A Belgian politician is proposing an unusual way to store intermittent renewable power from the nation's offshore wind turbines: build a hole in the ocean, then let it fill up to generate electricity. Johan Vande Lanotte, Belgium's Minister of Economy, Consumer Affairs and the North Sea, is proposing his government build a nearly two-mile-wide island off the coast of Flanders with a seawater reservoir to store surplus energy from Belgian offshore wind turbines for later use.
Despite the grand scale, the concept is fairly simple. The island would be atoll-shaped, with a 100-foot-deep lined reservoir in the middle, and a seagate with generating turbines connecting the reservoir to the open sea. When the wind is blowing, excess power from wind turbines would be used to pump water out of the reservoir into the ocean. When the wind dies down and extra power is needed, the seagate would be opened to allow seawater to flow back into the reservoir, generating electricity as it flows.
"The big advantage is that with such an energy storage depot we can supply wind power at peak times," says Vande Lanotte. "You can also save electricity produced on land, and we intend to examine the possibility of selling electricity to other countries."
The island would be located within transmission cable distance of Britain.
Obviously, given the project's scale and likely expense -- not to mention potential environmental impact -- it will take some time to implement the plan if it's approved. Nonetheless, government and businesses are taking the idea seriously, with dredging and construction firms, wind companies, and the nation's electrical utility forming a consortium to plan the storage project, possibly within the next seven years.
It's an interesting idea, with obvious potential applications in California. Our state is no stranger to pumped storage proposals, many of them involving scarce fresh water in abandoned desert mines, with obvious resulting problems from habitat alteration and evaporation. It's unlikely the prospect of building a large energy storage island off the California coast will gain much traction, given the state's strong environmental laws. Still, it may be that some modified form of the project -- deep coastal shaft reservoirs, or managed wetlands with wildlife habitat -- might work along the already altered portions of the California coast.
Which is, after all, where the energy demand is.