Using lithium-ion battery storage to stabilize the grid

For many, using lithium-ion batteries to store energy has proven to be too expensive to be worth-while. This happens to not be the case for Chris Shelton of AES Energy Storage. Shelton, and AES, have been able to use groups of lithium-ion batteries to increase the flexibility of some mid-Atlantic power grids.

The company earlier this week said it has provided 400,000 megawatt-hours worth of frequency regulation services to the electricity grid in the mid-Atlantic states, a portion run by grid operator PJM. The battery–actually 16 connected batteries packaged in shipping containers–draws its energy from 61 mountaintop wind turbines in West Virginia with a capacity of 98 MW. That configuration consistently outperforms natural gas and coal power plants in providing the service, says Shelton. “It’s competing every day in getting selected and winning. It’s a commercial, scalable proof point that storage is economic,” he says.

Frequency regulation is one of those essential but invisible grid services that few people outside the utility industry are aware of. Electric current needs to be sent at a consistent frequency and when the amount of power that’s being pumped into the grid is out of sync with the amount of power that’s being consumed–essentially a supply demand imbalance–then service can be interrupted. Right now, fossil fuel power plants provide bursts of power into the grid to maintain that stability. Energy storage can perform the same task either by quickly absorbing or delivering power.

Even though lithium-ion batteries are still very expensive when it comes to energy storage, even with current technology, they have the ability to play a significant role in electricity storage and regulation while other, cheaper alternatives are developed.

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