there are four) lower basins 33 .
• Fig. 4: Circular wall storage tank with a very deep inner basin as the lower basin of a PSKW (schematic diagram).
• Fig. 5: Variable series parallel connection of 12 pump turbines for 4 pressure levels
• Fig. 6: Circular wall storage tank with deep inner basin as the lower basin of a PSKW with additional water body WK2a for the use of “half-pump turbines” 71. (schematic diagram).
• Fig. 7: Variable series parallel connection of 8 standard pump turbines and 8 half pump turbines for 5 pressure levels.
• Fig. 8 Extended lower basin 333 with an additional bottom hole storage space 37 , shown here as a terraced hole made using open-cast mining methods.
• Fig. 9: Bottom hole storage space 37 with stabilization of a particularly steep slope through a pressure control structure 376 .
• Fig. 10: Calculation model of the extended lower basin 333 as a combination of a cylindrical circular wall basin 33 and a truncated cone as a bottom hole storage space 37 .
• Fig. 11: Potential storage energy of the bottom hole storage space 37 under the assumptions of the calculation model according to Figure 10.
• Fig. 12: Connection of a central machine house designed as an underwater bunker 777 to the individual lower basins 33 and also to a junction on the bank.
• Figure 13: Cross-section through the lower basin of the ring wall 33 with internally attached spiral track 53 from the crown of the pelvis to the bottom.
• Fig. 14: Interim operation: circular wall storage facility with a high inner basin as the upper basin of a PSKW during the filling phase of the remaining lake.
• Photo 15: Circular wall sub-basin 33 with a false ceiling and a short-circuit pipe between an uppermost and a lowermost body of water.

5. Refinements of the invention

5.1 Variable parallel series connection of pump turbines to utilize a high storage basin.

Current PSPs usually have a high level difference between the basins; within the basin (or body of water), on the other hand, there is only a relatively small level difference. For this only a modest tolerance in the pressure head of pump turbines is required and the current pump turbines are also not able to be used in a tolerance range greater than approx. 15 to 20% without a high risk of wear and a loss of efficiency.

The question arises as to whether and how one can operate a large level lift within a high storage basin without building storeys and nevertheless with the use of all available pump turbines and, at the same time, a time-series processing via multiple provision of the pump turbine capacity, each of which is only available to a single one continuous pressure head stages is designed, can avoid.

• • Die vorgegebene maximale Druckhöhe (=Pegeldifferenz Hmax) wird durch Serienschaltung einer geeigneten Anzahl N0 von Pumpturbinen zu einem Strang erreicht, wobei je nach der Gesamtzahl N_gesmt der verfügbaren Pumpturbinen auch mehrere derartige Stränge parallelgeschaltet werden können.
• • Fällt die Druckhöhe im Laufe der Entleerung des Speicherbeckens ab, so wird bei geeigneten Druckstufen die Anzahl der Pumpturbinen innerhalb eines Stranges verringert und die auf diese Weise zunächst freigesetzte Pumpturbinen zu einem oder mehreren weiteren Strängen, die nun alle die neu festgesetzte Anzahl N1 (und bei weitern Druckstufen: N2, N3 usw.) von Pumpturbinen enthalten, zusammengeschaltet; danach werden alle „N1-Stränge“ wieder parallelgeschaltet. Eine gute Ausnutzung der Drucktoleranzen der Pumpturbinen wird zunächst dann erreicht, wenn bei jeder Umschaltung die Anzahl der Pumpturbinen in den Strängen um 1 verringert wird (also: N1 = N0-1; N2= N1-1 usw.). - Es gibt jedoch noch weitere Optimierungswerkzeuge, die aber meist auf dem Einsatz verschiedener Pumpturbinen-Typen beruhen.
• • Bei der Umschaltung zur niedrigsten Druckstufe, N_e, wird dann die kleinste Anzahl der Pumpturbinen in einem Strang erreicht und dies wird meist N_e=1 sein ( aber auch andere Werte, insbesondere N_e=2 sind durchaus möglich). Im Falle Ne=1 sind dann alle Pumpturbinen parallelgeschaltet.

The inventive solution to this problem is based on the interconnection of primarily similar pump turbines.

• • The specified maximum pressure head (= level difference Hmax) is achieved by connecting a suitable number N0 of pump turbines in series to form a string, whereby several such strings can also be connected in parallel _{depending on the total number N total of available pump turbines.}
• • If the pressure level drops in the course of emptying the storage basin, the number of pump turbines within a line is reduced at suitable pressure levels and the pump turbines initially released in this way become one or more further lines, which now all have the newly set number N1 (and with further pressure levels: N2, N3 etc.) contained by pump turbines, interconnected; then all "N1 lines" are switched back in parallel. A good utilization of the pressure tolerances of the pump turbines is first achieved if the number of pump turbines in the strings is reduced by 1 with each switchover (i.e.: N1 = N0-1; N2 = N1-1 etc.). - There are other optimization tools, however, which are mostly based on the use of different types of pump turbines.
• • When switching to the lowest pressure level, N _e , the smallest number of pump turbines in a string is achieved and this will usually be N _e = 1 (but other values, in particular N _e = 2, are also possible). In the case Ne = 1, all pump turbines are then connected in parallel.

We refer to this process as "variable series parallel connection of hydraulic machines" and it can be applied to different types of advanced pumped storage power plants; we describe it more comprehensively and in more detail in a patent application filed at the same time, “PSPs with variable parallel series connection of pump turbines to utilize a high storage basin” (/ LuSchmB 2021_SeeEi5 /). The variable series parallel connection of pump turbines could, however, be essential for the profitability of the pumped storage power plant according to the invention with a high storage basin enclosed by a ring dam; therefore it is also part of the current patent application.

Figure 4 refers to a PSKW, the upper basin of which is a large body of water 0 is, for example, the recultivation lake that will be created after the end of the opencast mine in the Hambacher Loch, Rheinisches Braunkohlerevier, and its lower basin through a circular wall storage basin 33 is formed, the dams of which extend from the lake floor 1 to just above the maximum conceivable lake surface.

The division of the water bodies WKi corresponds to individual units, to which the existing pump turbines are connected together in order to cover the pressure range of each water body. The water body WK0 has the greatest storage potential and lies at the very bottom; then the level difference to the level of the upper basin is greatest. The same applies to the adjoining water bodies WK1, WK2 and WK3: in the high lower basin, they now connect upwards to WK0 and to each other at. The free air space above the uppermost body of water WK3 serves as a spacer for the minimum level difference H _min.

Figure 5 shows the interconnection of the pump turbines to the individual units to cover 4 pressure levels. We assume that we have N _total = 12 identical pump turbines 7th be available.

• Für den untersten Wasserkörper WK0 werden die N_gesamt gleichartigen Pumpturbinen in 3 parallelen Strängen zu je 4 Stück eingesetzt (Bild 5a). Innerhalb seines Toleranzbereiches überstreicht dann das Aggregat den Druckhöhenbereich um H0 = 360 m von 480 bis 240 [m].
• Für den direkt darüberliegenden Wasserkörper WK1 werden die N_gesamt gleichartigen Pumpturbinen in 4 parallelen Strängen zu je 3 Stück eingesetzt (Bild 5b). Innerhalb seines Toleranzbereiches überstreicht dann das Aggregat den Druckhöhenbereich um H1 = 270 [m] von 360 bis 180 [m] . Nach einer von uns gewählten Abgrenzungsregel belassen wir jeweils den Überlappungsbereich zwischen zwei Druckstufen bei dem unterhalb liegenden Wasserkörper (also demjenigen mit der höheren Druckhöhe) und legen daher den WK1 auf den Druckhöhenbereich 240 bis 180 [m].
• Für WK2 werden die 12 Pumpturbinen in 6 parallelen Strängen zu je 2 Stück eingesetzt (Bild 5c). Innerhalb seines Toleranzbereiches überstreicht dann das Aggregat den Druckhöhenbereich um H2 =180 [m] von 240 bis 120 [m] . Regelgerecht legen wir den Wasserkörper WK2 auf den Druckhöhenbereich 180 bis 120 m.
• Für WK3 schließlich werden alle 12 Pumpturbinen parallelgeschaltet (Bild 5d). Innerhalb seines Toleranzbereiches überstreicht dann das Aggregat den Druckhöhenbereich um H3 = 90 [m] von 120 bis 60 [m] und wir legen den Wasserkörper WK3 auf den Druckhöhenbereich 120 bis 60 m fest. Man beachte, dass wir den Toleranzwert x=1/3 für die Druckhöhe so gewählt haben, dass zwischen WK2 und WK3 gerade kein Überlappungsbereich mehr existiert.

To illustrate, we take a maximum pressure height of H _max = 480 m achieved with a completely empty lower basin and use pump turbines with a design pressure height of 90 m with a tolerance of x = +/- 1/3, i.e. + - 33.3% to their face value. The individual water bodies are then delimited as follows:

• For the lowest body of water, the N _total WK0 similar pump turbines used in parallel strands 3 to 4 pieces (Fig 5a). Within its tolerance range, the unit then sweeps the pressure height range around H0 = 360 m from 480 to 240 [m].
• For the directly overlying body of water, the N _total WK1 similar pump turbines used in parallel strands 4 to 3 pieces (Fig 5b). Within its tolerance range, the unit then sweeps the pressure head range by H1 = 270 [m] from 360 to 180 [m]. According to a delimitation rule chosen by us, we leave the overlap area between two pressure levels with the water body below (i.e. the one with the higher pressure height) and therefore place the WK1 on the pressure height range 240 to 180 [m].
• For WK2, the 12 pump turbines are used in 6 parallel strings of 2 each (Fig. 5c). Within its tolerance range, the unit then sweeps the pressure head range by H2 = 180 [m] from 240 to 120 [m]. We regularly place the water body WK2 at the pressure altitude range 180 to 120 m.
• Finally, for WK3, all 12 pump turbines are connected in parallel (Figure 5d). Within its tolerance range, the unit then sweeps over the pressure altitude range around H3 = 90 [m] from 120 to 60 [m] and we set the water body WK3 to the pressure altitude range 120 to 60 m. Note that we have chosen the tolerance value x = 1/3 for the print height so that there is no longer any overlap area between WK2 and WK3.

As you can see by trial and error, for pressure height tolerances smaller than x = + - 1/3 there is a gap in the pressure height area between the two upper bodies of water WK2 and WK3, which is no longer covered.
For pressure height tolerances that are smaller than 1/5 (i.e. +/- 0.20) there is a further gap in the pressure height range between the water bodies WK1 and WK2 one level below, and from pressure height tolerance of less than + - 1/7 = 0.1428565 then all pressure altitude ranges are separated from one another by a gap.

The aforementioned threshold values of the pressure height tolerance for the occurrence of the gaps are independent of the available maximum pressure _{height H max.} The mathematical principles for this are shown and derived in / LuSchmB 2021_SeeEi5 /.

• Wir ergänzen nun unsere Standard Pumpturbinen 7 mit der Druckhöhe H_P durch eine zweite Sorte mit der halben Druckhöhe H_P/2 und auch mit der halben elektrischen Leistung, so dass der Wasserdurchfluss gegenüber der Hauptsorte unverändert bleibt und man nach wie vor alle Druckturbinen in Serie schalten kann. Diese „halbierten Pumpturbinen“ bezeichnen wir als „Halb-Pumpturbinen“ 71. Wir setzen sie in allen bisherigen Pumpturbinen-Aggregaten auch als Doppelpack 72, also in der Serienschaltung von 2 Halb-Pumpturbinen 71, ein. Das Doppelpack 72 ist ein funktionsmäßiges Äquivalent zu einer Standard-Pumpturbine 7.
• Durch diesen weiteren Pumpturbinentyp 71 ergibt sich eine Möglichkeit, einen zusätzlichen Wasserkörper WK2a oberhalb des Wasserkörpers WK2 mit seinen 6 Strängen zu je 2 Pumpturbinen, zu schaffen. In Bild 6 ist die Lage der Wasserkörper angegeben. Bei einer geringeren Toleranz der Druckhöhe der Pumpturbinen ergibt sich zunächst eine sich immer mehr ausweitende Lücke zwischen den beiden oberen Wasserkörpern WK2 und WK3, die aber unter Verwendung von „Halb-Pumpturbinen“ 71 durch WK2a geschlossen werden kann. In Bild 7 ist die zugehörige Schaltung der Pumpturbinen -Aggregate angegeben.
• Jetzt kann man sich ausrechnen (siehe /LuSchmB 2021_SeeEi5/ Abschnitt „3.3 Halb-Pumpturbinen ermöglichen zusätzlichen Wasserkörper in der Lücke“) oder durch Probieren verifizieren, dass mit einer Toleranz der Druckhöhe aller Pumpturbinen von x = 1/5 die Lücke zwischen den Wasserkörpern WK2a und WK3 geschlossen wird. Wie in Bild 7 (Teilbild 7cb) angegeben, entsteht das dem Wasserköper WK2a zugeordnete neue Aggregat [77_28] durch 8 parallel geschaltete Stränge, die jeweils aus einer Kette aus einer Standardturbine 7 und einer Halb Pumpturbine 71 bestehen. Der Index „28“ bezieht sich auf Anzahl der Pumpturbinen in einem Strang, hier also , und die Anzahl der parallelgeschalteten Stränge (hier: 8). Die vorangesetzte Bezeichnung 77, verwenden wir generell für eine (ansonsten noch nicht weiter spezifiziertes ) Pumpturbinen-Aggregat. Wie das Bild 7 zeigt, kann man den Index auch als Zeilen-Spaltenindex auffassen.
• Alle sonstigen Aggregate bleiben gegenüber dem vorangehende Schaltungsbild Bild 5(!) funktional unverändert, wir haben lediglich in den übrigen Wasserkörpern jeweils 4 Standardturbinen 7 durch 4 Doppelpack 72 , die jeweils aus zwei verketteten Halb -Pumpturbinen bestehen, ersetzt.

What do you do when there are gaps between the pressure tolerance bands?
Pump turbines can presumably also be used slightly outside their official tolerance range for a short time, but with increased susceptibility to wear and lower efficiency. If this is no longer justifiable, there is still the possibility of lowering the level in the critical altitude areas in turbine operation, simply by allowing the turbines to fizzle out without generating any energy.
But there is also a "clean" solution, but then we have to refrain from the previously assumed rule of the similarity of all pump turbines:

• We are now adding to our standard pump turbines 7th with the pressure height H _P by a second type with half the pressure height H _{P / 2} and also with half the electrical power, so that the water flow remains unchanged compared to the main type and all pressure turbines can still be connected in series. We refer to these “halved pump turbines” as “half pump turbines” 71. We also use them in all previous pump turbine units as a double pack 72, ie in a series connection of 2 half pump turbines 71. The twin pack 72 is functionally equivalent to a standard pump turbine 7th .
• This further type of pump turbine 71 makes it possible to create an additional body of water WK2a above the body of water WK2 with its 6 strings of 2 pump turbines each. Figure 6 shows the position of the water bodies. With a lower tolerance of the pressure head of the pump turbines, there is initially an increasingly widening gap between the two upper bodies of water WK2 and WK3, but this can be closed by WK2a using “half-pump turbines” 71. Figure 7 shows the associated circuitry for the pump turbine units.
• Now you can do the math (see / LuSchmB 2021_SeeEi5 / section “3.3 Half-pump turbines allow additional water bodies in the gap”) or verify by trial and error that the gap between the water bodies WK2a with a tolerance of the pressure head of all pump turbines of x = 1/5 and WK3 is closed. As in picture 7th (Part 7cb), the new unit [77_28] assigned to the body of water WK2a is created by 8 parallel-connected strings, each consisting of a chain from a standard turbine 7th and a half pump turbine 71 exist. The index “28” refers to the number of pump turbines in a string, here in other words, and the number of strings connected in parallel (here: 8). The preceding designation 77 , we generally use for a (otherwise not yet further specified) pump turbine unit. Like the picture 7th shows, the index can also be understood as a row-column index.
• All other units remain functionally unchanged compared to the previous circuit diagram in Fig. 5 (!), We only have 4 standard turbines in each of the remaining water bodies 7th replaced by 4 twin packs 72, each consisting of two linked half-pump turbines.

To illustrate this, we again set a maximum pressure height of H _max = 480 m, achieved with a completely empty lower basin, but now use a design pressure height of 100 m for the standard pump turbines and 50 m for the half pump turbines. All pump turbines have the same tolerance of x = +/- 1/5, i.e. + - 20% around their nominal value.

• Für den untersten Wasserkörper WK0 werden die N_gesamt = 8 + 8/2 =12 funktional gleichartigen Pumpturbinen in 3 parallelen Strängen zu je 4 Stück eingesetzt (Bild 7a). Man beachte, dass im Vergleich zu Bild 5 vier Standard-Pumpturbinen 7 durch vier funktional gleichartige Doppelpack 72 aus je zwei Hab-Pumpturbinen 71 ersetzt sind. Innerhalb seines Toleranzbereiches von +/- 20% überstreicht dann das Aggregat den Druckhöhenbereich um H0 = 400 m von 4*120 bis 4* 80 m , also 480 bis 320 [m].
• Für den direkt darüberliegenden Wasserkörper WK1 werden die N_gesamt funktional gleichartigen Pumpturbinen in 4 parallelen Strängen zu je 3 Stück eingesetzt (Bild 7b). Innerhalb seines Toleranzbereiches überstreicht dann das Aggregat den Druckhöhenbereich um H1 = 300 [m] von 360 bis 240 [m] . Nach einer von uns gewählten Abgrenzungsregel belassen wir jeweils den Überlappungsbereich zwischen zwei Druckstufen bei dem unterhalb liegenden Wasserkörper (also demjenigen mit der höheren Druckhöhe) und legen daher den Wasserkörper WK1 auf den Druckhöhenbereich 320 bis 240 [m].
• Für WK2 werden die 12 Pumpturbinen in 6 parallelen Strängen zu je 2 Stück eingesetzt (Bild 7c). Innerhalb seines Toleranzbereiches überstreicht dann das Aggregat den Druckhöhenbereich um H2 = 200 [m] von 240 bis 160 [m] . Regelgerecht legen wir den Wasserkörper WK2 auf den Druckhöhenbereich 240 bis 160 m.

The pressure head of the strings for the individual water bodies are then delimited as follows (Fig 7th ):

• For the lowest water body WK0, the N _total = 8 + 8/2 = 12 functionally identical pump turbines are used in 3 parallel lines of 4 each (Fig. 7a). Note that compared to picture 5 four standard pump turbines 7th are replaced by four functionally identical double packs 72 each consisting of two Hab pump turbines 71. Within its tolerance range of +/- 20%, the unit then sweeps the pressure height range around H0 = 400 m from 4 * 120 to 4 * 80 m, ie 480 to 320 [m].
• For the directly overlying body of water WK1, the N _total functionally similar pump turbines in 4 parallel strands employed to 3 pieces (Fig 7b). Within its tolerance range, the unit then sweeps the pressure head range by H1 = 300 [m] from 360 to 240 [m]. According to a delimitation rule chosen by us, we leave the overlap area between two pressure levels with the water body below (i.e. the one with the higher pressure height) and therefore place the water body WK1 on the pressure height range 320 to 240 [m].
• For WK2, the 12 pump turbines are used in 6 parallel lines of 2 each (Fig. 7c). Within its tolerance range, the unit then sweeps the pressure head range around H2 = 200 [m] from 240 to 160 [m]. We regularly place the water body WK2 at the pressure altitude range 240 to 160 m.

For the newly inserted water body WK2a, which is intended to close the looming gap between WK2 and WK3, the 8 half-pump turbines are now each combined as a single piece with one of the 8 standard pump turbines to form a string. So there are 8 parallel strings, each with two, but now unequal, pump turbines (Fig. 7c1). Such a line has a design pressure height of 100 + 50 = 150 [m] and within the tolerance range x = +/- 1/5 the unit then sweeps the pressure height range around H2a = 150 [m] from 180 to 120 [m]. We regularly place the water body WK2a at the pressure altitude range 160 to 120 [m].

Finally, for WK3, all 12 pump turbines are switched in parallel (Fig. 7d). Within its tolerance range, the unit then sweeps over the pressure altitude range around H3 = 100 [m] from 120 to 80 [m] and we set the water body WK3 to the pressure altitude range 120 to 60 m. Note that we have chosen the tolerance value x for the pressure height so that there is no longer any overlap area between WK2a and WK3.

• Es ist naheliegend, das Verfahren der variablen Serien-Parallelschaltung von Standard-Pumpturbinen 7 und Halb- Pumpturbinen 71 zu verallgemeinern.
• Dieses Schema lässt sich nämlich leicht auf beliebige „Bruchteil -Pumpturbinen“ übertragen. Sei b der Bruchteil und M_b die Anzahl der benötigten „Bruchteil -Pumpturbinen“, also eine Sorte von Pumpturbinen mit der Druckhöhe (Hp* b) und der b - fachen Leistung, so dass der Wasserdurchfluss gegenüber der Hauptsorte unverändert bleibt und man nach wie vor alle Druckturbinen in Serie schalten kann. Dann müssen wir nur darauf achten, dass das Produkt $${\text{M}}_{\text{b}}*\text{b ganzzahlig}$$
  
  bleibt.

General scheme:

• The obvious solution is the variable series parallel connection of standard pump turbines 7th and semi-pump turbines 71 to generalize.
• This scheme can be easily transferred to any “fractional pump turbine”. Let b be the fraction and M _b the number of required “fraction pump turbines”, i.e. a type of pump turbine with the pressure head (Hp * b) and b - the power, so that the water flow remains unchanged compared to the main type and you can continue with how can connect in series before all pressure turbines. Then we just have to pay attention to the product $${\text{M.}}_{\text{b}}*\text{b is an integer}$$
  
  remain.

In our example above (see Figure 6 and Figure 7), b = 1/2 and M _b = 8,
so that b * Mb = 4, i.e. an integer.
The standard case (see Fig. 4 and Fig. 5) is also a borderline case in requirement Eq. (13) if b = 1/1 and M _b = 12 are used.

5.2 The diameter of the circular wall reservoir

Large reservoirs, the dam wall of which was designed as a curtain wall, have not yet become known to the inventors. But there are many reservoirs that are closed off by an arch dam, i.e. a section of a circular dam.
Unfortunately, in the easily accessible publications of the technical data, e.g. also in Wikipedia, in addition to the height of the dam, only the crown length is given. There is also a photograph from which one can estimate the angle of the circular arc but cannot determine it exactly.
In the case of a particularly large and famous system, namely the dam on the Sajano-Schuschensker reservoir / Jenissei / on the Jenissei in central Siberia, the radius of the circular arc on which the arch is based is also reported: 600 m. With the specified crown length of 1074 m an angle of 103 ° is calculated. This means that the completion of such an arch dam to form an annular dam according to the invention with the same diameter only requires an expansion by a factor of 3.

We therefore assume that a circular wall with the same diameter of 1200 m would also be technically manageable, and we use this size as the basis for our example calculation in Section 5.

A floor area of 1200 m in diameter offers enough space to develop a larger storage volume through excavations, see Section 5.

5.3 Development of the pool floor for storage purposes

The circular wall storage tank as a lower basin is built on solid, solid ground. If the inner diameter is large enough, it is worthwhile to deepen the initially level pool floor, especially since suitable large machines are still available on site in an open pit towards the end of the mining period; this has already been mentioned in DE 10 2019 118 725 A1 (/ LuSchmB 2019_SeeEi1 /) and DE 10 2019 118 726 B4 (/ LuSchmB 2019 SeeEi1v /) pointed out.
Of course, all such construction measures must take into account the stability of the curtain wall in every current construction phase, but also after completion.

1. 1. der innere Boden kann nach unten als Böschung abgetragen und die Standsicherheit durch den Böschungswinkel und eventuell auch durch Verbauungsmaßnahmen gewährleistet werden. Dadurch entsteht sozusagen ein inneres Ringböschungs-Becken. Die Böschung ist dann, sozusagen, der innere Teil eines Ringwalles und der fehlende äußere wird durch den anstehenden jungfräulichen Boden ersetzt.
2. 2. Die im Tagebau eingesetzten Verfahren des Terrassenförmigen Abtragens von Gesteinsschichten können wegen des großen Durchmessers des Beckenbodens zum Einsatz kommen, wobei man sich jedoch immer die spätere Belastung der äußeren Randzonen vor Augen halten muss. Einen an die Ringmauer innen anschließenden Randstreifen von vermutlich einigen 10m muss man als Arbeitsfläche für das Hochziehen der Mauer freihalten.
3. 3. Das „Bodenloch“ 37 kann in Teilbereichen durch druckfeste Formkörper ausgefüllt werden und dadurch eine innere Versteifung und perfekten Böschungsschutz auch bei steilem Böschungswinkel erhalten. Hierzu können auch die in DE 10 2020 111 844 A1 (/LuSchmB 2020_SeeEi3/) vorgestellten wabenförmigen Wandkonstruktionen eingesetzt werden. Allerdings herrschen jetzt völlig andere Auslegungskriterien, da es nicht mehr darum geht, Speicherhohlräume gegen hydrostatischen Außendruck abzuschließen, sondern vielmehr darum, dass die Wabenwände als Druckleitstruktur den an den steilen Böschungen anliegenden Seitendruck aufnehmen und abfangen.
4. 4. In genügend großem Abstand vom Sockel und außerhalb des Einwirkungsbereiches des Gewichtes der Ringmauer könnte man auch einen (oder auch mehrere) großen offenen Schacht graben mit senkrechten oder nur leicht sich verjüngenden Rändern. Im Gegensatz zu den im Bergbau eingesetzten Schächten und Stollen, muss man dabei beachten, dass man hier keine Zuwegung, sondern Speicherraum erstellt. Ähnliche Überlegungen wurden bereits in DE 10 2011 105 307 (/LuSchmB 2011_Bergei1/) und DE 10 2013 019776 B3 (/Lu-SchmB 2013_Bergei2/)) angestellt; aber im Vergleich zu den dortigen „Blindschächten“ liegen nun viel günstigere Bedingungen vor: man kann ja nun mit dem großen Bagger im Tagebau und mit breitem Durchmesser graben.
5. 5. Der Aushub vom Bodenloch kann in der Bauphase kurz hinter der aufstrebenden Ringmauer wieder abgekippt werden. Das vermeidet lange Wege, kann vielleicht sogar in einem Arbeitsgang erledigt werden. Zudem kann dadurch ein vorteilhafter Endzustand entstehen, da die Ringmauer eine außenliegende Abstützung und Absicherung erhält und ein weitgehend ebener und stabiler Seeboden entsteht. Außerdem wird ein übrigbleibender Wasserdurchtritt zur Ringmauer vermindert oder vermieden.
6. 6. die Baumaßnahmen im Bodenloch und an der Ringmauer können gleichzeitig oder abschnittsweise versetzt durchgeführt werden Dann wird der physikalische Arbeitsaufwand für das Abschütten des Aushubs minimiert, da die Schwellhöhe zum Abkippen nicht höher sein muss als durch die Höhe der außenseitigen Schutthalde vorgegeben wird.

There are the following approaches and possibilities for creating such a bottom hole storage space 37 :

1. 1. The inner soil can be removed downwards as an embankment and the stability can be guaranteed by the slope angle and possibly also by building measures. This creates an inner ring bank basin, so to speak. The embankment is then, so to speak, the inner part of a ring wall and the missing outer part is replaced by the pending virgin soil.
2. 2. The terraced removal of rock layers used in open-cast mining can be used due to the large diameter of the pool floor, although one must always keep in mind the later stress on the outer edge zones. An edge strip of probably a few 10m that adjoins the inner ring wall must be kept free as a work surface for pulling up the wall.
3. 3. The “bottom hole” 37 can be filled in partial areas with pressure-resistant molded bodies and thereby obtain internal stiffening and perfect slope protection even with a steep slope angle. The in DE 10 2020 111 844 A1 (/ LuSchmB 2020_SeeEi3 /) presented honeycomb wall constructions can be used. However, completely different design criteria now prevail, as it is no longer a matter of closing off storage cavities against external hydrostatic pressure, but rather that the honeycomb walls, as a pressure guiding structure, absorb and absorb the side pressure applied to the steep slopes.
4. 4. At a sufficiently large distance from the base and outside the area affected by the weight of the curtain wall, one could also dig one (or more) large open shaft with vertical or only slightly tapering edges. In contrast to the shafts and tunnels used in mining, it must be ensured that no access roads are created here, but storage space. Similar considerations have already been made in DE 10 2011 105 307 (/ LuSchmB 2011_Bergei1 /) and DE 10 2013 019776 B3 (/ Lu-SchmB 2013_Bergei2 /)) employed; But compared to the “blind shafts” there, the conditions are now much more favorable: you can now dig with the large excavator in the opencast mine and with a wide diameter.
5. 5. During the construction phase, the excavation from the hole in the ground can be tipped again shortly behind the rising curtain wall. This avoids long distances and can perhaps even be done in one step. In addition, this can result in an advantageous final state, since the circular wall receives external support and protection and a largely flat and stable seabed is created. In addition, any remaining water penetration to the ring wall is reduced or avoided.
6. 6. The construction work in the ground hole and on the ring wall can be carried out simultaneously or in sections offset.

In picture 8 is the bottom hole storage space 37 depicted as a terraced hole made using open-cast mining methods. Together with that directly through the circular dam 3 created curtain wall basin 33 it forms the enlarged lower basin 333 .
The machine bunker is at the lowest point 77 with the pump turbines and an access 44 to the upper basin, the free lake water 0 . Access 44 can of course also be easily accessible within the bottom hole storage space 37 run, which would certainly be easier for maintenance and repair purposes - but graphically a bit more complicated.

If there are several spatially separated lower basins, it can make sense to use the machine bunker 77 for all lower basins to be arranged centrally in only a single lower basin or in a separate bunker. Then the inflows and outflows in each sub-basin are via the receiving station 771 recorded and over the connecting tunnels 67 to the now central pump turbine station 77 guided. (see picture 9)

Otherwise a variant of the bottom hole storage space is shown in Figure 9 37 shown, in which special attention is paid to the stabilization of a particularly steep slope, for example, by means of a pressure control structure 376 is placed. Within the edge area of the bottom hole, for example, pressure-resistant storage bodies built flat against one another are reproduced DE 10 2020 111 844 A1 (/ LuSchmB 2020_SeeEi3 /), which absorb lateral pressure and divert it - also downwards. The storage bodies in this structure remain open and in hydraulic balance with each other and with the entire basin, so that the walls are not exposed to any direct hydraulic pressure difference; they are therefore to be designed according to the needs of slope support and force dissipation. In a way, the pressure control structure corresponds 376 an expansion of large cavities in underground mining.

A pressure control structure can also be constructed in other ways: the possibilities range from a bed with uniform rock or selected massive pressure bodies, with the intermediate spaces then remaining as storage cavities, to filling with hollow bodies.
The lateral support of the embankment has a downward-facing component, so the height of the filling can decrease towards the inside - as shown in Figure 9.

Sample calculation

We will now use a simple example to show what amounts of energy can be found in the extended lower basin 333 , and especially in its partial volumes of the curtain wall storage facility 33 and bottom hole storage space 37 can save. To do this, we start from the parameters shown in Figure 10 and given in the detailed caption.

Für den Bodenloch-Speicherraum 37 sehen wir einen 100 m breiten baufreien Streifen am inneren Rand der Staumauer vor, so dass sich der Durchmesser der Kegelstumpf-Grundfläche zu 1000 [m] ergibt. Über die wesentlichste Einflussgröße, die Steigung der Böschung können wir leider keine begründeten Vorgaben annehmen, da die Zulässigkeit der erwünschten möglichst steilen Böschungswinkel entscheidend von den geologischen Eigenschaften des Bodens und der anwendbaren Befestigungstechnik für die Böschung abhängen. Daher führen wir die Rechnung für eine Reihe von Vorgabewerten der Steigung durch. Als Nebenbedingungen legen wir noch fest, dass einerseits die Höhe H7 des Kegelstumpfes nicht größer als 500 m sein soll und somit die Gesamttiefe des Unterbeckens immer unterhalb der 1000 m -Marke verbleibt, und andererseits der Durchmesser D7u der Deckfläche nicht kleiner als 100 m wird, um ausreichend Platz für technische Anlagen zu gewährleisten.First, we lay out the geometry of the circular wall storage facility 33 and choose the figures largely in accordance with the earlier examples, see in particular the picture 7th . For the diameter D3 we choose the value D3 = 1200 m as the height H3 as the value of used in earlier examples H3 = 480 m, which was characterized above all by the fact that the considerations for the "variable parallel series connection of pump turbines" resulted in rounded values. We assume 60 m as the minimum value of the level difference.

For the sake of simplicity, we also assume that the level of the upper basin does not change during the storage process.
Under these assumptions, we get the available storage content of a single circular wall storage facility 33 the value: $$\text{E\_RM}=350\left[\text{GWh}\right]$$

For the bottom hole storage space 37 we envisage a 100 m wide construction-free strip on the inner edge of the dam, so that the diameter of the truncated cone base is 1000 [m]. Unfortunately, we cannot accept any justified specifications regarding the most important influencing factor, the slope of the slope, since the permissibility of the desired steepest possible slope angle depends crucially on the geological properties of the soil and the applicable fastening technology for the slope. Therefore we carry out the calculation for a number of default values of the slope. As ancillary conditions, we also stipulate that on the one hand the height H7 of the truncated cone should not be greater than 500 m and thus the total depth of the lower basin always remains below the 1000 m mark, and on the other hand the diameter D7u of the top surface should not be less than 100 m, to ensure sufficient space for technical systems.

In the table picture 11 are the results for the values of the storage energy of the bottom hole storage space calculated under the given assumptions 37 specified. The great influence of the slope of the slope m_K is striking.

It can be seen that the additionally excavated deep floor hole storage space 37 stores a potential amount of energy that is in the same order of magnitude as the storage energy of the much larger circular wall storage system 33 and can even exceed this mark, depending on the angle of approach.
Compared to the high structural effort involved in erecting the thick curtain wall, it seems tempting to remove some of the soil inside and thus gain additional storage space, the outer wall of which is formed by the surrounding lake floor.

All in all, we can hope that after detailed engineering planning it will be possible, even with a single extended lower basin 333 built in Hambacher Loch to increase the storage capacity of the German PSKW by more than ten times.

5.4 Common machine house in the underwater bunker and access road

For reasons of cost and because of the greater flexibility in the interconnection of the pump turbines, it may make sense to have all the pump turbines of a PSKW with several sub-basins 33 or extended sub-basin 333 to merge in a common machine house, the "underwater bunker" 777. This can be located pressure-resistant on the floor of one of the circular wall lower basins, but it can also be set up outside the circular wall lower basin as a separate bunker (Fig 12th ).

A small problem arises from the fact that the pump turbines require a pre-pressure for technical reasons. Therefore, it is reasonable to use the base of the underwater bunker 777 lower in relation to the base of the lower basins. All sub-basins of the ring wall must then be connected to this underwater bunker via pipes 777 get connected.

The question of access remains. The conventional way is to use a passable tunnel 5 from the shore to the underwater bunker 77 relocate. If you also want to reach the lower basin of the ring wall in a mobile way, then you have to use the hydraulic connecting pipes 6th in a passable tunnel 67 embarrassed. Since the lower basin of the ring wall can be completely emptied, a dry connection is created from the bank to the basin floor.

In an abandoned open-cast mine, however, the later lake floor consists of thick layers of relocated excavation, which is certainly not an ideal foundation for the tunnel 5 results in the shore. There is, however, another possibility (Fig. 13): an at least single-lane drivable access road 53, which is spiral-shaped on the inside of a circular wall lower basin 33 runs. When the lower basin of the ring wall is completely empty, you can drive a truck down to the ground. The so excellent ring wall lower basin can be reached from the bank by a ferry service or a bridge. Through the passable tunnels 67 can then continue to any other ring wall lower basin.
Will the access 53 Designed as an open "street" at the top, it can only be used when the lower basin of the ring wall is empty, which should actually happen almost every day in the rhythm of storage operations. This small disadvantage can be avoided by designing it as a road that is enclosed on all sides, for example as a tunnel.

In an extended lower basin 333 can the access 53 over the terraced slope of the bottom hole storage space 37 further down. The passable tunnels 67 to the other Extended Lower Basins 333 or to the underwater machine bunker 777 must then be laid in the deep seabed; for this, if necessary. the common methods of tunnel construction or route construction in underground mining are used.

Conclusion: The combination of on the one hand the access 53 along the inner rim of a single sub-basin 33 and if necessary. their extension on the inner slope of the bottom hole storage space 37 , and on the other hand the connection through passable tunnels 67 At the bottom of the lower basin there is a drivable access to all points of the PSKW.

5.5 Interim operation

The construction of a large circular wall basin will take several years, and the flooding of the remaining hole will take many years, maybe even more than a decade. On the other hand, an investor does not want to wait long for a completed plant to start operating.

Already in DE 10 2019 118 726 B4 (/ LuSchmB 2019_SeeEi1v /) we focused on this problem and then proposed an interim solution for the operation of parts of the PSP plant before the final completion of the remaining lake. In the following we will take up this basic idea again and adapt it to the special features and possibilities of the curtain wall PSKW according to the invention.

• Bei noch fast leerem Restsee kann das eigentlich als Unterbecken des PSKW vorgesehene Ringmauer-Speicherbecken 33 nämlich als Oberbecken betrieben werden; und das in ihm gespeicherte Wasser im Turbinenbetrieb in den noch unvollständig gefüllten Restsee, der nun die Funktion des Unterbecken ausübt, einspeisen. Auch wenn dann im Laufe der Jahre durch andauernde Füllung der Pegel des Restsee langsam ansteigt, verringert sich zwar die maximale Pegeldifferenz zum voll gefüllten Speicherbecken 33, aber man kann immer Zusammenschaltungen der Pumpturbinen zu geeigneten Aggregaten finden, die den Anforderungen an die neue Situation der Druckhöhen entsprechen.

Here it is a good thing that the procedure described in section “5.1 Variable parallel series connection of pump turbines to exhaust a high storage basin” enables the pump turbines to be used extremely flexibly and covers very different pressure levels. Even for the time in which the remaining lake is only partially filled with water, the PSKW can already be fully operated - but in a different mode:

• When the remaining lake is still almost empty, the circular wall storage basin, which is actually intended as the lower basin of the PSKW, can be used 33 namely operated as an upper basin; and feed the water stored in it in turbine operation into the still incompletely filled residual lake, which now functions as the lower basin. Even if the level of the remaining lake rises slowly over the years due to continuous filling, the maximum level difference to the fully filled storage basin is reduced 33 , but you can always find interconnections of the pump turbines to form suitable units that meet the requirements of the new situation of pressure heads.

1. 1. dem aktiv im Speicherbetrieb mit dem Unterbecken 0 austauschbaren Wasserkörper WK_aktiv; dieser besteht entsprechend den anliegenden Druckstufen wiederum aus mehreren Wasserkörpern (siehe /LuSchmB 2021_SeeEi5/, dort Bild 2: „Ringmauerspeicher mit sehr hohem Innenbecken als Oberbecken eines PSKW“), die den benötigten Pumpturbinen-Aggregaten (, also den einzelnen Verschaltungen der Pumpturbinen,) zugeordnet sind.
2. 2. dem darunter liegendem Wasserkörper WKu, der als „Unterlage“ für WK_aktiv dient, um die bereits erreichte Pegelhöhe des Restsee 0 zu kompensieren und dazu noch die für den Betrieb des PSKW notwendige Mindest-Pegeldifferenz H_min bereitzustellen.

Figure 14 shows the "interim operation" mode: The stately and now clearly visible storage basin 33 now rises as an upper basin far into the not yet flooded part of the open pit 00 , which is due to the terracing of the embankment 11 is marked.
The storage basin 33 has two functionally different water bodies:

1. 1. the active in storage operation with the lower basin 0 exchangeable body of water WK_aktiv; depending on the pressure levels applied, this in turn consists of several water bodies (see / LuSchmB 2021_SeeEi5 /, there Figure 2: "Ring wall storage facility with a very high inner basin as the upper basin of a PSKW"), which contains the required pump turbine units (i.e. the individual interconnections of the pump turbines) assigned.
2. 2. the underlying water body WKu, which serves as a "base" for WK_aktiv, around the level of the remaining lake that has already been reached 0 to compensate and to provide the _{minimum level difference H min} necessary for the operation of the PSKW.

At some point the level difference that can be used in this way becomes so small that it is worth noting the filled storage basin 33 to be emptied from above into the remaining lake, but now - finally as intended - water from the remaining lake 0 to flow into the storage basin, which was initially pumped completely empty, to carry out work. If the remaining lake is filled up further, the level differences increase in this way until the design case is reached and the maximum level difference between the remaining lake 0 as the upper basin and the storage basin 33 is available as a lower basin.

5.6 Accumulator with an intermediate ceiling.

With the method described in section “5.1 Variable parallel connection of pump turbines in series to exhaust a high storage basin”, we hope to solve the problem of high storage basins with the small pressure height tolerance of common pump turbines.

• (1.) Eine mehrfach vorgehaltene Pumpturbinen -Kapazität, wobei für jede Druckstufe ein besonderer Satz von Pumpturbinen vorgehalten wird, der nacheinander zum Einsatz kommt.
• (2.) Der Einsatz von wesentlich teureren Pumpturbinen mit einem außergewöhnlich großen Toleranzbereich.

But what if that doesn't work for whatever reason? Then there is a triple, but in all cases only moderately attractive plan B:

• (1.) A multiple pump turbine capacity, with a special set of pump turbines being kept for each pressure stage, which are used one after the other.
• (2.) The use of much more expensive pump turbines with an exceptionally large tolerance range.

We have dealt with these two alternatives in the example calculations in / LuSchmB 2021_SeeEi5 / in order to show how bad they are in comparison to the solution according to the invention.

• (3.) Ein Ringmauer-Staubecken mit einer Zwischen- Decke und einem Kurzschlussrohr.

In addition to the trivial solution of simply cutting the height of the storage tank by inserting false ceilings into the storage body (see eg DE 10 2013 019776 B3 (/ LuSchmB 2013_Bergei2 /), there is another structural measure that we want to briefly discuss below:

• (3.) A circular wall reservoir with an intermediate ceiling and a short-circuit pipe.

In picture 15 is a ring wall lower basin 33 shown with an additional false ceiling 310, which is divided into three bodies of water WK_31, WK_30 and WK_32. In addition, it also contains - which is very important for the functionality - a short-circuit pipe 612 between the top and bottom water bodies, WK_32 and WK_31. Note that there is no material separation between the two upper bodies of water, WK_30 and WK_32, but the delimitation only by the level of the upper opening of the short-circuit pipe 612 is defined. In addition, each of the 3 water bodies is separated by pipes 601,600 and 602 with the pump turbine unit 77 tied together.

This construction aims at the following property: The intermediate ceiling 310 has to withstand a maximum of only the water column of the height H0. The short-circuit pipe 612 namely ensures that water pressure from the upper body of water WK_32 cannot load onto the false ceiling, as the body of water WK_31 is always filled when there is water above the upper opening of the short-circuit pipe 612 is located.

In turbine operation, the two lower water bodies WK_31 and WK_30 are first filled in parallel with different pump turbines that are matched to the respective pressure level. Only then is the uppermost body of water WK_32 charged via a further set of pump turbines.

If there was no false ceiling, the pump turbines for the two lowest water bodies could not run at the same time, since only a single pressure head would be applied. This would halve the available power in these two areas (with the same power of the pump turbines).
Operation in the area of the uppermost body of water WK_32 is not influenced by the presence of the false ceiling 310.

Before considering installing another intermediate ceiling, one should keep in mind the structural effort that the one intermediate ceiling 310 already requires. It has to withstand the water pressure of the height H0 and for this on many massive supports or load-bearing walls (as in the case of DE 10 2020 111 844 A1 (/ LuSchmB 2020_SeeEi3 /)) rest. Because of the large spans, hemispherical ceiling structures will be used (as indicated in Figure 15).
The installation of a second false ceiling - we will call it 310x - at the borderline between the upper bodies of water WK_30 and WK_32, would lead to the following changes: This ceiling 310x would have to absorb the water pressure of height H2 and it will probably be in a worst case scenario demand that they must be able to withstand a water height up to the level of the upper basin. Since the energy density of the storage water is lowest in relation to the upper basin level in the uppermost water body, the greatest height difference is required for the same energy unit in the uppermost water body; then H2 would be significantly larger than H0 or H1.
But the load on the lower false ceiling 310 would now also be significantly greater, since it would no longer have to withstand the maximum pressure of the water level H0 but the water pressure of the height H0 + H2 (+ ceiling weight of 310x).
The only advantage of a second intermediate ceiling 310x would be that the turbines assigned to the water body WK_32 could already work during (and not after) the running time of the turbines for the two lower water bodies WK_31 and WK_30.

Similar considerations apply mutatis mutandis to pumping operations.

Conclusion: The proposed savings solution requires significantly less effort and already brings considerable advantages. But the mechanical solution is much more elegant.

6. Advantages of the invention

• • einer Ringstaumauer als Begrenzung eines hohen Speicherbeckens,
• • in Kombination mit einer variablen Zusammenschaltung von Pumpturbinen zu Aggregaten, die verschiedenen Druckhöhen angepasst sind,
• • und der wenig aufwendigen Erschließung des Beckenbodens zu einem zusätzlichen, tief liegenden Bodenloch-Speicherraum

könnte geeignet sein, auch langfristig eine effiziente technische und wirtschaftliche Alternative zu dem derzeit aufblühenden Einsatz von stationären Batteriespeichern als Kurzzeitspeicher der Energiewende darzustellen.The overall concept according to the invention

• • a circular dam as the boundary of a high storage basin,
• • in combination with a variable interconnection of pump turbines to form units that are adapted to different pressure levels,
• • and the easy development of the pelvic floor to an additional, deep-lying floor hole storage space

could be suitable to represent an efficient technical and economic alternative to the currently flourishing use of stationary battery storage as short-term storage of the energy transition.

Conclusion: Even with a generous realization of the invention on the area of the Hambacher Loch (Rheinisches Braunkohlerevier) the decisive step for the safeguarding of the energy turnaround through energy storage for the area of short-term storage could be achieved.

1. 1. Die Errichtung eines hohen Speicherbeckens in Form eines von einem Ringstaumauer umschlossenen Beckens vermeidet im Vergleich zu einem Unterwasser-PSKW (U.PSKW) die Erstellung eines schwer belastbaren „Deckels“, was bei großen Durchmessern und Bauwerkshöhen immer problematischer wird.
2. 2. Die Errichtung einer Ring-Staumauer schließt eng an den seit Jahrzehnten erprobten Stand der Technik von Bogen-Staumauern an. Die Schließung der Bogenmauer zu einer Ringmauer mit ähnlichem Radius erscheint als eine einfache Extrapolation vorhandener, jahrzehntelang erprobter Technik.
3. 3. Gegenüber einer Bogenstaumauer erledigt sich bei der Ringstaumauer ein wichtiges Problem von allein: Bei der Ringstaumauer gibt es keine u.U. schwierige seitliche Anbindung an massive Bergflanken mehr, denn die Ringstaumauer ist in ich selbst geschlossen.
4. 4. Die Ringstaumauer unterliegt keinen seitlichen Verschiebekräften mehr, denn die ringsum wirkenden hydrostatischen Druckkräfte heben sich gegenseitig auf.
5. 5. Die Errichtung eines hohen Speicherbeckens in Kombination mit einer variable Parallel-Serienschaltung von Pumpturbinen ermöglicht die besonders kosteneffiziente Erstellung eines PSKW, da sowohl der Pumpturbinensatz als auch der umbaute Speicherraum weitestgehend ausgenutzt wird; abgesehen von den kurzen Umschaltungsphasen sind alle verfügbaren Pumpturbinen während der gesamten Ladungs- oder Entladungszeit gleichzeitig im Einsatz.
6. 6. Die zusätzliche Erschließung des Beckenbodens als Bodenloch-Speicherraum ermöglicht mit vorhandener Tagebautechnik die Aufgrabung von Speicherraum, der an seiner Oberkannte später bereits einige 100 m unter dem Stauziel liegt und außer der Befestigung seiner Böschung keinen weiteren „Behälterbau“ mehr erfordert. Man kann daher das Aufgraben des Bodenloch-Speicherraum mit der Anlage eines Seegewässers auf dem Plateau eines hohen Berges vergleichen.
7. 7. Die durch das Konzept nahegelegte Option eines vorzeitigen und kaum Mehrkosten erfordernden Interim-Betriebes versöhnt die Investoren mit der ansonsten sehr langen Totzeit bis zum endgültigen Betrieb nach dem Abschluss der Flutung des Restsee.
8. 8. Nach der vollständigen Flutung des Tagebauloches wird von dem gewaltigen Speicherbekken nur noch dessen Krone als interessante Insel im Freizeitsee zu sehen sein. Das Speichebecken ist zwar nicht unsichtaber, sondern bleibt sichtbar - aber doch nur in seinem schönstenAnblick ( nämlich der Krone) .

In particular, the following “plus points” of the overall concept compared to the state of the art are to be emphasized.

1. 1. The construction of a high storage basin in the form of a basin enclosed by a ring dam avoids the creation of a heavy-duty "cover" compared to an underwater PSKW (U.PSKW), which becomes more and more problematic with large diameters and building heights.
2. 2. The construction of a ring dam is closely related to the state of the art of arch dams, which has been tried and tested for decades. The closure of the arched wall to form a circular wall with a similar radius appears to be a simple extrapolation of existing technology that has been tried and tested for decades.
3. 3. Compared to an arch dam, an important problem with the ring dam takes care of itself: With the ring dam, there is no longer any difficult lateral connection to massive mountain flanks, because the ring dam is closed in itself.
4. 4. The circular dam is no longer subject to lateral displacement forces, because the hydrostatic pressure forces acting all around cancel each other out.
5. 5. The construction of a high storage basin in combination with a variable parallel series connection of pump turbines enables the particularly cost-efficient construction of a PSP, since both the pump turbine set and the converted storage space are used to the greatest possible extent; Apart from the short switchover phases, all available pump turbines are in use simultaneously during the entire charging or discharging time.
6. 6. The additional development of the basin floor as a bottom hole storage space enables the excavation of storage space with the existing opencast mining technology, which later lies a few 100 m below the storage target on its upper edge and does not require any further "container construction" apart from the fortification of its embankment. One can therefore compare the digging up of the bottom hole storage space with the creation of a lake on the plateau of a high mountain.
7. 7. The option suggested by the concept of an early interim operation that hardly requires additional costs reconciles the investors with the otherwise very long dead time until the final operation after the completion of the flooding of the remaining lake.
8. 8. After the open-cast mine hole has been completely flooded, only the crown of the mighty Speicherbekken can be seen as an interesting island in the recreational lake. The reservoir is not invisible, but remains visible - but only in its most beautiful sight (namely the crown).

• Als kleinen Nachteil muss man nur in Kauf nehmen, dass durch die Nutzung von minderwertigen Höhenlagen des Speicherwassers, auch der Pegelhub im zugehörigen Partnerbecken (also dem Restsee) überproportional stärker ansteigt.

Only one small disadvantage:

• As a small disadvantage, one only has to accept that by using inferior altitudes of the storage water, the level lift in the associated partner basin (i.e. the rest of the lake) also rises disproportionately more.

• Die Errichtung eines Ringmauer-Speicherbeckens, das später von einem großen Gewässer umgeben ist, läuft - im Weichbild gesehen- darauf hinaus, ein „Loch“ in das Gewässer einzubringen: das „See-Speicherloch“.
• Die spannende Frage: Könnte man das auch im nach hinein machen, also ein „Loch“ in ein bestehendes Gewässer einfügen? Kandidaten derartiger tiefer Gewässer gäbe es wahrlich genug: Genfer See, Oberer See (USA) usw. und - last und nicht gerade least: das Meer. Im Gefolge des raschen Ausbaues der marinen Bergbau-Aktivitäten könnte man auf eine entsprechende Weiterentwicklung der Technologie hoffen.

Final vision:

• The construction of a circular wall storage basin, which is later surrounded by a large body of water, amounts to creating a “hole” in the water - seen in the soft image: the “lake storage hole”.
• The exciting question: Could this also be done retrospectively, i.e. insert a “hole” into an existing body of water? There are certainly enough candidates for such deep waters: Lake Geneva, Lake Superior (USA), etc. and - last and not least: the sea. In the wake of the rapid expansion of marine mining activities, one could hope for a corresponding further development of the technology.

Probably the most difficult problem will be in the area of the tight foundation. In an open pit, you should therefore consider laying the foundations for further construction in the dry phase.

Literature:

• / Goldisthal /: Homepage of the operator: https://powerplants.vattenfall.com/de/goldisthal
• / Jenissei / Sajano-Schuschensker reservoir on the Jenissei, Russia. https://de.wikipedia.org/wiki/Sajano-Schuschensker_Stausee
• / LuSchmB 2011_Bergei1 /
• Luther, G. and Schmidt-Böcking, H. (2011). "Shaft pumped storage power plant", DE 10 2011 105 307 ; available at: http://www.fze.uni-saarland.de/Speicher.htm
• / LuSchmB 2013_Bergei2 /
• Luther, G. and Schmidt-Böcking, H .: “Deep shaft pumped storage power plant”; DE 10 2013 019776 B3 ; available at: http://www.fze.uni-saarland.de/Speicher.htm
• / LuSchmB 2019_SeeEi1 /, Luther, G. and Schmidt-Böcking, H .: "Procedure for the construction of a pumped storage power plant in a depression, especially in an open pit"; DE 10 2019 118 725 A1 , available at: http://www.fze.uni-saarland.de/Speicher.htm PCT / EP2020 / 069 028
• / LuSchmB 2019_SeeEi1v /, Luther, G. and Schmidt-Böcking, H .: “Procedure for the provisional use of an at least partially constructed lower reservoir for an underwater pumped storage power plant”; DE 10 2019 118 726 A1 , available at: http://www.fze.uni-saarland.de/Speicher.htm DE 10 2019 118 726 B4 ,
• / LuSchmB 2020_SeeEi2 /: Luther, Gerhard and Schmidt-Böcking, Horst: "Underwater PSKW in the open pit residual lake" DE 10 2020 002 609 A1 ; available at: http://www.fze.uni-saarland.de/Speicher.htm
• / LuSchmB 2020_SeeEi3 /: Schmidt-Böcking, H and Luther, G .: "Modular underwater pumped storage power plant reservoir" DE10 2020 111 844 A1 ; available at: http://www.fze.uni-saarland.de/Speicher.htm
• / LuSchmB 2021_SeeEi4 /: Luther, G. and Schmidt-Böcking, H .: "Pumped storage power plant with a storage basin enclosed by a circular dam" DE10 2021 002 xxx.y4; available at: http://www.fze.uni-saarland.de/Speicher.htm
• / LuSchmB 2021_SeeEi5 /: Luther, G. and Schmidt-Böcking, H .: "PSKW with variable parallel series connection of pump turbines to exhaust a high storage basin" DE10 2020 111 xxx.y5; available at: http://www.fze.uni-saarland.de/Speicher.htm
• // Popp 2009 /: Popp, Mathias: "Ringwallspeicher", DE10 2009 005360 B4
• / Popp 2021 /: Updated topic page on the ring wall storage facility: http://www.poppware.de/Index.htm and following pages, in particular http://www.poppware.de/Ringwallspeicher/Ringwall-Bauweise.htm http://www.poppware.de/Ringwallspeicher/Ringwall-Groesse.htm http://www.poppware.de/Ringwallspeicher/Ringwall-Bebeispiel.htm)
• / Popp 2021_A /: http://www.poppware.de/Ringwallspeicher/Ringwall-Groesse.htm, there Fig. 3. "Circular dam on the flat land in cross-section", and: http://www.poppware.de/Ringwallspeicher/Ringwall-Bauweise.htm, there Fig. 3. Ring wall storage in the sea with a raised inner basin
• / Siol 1995 /: Siol, Ursula 1995: "Pumped storage plant", DE19513817 B4 ,
• / Sterner-Stadler 2014 /: Sterner, Michael and Stadler, Ingo (2014); "Energy storage requirements, technologies, integration"; Springer Verlag Berlin Heidelberg; ISBN = 978-3-642-37379-4)
• / Thuringia 2011 /: Free State of Thuringia (2011): “Pump storage cadastre - results of a potential analysis”, https://www.thueringen.de/de/publikationen/pic/pubdownload1272.pdf; there picture 2
• / Bild der Wissenschaft /: Bild der Wissenschaft issue 10/2010
• / Wikipedia ## arch dam /. accessed April 12, 2020) https://www.wikiwand.com/de/Bogenstaumauer
• / Wikipedia ## Arch weight dam /: (accessed April 12, 2020); https://www.wikiwand.com/de/Bogengewichtsmauer

List of names, some with a brief explanation

0

freies Seewasser, ohne Bebauung;

00

Noch nicht mit Wasser aufgefüllter Teil des späteren Restsee

1

Untergrund, z.B. der Seeboden oder auch der seitliche Hang der Rinne.

11

seitliche Böschung des Restsee

12

Seitliche Befestigung durch Abraumhalde

3

Ring-Staumauer, elementare Speicher-Grundzelle („SeeLoch“),

300

Arbeitssee (mit kleinem Hub), „Obersee“ des U.PSKW

33

Ringmauer -Becken von einer Ring-Staumauer 3 eingefasst,

333

Erweitertes Unterbecken, Kombination aus Ringmauer -Becken 33 und Bodenloch-Speicherraum 37.

37

Bodenloch-Speicherraum, der aus dem Abtragen von Bodenschichten im Innern des Ringmauerbeckens 33 entstanden ist.

376

Druckleitstruktur innerhalb der Randbereiche des Bodenloch-Speicherraumes 37 , bestehend z.B. aus senkrechten eng aneinander stehenden Hohlprismen, die zur Stabilisierung der Böschung seitlichen Druck aufnehmen und ableiten

44

Zugangsschacht (oder auch Verbindungsrohr) zwischen Pumpturbinen- Einheit 77 und freiem See 0.

5

Außenanbindung einer oder mehrere Strecken 67; dies kann durch einen Versorgungs- und Personenschacht oder auch durch eine steile aber noch befahrbare Tunnelröhre realisiert werden.

6

Sammelrohr als Zuleitung zur Pumpturbine , Verbindungsrohr, Verteilungsrohrwerk

60

Boden, u.U. auch mit Logistik und Zufahrtswegen

600, 601. 602

Verbindungsrohre von den Wasserkörpern WK_30, WK_31 bzw. WK_32 zur Pumpturbinen-Einheit 77

612

„Kurzschlussrohr zwischen den Wasserkörpern WK_31 und WK_32, eine kurzes Verbindungsrohr von Kugel zu Kugel“

67

Befahrbare Strecke im Seeboden 1, die auch die hydraulischen Verbindungrohre 6 beherbergt, zur Verbindung der Unterbecken untereinander bzw. mit einem zentralen Maschinenhaus 777.

7

Pumpturbine

77

Pumpturbinen Einheit. für eine Gruppe von Pumpturbinen

771

Aufnahmestation als Verbindung zu einer zentralen Pumpturbineneinheit 77

777

Zentrales Maschinenhaus als selbständige Einheit („Unterwasserbunker“), der alle Pumpturbinen einer PSKW-Anlage enthält.

0

free lake water, without buildings;

00

Part of what will later be the rest of the lake that has not yet been filled with water

1

Subsoil, e.g. the lake floor or the side slope of the channel.

11

lateral embankment of the rest of the lake

12th

Lateral attachment through spoil heap

3

Ring dam, elementary storage base cell ("SeeLoch"),

300

Working lake (with a small lift), "Obersee" of the U.PSKW

33

Circular wall basin from a circular dam 3 edged,

333

Extended lower basin, combination of circular wall basin 33 and bottom hole storage space 37 .

37

Bottom hole storage space that results from the removal of layers of soil inside the circular wall basin 33 originated.

376

Pressure control structure within the edge areas of the bottom hole storage space 37 consisting, for example, of vertical, closely spaced hollow prisms that absorb and dissipate lateral pressure to stabilize the slope

44

Access shaft (or connecting pipe) between the pump turbine unit 77 and open sea 0 .

5

External connection of one or more routes 67 ; this can be achieved through a supply and manhole or through a steep but still passable tunnel tube.

6th

Collecting pipe as feed line to the pump turbine, connecting pipe, distribution pipe work

60

Boden, possibly also with logistics and access roads

600, 601, 602

Connecting pipes from the water bodies WK_30, WK_31 or WK_32 to the pump turbine unit 77

612

"Short-circuit pipe between the bodies of water WK_31 and WK_32, a short connecting pipe from ball to ball"

67

Navigable route in the lake bottom 1 which also includes the hydraulic connecting pipes 6th houses, to connect the lower basins with each other or with a central machine house 777 .

7th

Pump turbine

77

Pump turbine unit. for a group of pump turbines

771

Pick-up station as a connection to a central pump turbine unit 77

777

Central machine house as an independent unit ("underwater bunker"), which contains all the pump turbines of a PSKW system.

Detailed picture description

• WK0 = Austauschvolumen für den Pumpspeicherbetrieb
• WKu = unter WK0 liegender Wasserkörper, der hier nur als „Unterlage“ dient.
• a = Abgrabungstiefe zur Gewinnung des Schüttmaterials für den Ringwall
• Hmax = maximale Pegeldifferenz zwischen Oberbecken und Unterbecken
• H0 = mittlerer Höhenunterschied zwischen Oberbecken und Unterbecken,
• dh0 = maximale Pegelschwankung im Oberbecken

Fig. 1: State of the art: Ring wall storage on the flat land with a raised inner basin as the upper basin (principle illustration based on / Popp 2021_A /; in its own name)
For this picture, drawings from two sources / Popp 2021_A / were used:
(1.) http: /www.poppware.de/Ringwallspeicher/Ringwall-Groesse.htm, there picture 3: "Ringwallspeicher on the flat land in cross section,"
and (2.) http://www.poppware.de/Ringwallspeicher/Ringwall-Bauweise.htm,
there picture 3: "Ring wall storage in the sea with raised inner basin"

• WK0 = exchange volume for pumped storage operation
• WKu = water body below WK0, which here only serves as a "base".
• a = excavation depth to extract the bulk material for the ring wall
• Hmax = maximum level difference between the upper and lower basins
• H0 = mean height difference between the upper and lower basins,
• dh0 = maximum level fluctuation in the upper basin

• 12 = seitliche Abstützung der Staumauer durch Abraumhalde
• 3 = Ring-Staumauer
• 33 = Unterbecken, von einer Ringstaumauer 3 umschlossen
• 44 = Zugangsschacht (oder auch Verbindungsrohr) zwischen Pumpturbinen- Einheit 77 und freiem See 0.
• 60 = Bodenfundament, u.U. auch mit Logistik

Image 2: PSKW with one through a circular dam 3 from Obersee 0 separated Unterbekken 33 , on its ground foundation 6th The pump turbines are arranged at the edge, which carry the storage water through wide lateral access shafts 44 from the Obersee 0 relate.

• 12 = lateral support of the dam wall by spoil heap
• 3 = ring dam
• 33 = lower basin, from a circular dam 3 enclosed
• 44 = access shaft (or connecting pipe) between the pump turbine unit 77 and open sea 0 .
• 60 = floor foundation, possibly also with logistics

• 300 = Rekultivierungssee im aufgelassenen Tagebauloch Speicher: 0_Bilder_HSB2019.1124_#2021.0417_HambacherWasserbatterie-mitSegler_Gesamt.PSKW_31p

Fig. 3: Pumped storage power plant consisting of the residual lake 300 of a former open pit as an upper lake and one (or more, in the picture there are four) lower basins 33 , which is the inner area of a ring dam built over the deep excavation channel 3 results.

• 300 = Recultivation lake in the abandoned open-cast mine hole Speicher: 0_Bilder_HSB2019.1124_ # 2021.0417_HambacherWasserbatterie-mitSegler_Gesamt.PSKW_31p

• 0 = freies Seewasser, ohne Bebauung, hier als Oberbecken genutzt.
• 1 = fester Untergrund,
• 3 = Hohes Unterbecken, hier durch eine Ring-Staumauer umschlossen.

• WKi = Wasserkörper, Nummerierung i (i=0;1;2;3) von unten nach oben
• WK0 = unterster Wasserkörper, der immer als Arbeits-Speicher genutzt wird
• Hi = Druckhöhe als mittlerer Höhenunterschied zwischen dem Wasserkörper WKi (mit i=0; 1 ;2;3) und dem dazugehörigen mittleren Pegel des Oberbeckens innerhalb des Arbeitsabschnitts, in dem sich der Wasserpegel des Unterbeckens im Bereich der WKi befindet.

Fig. 4: Circular wall storage tank with a very deep inner basin as the lower basin of a PSKW (schematic diagram).

• 0 = free lake water, without buildings, used here as an upper basin.
• 1 = solid ground,
• 3 = High lower basin, here enclosed by a ring dam.

• WKi = water body, numbering i (i = 0; 1; 2; 3) from bottom to top
• WK0 = lowest body of water, which is always used as working storage
• Hi = pressure head as the mean height difference between the water body WKi (with i = 0; 1; 2; 3) and the associated mean level of the upper basin within the working section in which the water level of the lower basin is in the area of the WKi.

Fig. 5: Variable series-parallel connection of 12 pump turbines for 4 pressure stages, each of which results from the parallel connection of the strings with 4 (Fig. 5a), or 3 (Fig. 5b), or 2 (Fig. 5c) series-connected pump turbines or a single pump turbine (Fig. 5d).

• 0 = freies Seewasser, ohne Bebauung, hier als Oberbecken genutzt.
• 1 = fester Untergrund,
• 3 = Hohes Unterbecken, hier durch eine Ring-Staumauer umschlossen.
• WKi = Wasserkörper, Nummerierung i (i=0;1;2;3) von unten nach oben
• WK2a = Zusatz-Wasserkörper, falls eine Lücke zwischen WK2 und WK3 besteht
• WK0 = unterster Wasserkörper, der immer als Arbeits-Speicher genutzt wird
• Hi = Druckhöhe als mittlerer Höhenunterschied zwischen dem Wasserkörper WKi (mit i=0;1;2;3) und dem dazugehörigen mittleren Pegel des Oberbeckens innerhalb des Arbeitsabschnitts, in dem sich der Wasserpegel des Unterbeckens im Bereich der WKi befindet.

Fig. 6: Circular wall storage tank with a very deep inner basin as the lower basin of a PSKW (schematic diagram).

• 0 = free lake water, without buildings, used here as an upper basin.
• 1 = solid ground,
• 3 = High lower basin, here enclosed by a ring dam.
• WKi = water body, numbering i (i = 0; 1; 2; 3) from bottom to top
• WK2a = additional water body, if there is a gap between WK2 and WK3
• WK0 = lowest body of water, which is always used as working storage
• Hi = pressure head as the mean height difference between the water body WKi (with i = 0; 1; 2; 3) and the associated mean level of the upper basin within the working section in which the water level of the lower basin is in the area of the WKi.

• 77_28 = Aggregat von Pumpturbinen , das logisch in 8 parallele Strängen mit jeweils 2 hintereinandergeschalteten ungleichen Pumpturbinen gegliedert ist.;
• 71 = „Halb-Pumpturbine“, eine Pumpturbine, die auf die halbe Leistung und die halbe Druckhöhe der Standard Pumpturbine 7 ausgelegt ist.
• 72 = Doppelpack von 2 hintereinandergeschalteten „Halb-Pumpturbinen“ 71 Das Doppelpack 72 ist funktional äquivalent zu einer Standard Pumpturbine 7 und kann dieselbe in einem Pumpturbinen -Aggregat ersetzen.

Fig. 7: Variable series parallel connection of 8 standard pump turbines and 8 half pump turbines for 5 pressure levels.

• 77_28 = Unit of pump turbines that is logically divided into 8 parallel strings with 2 unequal pump turbines each connected in series .;
• 71 = "Half-pump turbine", a pump turbine that has half the power and half the pressure head of the standard pump turbine 7th is designed.
• 72 = double pack of 2 "half pump turbines" connected in series 71 The double pack 72 is functionally equivalent to a standard pump turbine 7th and can replace the same in a pump turbine unit.

• 7 = Pumpturbine
• 77_zs = Aggregat von Pumpturbinen , das logisch in s parallelen Strängen mit jeweils z hintereinandergeschalteten Pumpturbinen gegliedert ist.; man kann z auch als Zeile 2 und s als „Spalte“ lesen. Das Zeichen C bedeutet hexadezimal die Zahl 12.
• Hj = Druckhöhe die sich am Pumpturbinen-Aggregat beim Durchlaufen des Pegels durch den Wasserköper WKj ergibt. (mit j = 0; 1; .2; .3)
• 61 =Oberer Verteiler
• 62 = Unterer Verteiler

Fig. 8: Variable series-parallel connection of 12 pump turbines for 4 pressure stages, each of which results from the parallel connection of the strings with 4 (Fig. 8a), or 3 (Fig. 8b), or 2 (Fig. 8c) series-connected pump turbines or a single pump turbine (Fig. 8d).

• 7 = pump turbine
• 77_zs = aggregate of pump turbines that is logically divided into s parallel strings with z pump turbines each connected in series .; you can also read z as row 2 and s as "column". The character C means the number in hexadecimal 12th .
• Hj = pressure head that results on the pump turbine unit when the water level passes through the water body WKj. (with j = 0; 1; .2; .3)
• 61 = upper distributor
• 62 = lower distributor

• 333 = Erweitertes Unterbecken, Kombination aus Ringmauer -Becken 33 und Bodenloch-Speicherraum 37.
• 37 = Bodenloch-Speicherraum
• 44 = Zugangsschacht (oder auch Verbindungsrohr) zwischen Pumpturbinen- Einheit 77 und freiem See 0.

Photo 9: Extended lower basin 333 with an additional bottom hole storage space 37 , shown here as a terraced hole made using open-cast mining methods. The machine bunker is at the lowest point 77 with the pump turbines and an access 44 to the upper basin, the free lake water 0 .

• 333 = Extended lower basin, combination of circular wall basin 33 and bottom hole storage space 37 .
• 37 = bottom hole storage space
• 44 = access shaft (or connecting pipe) between the pump turbine unit 77 and open sea 0 .

• 333 = Erweitertes Unterbecken, Kombination aus Ringmauer -Becken 33 und Bodenloch-Speicherraum 37.
• 376 = Druckleitstruktur innerhalb der Randbereiche des Bodenloch-Speicherraumes 37 , bestehend z.B. aus senkrechten eng aneinander stehenden Hohlprismen, die zur Stabilisierung der Böschung seitlichen Druck aufnehmen und ableiten
• 771 = Aufnahmestation als Verbindung zu einer zentralen Pumpturbinenstation 77

Fig. 10: Bottom hole storage space 37 with a stabilization of a particularly steep slope through a pressure control structure 376 . Inside the edge area of the bottom hole 37 are, for example, based on pressure-resistant storage bodies built flat against one another DE 10 2020 111 844 A1 (/ LuSchmB 2020_SeeEi3 /) that absorb and divert lateral pressure. The storage bodies in 376 are open and remain hydraulically balanced with one another and with the entire basin, so that the walls are not exposed to any direct hydraulic pressure difference but are only dimensioned when used as a pressure guide structure.

• 333 = Extended lower basin, combination of circular wall basin 33 and bottom hole storage space 37 .
• 376 = Pressure control structure within the edge areas of the bottom hole storage space 37 consisting, for example, of vertical, closely spaced hollow prisms that absorb and dissipate lateral pressure to stabilize the slope
• 771 = receiving station as a connection to a central pump turbine station 77

• 333 = Erweitertes Unterbecken, Kombination aus Ringmauer -Becken 33 und Bodenloch-Speicherraum 37.
• 37 = Bodenloch-Speicherraum

Fig. 11: Bottom hole storage space 37 . Calculation model of the extended lower basin 333 as a combination of a cylindrical circular wall basin 33 and a truncated cone as a bottom hole storage space 37 .

• 333 = Extended lower basin, combination of circular wall basin 33 and bottom hole storage space 37 .
• 37 = bottom hole storage space

• 5 = Tunnel zu einer Anschlussstelle am Ufer des Außensees
• 67 = Verbindungstunnel, die die Wasserrohre und eine befahrbare Zuwegung enthalten
• 777 = Zentrales Maschinenhaus als selbständige Einheit („Unterwasserbunker“), der alle Pumpturbinen einer PSKW-Anlage enthält.

Fig. 12: Connection of a central machine house designed as an underwater bunker 777
on the one hand to the individual ring wall lower basins 33 (or Extended Unterbekken 333 ) via connecting tunnel 67 containing the water pipes and a drivable access road,
and on the other hand to a connection point on the bank via an external connection, which is designed as a tunnel 5 to a connection point on the bank of the outer lake.

• 5 = tunnel to a junction on the shore of the outer lake
• 67 = connecting tunnel containing the water pipes and a drivable access road
• 777 = Central machine house as an independent unit ("underwater bunker"), which contains all the pump turbines of a PSKW system.

• 53 = spiralförmigem Fahrweg von der Krone des Beckens bis zum Boden

Figure 13: Cross-section through the lower basin of the ring wall 33 with internally attached spiral track 53 from the crown of the pelvis to the bottom.

• 53 = spiral path from the top of the pelvis to the bottom

• 0 = freies Seewasser, ohne Bebauung, hier als Unterbecken genutzt.
• 00 = Noch nicht mit Wasser aufgefüllter Teil des späteren Restsee
• 1 = fester Untergrund,
• 11 = seitliche Böschung des Restsee
• 3 = Ring- Staumauer umschließt das Speicherbecken, welches während der Auffüllungsphase des Restsee zunächst als Oberbecken genutzt wird.
• WK_aktiv = Wasserkörper, der als Arbeitsspeicher zur Energiespeicherung erschlossen werden kann.
• WKu = Unterster Wasserkörper, der die für den Kraftwerksbetrieb notwendige Mindesthöhe gewährleistet
• H_interim = Druckhöhe als mittlerer Höhenunterschied zwischen dem Wasserkörper WK_aktiv und dem dazugehörigen mittleren Pegel des Unterbeckens.
• dh = maximale Pegelschwankung im aktiven Wasserkörper WK_aktiv

Figure 14: Interim operation: circular wall storage facility with a high inner basin as the upper basin of a PSKW during the filling phase of the remaining lake (schematic diagram, not to scale).

• 0 = free lake water, without buildings, used here as a lower basin.
• 00 = Part of what will later be the rest of the lake that has not yet been filled with water
• 1 = solid ground,
• 11 = lateral embankment of the rest of the lake
• 3 = Ring dam encloses the storage basin, which is initially used as an upper basin during the filling phase of the remaining lake.
• WK_aktiv = body of water that can be tapped into as working storage for energy storage.
• WKu = lowest body of water that guarantees the minimum height required for power plant operation
• H_interim = pressure head as the mean height difference between the water body WK_aktiv and the associated mean level of the lower basin.
• ie = maximum level fluctuation in the active body of water WK_aktiv

• 310 = Zwischendecke zwischen dem untersten und dem mittleren Wasserkörper eines Ringmauer -Speichers
• 612 = Kurzschlussrohr zwischen einem obersten und einem untersten Wasserkörper.

Photo 15: Circular wall sub-basin 33 with a false ceiling 310 and a short-circuit pipe 612 between an uppermost and a lower water body, WK_32 and WK_31.

• 310 = false ceiling between the lowest and the middle water body of a circular wall reservoir
• 612 = short-circuit pipe between an uppermost and a lowermost body of water.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 19513817 B4 [0008, 0109]
• DE 102019118725 [0008]
• DE 102019118726 [0008]
• DE 102020002609 A1 [0008, 0009, 0011, 0013, 0045, 0109]
• DE 102020111844 [0010]
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• DE 102009005360 B4 [0109]

Claims (13)

Pumped storage power plant (PSP), primarily with a large variation in the height difference between the upper and lower basins, characterized in that at least one of the storage basins is formed by a ring-shaped closed dam (ring dam). PSKW according to Claim 1 , characterized in that a ring-shaped closed dam wall (ring dam) forms the upper basin in its outer space and the lower basin in its interior within the bottom depression of a closed open-cast mine. PSKW according to Claim 1 and Claim 2 , characterized in that it has several pump turbines, which are combined as a single line or as a parallel connection of several similar lines to form a unit, and the number of these in a line is such that the pending level difference is within the tolerance range of the resulting pressure head of the line and that the pump turbines combined to form a certain unit can be transferred to another unit by a switching device and that during a continuous storage or withdrawal process when the level difference between the upper and lower basins is changed to a different pressure stage, the switching device mentioned switches the pump turbines interconnects to the unit that is designed for the new pressure level. PSKW according to Claim 3 , characterized in that all pump turbines are of the same type. PSKW according to Claim 3 , characterized in that in addition to a class of standard pump turbines with the pressure head H _P there is a second class of "fraction pump turbines" with the pressure head b * H _P and in a number M _b , the product of fraction b and Number M _{b is} an integer. PSKW according to Claim 1 until Claim 3 , Claim 4 or Claim 5 , characterized in that the soil enclosed by the circular dam is excavated to increase the storage capacity of the lower basin to form a primarily funnel-shaped hole in the bottom PSKW according to Claim 6 , characterized in that the excavation funnel or parts of it is excavated using the terrace method known from open pit mining. PSKW according to Claim 6 and Claim 7 characterized in that the excavation funnel or partial areas of the same to improve the stability of the inwardly running slopes by pressure-resistant hollow storage bodies, primarily through a modular arrangement of several individual, mainly flat adjacent pressure vessel modules according to DE 10 2020 111 844 A1 or by hollow ball storage according to DE 10 2020 002 609 A1 and DE 10 2019 118 725 A1 Procedure for digging the hole in the ground Claim 6 until Claim 8 characterized in that the excavation of the bottom hole behind the rising ring wall 3, which is still under construction, is tipped again, with a largely flat and stable new seabed being created in the final state. Procedure for the provisional operation of a PSKW according to Claim 1 until 9 in a residual lake of an open pit that is only partially filled with water, characterized in that the storage basin intended in final operation as lower basin 33 or 333 is now used as the upper basin, and the later residual lake 0, which is only slightly filled with water, is used as the lower basin. PSKW, erected in the area of a closed open pit, characterized in that several lower basins, each with their own ring dams, are built on the natural soil of the elongated excavation channel. PSKW according to Claim 11 and one or more of the other preceding claims, characterized in that the machine house for supplying one or more circular wall lower basins is housed outside of the same in an underwater bunker and is connected directly or indirectly to all the circular wall lower basins by one or more connecting tunnels 67 and via a drivable access road 53, which runs as an open top or pressure-tight enclosed, spirally on the inside of a circular wall lower basin, or a tunnel 5 running in the upper basin is connected to the bank with the surroundings of the PSKW. PSKW comprising a lower basin 33 formed by a circular wall 3 Claim 2 and one or more of the Claims 10 until 12th , which is equipped with an additional false ceiling 310 between the lowest and the middle body of water and a short-circuit pipe 612 between the uppermost and the lowest water body.

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