Fuel from only water and sunlight? Talk about an endless supply. That's what researchers at the U.S. Department of Energy's National Renewable Energy Laboratory are counting on. Senior Scientist Dr. John Turner and postdoctoral fellow Dr. Oscar Khaselev developed an all-in-one device using an advanced semiconductor material. The instrument splits water into hydrogen and oxygen, converting up to 12% of available sunlight into hydrogen. Current systems link photovoltaic cells that generate electricity with an electrolyser. Because they lose efficiency by transferring electricity to the electrolyser, they only convert about 4 to 5% of the available sunlight into hydrogen. The potential of hydrogen is enormous, says Turner. Internal combustion engines can run with pure hydrogen or hydrogen blended with natural gas, producing fewer emissions. Hydrogen fuel cells, with no emissions, also can power vehicles and provide heat and electricity. When hydrogen is used as an energy resource, it generates no emissions other than water, which can be used to make more hydrogen. The Department of Energy's Hydrogen Program hopes to replace 2 to 4 quads of conventional energy with hydrogen by 2010 and 10 quads a year by 2030. A quad equals the amount of energy consumed by 1 million households in the U.S. E-mail: email@example.com.