Researchers at MIT may have found a new way to address one of the primary challenges of integrating off-shore wind power into the grid – its intermittency. The idea involves large spheres of concrete on the sea floor that would both anchor the turbines and provide energy storage. When there is an abundance of energy, water is pumped out of the spheres. Later, if energy is required and there is no wind present, water can be let back in through a turbine to generate electricity.  A sphere of 25 meters submerged in 400 meter-deep water could hold reserves of as much as 6 megawatt-hours. The weight of the spheres could also provide stabilization to the turbines. 
NRG Expert Analyst Edgar van der Meer, when asked for comment, noted that “this is an interesting idea, and one worth watching. If this technology becomes operational it could help improve the capacity factor of wind power and make it a more reliable contributor to the grid.”
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