Compressed Air for Energy Storage

Energy storage is the new technology for green companies who are keen on developing renewable energy sources. Energy from wind turbines and solar farms are then collected when they are at their most productive to be used later when it is needed. Nova Scotia, for example, is a good candidate for energy storage since most of its wind energy is produced at night but the higher demand is during the daytime.

Experts are now looking at compressed air to do the job. Various companies are already developing the technology. For Hydrostor, a company in Toronto, large inflatable balloon-like bags called "flexible accumulators" are used to store the compressed air 50 to 500 meters underwater. An underwater transmission line transmits excess power to an offshore floating platform. During the compression process, heat produced is stored in the platform. To recover the stored energy, air is released which then pushes upwards and drives a generator. An estimated 70 percent of the energy is recovered. The Hydrostor model is set to produce 1 MW/4 MWh.  Although cost-effective, the problem with pumped hydro is that it only work for cities located near bodies of water. A California-based company, LightSail Energy is now working on grid-scale storage which is as cost-effective and efficient as pumped hydro minus the geographic restrictions.

Now, Watts Wind Energy Inc. has partnered with LightSail Canada Inc. of Halifax to conduct trials on their compressed air system in Nova Scotia. Electricity from wind turbines will be converted to compressed air and stored in metal tanks. A generator is then used to turn the energy back to electricity when it is needed.

Nova Scotia is said to be an ideal place for energy storage development because of its stringent policies on renewable energy and its wind and in-stream tidal potential. Other tests are set to be carried out in Digby and Cape Breton. Batteries and compressed air are considered for the pilot testing in Digby while the testing in Cape Breton will involve the use of pumped hydro.

General Compression, another company working on energy storage, is also developing a system to store compressed air in underground caves and old mines.

Energy storage is set to become a crucial component of Canada’s energy industry. It currently ranks sixth globally insofar as total installed wind capacity goes, according to a report released recently by Industrial Info Resources.