Without a way to store their power, no number of solar panels will free a home from the electrical grid. Researchers at Utah-based Ceramatec have developed a new battery that can be scaled up to store 20 kilowatt-hours—enough to power an average home for most of a day. An easy sell for solar users, but it could also allow the grid-bound to stockpile energy during less expensive off-peak hours.
The new battery runs on sodium-sulfur—a composition that typically operates at greater than 600 F. “Sodium-sulfur is more energetic than lead-acid, so if you can somehow get it to a lower temperature, it would be valuable for residential use, Ralph Brodd, an independent energy conversion consultant, says.
Ceramatec’s new battery runs at less than 200 F. The secret is a thin ceramic membrane that is sandwiched between the sodium and sulfur. Only positive sodium ions can pass through, leaving electrons to create a useful electrical current. Ceramatec says that batteries will be ready for market testing in 2011, and will sell for about $2000.

Popular Mechanics