BBC NEWS - Turning air into liquid may offer a solution to one of the great challenges in engineering - how to store energy.
The Institution of Mechanical Engineers says liquid air can compete with batteries and hydrogen to store excess energy generated from renewables.
IMechE says "wrong-time" electricity generated by wind farms at night can be used to chill air to a cryogenic state at a distant location.
When demand increases, the air can be warmed to drive a turbine.
Engineers say the process to produce "right-time" electricity can achieve an efficiency of up to 70%.