GB2429045A

GB2429045A - Tidal power station

Info

Publication number: GB2429045A
Application number: GB0516660A
Authority: GB
Inventors: Leslie Norman Bailey
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-08-13
Filing date: 2005-08-13
Publication date: 2007-02-14
Also published as: GB0516660D0

Abstract

A tidal power station or island driven by vertical tidal movement for the production of electricity. The island comprises of at least one unit containing an artificial tide created from the natural external tide by allowing a flow of water to pass through control valves. Inside each unit the vertical tidal movement is converted into mechanical energy using a machine comprising of a buoyant vessel driving a gearbox by means of a connecting device. Units can be synchronised such that each is either: 1) sealed, allowing the storage of potential energy as there is no change in the internal tidal height despite the external change; 2) with the valves allowing a steady flow of water into the tank, so that kinetic energy is created by the generation mechanism. A power island will therefore create electricity constantly, even when the natural tide is virtually static.

Description

I

TIDAL POWER STATION

This Invention relates to a tidal power station.

Tidal power is currently used as a source of energy generation. The method of turbines mounted in a barrage is well known, but is limited in several respects. It is highly desirable for power to be generated with a controlled output, 24 hours per day, which this system cannot achieve.

Also these systems are inherently destructive, effectively turning a free running river into a stagnant lake, destroying the ecological system in the process.

This invention relates to an unobtrusive island, which can be situated in any tidal location, with greater tidal rise resulting in higher output levels, assuming the standard sine curve model for tidal change. It relies solely upon the change in height of tide, rather than any bi- product of this change.

The structure works with one or more docks, or tanks. The tank houses a float, which using an arm and shaft arrangement drives a gearbox. The internal tank is completely isolated from the outside environment, therefore making the internal tidal level completely controllable. It is necessary to control the internal tide level, since the rate of change of the height of a natural tide is not constant, therefore making it extremely limited as a means of electricity generation.

Figure 1 is a side elevation of the unit at low internal tide Figure 2 is a side elevation of the unit with maximum internal tide Figure 3 is a plan view of the unit Figure 4 is a front view of the unit at low internal tide Figure 5 is a perspective view of the unit during operation To allow water 3 in or out of the tank I one or more valves 2 or gates can be opened; these valves control water flow X between the structure and the external tide. The control valve is situated at the base of the tank, such that the flow of water is in the same direction as the movement of the float. A regulator, part of the gearbox unit 6 controls these valves, to allow a constant electrical output, by maintaining a constant flow of water into the tank. When the tank is empty and an external head of water is present, the control valve can be opened to allow water to flow into the tank. The rising internal tide Y forces the float to rise, which drives the float arm 5 fixed to the float by brackets 11, in an upward rotational motion. The float arm 5 turns the gearbox driveshaft 9, supported by bearings 10. The gearbox drives an alternator 7which generates electricity.

The gearbox required in this invention is based on a gearbox with a reverse gear. This enables the alternator to run in the same direction, when the float is moving both up and down. When the internal tide is at maximum height as in Fig. 2 the reverse gear is selected.

The float is a vessel comprising of a purely buoyant component 4 beneath a ballast tank 8.

When the internal tide is at maximum height Fig. 2 the ballast tank is filled with water, which creates a downward force on the float, due to the weight of the water. It is this force that is employed to drive the gearbox as the float follows a downward rotational path. When the float has returned to the point of lowest internal tide, valves on the ballast tank open. The ballast water then drains from the ballast tank into the main tank.

For optimum results an example enabling 24 hour power generation, a multiple tank method must be employed. The preferred embodiment of this invention is the dual tank method, whereby two tanks are used to produce a continuous electrical output throughout a tidal cycle.

Figure 6 is an illustration of how two tanks can be situated in the same island for optimum performance.

Figure 7 is a demonstration of how the tanks will be used together to create a constant supply of electncity. It shows how the height of the internal tide in the tanks A and B vary compared with that of the external tide. It is assumed that the Sine curve is an accurate model for the variance in natural tidal height.

This method allows the purpose of the tanks to alternate between the creation of kinetic energy and storage of potential energy. If the valves of a tank are closed, then the internal tide level must remain constant. As the natural tide outside the environment changes, potential energy is being created within the sealed tank, purely as a result of its maintained tide level. When the valves are opened the artificial tide level will adjust to meet the natural tidal level, which transfers the potential energy stored in the tank into kinetic energy, through the movement of the float. Kinetic energy will be produced whether the float moves up or down, so this method will work equally, whether the tank is sealed at its lowest or highest tide.

External to the tank is a series of turbines 12, which harness the energy of the external flow of water 16 to drive a water pumps (connected to the turbines but not illustrated). This pump fills a header tank or container 13, situated at the top of the island. When the internal tide is at maximum height, this container releases water into the ballast tank through outlet pipes 14.

The rate of flow of water passing through the valves can be regulated to extend the duration of the adjustment process, thereby allowing the generation of electricity to be consistent.

When the external tide is at the lowest point, the valve 2A in tank A is closed, and the valve 2B in B is open. At point I valve 2A is then opened, and allows a regular controlled flow of water into the tank, valve 2B is closed.

Valve 2A is then closed at point 2, holding the high internal tide inside the tank. At point 2, tank B contains its lowest internal tide. The external tide is high however, so when valve 2B is opened, this tank fills up regularly, reaching its high tide point at point 3.

At point 3 Valve 2B is closed, and valve 2A is opened, allowing the tide level to drop between points 3 and 4, since the external tide height also drops.

At point 4 tank A is at its lowest internal tide, and valve 2A is closed. Tank B is at its highest internal tide point and valve 2B is opened, allowing the tide in tank B to drop to its lowest point.

Claims

I A unit for creating mechanical energy by the control of vertical tidal movement within an artificial environment using a machine comprising of a buoyant vessel driving a gearbox by means of a connecting device.
2 The creation of internal tide for use according to I with the use of regulated control valves, which connect the artificial and natural tides.
3 The synchronisation of multiple units according to 2 whereby: the valves of one or more units are closed to create a static internal tide level, whilst the external tide level naturally changes, creating potential energy; the tide level in any other unit is allowed to change such that it creates kinetic energy.

3 The synchronisation of multiple units according to I whereby: the valves of one or more units are closed to create a static internal tide level, whilst the external tide level naturally changes, creating potential energy; the tide level in any other unit is allowed to change such that it creates kinetic energy.

Amendments to the claims have been filed as follows

I The creation of an internal tide for the purpose of energy generation, with the use of regulated control valves, which connect the artificial and natural tides.

2 A unit for creating mechanical energy by the control of vertical tidal movement within artificial environment above, using a machine comprising of: a buoyant vessel driving a gearbox by means of a connecting device.