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NREL Tests Energy Storage System to Fill Renewable Gaps

April 24, 2017

Solar energy generation, which is driven by weather, is a variable resource that can be difficult to integrate into the grid. But adding on-site energy storage can fill in the gaps in solar generation and reduce the uncertainty that comes from the ever-changing weather.

A 1-megawatt energy storage system from Renewable Energy Systems (RES) Americas will assist research that aims to optimize the grid for wind and solar plants. The system arrived at NREL’s National Wind Technology Center (NWTC) in March 2017 and will connect directly into the power grid through the NWTC’s controllable grid interface.

RES Americas and NREL will use the RESolve energy storage system to test advanced controls for integrating battery energy storage with renewable energy systems. As part of that testing, the storage system will be integrated with a nearby 400-kilowatt photovoltaic system to provide a consistent energy output.

“A key piece of solving the grid congestion problems is the addition of storage,” says Project Manager Mark McDade. “We’re learning how to use storage as a dispatchable resource,” he says.

NREL researchers will use the RESolve system to interpret a range of information—from analyzing the performance of individual battery cells to understanding how storage can be controlled at the grid level. Testing frequency regulation, renewable energy integration, and seamless grid-to-island transitions will lay the groundwork for a large-scale rollout of the technology.

When dispatched widely, this storage system—which allows controllers to respond to a command in 200 milliseconds—could be “very leading-edge,” McDade says. The RES system can react immediately to a lull in energy intake, taking only a few electrical cycles to respond and allowing the plant to provide advanced energy services to the grid.

Then, the weather can do as it pleases—without affecting the productivity of solar plants.