Can US fast-track vital energy storage?

Utility companies have long been in the business of generating energy, but storing energy is another matter. We could soon start seeing that change, though, as electricity utilities begin rolling out a number of stimulus-funded energy storage projects across the US.

With the growing pressure to reduce carbon emissions, increase the use of renewables and build a smarter, more resilient electricity grid, such projects can’t come online quickly enough.

In a new analysis of energy storage technologies and their market potential, the Electric Power Research Institute (EPRI) points to a number of grid-integrated storage demonstrations in development in several US states. They include:

• Two battery-based projects with a total discharge capacity of 505 kilowatts being built by the Sacramento Municipal Utility District (SMUD);
• Two battery-based initiatives — one with a discharge capacity of eight megawatts — under development by Southern California Edison;
• Two Pacific Gas & Electric projects, one using batteries, the other testing advanced compressed-air energy storage;
• A 20-megawatt flywheel-based storage project being developed in Chicago by PJM;
• A 500-kilowatt, battery-based project  in Syracuse, New York, led by National Grid; and
• A Duke Energy battery-based project to store power at the utility’s Notrees wind farm in Texas.

In all, the 2009 American Recovery and Reinvestment Act included 16 smart-grid energy storage demonstration grants.

“In general, based on present-day technology, some energy storage systems will not be economical because more technology development is needed to lower their capital costs,” the EPRI states in its study. “Technology costs and application benefits are very sensitive to the configuration of the storage system both in terms of discharge capacity (MW) and energy storage capacity (MWh).”

The EPRI concludes the US energy storage market could in theory provide as much as 14 gigawatts of capacity. As always, though, the devil is in the details. Those numbers could be achieved only if storage systems could be installed at a cost of $700 to $750 per kilowatt-hour, and only if storage owners and operators would be able to “monetise the estimated benefits.”

“There are a wide range of potential benefits for energy storage applications and when aggregated, these benefits can justify the costs of installing storage in many places,” said Mark McGranaghan, vice president of power delivery and utilisation at EPRI. “Storage systems dedicated to a single application can be valuable, but the true value of storage appears when the same system serves multiple applications.”

This means some big ifs remain in the potential for energy storage. If we want to make the transition to a more efficient and cleaner energy future anytime soon, we’ll need storage technologies that become affordable on a scale of years, not decades.