A company called Xcel Energy is looking to store excess wind energy from utility scale turbines inside of batteries, very large batteries. In fact, the batteries for testing are so large they are about the size of two semi-tractor trailers stack on top of each other.
There are times when the wind blows so hard for so long that without a storage system the wind turbines will have to be shut down so that too much power is not going to the grid. Storing the excess wind energy in some sort of battery system also allows the energy to be put back on the grid when the wind isn’t blowing hard.
The Xcel batteries can store enough energy to supply electricity to 500 homes for seven hours if need be. As the battery technology is expanded so will this capacity. Xcel is also investigating storing the excess wind energy as compressed air deep underground.
When needed the air will be brought to the surface, combined with natural gas and turn some turbines to create energy. Another method for storing excess wind energy that this company hasn’t talked about is hydrogen.
Some wind farms are investigating the viability of using excess wind energy to electrolyze water into hydrogen and storing it. When more energy is needed on the grid the hydrogen can be run through a fuel cell to provide this.
And one other idea that comes from the solar energy sector is storing excess wind energy as molten salt. The energy could be turned into heat and stored large pools of molten salt for later use. Of course, this method when used with wind turbines may require more energy output than batteries, compressed air, or the hydrogen storage methods.
No matter what, though, the wind to battery idea seems to have merit in the testing conducted so far. The winning wind technology may come down to economics so we’ll have to wait and see a bit who pulls ahead in this race.