Whilst there now seems to be countless ways of generating energy (biogas, wind, solar, nuclear, fossil and so on) one of the great challenges that faces emerging forms of energy generation is how to store it. Case in point; the electric car industry has quickly discovered that the dream of a ‘green’ car is tainted by the carbon footprint left by producing the battery that powers it.
So, how does a commercial electricity body store up energy that’s produced in times of plenty for when it’s most needed? The answer, as it turns out, could be all around us.
The Institution of Mechanical Engineers says that turning air into a liquid form could provide a viable solution. Originally developed by Peter Dearman, a garage inventor in Hertfordshire, IMechE says excess electricity generated by wind farms at night can be used to chill air to a cryogenic state at a distant location.
Then, during times when there’s little-to-no wind, the air can be ‘warmed up’ again to power a turbine, providing power when it’s needed most – something that engineers say can increase the efficiency of traditional wind-power by 70%.
Liquid Air – or Cryopower as it is quickly being dubbed – has been part-funded by the British government, and has actually been trialled successfully in the back of a power station in Slough, Buckinghamshire.
Tim Fox, head of energy at IMechE told the BBC, “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.”
Liquid Air Energy – Not Just Hot Air
In terms of it’s applications for commercial energy, Dr. Fox has urged ministers to prove incentives for energy firms to store energy on a commercial scale with this and other technologies – claiming that many will find the elegance of the process worth the investment, as it also negates the issue of waste industrial heat.
How Does it Work?
- “Wrong-time electricity” is used to take in air, remove the CO2 and water vapour (these would freeze otherwise)
- The remaining air, mostly nitrogen, is chilled to -190C (-310F) and turns to liquid (changing the state of the air from gas to liquid is what stores the energy)
- The liquid air is held in a giant vacuum flask until it is needed
- When demand for power rises, the liquid is warmed to ambient temperature. As it vaporizes, it drives a turbine to produce electricity – no combustion is involved