Liquid air offers ripple of hope

Engineers have often been challenged as to how we might store energy. However, they may have come up with an effective solution - liquid air.

The Institute of Mechanical Engineers (IMechE) believes that liquid air can store excess energy that is generated from renewable sources. It claims that electricity generated by wind farms during the night can be used to chill air to a cryogenic state at a different location. This air can then be warmed at a later date and used to drive a turbine. The process could apparently achieve an efficiency of up to 70%.

Highview Power Storage was established in order to transfer inventor Peter Dearman's technology into an effective system in a process that was part funded by the Government and which has now been trialled for two years.

The process is as follows:

• renewable energy generated at night is used to take in air, remove the carbon dioxide and water vapour;
• the remaining air is chilled to -190C where it turns to liquid;
• that liquid air is held in a giant vacuum flask until needed;
• when demand for power rises, the liquid is warmed to ambient temperatures and as it vapourises it drives a turbine to produce electricity.

Dr Tim Fox, head of energy at IMechE said, "I get half a dozen people a week trying to persuade me they have a brilliant invention . . . In this case, it is a very clever application that really does look like a potential solution to a really great challenge that faces us as we increase the amount of intermittent power from renewables."

Dr Fox has also urged the Government to provide incentives in its forthcoming electricity legislation for firms to store energy with this and other technologies.