OUR FUTURE ECONOMY MAY BE BASED ON HYDROGEN

One wafer of n-type silicon and one wafeT of p-type are pressed together, with no wire connecting the outside faces. An initial flow of electrons from n-type to p-type results in a charge buildup at the junction. What happens to this charge buildup as light shines on the n-type wafer does it increase, decrease, ot stay the same  

Perhaps the most promising area of photovoltaic research involves thin-film photovoltaic cells. These cells are not produced from expensive crystalline silicon. Rather, they are formed as vaporized silicon or some other photovoltaic material is deposited on a glass or metal substrate. The resulting films are about 400 times thinner than traditional silicon wafers, which saves in material costs. Furthermore, the films are easy to mass-produce. 

Ine of the most ideal fuels is hydrogen, H2. By weight, hydrogen packs more energy than any other fuel, which is why it is used to launch spacecraft. It is readily produced from the electrolysis of water, and the electrolysis equipment can be driven by solar-derived electricity. In this way, hydrogen provides a convenient means of storing solar energy. 

Hydrogen burns very cleanly, producing almost nothing but water vapor. The vapor can be used to drive a gas turbine for the production of electricity. The waste heat can be used either for industrial purposes or to warm buildings. The water that condenses from the turbine can be used for agriculture or human consumption, or it can be recycled for the production of more hydrogen. 

A hydrogen-powered test vehicle developed by BMW. The exhaust consists primarily of water vapor. 

This special photoclcctrochemi-cal electrode submerged in water uses the energ) of sunlight to generate hydrogen gas, which forms on its. surface. 

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Our Future Economy May Be Based on Hydrogen Electricity-producing hydroelectric dams depend on the water cycle, which is driven by solar radiation. Windmills harness wind to produce electricity and also to pump water, and... 

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