Grid batteries investment promises lower renewable costs

May 06, 2014 // By Paul Buckley
Battery start-up Ambri, developer of the novel Liquid Metal Battery grid-scale energy storage technology, has raised a $35 million series-C round to fund the production of prototype batteries from an existing factory and finance construction of a commercial-scale plant.

The MIT spin-off company intends to test prototypes in the field in 2014 and produce full-size batteries for paying customers by 2016.  Ambri’s energy storage technology has been developed to facilitate full integration of variable renewable generation like wind and solar, reduce electricity costs by reducing the need for power plants and transmission and distribution infrastructure, and lead to more reliable and resilient electricity systems.

The round was funded by new investors KLP Enterprises, the family office of Karen Pritzker and Michael Vlock, and Building Insurance Bern (GVB), the Swiss Insurance company, as well as existing investors, including Khosla Ventures, Bill Gates and the energy company Total.

The investment marks a shift for Ambri from demonstrating the science behind the company's technology - a battery cell that uses two liquid metals as electrodes and a salt electrolyte - to engineering a commercially viable product. The cash injection also reflects a growing confidence that utilities and renewable energy project developers are willing to invest in new energy storage technologies.

The new funding round will enable Ambri to deliver commercial systems to customers, build its initial commercial-scale manufacturing plant, and continue technology development.

The cost of producing batteries is another important factor in undercutting incumbent battery technologies. Because Ambri’s manufacturing process is simple - it involves placing metal pucks and salt electrolyte material in a four-inch-square stainless steel cell - much of the production can be automated, said David Bradwell, the company’s chief technology officer.

At its existing manufacturing plant in Marlboro, Massachusetts, Ambri assembles its cells with robots normally used in the auto industry. The same kind of robot will be used at the company’s full-scale factory, which will make 130 megawatt-hours of batteries per year, explained Bradwell. “We expect to be almost an order of magnitude less in production cost than lithium-ion batteries, based on the elegance of the cell,” said Bradwell.

“Total has been a long-time supporter of the