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"Today's photovoltaic systems are used to generate electricity to pump water, light up the night, activate switches, charge batteries, supply power to the utility grid, and much more. 1839: Nineteen-year-old Edmund Becquerel, a French experimental physicist, discovered the photovoltaic effect while experimenting with an electrolytic cell made up of two metal electrodes. 1873: Willoughby Smith discovered the photoconductivity of selenium. 1876: Adams and Day observed the photovoltaic effect in solid selenium. 1883: Charles Fritts, an American inventor, described the first solar cells made from selenium wafers. 1887: Heinrich Hertz discovered that ultraviolet light altered the lowest voltage capable of causing a spark to jump between two metal electrodes. 1904: Hallwachs discovered that a combination of copper and cuprous oxide was photosensitive. Einstein published his paper on the photoelectric effect. 1914: The existence of a barrier layer in PV devices was reported. 1916: Millikan provided experimental proof of the photoelectric effect. 1918: Polish scientist Czochralski developed a way to grow single-crystal silicon. 1923: Albert Einstein received the Nobel Prize for his theories explaining the photoelectric effect. 1951: A grown p-n junction enabled the production of a single-crystal cell of germanium. 1954: The PV effect in Cd was reported; primary work was performed by Rappaport, Loferski and Jenny at RCA. Bell Labs researchers Pearson, Chapin, and Fuller reported their discovery of 4.5% efficient silicon solar cells; this was raised to 6% only a few months later (by a work team including Mort Prince). Chapin, Fuller, Pearson (AT&T) submitted their results to the Journal of Applied Physics. AT&T demonstrated solar cells in Murray Hill, New Jersey, then at the National Academy of Science Meeting in Washington, DC. 1955: Western Electric began to sell commercial licenses for silicon PV technologies; early successful products included PV-powered dolla

What fuel cell is and how its made 

how wind becomes electricty

" Where does Wind Energy come From? All renewable energy (except tidal and geothermal power), and even the energy in fossil fuels, ultimately comes from the sun. The sun radiates 174,423,000,000,000 kilowatt hours of energy to the earth per hour. In other words, the earth receives 1.74 x 10 17 watts of power . 1) About 1 to 2 per cent of the energy coming from the sun is converted into wind energy. That is about 50 to 100 times more than the energy converted into biomass by all plants on earth. 2)"

how much solar energy is being converted in the USA?

"How much power is generated in the United States by solar power? ted-vollgraff According to the Energy Information Administration (EIA), renewable energy accounted for 7 percent of U.S. energy consumption in 2008. Solar power accounted for only one percent. But, considering how much energy is consumed each year in the United States, that is still a decent bit of power. The EIA states that just over 843,000 kilowatt-hours of electricity were provided by solar power. The vast majority of that, more than 666,500 kWh, were produced in California. Roughly 14 percent of the total renewable energy generated in the U.S. in 2008 was solar energy. And remember that these numbers continue to grow each year. The solar industry has been growing on an average of 30-40 percent each year, and as the industry grows, so will the amount of clean, renewable power it puts out. "

How a generator works

"tidal power has potential for future electricity generation. Tides are more predictable than wind energy and solar power."

Wind Power News | Wind Power Forum | Wind Power Directory | Videos Wind power is produced by using wind generators to harness the kinetic energy of wind. It is gaining worldwide popularity as a large scale energy source, although it still only provides less than one percent of global energy consumption.

Solar is not always connected to grid. Sometimes there are batteries, otherwise your system is connected to grid to share excess electricity.

Challenges Producing hydrogen in the large quantities necessary for the transport and stationary power markets could become a barrier to progress beyond the initial demonstration phase.  Uses: Fuel cells will be used in a wide range of products, ranging from very small fuel cells in portable devices such as mobile phones and laptops, through mobile applications like cars, delivery vehicles, buses and ships, to heat and power generators in stationary applications in the domestic and industrial sector. Future energy systems will also include improved conventional energy converters running on hydrogen (e.g. internal combustion engines, Stirling engines, and turbines) as well as other energy carriers (e.g. direct heat and electricity from renewable energy, and bio-fuels for transport). 

" Combustion engines like the turbine and the gasoline engine burn fuels and use the pressure created by the expansion of the gases to do mechanical work. Batteries convert chemical energy back into electrical energy when needed. Fuel cells should do both tasks more efficiently."