Ann de Rouffignac
Tennessee Valley Authority (TVA) is considering building a fuel cell power plant that also stores electricity. The technology, owned by a unit of National Power PLC, the UK, has been in use since 1996 at a pilot plant in South Wales.
National Power said it will build the first commercial fuel cell power plant with storage capability near Cambridge, England, for $22 million. The plant can store 120 Mw-hr of electricity and produce 15 Mw of power at any one time.
TVA is interested in the technology because it’s an innovative way to store electricity for peak times. The federally owned and operated public power company is taking a “good strong look” at the idea, says Tim Meeks, TVA spokesman.
The new commercial plant planned for the UK will be constructed alongside an existing natural gas-fired plant and will provide electricity to the grid in the event of a shortage. It will be used mostly to shore up supply during times of peak demand.
The plant is designed to be capable of storing 120 Mw-hr of electricity. The technology called ‘Regenesys’ is an electrochemical process that operates like a rechargeable battery. It can store electricity when demand and costs are low and then release energy quickly when it is needed to meet demand.
The potential uses of such a plant include:
- An alternative to using power plants to ensure the grid at peak demand.
- An environmentally sounder alternative to using less efficient peaking plants.
- A more flexible and reliable source of renewable power.
- Provision of services that can maintain the grid, including frequency response, reserve, and voltage support.
National Power which owns the Regenesys technology will be split in October into two separate companies. Innogy will become the domestic UK business of National Power and will own Regenesys. International Power will be the global independent power business.
“The Regenesys technology should offer grid system planners a flexible means of storing electricity in bulk. This would allow better use to be made of a cleaner generating plant by reducing the need to operate less efficient peaking plant,” said Ross Sayers, executive chairman of Innogy in a statement.
Electricity storage is the “holy grail” of the electricity business. Any advances on the storage front could revolutionize trading of the commodity, says Ike Zeringue, TVA chief operating officer. Electricity is the only commodity that can’t be stored and sold or consumed later.
Industry observers warn that electricity storage may be possible technologically but still may not be economical.
“It’s all a question of costs,” says Paul Freemont, analyst with Jefferies & Co., New York. “The concept may be easy to do. The economics depend on the market prices for peaking power.”
Capital costs of the Regenesys plant are roughly twice the cost/kilowatt for a combined cycle plant, he says.