GB2424674A

GB2424674A - Generating electricity from flowing water, eg tidal currents

Info

Publication number: GB2424674A
Application number: GB0506776A
Authority: GB
Inventors: Clive Slocombe
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-04-02
Filing date: 2005-04-02
Publication date: 2006-10-04
Also published as: GB0506776D0

Abstract

Tethered paddles 1 are released and retrieved repeatedly from a fixed or floating platform 10 to capture the energy of flowing water, eg tidal or river flow. Each paddle 1 may be tethered by primary tethers 6 and a main tether 7 that is pulled off its storage drum to drive an electrical generator 8. At the end of each down stroke, the primary tethers 6 may be adjusted to align the paddle with the current so that its resistance is reduced while it is retrieved to the platform 10 by winches (13, fig.7). Each paddle 1 may have buoyant chambers 4 and adjustable control surfaces 2, 3. The paddles my be replaced by other devices eg collapsible parachutes. The retrieval winches may be replaced by a mechanism linking pairs of paddles so that a down tide paddle is used to retrieve an up tide paddle. In a further modification, pairs of massive paddles may operate in on direction over one tide then in the opposite direction as the tide reverses.

Description

TIDAJ. CURRENT GENERATOR The invention relates to a method and apparatus

for generating electrical energy from flowing water, typically a tidal current.

Many proposals have been put forward to harness the power of the Earth's sustainable resources to reduce our reliance on fossil fuels. Some have been successful, but none have managed to efficiently capture the force of the tides without the installation of major Civil Engineering works and the investment of vast amounts of capital.

The object of this invention is to provide electrical energy generation from tidal current flow.

Accordingly, this invention comprises a number of buoyant paddles whose structure and tethering to a stable platform allows them to be pushed in turn, in the same direction as the flow of the current, by the current, in a smooth and stable manner and then allows them to be pulled back to the platform using a powered winch, against the flow, with minimal resistance. Each paddle is linked by its tethers through a system of gears which transfers the power on the down stroke of the paddle to a generator, which itself is mounted along with the gearboxes on the stable platform located within the tidal current.

The orientation of the paddles in the tidal flow will be governed by the length of the primary tethers, these being controlled by the electronic operating system located on the stable platform, which will decide the setup for given conditions.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a front view of one paddle.

Figure 2 is a top view of a paddle.

Figure 3 is a side view of the invention.

Figure 4 is an enlargement of a portion of Figure 3.

Figure 5 is a side view of the invention at rest.

Figure 6 is a front view of the invention.

Figure 7 is a top view of the invention.

Figure 8 is a representation of one cycle of operation.

In this the first preferred embodiment of the invention, the power of the tide is captured by the force of the tidal current pushing against four paddles. Figure 1 shows the front view of one paddle in which a rigid body of the paddle (1) provides the necessary structural support for the buoyant chambers (4) and the tether attachment points (5). The structure of the paddle gives the necessary large surface area and variable buoyancy which allows the paddle to float in an upright and stable manner in the current and also allows the paddle to be installed and maintained. The angle of the horizontal (2) and vertical (3) control surfaces can be adjusted to vary the depth at which the paddle will operate and allow it to be steered to avoid collisions with other paddles Figure 2 is the top view of a paddle and shows the arrangement of the primary tethers (6) in relation to the main tether (7). At the end of the down stroke the primary tethers on one side of the paddle will be lengthened and those on the other side shortened so that the orientation of the paddle is inline with the direction of the current and will allow the paddle to be winched back to the platform with minimal resistance.

Figure 3 shows the invention in cross-section where the gearbox (9) and generator housings (8) sit on the stable platform (10). The stable platform is supported by a pair of multi-legged rigs (11) which are anchored to the sea bed (12). Figure 3 also shows the relative positions of two of the four paddles (1) at one point during their cycle, along with their primary tethers (6) and main tethers (7).

Figure 4 shows a portion of Figure 3 in more detail, the locations of the stable platform (10), generator (8) and gearbox housings (9) being clarified.

Figure 5 is a front view of the invention which shows the location of the four generators (8) and gearboxes (9) along the stable platform (10) and how this is supported by the rigs (11). The four paddles (1) and main tethers (7) are also shown.

Figure 6 is another side view of the invention similar to Figure 3 but with the paddles (1) filly wound in on their winches.

Figure 7 is a detailed top view of the invention showing the location of the primary tethers (7), retrieval winches (13), generator (8), gearboxes (9) and stable platform (10).

Having described the structure of the invention, what follows is a description of one cycle of operation for one of the four paddles as shown in Figure 8.

With the tide flowing from right to left, position 1 shows the paddle fully rewound on the main tether and orientated across the tidal flow. In this position the tidal force will push against the surface of the paddle and so result in the generator operating as the paddle moves down tide.

Positions 2 through to 5 shows the paddle moving with the tide, the main tether being pulled off its storage drum and resulting in electricity being generated. By position 5 the main tether is at its maximum length, at this point the direction of the paddle is changed by altering the length of the primary tethers to bring the paddle into the same orientation as the tidal current.

Position 6 represents this change which allows the paddle to be retrieved with minimal effort by the retrieval winch and is depicted in positions 7 and 8. By position 8 the paddle is again fully rewound and the orientation of the paddle is changed back to that shown in position 1 at which point another cycle begins.

When the tide flows in the opposite direction the cycle will operate in the same manner but the paddles will have been reversed. Reversal will be done by fully retrieving the paddles when the tide is not flowing and then releasing them and beginning the generation cycle when there is sufficient flow to push the paddles along with the tide.

Figure 6 shows two paddles fully retrieved and ready for the tide to begin flowing from left to right.

In a second embodiment of the invention, the number of paddles may be varied to any number which can be practicable operated in a given tidal current.

In a third embodiment of the invention, the paddles may be replaced by any other device which may be retrieved against the tide with less expenditure of energy than can be harnessed from the tide, for example a collapsible underwater parachute.

In a fourth embodiment of the invention, the retrieval winch may be replaced by a mechanism by which pairs of paddles are linked and the down tide paddle is used to retrieve the up tide paddle.

In a fifth embodiment of the invention, pairs of massive paddles may operate in only one direction over one tide and then in the opposite direction as the tide reverses.

In a sixth embodiment of the invention, the stable platform may be supported by a floating platform anchored to the sea bed.

In a seventh embodiment of the invention, the current may be provided by a river and the stable platform may be on or supported by the river banks.

Claims

An apparatus for generating electrical energy from flowing water in which the tethered paddles used to capture the energy of the flow are released and retrieved repeatedly from a stable platform, the orientation of the paddles being altered so as to achieve a net gain in energy over one cycle of operation.