New solar battery technology offers household power at 2.5c per kWh

By Jeff Salton

00:14 September 2, 2009 PDT

One of the smaller prototypes of the Ceramatec NaSICON solar batteries.

As part of man's ongoing quest to extract the greatest benefits from solar power, Salt Lake City-based company Ceramatec, the R&D arm of CoorsTek, has made what it believes to be a massive breakthrough in batteries for storing energy harnessed from the sun. The company is making impressive inroads on the prototype of a deep storage battery, the size of a small refrigerator, that safely operates at room temperature, consists of everyday materials, and can output household power at 2.5c per kWh. What’s more, Ceramatec says it will be cheap to purchase.

As solar energy capture gets better and cheaper, safety has remained an issue when discussing battery storage. Currently, great performing energy-dense batteries are nothing more than man-made volcanoes - huge containers of super-hot molten sodium that hover around 600°C. At that temperature the material is highly conductive of electricity, however, it is also toxic and corrosive. Would you want one in your basement?

Instead, Ceramatec's battery comprises a large piece of solid sodium metal mated to a sulfur compound by a paper-thin ceramic membrane. The membrane conducts ions - electrically-charged particles - back and forth to generate a current. The company calculates that the battery will be able to sustain 20-40kWh of energy into a refrigerator-size housing that operates at around or below 90°C. This is possibly the only way that this type of dense battery technology will ever be approved for household use – safe, small (relatively) and cheap to purchase.

Ceramatec says its new generation of battery would deliver a continuous flow of 5kW of electricity over four hours. If that doesn’t power your whole house it will certainly supplement it. And these batteries are expected to withstand daily discharge/recharge cycles over 10 years (3,650 times). The batteries would hopefully sell for around USD$2,000, which is less than 3c per kWh over the battery's life. Conventional power from the grid typically costs around 8c per kWh – and continues to rise.

Presently, most deep cycle batteries don’t have a lifespan anywhere near that long. Daily usage usually results in a permanently dead battery in around 12 months.

It’s no wonder that, as America’s electricity grid, and other electrical infrastructure around the world, nears breaking point, the ability for households to generate, store and time-shift their own power has governments and corporations taking a keen interest in developments.

Eric Layton

05 Sept 09