Molten Metal Batteries Return for Renewable Energy Storage - Feb 6, 2011 - Peter Behr and ClimateWire - - batteries storage - Generation - Technical Articles - Index - Library - GENI - Global Energy Network Institute

Molten Metal Batteries Return for Renewable Energy Storage

Sept 14, 2009 - Phil Taylor - Scientific American

The Streator Cayuga Ridge South Wind Farm NOT ALWAYS BLOWING IN THE WIND: Energy storage is crucial to handle the intermittent nature of wind power. Image: Courtesy

EaglePicher Technologies, a manufacturer of specialized batteries for military and space programs, is partnered with the federal government to develop a powerful battery storage technology to help utilities smooth out the ups and downs of renewable power.

It's a familiar path for the Joplin, Mo., company.

EaglePicher began developing a battery for space applications in the mid-1980s that used sodium and sulfur components. Its model performed successfully on the Columbia space shuttle in 1997.

But by then, the focus for military and space batteries had shifted to lithium-ion models in the United States and the impetus for a sodium sulfur battery vanished in this country. EaglePicher mothballed its work.

Now EaglePicher is back in the game, working on a sodium sulfur battery with the Pacific Northwest National Laboratory (PNNL), backed by a $7.2 million grant from the Energy Department's Advanced Research Projects Agency-Energy (ARPA-E). It was one of 37 such awards made in 2009 to foster clean energy breakthroughs. EaglePicher is funding the $1.8 million balance of the three-year project.

With Energy Department research and development budgets facing an uncertain future in Congress, the future for such clean energy partnerships is also uncertain. This week, ARPA-E will show off its grantees at the 2011 Innovation Summit in Washington, bringing together scientists, venture capital funders and elected officials in a bid for political support for President Obama's goal of producing 80 percent of the U.S. electricity supply from clean energy sources by 2035.

PNNL estimates that more than 200,000 megawatt-hours of power from energy storage would be needed in 2030 if the United States were to get 20 percent of its electricity from renewable sources then. The concept is to store electricity made from renewable energy when it is in surplus -- such as wind energy at night -- and use it during during peak demand periods during the day.

The characteristics of sodium sulfur batteries are well-suited for that. While the technology was pioneered in this country, but then abandoned, Japan saw the promise and picked it up. Its Ministry of International Trade and Industry chose it as a targeted opportunity.

Japan takes the idea and runs with it
Tokyo Electric Power Co. and NGK Insulators pushed sodium sulfur development in the 1990s, and today, NGK is the primary commercial manufacturer. U.S. utilities seeking large storage batteries for renewable energy can face a wait of a year or more.

It amounts to the second big battery technology fumble the United States has been involved with. The technology that underpins the ubiquitous lithium-ion batteries in consumer electronics products was invented by American physicist John Goodenough in the late 1970s, helped by a $20,000 grant from the U.S. Air Force. Ignored by U.S. manufacturers, it was commercialized by Sony and other Japanese companies in the 1990s.

PNNL scientist and project coordinator Gordon Graff says the laboratory's partnership with EaglePicher seeks to leapfrog NGK's design to perfect a more compact architecture that could significantly boost the battery's efficiency and performance while also greatly simplifying the manufacturing process.

"This is a radical change in design," said Graff, who holds 22 patents. "This is one of the ways we can make this step jump."

In the PNNL facility in Richland, Wash., Graff hefts one of the NGK batteries as he explains the opportunities that PNNL and EaglePicher team hope to exploit.

The NGK battery is a cylinder with sodium in the center, separated from molten sulfur by a ceramic membrane that allows the passage of sodium ions to create the battery's current. The tubular design of the NGK membrane and casings simplifies maintaining a secure seal on the volatile chemicals within the battery, whose internal temperature reaches 350 degrees Celsius.