USA

Right now people who live off-grid with PV panels on their roofs rely on ordinary batteries to get through the night.In the future they might have solar-powered electrolyzers that split water molecules into hydrogen and oxygen.Recombining the gases in a fuel cell would yield electricity again.The idea is old,but last year Daniel Nocera,a chemist at MIT,reported what may be breakthrough: a new catalyst that makes splitting water much cheaper.At public lectures Nocera likes to hold up a large plastic water bottle.All of a family´s nighttime electricity requirements,he says,could be stored in five of these,with enough left over to run the electric car.No one knows in detail the future of solar energy.But there is a gathering sense that it is wide open-if we can make the commitment to jump-start the technology."Originally it seemed like a pie-in-the-sky idea," Michelle Price,the energy manager at Nellis,told me last fall when I toured the base´s new photovoltaic plant."It didn´t seem possible." Many things seem possible now.ON A COLD DECEMBER MORNING west of Franfurt,Germany,fog hung frozen in the trees,and clouds blocked the sun.Shivering on a ridge above the town of Morbach,I watched the blades of a 330-foot-high wind turbine swoop in and out of the gloom.Down below,a field of photovoltaic panels struggled for light.Who would have thought that Germany would transform itself into the largest producer of photovoltaic power in the world,with a capacity of more than five gigawatts?A fraction of this power comes from centralized plants like the small one at Morbach or even the spawling 272-acre Waldpolenz Solar Park,which was constructed recently with thin-film technology on an abandoned Soviet air base near Leipzig.With land at a premium in Germany,solar panels are mounted on rooftops,farmhouses,even on soccer stadiums and along the autobahn.Though dispersed across the countryside,they are connected to the national grid,and utility companies are required to pay even the smallest producers a premium of about 50 euro cents a kilowatt-hour. "We are being paid for living in this house," saidWolfgang Schnürer,a resident of Solarsiedlung-"solar settlement"-a condominum complex in Freiburg.Outside,snow was sliding off the solar panels that covered the roofs of the development.The day before,Schnürer´s system had produced only 5.8 kilowatt-hours,not enough even for German household.But on a sunny day in May it had yielded more than seven times that much.After serving coffee and Christmas cookies,Schnürer spread some printouts on the table.In 2008 his personal power plant generated 6,187 kilowatt-hours,more than double what the Schnürers consumed.When the amount they used was subracted from the amount they produced,they came out more than 2,500 euros(nearly USD3,700)ahead.Jätkub...Ainult lollakad ostavad elektrit...sest elektrit saab tasuta!