Giant batteries plugged as new power supply

National Power has developed the technology to build giant rechargeable batteries that can store enough electricity to provide up to 500MW of power. The company is talking to a number of potential customers, including Railtrack, the Manx Electricity Authority and several US utilities. The technology will have wide-ranging applications for large-scale energy storage in power […]

National Power has developed the technology to build giant rechargeable batteries that can store enough electricity to provide up to 500MW of power.

The company is talking to a number of potential customers, including Railtrack, the Manx Electricity Authority and several US utilities. The technology will have wide-ranging applications for large-scale energy storage in power grids.

The Regenesys system converts electrical energy into chemical energy by `charging’ two liquid electrolyte solutions and releasing the stored energy when they are discharged.

At the heart of the system is a modular cell with two compartments, which the company’s engineers and specialist contractors have developed in three sizes: 5kW, 20kW and 100kW.

The two electrolytes flow through the compartments in the cell either side of an ion-exchange membrane where the electrochemical reaction takes place. Unlike most types of battery, economies of scale can be achieved by linking cells together with an electrode shared between two cells.

Stewart Male, technology manager for the project, said the only difficulty with the mass configurations required for plants of over 100MW was the number of connections between the cells: `Essentially what you’ve got is a plumbing problem.’

National Power also insists that its Regenesys system will have much lower lifetime costs than present options for storing power: hydro pumped storage or conventional battery plants.

Philip Johnson, general manager of the new business, said capital costs of £100 per kilowatt hour should be achievable now – compared with £500 per hour for other battery technologies. He said the costs should fall further with volume production.

National Power plans to build a 15MW facility at its Didcot site in Oxfordshire. This will cost £13.9m and have a storage capacity of 120MW/h. `It will be the largest plant of its kind in the world,’ said Johnson.

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