DE102012022096A1 - Method for storing electrical energy in natural storage, involves passing water over turbines of hydropower plant or pumped storage power plant from reservoirs, when required, so that potential energy is converted into electrical energy - Google Patents

Abstract

The method involves pumping the water of a reservoir (3) of a hydropower plant or pumped storage power plant (2) to a higher natural memory (4) by using electrical energy, where electrical energy is stored in form of potential energy of an ice layer (5). The ice layer is partially or completely melts under suitable environmental conditions, for forming water, which flows back into the reservoir. The water is passed over one or more turbines of the hydropower plant or pumped storage power plant from the reservoirs, when required, so that the potential energy is converted into electrical energy.

Description

The invention relates to a method for storing electrical energy in a natural memory.

The share of electricity from renewable energy sources, in particular from wind and solar energy, is becoming increasingly larger. The problem is, however, that the power generation is not continuous, but according to the current weather conditions. It is therefore necessary to provide storage in particular for the fluctuating current peaks from renewable energy sources available. These must have sufficient capacity and be easy to integrate into the existing infrastructure.

The Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) in cooperation with the Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) has already developed a method for storing fluctuating green electricity in the form of synthetic natural gas. The excess renewable electricity is used to electrolytically split water into hydrogen and oxygen. Chemical reaction of hydrogen with carbon dioxide produces methane. This will be fed into the existing natural gas grid like conventional natural gas, in order to drive natural gas cars or to fire natural gas heaters (cf. "Surplus electricity from wind power and photovoltaics as natural gas storage", article dated 19.04.2010, printed on 12.05.2012 on www.solarportal24.de ).

However, the above method has the particular disadvantage that it limits the use of the current spikes on a utilization in the form of natural gas.

Electricity can also be recovered from natural gas, but the start-up and shut-down time is greater than for hydropower plants, and natural gas is only limitedly suitable for storing peak loads. In addition, the efficiency is smaller than for pumped storage power plants.

It was accordingly an object of the present invention to provide an improved method for the use of power peaks from renewable energies. For this purpose, especially natural energy storage and existing infrastructures should be used. The use of the stored stream should not be restricted.

• 1. die elektrische Energie eingesetzt wird, um Wasser aus einem Speicherbecken eines Wasserkraftwerks oder Pumpspeicherwerks auf einen höher gelegenen natürlichen Speicher zu pumpen, der auf einer Höhe liegt, in der
• 2. eine Oberflächentemperatur des natürlichen Speichers vorliegt, bei der das Wasser zu einer Eisschicht gefriert, wobei die elektrische Energie in Form von potentieller Energie der Eisschicht gespeichert wird und wobei
• 3. zu einem späteren Zeitpunkt unter geeigneten Umgebungsbedingungen die Eisschicht teilweise oder vollständig schmilzt, wobei Wasser entsteht, das
• 4. zurück in ein Speicherbecken fließt, und wobei
• 5. das Wasser aus dem Speicherbecken bei Bedarf über eine oder mehrere Turbinen eines Wasserkraftwerks oder Pumpspeicherwerks geleitet wird, wobei die potentielle Energie in elektrische Energie umgewandelt wird.

This object is achieved by a method for storing electrical energy in a natural memory, which is characterized in that

• 1. The electrical energy is used to pump water from a storage tank of a hydroelectric power plant or pumped storage plant to a higher natural storage, which is at an altitude in the
• 2. a surface temperature of the natural memory is present, in which the water freezes to an ice layer, wherein the electrical energy is stored in the form of potential energy of the ice layer and wherein
• 3. at a later time under appropriate environmental conditions, the ice layer partially or completely melts, with water being produced, the
• 4. flows back into a reservoir, and where
• 5. the water from the reservoir is directed, if necessary, through one or more turbines of a hydroelectric power plant or pumped storage plant, the potential energy being converted into electrical energy.

Preferably, the electrical energy is also used to pump water from an original tank in a higher-lying original tank.

More preferably, the electrical energy is additionally or alternatively used to pump water from an original tank in a higher storage reservoir.

In addition, the electrical energy can additionally or alternatively be used to pump water from an original tank to a higher natural storage.

It is also possible to additionally or alternatively use the electrical energy to pump water from a standing or flowing natural body of water into a higher-level original reservoir, into a higher-level reservoir or to a higher natural reservoir.

For reasons of better readability, the terms natural storage, reservoir, reservoir, hydroelectric power station and pumped storage plant are all listed here in the single number; However, the subject matter of the invention includes not only a single but also each two or more of the above features.

Preferably, the electrical energy comes from excess capacity of renewable energy sources.

Glacier fields, glacier beds, are particularly suitable as natural energy stores defrosted glaciers, boulders, high valleys or north-facing slopes.

The proposed method virtually increases existing glacier areas and extends the capacities of existing water and / or pumped storage power plants.

As a natural energy storage usable scree fields are stone heap works with a void level of in particular 15 to 60%, preferably from 20 to 45%. The water fills the cavities between the stones and freezes at appropriate ambient temperatures to ice.

As the ambient temperature increases, the ice formed melts again, flowing back through pipes and / or as surface water, for example in stream beds.

The melting can be controlled by suitable covers, in particular adjustable lamellae or foils, which can be coated with light or heat-reflecting or light or heat-absorbing materials. Depending on the season, additives which delay or prevent melting can be introduced into the ice, preferably natural substances which do not pollute the environment, for example natural sands or even fine dust.

Advantageously, for this purpose, a film can be used which has a heat and light-reflecting coating on one side and a heat and light-absorbing coating on the opposite side. This film can then be used as needed with the appropriate side up to cover the ice layer.

It is also possible with preference to use films whose color can be controlled by irradiation with light as a function of their wavelength.

Advantageously, a film can be used which changes its reflection properties by applying a voltage, in particular from a light and heat and light-reflecting color, to a dark, heat and light absorbing color.

In a further preferred embodiment, a cover in the form of lamellae can be provided, over which, by different position of the same, the light incidence can be controlled. The lamellae may have a different color on the two sides thereof, for example a light, especially white, and a dark, especially black, color. By crossing the slats further water can be applied to the ice formed.

If films are provided, it is advantageous not to apply them in the winter months, so that more water can be applied to the surface of the ice formed, for example by spraying. In spring, the film is then pulled over the entire ice formed.

It is also advantageous to use decomposable films which do not have to be removed again.

Advantageously, the water can be distributed via nozzles which can be movably mounted on a construction, in particular a hanging structure, so that they can be driven over the natural storage.

Advantageously, existing standard snowmaking systems, such as those used in ski resorts, can be used: these are already established in the corresponding regions and do not represent any further intervention in the natural environment.

Ice layers in the context of the invention are both compact ice sheets and layers provided with stones or boulders or other additives or also loose or compressed porous layers of ice particles, ice or snowflakes.

Pumping up the water can be done with fixed or mobile equipment. The distribution of the water can be controlled so that only an amount is pumped up locally, which under the current weather conditions, d. H. can also freeze at about 0 ° C or below.

In a preferred embodiment, the conversion of potential into electrical energy takes place with the aid of the existing water or pumped storage power plants in the infrastructure.

In a further preferred embodiment, the conversion of the additional potential energy due to the higher level of the natural storage by another water or pumped storage power plant is above the level of the storage tank of an existing water or pumped storage power plant.

Preferably, the electrical energy comes from excess capacity of renewable energy sources.

The electricity from renewable energy sources, in particular from wind and solar energy, fluctuates depending on the weather conditions, so that excess capacities alternate with times where no or not enough energy can be generated.

The water is pumped up with excess current from current spikes, which is reasonably priced. If there is no excess current, the pumps will shut off and the lines will automatically drain. The lines and distribution heads are advantageously isolated and / or provided with an electrical support heater.

The lines can be advantageously laid underground.

It is also possible to connect power plants in series.

Regulation of water distribution:

The water is pumped by pumps, which are already used in power plant technology for power generation, for example, pump turbines from the company. Sulzer Hydro or the company Voith via pipelines from the reservoir into higher regions. The pipelines are laid above ground or underground. The water distribution then takes place through appropriate distribution systems (multi-branched pipe system with holes, spray systems, etc.), which in turn are controlled by sensors that are installed locally or non-contact. Locally installed sensors may be, for example, temperature, compressive, layer thickness and conductivity sensors. Non-contact sensor methods are to be understood in particular as GPS methods and infrared measurement methods. The control method works such that, for example, the water is conveyed to the natural reservoir through a controlled system of branched perforated pipes until the nearest sensor indicates that the water at that point is no longer sufficiently solid then it changes to another Switched branch. If the water at the sensor is completely frozen to ice, then fresh water is given up again. The locally installed sensors are functionally reliable, especially in case of additional snowfall.

The distribution of the water can also be controlled and regulated by means of non-contact technology, in particular satellite technology (GPS, altimeter, etc.), infrared technology (thermal imaging camera) and video surveillance. Also possible is an optical measurement technology with night vision options or laser measurements.

The electrical energy can also come from conventional power plants, coal power plants and nuclear power plants, especially if they are used to cover base loads and this base load is not retrieved.

By supplying water from other sources (lakes, rivers, drains from smaller power plants), the cycle time, i. H. the time in which the entire memory (ice layer) is once built and melted again, significantly shortened and thus improve the efficiency.

In autumn and spring, there is often more rainfall than in winter. Since there are already minus degrees in autumn / spring in the corresponding regions and, above all, because of the longer daylight and the not yet started or already ended heating season, there is more surplus electricity available at this time, it is particularly advantageous to exploit it to pump up water. On the other hand, in winter there is usually less excess flow and less water available for pumping up.

Cycle time is the time it takes to completely fill the natural reservoir with ice and melt it again. The cycle time should be less than 180 days, preferably less than 150 days, more preferably less than 120 days, in particular less than 90 days, in order to fill the natural reservoir within a winter season or within a spring or fall season. Of course, the memory can be partially melted in the corresponding ambient conditions in the winter or spring or fall and so a part of the memory not seasonal but in the day-night change or weekly change.

The inventive method has the great advantages that it uses known and already installed systems to store electrical energy from excess capacity of particular renewable energy sources. This means low investment costs and a low investment risk.

In addition, the inventive method provides a simple, cost-effective and ecologically advantageous solution to replenish the basins of pumped storage power plants, for which previously other energy sources (nuclear power, coal, etc.) were used.

The invention will be explained in more detail by embodiments and a drawing.

In the drawings, like reference characters designate like or corresponding features.

In detail in the drawing:

1 a schematic representation of a preferred embodiment of the inventive method,

2 a schematic representation of another preferred embodiment of the inventive method.

In the in 1 illustrated preferred embodiment, water from an original tank 1 through a power plant / pump house 2 in a higher reservoir 3 pumped. Using current spikes, water is removed from the reservoir 3 to a higher natural memory 4 , in the present case a glacier and pumped into a subsequent glacier bed. The water is called ice layer 5 deposited thereon.

1A shows a cross-sectional view in the area AA, with on the glacier bed 4 formed ice layer 5 ,

1B shows a cross-sectional view in the area BB, with on the glacier 4 formed ice layer 5 ,

In the 2 illustrated preferred embodiment shows natural memory 4 in the form of boulder fields in high valleys above a reservoir 3 , with connecting channels 6 for the melt water from the boulder fields 4 to the reservoir 3 ,

3 schematically shows a boulder field, which is used for the storage of water. About the pump P, the water from a storage tank, not shown in the region of the higher scree field 4 pumped up through a pipeline and distributed over piping systems with distribution facilities in several levels over the usable width of the boulder field and thus at appropriate temperatures an ice layer 5 generated. If the ice melts, the melt water is collected in the natural waterways and led back to the reservoir, or if an ice layer was formed on another side of the mountain, with the appropriate supply lines (connecting tunnel) back to the reservoir.

3A shows in section CC a variant for the distribution of water. The water distribution system hangs on a metal structure 7 across the entire width of the usable boulder field 4 , The water is made by means of nozzles 8th or directly from the holes / holes initially on the boulder field 4 and later on the growing egg layer 5 applied.

4 shows a variant of the distribution system. The distributors 9 are over slider 10 individually on and off. In the areas where the ice layer 5 is built, are sensors 11 built-in, which monitor the condition of the ice.

4A shows a particular embodiment in which the slide 10 directly over the sensors 11 be managed. Notice the sensor 11 that z. B. the water is not completely frozen in the appropriate place, then this closes the corresponding distributor arm and switches to another.

5 schematically shows a particularly preferred embodiment: schematically illustrated are storage tanks 3 (Silvretta Reservoir and Kops Reservoir), original reservoir 1 (Vermunt artificial lake, equalizing basin Partenen and Rodundbecken), power plants 2 with pumping operation and the Rhine as flowing water 6 and Lake Constance as stagnant water 6 ,

Embodiment 1

On the basis of the barrages and power plants of Vorarlberger Illwerke AG, the potential of the invention can be exemplified. In the exemplary embodiment, a section of the barrage and power plant network of Illwerke AG is described. The embodiment is based on the idea of storing ice in the Silvretta region in the form of potential energy. The catchment area of the Silvretta region lies at an altitude of 1800-3300 m and is about 45 km ² large. Of these, about 10 km ^{2 are} glaciated. The glaciers have declined sharply, so that, for example, the III, which rises at Piz Buin, flows through the Ochsental (a 5 km long high valley) directly into the Silvretta Reservoir. The still existing glaciers of the Silvretta region (eg Ochsentaler, Klostertaler, Schattenspitz, Schneeglocken, Vermunt and Rauher head glaciers, etc.) have economically useful dimensions of approximately 0.5-1.0 km ² each. With utilization of about 1/3 of the total glaciated area (about 3.33 km ² ) and an applied ice thickness of 50 m, about 166 million m ^{3 of} water can be stored in the form of ice. The usable rear Ochsental itself is about 4 km long and has a mean width of about 500 m. When applying a mean ice thickness of 50 m results in a potential storage volume of 50 million m ³ .

This results in a simplified estimated potential in the catchment area of the Silvretta Reservoir of 216 million m ³ (166 + 50 million m ³ ) ice storage capacity alone. Most of the meltwater from this ice reaches natural waterways or already existing enclosures and piping systems in the reservoirs (Silvretta or Vermunt reservoirs). The Collected water can then be used from the storage or original tank over several power plant and reservoir stages for electrical power generation. In the examined area of the Illwerke AG a height difference of altogether approx. 1538 m is available. This results in a capacity of 30 m ³ / s of water through the turbines, an output of 453 MW. If the complete ice storage capacity of 216 million m ^{3 were converted} into electrical energy, then this power of 453 MW could be maintained for approximately 2,000 hours. This corresponds to approx. 900 million KWh of electricity during a one-off cycle build-up / meltdown.

Since the precipitation or the actual natural water supply for an annual construction of the ice masses is not sufficient to fully use the ice storage capacity, it is expedient to bring the necessary water from other regions, for example from the Rhine or Lake Constance. The water would have to be through a newly installed piping system of about 400 m above sea level. NN / 450 m above sea level. NN (Lake Constance / Rhine) at 645 m above sea level. NN height be pumped into the Rodundbecken I to III. From there, the infrastructure is already largely available to the water to the original reservoir Vermunt reservoir in 1743 m above sea level. NN or in the reservoir Silvretta Reservoir in 2030 m above sea level. NN. to pump.

Embodiment 2

The potential of the invention is shown using the example of the Kaprun power plant, which belongs to the Verbund Hydro Power AG.

The reservoir on the Moserboden (usable volume 84.9 million m ³ ) is at 2005 m above sea level. NN and is supplied via the Möllüberleitungsstollen from the other reservoir Margaritze (2000 m above sea level with 3.3 million m ³ net capacity) and various streams. The construction of the Pasterze glacier on the Großglockner could build up an additional ice storage with a mean width of 750 m, a length of 3500 m and a thickness of 75 m. The ice storage would have a capacity of about 197 million m ^{3 of} ice. The meltwater of this ice storage is collected in the reservoir Moserboden, which also serves as a reservoir for the meltwater. A number of eleven lakes (power plants) with a height difference of 1157 m (2004 m Moserboden - 847 m Kaprun power plant) are available via several reservoirs / power plants connected in series. With a volume flow of 30 m ³ / s, this results in an output of 340 MW with a total power duration of 1824 h. This equates to 620 million KWh of electricity for a one-off full build / melt cycle. The economy is increased by shortening the cycle time.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited non-patent literature

• "Surplus electricity from wind power and photovoltaic as natural gas storage", article dated 19.04.2010, printed on 12.05.2012 on www.solarportal24.de [0003]

Claims (12)

Method for storing electrical energy in a natural store, characterized in that 1. the electrical energy is used to extract water from a reservoir ( 3 ) of a hydroelectric power station or pumped storage plant ( 2 ) to a higher natural memory ( 4 ), which is at a height in which 2. a surface temperature of the natural memory ( 4 ), in which the water is converted into an ice layer ( 5 ), wherein the electrical energy in the form of potential energy of the ice layer ( 5 3. and at a later time, under suitable environmental conditions, the ice layer ( 5 ) partially or completely melts, whereby water is produced, the 4. back into a storage tank ( 3 ), and where 5. the water from the reservoir ( 3 ) if necessary via one or more turbines of a hydroelectric power plant or pumped storage plant ( 2 ), whereby the potential energy is again converted into electrical energy. A method according to claim 1, characterized in that the electrical energy is additionally used to water from an original tank ( 1 ) in a higher-lying original basin ( 1 ) to pump. A method according to claim 1 or 2, characterized in that the electrical energy is additionally used to recover water from an original basin ( 1 ) into a higher reservoir ( 3 ) to pump. Method according to one of claims 1 to 3, characterized in that the electrical energy is used in addition to water from an original basin ( 1 ) to a higher natural memory ( 4 ) to pump. Method according to one of claims 1 to 4, characterized in that the electrical energy is additionally used to water from a standing or flowing natural waters ( 6 ) in a higher-lying original basin ( 1 ), into a higher reservoir ( 3 ) or to a higher natural memory ( 4 ) to pump. Method according to one of claims 1 to 5, characterized in that the electrical energy comes from excess capacity of renewable energy sources. A method according to claim 1 or 2, characterized in that as a natural memory ( 4 ) a glacier field, a glacier bed of a defrosted glacier, a boulder field, a high valley or a northern slope is used. Method according to one of claims 1 to 7, characterized in that the regulation of the water distribution via one or more distributors ( 9 ), which individually by means of sliders ( 10 ) and wherein the slides are preferably connected to a control unit which controls the same in response to a signal, whereby sensors ( 11 ), which are in the ice layer ( 5 ) are arranged to register the degree of freezing thereof. Method according to claim 8, characterized in that the distributors ( 9 ) on a preferably mobile metal construction above the natural memory ( 4 ) are arranged. Method according to claim 9, characterized in that the mobile metal construction extends over the entire width of the natural memory ( 4 ). Method according to one of claims 1 to 10, characterized in that the melting of the ice layer ( 5 ) by means of suitable covers, in particular adjustable lamellae or films, which are preferably coated with light and heat-reflecting or light and heat absorbing materials, is controllable. Method according to one of claims 1 to 11, characterized in that in the ice layer ( 5 ) Additives are added, which delay or prevent the melting, preferably natural substances that do not pollute the environment, in particular natural sands or fine dust.

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