LightSail Energy aims to power cities with compressed air

 
 

Danielle Fong, the brain behind the innovative energy storage solution developed by LightSail Energy, believes that in much of the world, the most affordable sources of energy are the ones that are green too. However, with little or expensive energy storage solutions, primarily batteries, the cost of produced energy goes well beyond the price quoted by conventional energy generating plants. To reduce the cost of renewable energy Fong at LightSail Energy has come up with an innovative solution – storing excess renewable energy during off-peak hours in compressed air and reversing the process during peak conditions.


Storing energy as compressed air isn’t new, but most systems lack scalability or lose too much of energy during the storage process. The idea is simple, when renewable energy generation is at its maximum but the demand for energy is low, utilities can use energy to power pumps to compress air. However, during this compression, air temperatures can reach up to 1000 degrees Celsius, and hence a majority of the energy is lost as heat. LightSail Energy aims to better the credentials of this form of energy storage by spraying water on air during the compression. Water cools down the air and heats up, and heat can be harvested from water bringing down the energy losses. The process is just as efficient as the best batteries and for every 10kWh of electricity that goes into the system, 7kWh can be used when needed.

The invention has its share of associated challenges as well, the first being the development of a system which can filter out water from the highly compressed air and the second is the development of a system that can compress air as well as expand it to drive a generator when need be. LightSail met those challenges with a compound which can be used more efficiently than steel to make compressed-air storage tanks. Moreover, the turbine developed by the firm doesn’t need to run at a constant speed to get effective compression, making it ideally suited to be employed at renewable energy power plants.

A single system about the size of a standard shipping container along with a car-size unit will be able to store to store energy generated by a one-megawatt wind turbine running for three hours. Fong states that there are no technical barriers in the development of large scale units that will be able to power entire cities with energy stored from renewable sources.  The first system is expected to be ship in late 2013 or early 2014.

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