GB2309268A

GB2309268A - Tidal power scheme uses pontoons in locks between first and second storage basins to produce electricity

Info

Publication number: GB2309268A
Application number: GB9700736A
Authority: GB
Inventors: Roland Robinson
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-01-17
Filing date: 1997-01-15
Publication date: 1997-07-23
Also published as: GB9600890D0; GB9700736D0

Description

TITLE: Utilisation of tidal energy to generate electricity DESCRIPTION This invention relates to the utilisation of tidal energy, particularly for generating electricity.

Many attempts have been made to harness the energy of tidal water for the generation of power, particularly electricity, in order to reduce the consumption of fossil fuels. However, a major problem exists in that, due to the long interval of time between successive tides, the power generated is intermittent.

Various schemes have been proposed for extending the period of power generation in order to produce a continuous production of electricity.

The majority of schemes provide storage means for the tidal water which is released during the ebb of the tide. This creates an artificial head of water which is used to power turbines and thereby generate electricity.

For example, French Patent No. 485,043 describes a process for storing tidal water in adjacent reservoirs. Water is released from each of the reservoirs in turn during the ebb tide by the opening of sluice gates, the head of water thus created being used to power turbines and thereby generate electricity. German Patent No. 802,568 describes a system having a principal reservoir separated from the sea by a dam and an auxiliary reservoir behind the principal reservoir, being separated therefrom by a further dam.

Again, the use of sluice gates provided in the dams allows the flow of water between the adjacent reservoirs and the sea to be controlled and used to drive turbines to generate power. These types of systems have not proved successful due to a sufficient head of water only being achieved where there is a substantial rise and fall of the tide.

It is an object of the present invention to provide a system for utilising tidal energy for generating electricity, possibly allowing continuous power generation.

According to this invention there is provided a system for utilising tidal energy for generating electrical power, the system comprising a first water storage basin for receiving tidal water and a second water storage basin for receiving stored water from the first water storage basin, the first and second storage basins being connected by at least one lock having means for using the rise and fall of the water level therein to generate power.

The first storage basin is preferably alongside a tidal estuary, being separated therefrom by a sea wall. Preferably, sluice gates are provided low down in the wall to allow controlled entry of tidal water into the basin.

Preferably, the size of the basin is in the range of 75m x 25m to 150m x 75m, ideally being 100m x 50m.

The second storage basin is preferably alongside the tidal estuary upstream and on a higher level to the first storage basin. Preferably, the second storage basin is separated from the estuary by the sea wall.

Preferably sluice gates are provided low down in the sea wall to allow controlled release of the water from the second stage basin.

Preferably, turbines are positioned at points of outflow to enable electricity to be generated by the release of the water.

The at least one lock connecting the first and second water storage basin preferably has an inlet gate on the side of the first water storage basin and an outlet gate on the side of the second water storage basin. Preferably, the inlet and outlet are in the form of sluice gates which can be opened in turn to allow the filling and emptying of the lock with tidal water.

The means by which the rise and fall in the level of the lock is used to generate power preferably comprises a pontoon or barge secured to the base of the lock but able to float upwards and downwards with the change in level of water. Preferably, the pontoon or barge is attached to a rope, wire or the like which runs between two pulleys. Movement of the rope, wire or the like rotates the pulleys, the movement of which is used to drive a generator, thereby producing electricity.

It is to be appreciated that any number of locks, each with pontoons or barges, could be situated between the first and second water storage basins depending upon the amount of water available between the tides. Preferably, the locks are filled and emptied in sequence to produce a continuous generation of energy. Preferably, the gates of adjacent locks are opened at intervals, for example, of between six and ten minutes.

The sluice gates provided throughout the system are preferably operated at predetermined times by remote control. The opening and closing of the gates is preferably timed to the changing of the tide in order to produce optimum periods of continuous flow of water.

For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made by way of example only, to the accompanying drawings in which: Figure 1 shows schematically an electrical power generating system according to the present invention for utilising tidal energy; and Figure 2 is a schematic diagram of a longitudinal section of a lock of the type shown in Figure 1.

Referring to Figure 1 of the accompanying drawings, a sea wall 20 is provided alongside a tidal estuary. A first water storage basin 30 is provided behind a section of the sea wall and sluice gates 35 are provided low down in the wall to allow controlled entry of tidal water therethrough into the first water storage basin. Adjacent to the first water storage basin, and again being separated from the tidal estuary by the sea wall 20, are a series of parallel locks 40, 41, 42, 43 which each have inlets 12 in the form of sluice gates to enable controlled entry of water into the locks from the first water storage basin 30.

Each of the locks 40, 41, 42, 43 are provided with a pontoon 50, 51, 52, 53 which are fixed to the locks such that they remain in position but can rise and fall with water in the lock.

A second water storage basin 60 is provided adjacent to the locks, opposite to the first storage basin and on a higher level. Outlets 14 in the form of sluice gates are provided in the locks to enable controlled flow of water therefrom into the second water storage basin. The second storage basin is also separated from the tidal estuary by the sea wall 20 and has sluice gates 65 provided in the wall to allow controlled release of the water back into the estuary.

In operation, the sluice gates 35 in the section of the sea wall which separates the first water storage basin from the estuary, are opened by remote control means to allow water to enter the basin 30. Water continues to enter the basin until the tide level begins to fall at which point the sluice gates are shut to prevent water in the basin flowing back into the estuary.

When the tide reaches a predetermined level, the sluice gates between the locks 40, 41, 42, 43 and the basin 30 are opened by remote control means. Water enters the locks and causes the pontoons 50, 51, 52, 53 to rise with the corresponding rise in the level of water in the locks. The motion of the pontoons is coupled to a generator to enable the mechanical energy to be converted into electrical energy. It is to be appreciated that the series of locks can be filled and emptied in sequence to provide continual power generation.

Once a critical water level is reached in the locks, sluice gates 14 which connect the locks to the second water storage basin 60 are opened by remote control means. Water flows from the locks into the basin thereby causing a rise in the water level of the basin 60 but a fall in the water level of the locks. The pontoons 50, 51, 52, 53 fall with the corresponding drop in water level and again the mechanical energy produced by the motion of the pontoons is used to produce electricity.

The water that has entered the second storage basin 60 remains therein until the tide has fallen to a predetermined level. At this point, sluice gates 65 provided in the section of the sea wall separating the basin 60 from the estuary are opened by remote control to release the water. Turbines can be positioned at the points of outflow whereby the flow of water can be used to generate electricity.

Figure 2 of the accompanying drawings illustrates the mechanism for coupling the motion of a pontoon to the generation of power. The pontoon 50 is attached to a length of rope 73 which passes around a pulley P positioned at the top of the lock 40 and a pulley P' fixed to the bottom of the lock. The top pulley is provided with teeth which engages with a cog-wheel 77 which, via a series of further cog-wheels, drives a generator 79.

Each pontoon may be provided with a number of such ropes, pulleys and cog-wheels to increase the amount of power generated.

At low water levels the pontoon 50 lies towards the bottom of the lock 40. Water enters the lock from the first water storage basin 30 through the inlet 12 causing the floating pontoon to rise with the rising water level.

Movement of the pontoon causes a corresponding movement of the rope 73 around the pulley. The teeth of the pulley at the top of the lock engage with a cog-wheel causing the rotation thereof. A series of further cog-wheels drive a generator 79 which converts mechanical energy into electricity.

Once a critical water wheel is reached in the lock, the inlet 12 is shut and the outlet 14 opened. Water from the lock enters the second water storage basin 60 causing a fall in the level of water in the lock and a corresponding fall in the level of the pontoon 50. This results in a further movement of the rope 73 around the pulley which can be used to generate electricity as described above.

In this manner, electricity is not only produced by the conventional release of stored tidal water from the second storage basin but is continually produced by the filling and emptying of the locks. It is to be appreciated that a number of such systems may be provided to increase the power output, with the locks working in rotation to result in a more continuous power generation.

Claims

CLAMS

1. A system for utilising tidal energy for generating electrical power, the system comprising a first water storage basic for receiving tidal water and a second water storage basic for receiving stored water from the first water storage basin, the first and second storage basins being connected by at least one lock having means for using the rise and fall of the water level therein to generate electrical power.

2. A system as claimed in claim 1, wherein the first storage basic is alongside a tidal estuary and separated therefrom by a sea wall.

3. A system as claimed in claim 2, wherein sluice gates are provide low down in the sea wall to allow controlled entry of tidal water into the first storage basic.

4. A system as claimed in claim 2 or 3, wherein the second storage basin is alongside the tidal estuary upstream and on a higher level to the first storage basin.

5. A system as claimed in claim 4, wherein the second storage basin is separated from the estuary by the sea wall.

6. A system as claimed in claim 5, wherein the sluice gates are provided low down in the sea wall to allow controlled release of water from the second storage basin.

7. A system as claimed in any one of claims 1 to 6, wherein turbines are provided at positions of water outflow to enable generation of electricity by release of water.

8. A system as claimed in any one of claims 1 to 7, wherein at least one lock has an inlet sluice gate and an outlet sluice gate for filling and emptying of the lock from and into the first and second storage basins respectively.

9. A system as claimed in any one of claims 1 to 8, wherein the electrical power generation means comprises a pontoon or barge in the lock is able to float up or down with changes of water level in the lock.

10. A system as claimed in claim 9, wherein the pontoon or barge is attached to a rope, wire or the like which runs between pulleys to rotate same, rotation of the pulley being usable to drive an electricity generator.

11. A system as claimed in any one of claims 3 to 10 having remote control means for opening and closing sluice gates.

12. A system for generating electricity by using tidal energy substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.