One of the biggest challenges facing wind energy is intermittency. Wind often blows strongest when power demand is lowest, and weakest when electricity is needed the most. Because today’s power grid needs electricity to be consumed the moment it’s generated, that means wind turbines send energy to the grid half as often as an average coal plant. 

What if wind farms could store the power that isn’t needed right away and sell it later when demand is high? energyNOW! correspondent Patty Kim visited an energy storage system built alongside a wind farm in the heart of coal country. The full video is available below:

Wind energy has come a long way in the United States. It’s a multi-billion dollar industry that employs 75,000 people in 42 states and generates about 2 percent of the nation’s electricity. And, the Department of Energy says that number could grow to 20 percent of America’s electricity by 2030. 

That potential is far from reality though, mainly because of wind’s intermittent nature. In order to reach 20 percent, one in five new turbines will have to be built offshore where the wind is faster and more consistent, and offshore wind is stalled in this country. But intermittency is only a problem because the energy industry hasn’t come up with an efficient way to store electricity on a large scale – until now. 

A massive new battery storage system has sprung up in the heart of coal country, and it could change wind energy forever. AES Corporation, a global power project developer, has built a wind farm of more than 60 turbines spread across twelve miles of West Virginia’s Laurel Mountains. The farm generates enough power for 20,000 homes, and feeds power into the PJM Interconnection regional grid. 

But the really impressive aspect of this wind farm is a series of white shipping containers, nondescriptly nestled into the hills, containing 1.3 million lithium ion batteries. Each battery is about the size of a typical C or D cell, and together they provide frequency regulation to the grid. 

Grid operators at PJM send signals to the battery system every four seconds, telling it to either send the electricity generated by the wind farm onto the grid, or store it for later use when the wind isn’t blowing. “It’s a level of control over power that we haven’t seen,” said Praveen Kathpal, Vice President of Market and Regulatory Affairs for AES Energy Storage. 

The storage system technology is impressive, but for now, its impact is relatively small. The West Virginia project can only hold enough electricity at any one time to power about 5,000 homes for 15 minutes. “Projects like these are the beginning of a long wave of energy storage projects to come,” said Kathpal. AES is taking the next step in West Texas, where it want to build a second battery project, roughly three times larger than the West Virginia system.