The O.H.E.G. Flow Diagram shows the three power generating systems used in the plant…
" Tidal Turbines, located within the main channel.
" Chamber Turbines, located within the walls of the chambers.
" Accumulators, located within the chambers.
The flow diagram shows power being transmitted to the generator through a balancing system, containing a compression vessel and header tank, this ensures that the generator receives a constant supply of hydraulic pressure throughout the whole tidal sequence. Automated valves, hydraulic motor and gearbox have been omitted for clarity.
The tide floods into the channel, increasing in velocity as it flows through the venturi inlet. This drives the tidal turbines, creating a hydraulic pressure in the system which feeds the compression vessel. The compression vessel in turn feeds the generator.
As the tidal turbines stop producing power the chamber turbines are opened allowing water to flood into the chambers. The hydrostatic head drives the chamber turbines as the water flows into the chambers. The accumulators are submerged, locked into position by the hydraulic cylinders.
As the chamber turbines stop producing power the accumulators are allowed to rise. Chamber turbines are closed, trapping water within the chambers. The upward buoyancy force acting on the accumulator creates power in the downward facing cylinders. The upward facing cylinders recharge with hydraulic fluid, which is drawn from the header tank. As the accumulator reaches the top of its stroke the tide begins to ebb and the process repeats itself in reverse, starting with the tidal turbines.