Utility-scale battery solutions facilitate the integration of renewables from several fronts. First, they can help cope with the variability of renewables by storing energy in cases of excess generation, avoiding curtailment and supplying electricity to the grid when resources are scarce. Second, they are flexible and fast-responding technologies that help to maintain the balance in the system when sudden changes occur. In addition, using batteries to reduce congestion in the grid is also an emerging solution for some transmission system operators.
Illustration Photo: Portland General Electric's Salem Smart Power Center includes a large-scale energy storage system. (credits: Portland General Electric / Flickr Creative Commons Attribution-NoDerivs 2.0 Generic (CC BY-ND 2.0))