Grid-scale electricity storage can improve reliability of the grid, lower wholesale electricity costs, enable Smart Grid concepts and support renewable energy sources.

The growth of renewable generation satisfies many goals. However, some renewable intermittent sources such as wind and solar are 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. One way to address the issue of intermittency is through grid-scale storage. Electricity storage technologies (PDF) can make the power generated 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

There are many different forms of bulk energy storage. For example, across the U.S. there are a number of pumped-hydro storage facilities. Today, this is the most mature large-scale storage technology in operation. However, the length of time to site and build a pumped-hydro facility and the necessary topography and geology, among other factors, limit both the expansion and immediacy of this resource. The largest pumped storage facility in the U.S. is located in the PJM region.

PJM sees firsthand the power of energy storage through a number of advanced technology pilot programs with our member companies. 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.

Flywheel technologies also are being developed and tested to provide options for regulation service. This technology involves the use of a rotating flywheel to store energy.

Watch a video to explore further the alternative energy projects going on within PJM, including the latest developments with lithium ion batteries and plug-in hybrid electric vehicles.

Another pilot underway on the PJM campus demonstrates how thermal storage can participate as demand response in PJM’s energy and regulation markets. An oversized 105-gallon electric water heater, with 26 kWh of storage, shows the potential to minimize the cost of operation by responding to the PJM wholesale energy price signal and shows revenue potential by responding to the PJM frequency signal. Watch a video to learn more about how the water heater works.

Innovative storage technologies are one way grid operators and utilities intelligently integrate renewable resources into grid operations. It’s through a combination of solutions that the electricity industry will enable greater amounts of renewable resources to be integrated in the most efficient manner and with the least amount of risk.

Visit PJM’s Exploring Tomorrow’s Grid for the latest developments and technologies to advance the grid.