CAMBRIDGE: A US scientist has developed a new way of powering fuel cells that could make it practical for home owners to store solar energy and produce electricity to run lights and appliances at night.

A new catalyst produces the oxygen and hydrogen that fuel cells use to generate electricity, while using far less energy than current methods.

With this catalyst, users could rely on electricity produced by photovoltaic solar cells to power the process that produces the fuel, said the Massachusetts Institute of Technology professor who developed the new material.

"If you can only have energy when the sun is shining, you're in deep trouble. And that's why, in my opinion, photovoltaics haven't penetrated the market," Daniel Nocera, an MIT professor of energy, said in an interview at his Cambridge, Massachusetts, office. "If I could provide a storage mechanism, then I make energy 24/7 and then we can start talking about solar."

Solar has been growing as a power source in the US. But it is still a tiny power source, producing enough energy to meet the needs of about 600,000 typical homes, and only while the sun is shining.

Nocera said his development would allow people to bank solar energy as hydrogen and oxygen, which a fuel cell could use to produce energy when the sun was not shining.