Five Ways Companies Can Store Renewable Energy for the Grid

Even the best lithium-ion batteries stink at storing the large amounts of electricity a massive wind or solar installation is capable of generating. They’re expensive and hold, at most, about four hours’ worth of that grid-scale juice. Here are five potentially less costly—if somewhat Rube Goldberg-y—methods companies are trying to store power as potential energy in other forms, smoothing out renewable energy’s peaks and valleys.

Hydrostor Inc. in Toronto expends grid power to compress air, which it pumps underground for storage, with a column of water keeping it compressed. Abating the pressure allows the air to decompress, releasing its energy to drive turbines on the surface for 24 hours or more. Hydrostor has two demo plants in Canada and others slated for development in the U.S., Chile, and Australia. Chief Executive Officer Curtis VanWalleghem says Hydrostor has raised $30 million and expects to double that this year.