A Toronto company has developed a novel technology for storing excess electrical energy and retrieving it for use when needed. The concept, from a company called Hydrostor, aims to solve the problem of what to do with excess energy in the grid, while providing a way to retrieve that energy when needed, either hours or days later. The novel concept would allow an electrical utility to store its excess power for use at high-demand times like heat waves in the summer.
A press release describes how it works: “Surplus renewable electricity is used to drive a compressor that pressurizes atmospheric air to the pressure found at the sea floor offshore. The heat produced during compression is extracted from the air and stored in an insulated thermal reservoir. The air is stored in low-cost underwater accumulators, where the weight of the water keeps it at a constant pressure until required. When demand for electricity is again high, the system is reversed: The weight of the water forces the air back to the surface, where it collects the stored heat and drives an expander, reproducing approximately 70 per cent of the input electricity and releasing the air back into the environment.”
Note that the description specifies “renewable” electricity. The MaRS Cleantech Fund, which is providing venture capital for Hydrostor, is mandated to work with renewable energy companies and help them compete with the fossil fuel giants. One of two projects that Hydrostor has currently underway is with the national utility of “a Caribbean island.” The project will show, according to Cam Lewis, CTO and founder of Hydrostor, that we can store wind power at night and release it during the day, even doing away with the need for conventional back-up systems such as diesel-powered generators.
“Our project in the Caribbean will show renewables can compete directly with fossil fuels for island nations,” says Lewis. “By storing wind power at night and releasing it during the day, we turn wind power into something really useful. We can replace diesel generation today.”
What’s important about this development, economically speaking, is that the system is designed with “grid-scale technology,” meaning that it has the ability to store enough energy to “significantly impact” the electricity grid. This means that wind and solar developers will be able to bid on “base-load energy contracts,” says Murray McQuaig, a director of the Cleantech Fund. “We’ll be working with global partners, who can deliver large-scale energy projects, to bring this technology to market.”
How important is this market? According to Cleantech, the global cleantech sector is estimated to be worth between $2 and $3 trillion by 2020.