A project set to take place off the coast of southern China will exploit the temperature differential in the sea to generate sustainable energy for a low-carbon leisure resort.
Designed by Lockheed Martin, the Ocean Thermal Energy Conversion (OTEC) pilot power plant is expected to fulfil the energy requirements of the resort being built by Beijing-based Reignwood Group.
To be located between 30 and 70km offshore, the Rankine cycle closed loop OTEC will pump warm water from the surface of the sea into a heat exchanger to vaporise anhydrous ammonia, the system’s working fluid.
The expanding ammonia vapour then drives a turbine coupled to a generator to produce electricity.
The vapour is condensed in another heat exchanger using cold seawater from below the surface to remove the heat. The working fluid is then pumped back to the evaporator to repeat the cycle.
Tim Fuhr, director of Ocean Energy, Lockheed Martin told The Engineer that cold water is likely to be drawn from a depth of 1,000m and that warm water would be pumped at a rate of around 45m3 a second.
Lockheed Martin developed the Mini-OTEC in the 1970s and has gone on to refine the technology further with the US Department of Energy and US Navy.
Fuhr said that at 10MW, the proposed plant will be largest of its kind developed to date and will demonstrate that it can be scaled up to build plants with greater capacity.
He said, ‘We believe our work in cold water pipe is scaleable, not only to go to the 10MW size OTEC plant…Our mutual goal with Reignwood is to then – in one step – scale up that technology to where you’re getting utility and large commercial scale OTEC of 100MW or above.’