Pocket Sockets

At Germany's weeklong Hannover Fair last April, a camcorder monitored the crowds visiting the energy-exhibits section of the giant technology trade show. The device had no battery nor was it plugged into the wall. Instead, the palmsize camera got its power from a prototype fuel cell that transformed hydrogen gas and oxygen into water and electricity. The unusually compact fuel cell was "pretty reliable," though not dependable enough to keep the camera running continuously, says Christopher Hebling of the Fraunhofer Institute for Solar Energy Systems in Freiburg, Germany, the alternative-energy laboratory that built the fuel cell.