From Google to Gates: Malta Targets Power Storage With Molten Salt

Xconomy Boston — 

A new and unconventional power storage startup is preaching the gospel of salt and antifreeze as the long-sought answer to how to bottle up renewable electricity from intermittent solar and wind projects.

Malta, based in Cambridge, MA, announced today it has graduated from Alphabet’s X, the Moonshot Factory—where it was known as Project Malta—and is heading off into the world with a $26 million Series A funding round led by Breakthrough Energy Ventures, the climate change fund led by Bill Gates.

Innovations in renewable power sources has led to massive cost reductions and an explosion of clean energy projects around the world. But currently the power needs to be used the moment it’s created because current power storage technologies can’t bottle it up for later use. In some cases, power generated when there’s little electricity demand goes to waste.

Malta’s technology is based off of research from Stanford University physicist Robert Laughlin that theorized electricity could be transformed into heat and cold for storage and then turned back into electricity on demand. The “hot” side of the system stores the energy in super-heated molten salt, and the “cold” side stores it in a type of antifreeze liquid. When power is needed, the two sides power a heat engine that produces electricity.

Malta CEO Ramya Swaminathan says the challenge ahead doesn’t lie in the research underlying the technology. She says the thermodynamics is settled science. It’s the implementation that keeps her and her team awake at night.

“It’s about design and manufacturing,” Swaminathan says. “That’s not a small task.”

Swaminathan joined Malta from Rye Development, a large developer of hydroelectric projects across the U.S., including hydroelectric systems that store power by pumping water up hills into lakes then releases the water to run through turbines when power is needed. This is currently the most popular form of power storage.

Malta is based in the Boston area, in part, because it’s where Swaminathan calls home. But the proximity to the area’s tech ecosystem, research talent, and heavy industry were also factors.

Swaminathan says Malta is looking at a competitive cost curve that could make its solution cheaper than lithium-ion battery storage, which is also seeing major cost declines.

Malta says it is working to manufacture and rig up its first pilot system. The location of the pilot has not been decided, the company says. But the system will sit on a 50 meter-by-50 meter footprint, should be able to store six hours of energy, and will be a grid-connected 10-megawatt system (which could support about 5,000 homes). If needed, the system could keep the electricity bottled up as cold and hot for a week, Swaminathan says.

A design for Malta’s 10 megawatt pilot system that would store enough power to support about 5,000 homes. (Courtesy photo)

The company expects to—and will need to, eventually—price its system at a compelling rate. Malta says that should not be an issue because the materials are inexpensive and abundant.

Swaminathan says she expects the company’s customers to come from a variety of points in the energy system.

“We expect developers with wind or solar projects who want firm power, to grid scale applications that can be in the hundreds of megawatts range, to critical backup for data centers, to isolated grid systems like island economies,” she says.

The company claims its technology will have the advantage over existing grid-scale power storage technologies because it can be sited anywhere, isn’t limited by geographic considerations, will be much less expensive, and can store power for longer durations.

Other investors that joined Malta’s funding round were Alfa Laval Group and Concord New Energy Group.

The name “Malta” isn’t metaphorically significant to the team. It sounds a bit like molten, they say, but Malta stuck as the company’s name because it burrowed into the team’s psyche after being randomly assigned the project title at X.