New fuel cell technology could cost one-tenth the price of Bloom

redox fuel cell
© Redox Power Systems

A new solid-oxide fuel cell (SOFC) could be more efficient and one-tenth the price of the Bloom Energy Server. Startup company Redox Power Systems is calling their SOFC "The Cube" and claim that once it's built, it will cost $800 per kilowatt compared to Bloom's $10,000 per kilowatt.

Redox says that the big difference is its use of technology that can operate at lower temperatures and has greater energy density made possible by using less expensive materials. The Cube is based on research done by scientist Eric Wachsman.

Greentech Media reports that "Redox uses 'aliovalent-doped ceria and isovalent-cation-stabilized bismuth oxides in the electrolyte,' which allows it to accomplish a few different things, Wachsman said in Tuesday’s interview. First, it allows for a much higher conductivity -- about ten to 100 times more than many other SOFC materials can yield, he said.

Secondly, it allows it to move from an 'electrolyte-supported cell' structure, which Bloom uses, to the 'electrode-supported cell' structure taken up by Redox and other SOFC developers today. That’s important, because electrode-supported cells, also known as anode-supported cells, can be created using deposition processes that yield a much thinner cell than electrolyte-supported cells, he said."

That thinner cell means higher energy density, about ten times as much as Bloom. Also the thinner electrolytes let it operate at lower temperatures, which allows for cheaper materials to be used (higher operating temperatures require more complex and expensive materials). Bloom operates at about 900 degrees Celsius, while Redox claims that it will bring temps down to 550 degrees Celsius. The DOE goal for SOFCs is below 800 degrees Celsius.

The Cube will be able to use natural gas, hydrogen and biofuel and also, less attractively, gasoline and propane for fuel. It's designed to be used as base power and back-up power so that it can provide a building's complete power needs and also act as a back-up power source in the event that grid power is lost like during natural disasters. Where net metering is available, customers could sell back excess power to the grid.

Redox has raised $5 million in funding and plans to have a 25 kW prototype finished by December and to be ready for mass production by late 2014.

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