The problem of excess energy storage might just have been resolved, as, according to the Institution of Mechanical Engineers (IMechE), liquid air is a strong competitor of batteries and hydrogen. Wind farms generate electricity at any time, therefore, when not used, this electricity can cool air to a cryogenic state. When needed, the air can be heated again in order to drive a turbine. The estimated efficiency of the process can reach up to 70%.
The idea for this technology belongs to an English garage inventor – Peter Dearman, who initially developed it to power vehicles. The process is now partly supported by the government and it will be trailed at a power station in Buckinghamshire.
In more detail, the process involves removal of CO2 and water vapour using the excess electricity. The remaining air, majority of which consists of nitrogen, is cooled and turned into liquid. This liquid is stored in vacuum containers and used when the demand for power rises. During the process of vaporization, it can be used to power the turbine and produce electricity.
IMechE officials state that this technique has the potential to boost the power generated by renewables. The process not only provides solutions for energy storage, but also can deal with the problem of waste industrial heat. Specialists at IMechE have estimated that although the efficiency of the technique reaches only 25%, when located next to a power station, the low-grade heath produced by the power plants can be stored and therefore increase the numbers drastically.
It is predicted that not long from now, batteries used to power electric cars might be used for household energy storage. However, as stated by the head of energy strategy for National Grid- Richard Smith, high importance should be given to alternative storage techniques, as they are of high demand. In addition, as John Scott from the Institution of Engineering Technology (IET) comments, currently the only storage medium in the UK is the pumped-hydro storage, which is highly limited to certain locations.
The Department of Energy and Climate Change (Decc) is now preparing a scheme to encourage innovations in energy storage.