WO2016185210A1

WO2016185210A1 - Tidal energy system

Info

Publication number: WO2016185210A1
Application number: PCT/GB2016/051437
Authority: WO
Inventors: Stuart Frank MURPHY
Original assignee: Murphy Stuart Frank
Priority date: 2015-05-18
Filing date: 2016-05-18
Publication date: 2016-11-24
Also published as: GB201508509D0; GB2539638A; GB2539638B

Abstract

A tidal energy system is provided, comprising: a seaward storage basin (10); a landward storage basin (30); and an intermediate storage basin (20) between the seaward and landward storage basins; wherein: the seaward storage basin (10) is in use operable: to receive and store incoming tidal water; to deliver water therefrom to the intermediate storage basin (20); to receive and store outgoing tidal water from the intermediate storage basin (20); and to deliver water therefrom out of the system; the landward storage basin (30) is in use operable to: receive and store water from the intermediate storage basin (20); and to deliver water therefrom to the intermediate storage basin (20); and the intermediate storage basin (20) is in use operable: to receive and store water from the seaward storage basin (10); to deliver water therefrom to the landward storage basin (30); to receive and store water from the landward storage basin (30); and to deliver water therefrom into the seaward storage basin (10).

Description

Tidal Energy System

FIELD

[01 ] The present invention relates to tidal energy systems, and to related methods. BACKGROUND

[02] Tidal energy systems offer the potential to generate electricity while avoiding disadvantages associated with using fossil fuels in generation. In order to increase the efficiency of tidal energy systems it is desirable to maximise the amount of water that flows through the turbines, so for systems that employ tidal storage a location that that has a large tidal range is preferred. Use of a single basin for tidal storage leads to significant periods of time during which electricity is not being generated. These periods are typically while the tide is incoming and water is being accumulated in the basin, and while waiting for the outgoing tide to cause a reduction in water level outside the basin.

[03] Furthermore, in systems that use the head of accumulated water in a storage basin to drive turbines it may be difficult to ensure that the turbines are working at high efficiency as the basin empties and the head of accumulated water drops.

[04] Example embodiments aim to address issues associated with the prior art, whether identified herein or otherwise.

SUMMARY

[05] In one example embodiment there is provided a tidal energy system comprising: a seaward storage basin; a landward storage basin; and an intermediate storage basin between the seaward and landward storage basins; wherein: the seaward storage basin is in use operable: to receive and store incoming tidal water; to deliver water therefrom to the intermediate storage basin; to receive and store outgoing tidal water from the intermediate storage basin; and to deliver water therefrom out of the system; the landward storage basin is in use operable to: receive and store water from the intermediate storage basin; and to deliver water therefrom to the intermediate storage basin; and the intermediate storage basin is in use operable: to receive and store water from the seaward storage basin; to deliver water therefrom to the landward storage basin; to receive and store water from the landward storage basin; and to deliver water therefrom into the seaward storage basin. Suitably, a turbine is provided between the seaward storage basin and the intermediate storage basin and a turbine is provided between the intermediate storage basin and the landward storage basin, the turbines arranged such that movement of water from one storage basin to the next is arranged to drive the turbine there-between, and wherein the turbines are mounted for movement relative to the water levels in the storage basins to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin to the next.

[06] In one example embodiment a turbine is provided between the sea and the seaward storage basin, said turbine arranged such that movement of water into the system from the sea, or movement of water out of the system from the seaward storage basin is arranged to drive said turbine, and wherein said turbine is mounted for movement relative to the water levels in the sea and the seaward storage basin to in use maintain a predetermined water level difference between input and output sides thereof as water moves into or out of the seaward storage basin.

[07] In one example embodiment one or more of the storage basins is provided with an associated reserve basin, arranged so that water may in use move between the basin and its reserve basin and from a reserve basin to the storage basin with which it is associated.

[08] In one example embodiment a turbine is provided between a storage basin and its reserve basin, and wherein said turbine is arranged such that movement of water into the reserve basin from the storage basin with which it is associated, or movement of water from the reserve basin into the associated basin is arranged to drive said turbine, and wherein said turbine is mounted for movement relative to the water levels in the basin and the associated reserve basin to in use maintain a predetermined water level difference between input and output sides thereof as water moves into the reserve basin from the associated storage basin or out of the reserve basin into the associated storage basin.

[09] In one example embodiment the tidal energy system further comprises a forward lagoon arranged seaward of the seaward storage basin and wherein the forward lagoon is arranged to shelter the seaward storage basin from the sea by pontoons, a solid or permeable breakwater or the like while still allowing tidal flow to and from the seaward storage basin.

[10] In one example embodiment one or more of said turbines is provided as a turbine assembly comprising an inlet/outlet on each side, operable so that in use movement of water through the turbine assembly in either direction drives the turbine.

[1 1 ] In one example embodiment one of more of said turbines is provided as a turbine assembly including a rotary mount, wherein rotation of the rotary mount changes the level of the turbine.

[12] In one example embodiment one or more of said turbines is provided as a turbine assembly comprising sluice gates operable to in use control movement of water there-through. [13] In one example embodiment wherein one or more of said turbines is provided in a turbine assembly comprising two inlets on each side, wherein said inlets are mounted to move together in use according to the water level difference between input and output sides of the turbine assembly.

[14] In one example embodiment said inlets are mounted such that movement of one in an upward direction is accompanied by movement of the other in a downward direction.

[15] In one example embodiment there is provided a method of tidal energy generation using the tidal energy system of any preceding claim, the method comprising an incoming phase including:

(a) receiving incoming tidal water in the seaward storage basin;

(b) delivering water from the seaward storage basin to the intermediate storage basin; and

(c) delivering water from the intermediate storage basin to the landward storage basin; wherein during the energy storage phase movement of water from one storage basin to the next is arranged to drive the turbine there-between, and wherein the turbines are moved relative to the water levels in the storage basins to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin to the next; and comprising an outgoing phase including:

(d) delivering water from the landward storage basin to the intermediate storage basin;

(e) delivering water from the intermediate storage basin to the seaward storage basin; and

(f) delivering water from the seaward storage basin out of the system; wherein during the energy delivery phase movement of water from one storage basin to the next is arranged to drive the turbine there-between, and wherein the turbines are moved relative to the water levels in the storage basins to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin to the next; and characterised by further comprising an intermediate phase between the incoming phase and the outgoing phase, the intermediate phase including:

(g) delivering water from the intermediate storage basin to the seaward and landward storage basins; wherein during the intermediate phase movement of water from one storage basin to the next is arranged to drive the turbine there-between, and wherein the turbines are moved relative to the water levels in the storage basins to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin to the next.

[16] According to the present invention there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

BRIEF DESCRIPTION OF DRAWINGS

[17] For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which:

[18] FIG. 1 shows a schematic plan view of a tidal energy system according to an example embodiment of the present invention;

[19] FIG. 2 shows a schematic side sectional view of the tidal energy system of FIG. 1 , the section being along the centreline;

[20] FIG. 3A-3D show schematic front views of a turbine assembly for use in the tidal energy system of FIG.1 ;

[21 ] FIG. 4A-4G show a schematic side sectional views of the turbine assembly of FIG. 3A- 3D;

[22] FIG. 5A-5D show schematic front views of a turbine assembly for use in the tidal energy system of FIG.1 by way of explanation of the operation of the tidal energy system during a tidal cycle;

[23] FIG. 6A-6M shows schematic side sectional views of the tidal energy system of FIG. 1 by way of explanation of the operation of the tidal energy system during a tidal cycle; and

[24] FIG. 7 shows a graphical representation of operation of the turbines of the tidal energy system of FIG. 1 during a tidal cycle.

DESCRIPTION OF EMBODIMENTS

[25] FIG. 1 shows a schematic plan view of a tidal energy system 1 according to an example embodiment of the present invention. The tidal energy system 1 is for generating electrical energy from the tidal movement of sea water. Water is allowed to flow from the sea S into storage basins 10, 20, 30, which are also referred to as lagoons, as the tide rises, and allowed to flow from the tidal energy system 1 once the tide has gone out. Movement of water into and out of some of the storage basins 10, 20, 30, is used to drive turbines that are coupled to electrical generators, as described in detail further below.

[26] The tidal energy system 1 comprises a seaward storage basin 10, a landward storage basin 30, and an intermediate storage basin 20. The intermediate storage basin 20 is located between the seaward storage basin 10 and the landward storage basin 30. The boundaries between the sea S and the seaward storage basin 10, between the seaward storage basin 10 and the intermediate storage basin 20 and between the intermediate storage basin 20 and the landward storage basin 30 are provided by first, second and third dams 1 1 , 12, 13 respectively.

[27] FIG. 2 shows a schematic side sectional view of the tidal energy system 1 , the section being along the centreline.

[28] During an incoming tide the seaward storage basin 10 receives and stores incoming tidal water 10. Water from the seaward storage basin 10 may be delivered to the intermediate storage basin 20, and likewise the seaward storage basin 10 may receive and store outgoing tidal water from the intermediate storage basin 20 during operation of the tidal energy system 1 . In addition, the seaward storage basin 10 may deliver water therefrom and out of the tidal energy system 1 to sea S during an outgoing tide.

[29] The landward storage basin 30 is in use operable to receive and store water from the intermediate storage basin 20, and to deliver water to the intermediate storage basin 20 during operation of the tidal energy system 1 .

[30] The intermediate storage basin 20 is, as already indicated, operable to receive and store water from the seaward storage basin 10, to deliver water therefrom to the landward storage basin 30, to receive and store water from the landward storage basin 30, and to deliver water therefrom into the seaward storage basin 10 during operation of the tidal energy system 1 .

[31 ] Turbines are provided between the seaward storage basin 10 and the intermediate storage basin 20. Furthermore, turbines are provided between the intermediate storage basin 20 and the landward storage basin 30. The turbines are arranged such that movement of water from one storage basin 10, 20, 30 to the next drives the turbine between the respective storage basins 10, 20, 30. By regulating movement of water within the system, the turbines that sit at the boundaries of the intermediate storage basin 20 can used to generate electricity during both incoming and outgoing tides, increasing the flexibility to match the output of the tidal energy system 1 to demand.

[32] It will be appreciated that in order for the system to drain completely under gravity, the seaward storage basin may be provided with an outflow that is lower than that of the intermediate storage basin, and in turn the intermediate storage basin may be provided with an outflow that is lower than that of the landward storage basin, However, this need not necessarily be achieved by a general downward slope from landward to seaward, as there may be drainage flues, pumps, or cambered or other surface features provided at the bottom of the storage basins. Furthermore, although a generally linear arrangement from seaward to landward is preferred in order that the bulk flows water may move in the system may take place also in a generally linear manner, it is to be understood that other geometries may be used, and "seaward" and "landward" ought to be interpreted herein in relation to their functions in receiving and delivering water. Similar considerations apply to the reserve storage basins, described in more detail below.

[33] The turbines are mounted for movement relative to the water levels in the storage basins 10, 20, 30 to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin 10, 20, 30 to the next. In this way demand matching is facilitated because the output of the turbines when operational is relatively constant, independent of the particular head of water in a single storage basin.

[34] The advantages of the arrangement of turbines at the boundaries of the intermediate storage basin 20 are built upon in the tidal energy system 1 by providing turbines between the sea S and the seaward storage basin 10. The turbines at the boundary between the sea S and the seaward storage basin 10 are arranged such that movement of water into the tidal energy system 1 from the sea S, or movement of water out of the tidal energy system 1 from the seaward storage basin 10 is arranged to drive said turbines. The turbines at the boundary between the sea S and the seaward storage basin 10 are mounted for movement relative to the water levels in the sea S and the seaward storage basin 10 to in use maintain a predetermined water level difference between input and output sides thereof as water moves into or out of the seaward storage basin 10.

[35] In the tidal energy system 1 each of the storage basins 10, 20, 30 is provided with associated reserve basins 101 , 201 and 301 respectively. The reserve basin 101 for the seaward storage basin 10 is arranged so that water may in use move between the seaward storage basin 10 and the reserve basin 101 for the seaward storage basin 10, and in the reverse direction. Similarly, the reserve basin 201 for the intermediate storage basin 20 is arranged so that water may in use move between the intermediate storage basin 20 and the reserve basin 201 for the intermediate storage basin 20, and in the reverse direction. Again similarly, the reserve basin 301 for the landward storage basin 30 is arranged so that water may in use move between the landward storage basin 30 and the reserve basin 301 for the landward storage basin 30, and in the reverse direction. The reserve basins 101 , 201 , 301 as shown in the tidal energy system of Figure 1 are provided in two parts, one on either side of the associated storage basin, but this is not essential to their operation as described below. However, the two part reserve basins 101 , 201 , 301 provide a degree of symmetry for the tidal energy system 1 and increase the flexibility and potentially an increased rate of movement of water.

[36] Further turbines are provided between each of the storage basins 10, 20, 30 and its respective reserve basin 101 , 201 , 301 , at dams 1 1 ', 12', 13'. These turbines are arranged such that movement of water into the reserve basin 101 , 201 , 301 from the storage basin 10, 20, 30 with which it is associated, or movement of water from the reserve basin 101 , 201 , 301 into the associated storage basin 10, 20, 30 is arranged to drive said turbines. As described in relation to the turbines between the storage basins 10, 20, 30, the turbines for the reserve basins 101 , 201 , 301 are mounted for movement relative to the water levels in the storage basin and the associated reserve basin to in use maintain a predetermined water level difference between input and output sides thereof as water moves into the reserve basin from the associated storage basin or out of the reserve basin into the associated storage basin.

[37] Further turbines are also provided between adjacent reserve lagoons, again as described in relation to the turbines between the storage basins 10, 20, 30.

[38] In the tidal energy system 1 a forward lagoon 40 is provided. The forward lagoon 40 is arranged seaward of the seaward storage basin 10 and serves to shelter the seaward storage basin 10. A permeable breakwater 41 and pontoons 42 provide protection from storms etc. while still allowing tidal flow to and from the seaward storage basin 1 1 . Similar provisions are made for the reserve basins 101 to provide corresponding lagoons 40' by use of a permeable breakwater 41 ' and pontoons 42'.

[39] The turbines as described herein are provided in a turbine assembly comprising an inlet/outlet on each side, and are operable so that in use movement of water through the turbine assembly in either direction drives the turbine. Furthermore the turbine assemblies include a rotary mount, wherein rotation of the rotary mount changes the level of the turbine. The turbine assemblies further comprise sluice gates operable to open and close to thereby control movement of water through the turbines.

[40] FIG. 3A-3D show schematic front views of a turbine assembly 50 and FIG. 4A-4G show a schematic side sectional view of the turbine assembly 50. FIG. 3A-3D and FIG. 4A-4G show the turbine assembly 50 in different configurations according to the operational configuration of the tidal energy system 1 as will now be described.

[41 ] The turbine assembly 50 comprises first, second and third turbines 51 , 52, 53. Each turbine 51 , 52, 53 has individually operable sluice gates that open to allow water to flow through inlets to the turbine or to close to interrupt the flow of water through the inlets turbine. By rotating the turbine assembly 50 the vertical position of the inlets to the first and third turbines 51 , 53 can be altered according to the water level in the basins at either side of the turbines. [42] The inlets are mounted such that movement of the first turbine 51 in an upward direction is accompanied by movement of the third turbine 53 in a downward direction.

[43] FIG. 3A-3D show how the sluice gates can be controlled in accordance with the rotational position of the turbines, which as indicated is itself in use dependent on the relative water levels between the inlet and outlets for the turbines. The wall of the dam 1 1 shown in the drawings is provided with sluice gates that allow drainage there-through. The sluice gates are shown as V- shaped notches, which may be covered or uncovered as appropriate.

[44] FIG. 4A-4G show the turbine assembly 50 in different configurations according to the operational configuration of the tidal energy system 1 during a complete tidal cycle. It will be appreciated that the angle of the turbine within the turbine assembly, or other characteristics thereof, can be adjusted according to the direction of operation.

[45] FIG. 6A-6M show schematic side sectional views of the tidal energy system of FIG. 1 by way of explanation of the operation of the tidal energy system during a tidal cycle. In these views the movement of water between storage basins, and the accompanying generation of electrical energy is indicated symbolically. It is also shown in these views, where appropriate, that water may be moved between storage basins using sluice gates to drain, or to/from reserve storage basins to drain/top-up the storage basins, and that pumping or drainage of water out of the system may be provided for.

[46] The method of operation comprises an incoming phase including the steps of:

(a) receiving incoming tidal water in the seaward storage basin;

(b) delivering water from the seaward storage basin to the intermediate storage basin; and (c) delivering water from the intermediate storage basin to the landward storage basin.

[47] The method further comprises an energy storage phase during which movement of water from one storage basin to the next is arranged to drive the turbine there-between, and wherein the turbines are moved relative to the water levels in the storage basins to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin to the next.

[48] The method still further comprises an outgoing phase including:

(e) delivering water from the intermediate storage basin to the seaward storage basin; and (f) delivering water from the seaward storage basin out of the system. [49] During the energy delivery phase, movement of water from one storage basin to the next is arranged to drive the turbine there-between, and the turbines are moved relative to the water levels in the storage basins to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin to the next.

[50] The method further comprises an intermediate phase between the incoming phase and the outgoing phase, the intermediate phase including:

(g) delivering water from the intermediate storage basin to the seaward and landward storage basins;

[51 ] During the intermediate phase movement of water from one storage basin to the next is arranged to drive the turbine there-between, and wherein the turbines are moved relative to the water levels in the storage basins to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin to the next.

[52] As is illustrated in FIG. 7, operation of the turbines of the tidal energy system of FIG. 1 during a tidal cycle can smooth the electrical output of the system over time. The left graph shows the tide level over time, superimposed over blocks of time during which turbines in the first dam 1 1 are operational. These blocks are extended in size, to cover the hashed additional areas in embodiments that use wave valves or other techniques to increase the amount of water captured in the seaward storage basin so that the level is greater than provided by the high tide. The right graph shows the tide level over time, superimposed over blocks of time during which turbines in the third dam 13 and second dam 12 are operational. These blocks alternate between the third dam turbines at hours 0-1 , the second dam turbines at hours 2-4 and so on in sequence. Forced or other drainage from the intermediate storage basin is shown in the second and fourth operation blocks for the second dam.

[53] The methods and apparatus described herein may increase efficiency in tidal energy systems and thus enhance the environmental and other benefits associated with generation of electrical energy by capturing energy from tidal sources.

[54] Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[55] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. [56] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[57] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[58] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1 A tidal energy system comprising: a seaward storage basin; a landward storage basin; and an intermediate storage basin between the seaward and landward storage basins; wherein: the seaward storage basin is in use operable: to receive and store incoming tidal water; to deliver water therefrom to the intermediate storage basin; to receive and store outgoing tidal water from the intermediate storage basin; and to deliver water therefrom out of the system; the landward storage basin is in use operable to: receive and store water from the intermediate storage basin; and to deliver water therefrom to the intermediate storage basin; and the intermediate storage basin is in use operable: to receive and store water from the seaward storage basin; to deliver water therefrom to the landward storage basin; to receive and store water from the landward storage basin; and to deliver water therefrom into the seaward storage basin; wherein a turbine is provided between the seaward storage basin and the intermediate storage basin and a turbine is provided between the intermediate storage basin and the landward storage basin, the turbines arranged such that movement of water from one storage basin to the next is arranged to drive the turbine there-between, and wherein the turbines are mounted for movement relative to the water levels in the storage basins to in use maintain a predetermined water level difference between input and output sides thereof as water moves from one storage basin to the next.

2. The tidal energy system of claim 1 , wherein a turbine is provided between the sea and the seaward storage basin, said turbine arranged such that movement of water into the system from the sea, or movement of water out of the system from the seaward storage basin is arranged to drive said turbine, and wherein said turbine is mounted for movement relative to the water levels in the sea and the seaward storage basin to in use maintain a predetermined water level difference between input and output sides thereof as water moves into or out of the seaward storage basin.

3. The tidal energy system of claim 1 or 2, wherein one or more of the storage basins is provided with an associated reserve basin, arranged so that water may in use move between the basin and its reserve basin and from a reserve basin to the storage basin with which it is associated.

4. The tidal energy system of claim 3, wherein a turbine is provided between a storage basin and its reserve basin, and wherein said turbine is arranged such that movement of water into the reserve basin from the storage basin with which it is associated, or movement of water from the reserve basin into the associated basin is arranged to drive said turbine, and wherein said turbine is mounted for movement relative to the water levels in the basin and the associated reserve basin to in use maintain a predetermined water level difference between input and output sides thereof as water moves into the reserve basin from the associated storage basin or out of the reserve basin into the associated storage basin.

5. The tidal energy system of any preceding claim, further comprising a forward lagoon arranged seaward of the seaward storage basin and wherein the forward lagoon is arranged to shelter the seaward storage basin from the sea by pontoons, a solid or permeable breakwater or the like while still allowing tidal flow to and from the seaward storage basin.

6. The tidal energy system of any preceding claim, wherein one or more of said turbines is provided as a turbine assembly comprising an inlet/outlet on each side, operable so that in use movement of water through the turbine assembly in either direction drives the turbine.

7. The tidal energy system of any preceding claim, wherein one of more of said turbines is provided as a turbine assembly including a rotary mount, wherein rotation of the rotary mount changes the level of the turbine.

8. The tidal energy system of any preceding claim, wherein one or more of said turbines is provided as a turbine assembly comprising sluice gates operable to in use control movement of water there-through.

9. The tidal energy system of any preceding claim, wherein one or more of said turbines is provided in a turbine assembly comprising two inlets on each side, wherein said inlets are mounted to move together in use according to the water level difference between input and output sides of the turbine assembly.

10. The tidal energy system of claim 9, wherein said inlets are mounted such that movement of one in an upward direction is accompanied by movement of the other in a downward direction.

1 1 . A method of tidal energy generation using the tidal energy system of any preceding claim, the method comprising an incoming phase including:

(a) receiving incoming tidal water in the seaward storage basin;

12. A tidal energy system or a method substantially as described herein, with reference to the accompanying drawings.