This theory is going to be put into practice this year, by attaching a machine such as the Ocean Treader to an Offshore Wind Turbine, to create a full size prototype named the Wave Treader. This wind/wave power mash-up can generate up to 500KW, enough to power 125 average homes. The device will probably be available on the market by 2011, after the Feasibility Study will be cleared.
The concept device uses sponsons which will react through an interface structure onto the foundation of an offshore wind turbine. Between the arms, that hold the sponsons, and the interface structure, hydraulic cylinders are mounted. As waves move the machine, the sponsons rise and fall stroking their hydraulic cylinders. They will drive a hydraulic motor which in turn drives an electricity generator. The electricity is then transported through the cable shared with the Wind Turbine. The interface structure can move vertically if tides are high and also rotate to ensure that the sponsons are optimally aligned with the wave direction.
Wave Treader will have no affect on the stability of the wind turbine as additional loads placed on the foundation are relatively small.
Reliability of the device is a key feature. It has an overall design life of 25 years with refits every 5 years. All the hydraulic and electrical equipment will have to be built as per the marine industry standards specifications, with experienced and skilled personnel. The system will be designed in such way that if one of the energy producing parts will fail, the other one will continue producing energy on its own.
The Wave Treader is said to produce over 500kW. I know the energy output over a period of 5 years would be immense, but the ocean is a very unstable environment. It remains to be seen, if this project gets green light, if the maintenance costs don’t outweight a reasonable percent of the energy produced by one unit. Anyway, nice machine!