A Giant, Man-Made Island Could Act as a Battery for Wind Power


This is an entry in my series on Denmark's myriad efforts in the climate and clean energy arena, and why they seem to work. I'm trying to find out if Denmark-ifying societies around the world might stop climate change ... Images courtesy of GreenPowerIsland.dk

Yesterday, I reported that Denmark may one day rely primarily on wind power -- an energy source that's all but impossible to use as a baseload. So the nation is looking to ensure that when the wind isn't blowing, the lights don't go off. Distributing that power between neighboring nations is one solution, but there's another, more radical option as well: Using a giant, man-made island to act as a battery. It's called Green Power Island. The idea was announced last year, and the Danish researcher at Riso DTU notes that the concept is still under development. But it's still very much that: a concept.

Earth Techling explains how it would work:

The Green Power Island makes use of pumped hydro, a storage strategy that's already in wide use. Conventional pumped hydro systems use vertically separated reservoirs to utilize the power of water and gravity; during times of low demand (off peak), water is pumped using excess energy from the lower to the upper reservoir. As demand increases, the water is allowed to flow downhill into the lower reservoir, generating electricity in the process ...


Paludan has taken this strategy and given it a new twist ... His design makes use of seawater pumped into a lagoon-like reservoir built into an artificial island. When demand is low, pumps driven by wind turbines empty the reservoir. At peak periods, water is allowed to flow back into the reservoir, through turbines generating electricity to meet the rising demand. By positioning the reservoir within an existing body of water, the system removes the necessity of having to create two reservoirs at different heights.
Similar systems already exist, of course. France, for instance, uses energy generated from its nuke plants during low demand hours to pump water up a hill, and releasing it during peak hours.

Whether or not we see massive wind power batteries built into artificial islands off the coast, such designs make clear that storage solutions are out there -- and that it will indeed be possible to power societies entirely on renewables, as Denmark intends to do.

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