It will be the first emission-free compressed-air storage plant
With the global focus turning to green energy, compressed air storage plants are among the most promising emerging techniques, given that energy storage is essential when it comes to renewables. Their greatest benefit in comparison to home batteries is that they can store and provide power to entire communities and top up power grids when electricity is in short supply. The market for compressed-air treating equipment is expected to grow by more than 6%, reaching $11.2 billion by 2025.
Current technique
Up to now, the procedure involves excess off-peak electricity being converted into compressed air, which is then stored in underground caves of porous basalt stone when the demand is low. When the energy demand increases, natural gas is burned in order to heat the air that is then piped through turbines to generate power.
The innovative Hydrostor Terra system
The Canadian company Hydrostor Inc. is a global leader in Compressed Air Energy Storage (CAES), and last April it introduced Hydrostor Terra, a bulk energy storage system that takes advantage of the heat exchange process, without the use of natural gas. While compressing the air, the generated heat from the compressors is stored in a patented ‘adiabatic’ thermal management system, which heat cannot escape. When electricity is in short supply, it is simply released to increase the air temperature, in order to move a turbo-expander connected to a generator, creating electricity. The Terra system can be deployed at any site within proximity to a body of water, including inner-city and urban areas.
"Hydrostor Terraâ„¢ is an industry-changing breakthrough in cost-competitive bulk energy storage," says Curtis VanWalleghem, President & CEO of Hydrostor. "We are engaged with several utilities around the world to deploy systems rated at hundreds of megawatts, delivering GWh of storage at durations ranging from 4 hours up to multiple days." He added that the market response to Terraâ„¢ was tremendously positive, as "battery technologies can't compete with new natural gas plants, but Terraâ„¢ does. The value proposition for utilities is compelling, and for us that's translating into projects."
Its efficiency
According to the Energy Storage Association, adiabatic compressed air systems can be up to 70% efficient, and Hydrostor suggests its system can reach approximately 60% efficiency. Diabatic systems with natural gas burning on the other hand, have an efficiency of 42-54%.
The new 7MWh plant
A new 7MWh compressed-air storage plant is approved to be built in an abandoned salt cavern in Goderich, Ontario. The cavern is located on property owned by Compass Minerals in a mine located 550 metres under Lake Huron – the largest underground salt mine in the world. It is expected to be operational by May 2018 and although there are similar projects in Germany and in US, it will be the first plant of its kind as it will be completely emission-free. Apart from this 1.75MW, 7MWh A-CAES system in Goderich, Hydrostor is also contracted to build another 1MW, 6MWh system in Aruba.
