Electricity ‘warehouse’ makes alternative energy more viable

Energy: New storage system will make wind and wave power more competitive

Remember those National Power adverts with the electricity boxed as if it were washing powder? Scientists at Swindon-based power technology company Innogy, soon to be de-merged from National Power, have developed Regenesys, a technology which they claim will make electricity as storable as soapflakes.

The Regenesys system is based on regenerative energy cell technology, in which electrical energy is converted into chemical potential energy by charging two liquid electrolyte solutions, made up of sodium bromide and sodium polysulphide salts, via inert electrodes, and then releasing the stored energy on demand. The charged potential of a single Regenesys cell is only 1.5V, no more than a normal small battery, but stacking many cells together in series allows higher voltages to be generated. Further modules can be added in parallel to provide the required power.

The system is capable of =storing 5-500MW from durations of a few seconds to over 12 hours, with a cell lifespan of 20 years. David Trelfall, director of Regenesys, said: ‘We like to think of this as an electricity “warehouse” rather than a giant rechargeable battery. Just like a warehouse it will allow generators to put electricity in when the price is low and to sell it again when the price is high.’ The ability to store large quantities of energy for long periods may transform the economics of alternative energy, such as wind or wave farms. At present, these sources can only provide sustained amounts of electricity when conditions are constant, preventing them bidding to supply power at lucrative peak times. Being able to store electricity in this way could also end the need for the centrally operated National Grid. Smaller distributed generating plants could become more economic as storage facilities and small-scale generating stations would only need a small cable network to deliver electricity to their local users.

The first energy warehouse is being built in Little Barford in Cambridgeshire where it will work in conjunction with the Little Barford combined cycle gas turbine power station. The warehouse will begin to operate in February 2002