he adoption of renewable energy on a large scale by utilities has been on hold, waiting for a breakthrough to solve the biggest problem for large-scale use: how to store energy produced by wind and solar power for those times when the wind doesn’t blow and the sun doesn’t shine? Without the ability to store excess energy from variable renewable generators during peak production times, utilities have been unable to deploy them on a commercial, financially viable scale. Grid-sized batteries have been tried, but they are expensive and have a short life span.