Storing energy produced during off-peak times is one of the challenges the renewable energy industry faces and which will be exacerbated as more intermittent forms of electricity generation enter the grid. One of the latest propositions to solve the problem has surfaced in the UK, via the Institution of Mechanical Engineers, who said that turning air into liquid may well achieve the feat. The technology is being presented today in London to an audience of academics, policy makers, industry bodies and developers.

The technology was developed by Peter Dearman, from Hertfordshire, who attracted IMechE’s attention for its ingeniousness (watch this video to find out more). The technology is being further developed by a company called Highview Power Storage, which was created test and scale up Mr Dearman’s technology.

There are four stages in the process. First the wrong-time electricity (such as the power produced by wind turbines during the night) is used to take in air, remove carbon dioxide and water vapor. Then the remaining air, mostly nitrogen, is chilled at -190C (-310F) and turns to liquid. This liquid air is kept in a giant vacuum flask until needed. Finally, as demand for electricity resumes, the liquid is warmed to ambient temperature. It will vaporize and drive a turbine to produce electricity, without any combustion involved.

Highview Power Storage says liquid air’s efficiency is not as good as current batteries in the market, but the appeal lies in the scalability of the technology. Besides, the technology around it is mature, making the capital expenditure much lower. Life expectancy is also longer. By siting projects next to power stations, the liquid air storage system can use waste heat from the stations and turn it back to electricity.

The UK government is keen to promote new ideas such as this to promote a low-carbon economy and will soon launch a scheme to incentivize new ideas in energy storage.

(Via BBC)

Watch the video about the liquid air pilot site in the UK:

What do you think? Does liquid air hold promise as an energy storage system?