Dive Brief:

• The Department of Energy on Wednesday announced a $30 million funding program for long duration energy storage.

• The funding opportunity, which is being done under the DOE’s Advanced Research Projects Agency-Energy program, targets energy storage systems that can provide power to the electric grid for durations of 10 hours up to approximately 100 hours.

• The Duration Addition to electricitY Storage (DAYS) program is open to a range of storage technologies, including thermal, mechanical, electrochemical and chemical.

Dive Insight:

Lithium-ion batteries have about 90% or more of the stationary energy storage market, but they have their limitations. Most notably, li-ion batteries have limited durations. Energy storage experts say new li-ion projects are beginning to stretch those durations up to the four-hour mark, but the technology is not well suited for longer durations.

Longer duration energy storage solutions are expected to become more important as more intermittent generation sources, such as wind and solar power, come onto the grid. The DAYS program is designed to address those needs by enabling a new set of applications that can provide long lasting backup power and facilitate the integration of renewable energy resources onto the grid.

Long duration energy storage is already within the capability of some technologies, but they have not been as widely deployed in recent years as have energy storage projects that use li-ion batteries. For example, emerging technologies such as flow batteries can provide power for durations of 10 hours or more, but so far they have been more expensive than lithium-ion battery projects on a cost of capital basis.

Pumped storage hydro can also provide large amounts of energy over a long time period and, in fact, accounts for more than 95% of the stationary electricity storage capacity on the U.S. grid today, according to the DOE. Nonetheless, there have been few new installations in the United States in the last three decades, mostly because of the difficulty of permitting new sites and the cost of financing large projects.

A recent paper by MIT’s Energy Initiative argued that if li-ion batteries become the dominant technology for utility-scale energy storage, it could make it difficult for alternative storage technologies to survive, much less continue to innovate and scale up. That could block the entry of more optimal alternative technologies that may be longer lasting and have a longer cycle life, according to the report.