The growth of renewable generation satisfies many goals: state and federal renewable portfolio standards, carbon reduction targets, new generation to meet demand and consumer interest in renewable energy. This growth is encouraging, with more than half of new proposed generation projects being renewable ones. However, some renewable intermittent sources such as wind and solar are still challenged with their dependency on the weather in order to generate. The time of peak production of wind power does not always match the time of peak use of electricity by consumers. Electricity storage technologies (PDF) can make the power generated by wind during off-peak times available to consumers during times when it’s most needed.

Inside the 1 megawatt AES Corp. battery trailer connected to the PJM grid

For example, companies within PJM are exploring the use of compressed air energy storage as a means to balance the availability of renewable energy, and lithium ion batteries are being piloted as a means to provide regulation service. Regulation service (PDF) corrects for short-term changes in electricity use that might affect the stability of the power system. It helps match generation and use.