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Underwater Energy Storage Spheres

One of the biggest drawbacks of offshore wind is that often times it is producing too much for the grid to consume. The turbines are then shut down until demand returns. In addition there are times where demand for electricity is high and wind speed is low; relying on the conventional sources of power to make up the gap. According to a new report released by MIT, there is a way to make offshore wind power much more reliable, but utilizing a new concept in energy storage underwater storage spheres. These spheres would be constructed out concrete with 10ft thick walls and would also act as anchors for a floating wind turbine array. During times when grid consumption is low but wind power is high the turbines would run a pump that would drain the spheres. Then power can be produced by refilling the spheres, which then turns the pump in reverese actually sending power back to the grid. An 82ft diameter sphere could store up to 6megawatt hours of power. According to this release roughly 1,000 of these storage devices could supply as much power as a nuclear power plant for several hours. At an upfront cost of 12 million dollars per sphere they would be a little costly at first, with economies of scale though the cost could easily be brought to around 6cents per kwh, one that is more in line with current competitive utility pricing. The link to the paper published in IEEE is here.


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