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The first tidal power station was the Rance tidal power plant built over a period of 6 years from 1960 to 1966 at La Rance, France.[8] It has 240 MW installed capacity.

Historically, tide mills have been used, both in Europe and on the Atlantic coast of North America. The incoming water was contained in large storage ponds, and as the tide went out, it turned waterwheels that used the mechanical power it produced to mill grain. [1] The earliest occurrences date from the Middle Ages, or even from Roman times.[2][3] It was only in the 19th century that the process of using falling water and spinning turbines to create electricity was introduced in the U.S. and Europe.[

Tidal energy use harnesses the water flow created primarily by the moon orbiting the Earth. As water is pulled toward the gravity of the moon, currents are created that can turn generator turbines.

Tidal energy use involving dams creates many of the same environmental concerns as damming rivers. Tidal dams restrict fish migration and cause silt build up which affects tidal basin ecosystems in negative ways. Systems that take advantage of natural narrow channels with high tidal flow rates have less negative environmental impact than dammed systems. But they are not without environmental problems. Both systems use turbines that can cause fish kills. But these are being replaced by new, more fish friendly turbines. The art and science of environmentally friendly hydro engineering is well advanced and will certainly be applied to any tidal energy project.

Because of intermittency and variable flow problems of tidal energy, it is a very limited resource. The DOE Tidal Energy link, above, states that there are only about 40 really good sites on Earth with high enough flows to be considered economically practical

Where Does Tidal Energy Come From? The gravitational force of the Earth stops the ocean from floating off into space, just like everything else. The Moon also has a very weak gravitational effect on the Earth, which is not normally noticable as far as falling teacups are concerned, but the ocean, which can flow around the globe to even out differences, is noticably affected.

The elimination of pollution caused by fossil fuels - When hydrogen is used in a fuel cell to create power, it is a completely clean technology. The only byproduct is water. There are also no environmental dangers like oil spills to worry about with hydrogen. The elimination of greenhouse gases - If the hydrogen comes from the electrolysis of water, then hydrogen adds no greenhouse gases to the environment. There is a perfect cycle -- electrolysis produces hydrogen from water, and the hydrogen recombines with oxygen to create water and power in a fuel cell. The elimination of economic dependence - The elimination of oil means no dependence on the Middle East and its oil reserves. Distributed production - Hydrogen can be produced anywhere that you have electricity and water. People can even produce it in their homes with relatively simple technology.

Method Cents/kW-h Limitations and Externalities WindCurrently supplies approximately 1.4% of the global electricity demand. Wind is considered to be about 30% reliable. 4.0 - 6.0 Cents/kW-h Wind is currently the only cost-effective alternative energy method, but has a number of problems. Wind farms are highly subject to lightning strikes, have high mechanical fatigue failure, are limited in size by hub stress, do not function well, if at all, under conditions of heavy rain, icing conditions or very cold climates, and are noisy and cannot be insulated for sound reduction due to their size and subsequent loss of wind velocity and power. GeothermalCurrently supplies approximately 0.23% of the global electricity demand. Geothermal is considered 90-95% reliable. 4.5 - 30 Cents/kW-h New low temperature conversion of heat to electricity is likely to make geothermal substantially more plausible (more shallow drilling possible) and less expensive. Generally, the bigger the plant, the less the cost and cost also depends upon the depth to be drilled and the temperature at the depth. The higher the temperature, the lower the cost per kwh. Cost may also be affect by where the drilling is to take place as concerns distance from the grid and another factor may be the permeability of the rock. HydroCurrently supplies around 19.9% of the global electricity demand. Hydro is considered to be 60% reliable. 5.1 - 11.3 Cents/kW-h Hydro is currently the only source of renewable energy making substantive contributions to global energy demand. Hydro plants, however, can (obviously) only be built in a limited number of places, and can significantly damage aquatic ecosystems. SolarCurrently supplies approximately 0.8% of the global electricity demand. 15 - 30 Cents/kW-h Solar power has been expensive, but soon is expected to drop to as low as 3.5 cents/kW-h. Once the silicon shortage is remedied through alternative materials, a solar energy revolution is expected.

Tide 2 - 5 Cents/kW-h Blue Energy's tidal fence, engineered and ready for implementation, would provide a land bridge (road) while also generating electricity. Environmental impact is low. Tides are highly predictable.

Method Cents/kW-h Limitations and Externalities GasCurrently supplies around 15% of the global electricity demand. 3.9 - 4.4 Cents/kW-h Gas-fired plants and generally quicker and less expensive to build than coal or nuclear, but a relatively high percentage of the cost/KWh is derived from the cost of the fuel. Due to the current (and projected future) upwards trend in gas prices, there is uncertainty around the cost / KWh over the lifetime of plants. Gas burns more cleanly than coal, but the gas itself (largely methane) is a potent greenhouse gas. Some energy conversions to calculate your cost of natural gas per kwh. 100 cubic feet (CCF)~ 1 Therm = 100,000 btu ~ 29.3 kwh. CoalCurrently supplies around 38% of the global electricity demand. 4.8 - 5.5 Cents/kW-h Increasingly difficult to build new coal plants in the developed world, due to environmental requirements governing the plants. Growing concern about coal fired plants in the developing world (China, for instance, imposes less environmental overhead, and has large supplies of high sulphur content coal). The supply of coal is plentiful, but the coal generation method is perceived to make a larger contribution to air pollution than the rest of the methods combined.

Appliances like television sets can also be powered by portable fuel cells. This is a 100-Watt portable Ballard® fuel cell demonstration unit powering a television and VCR combo

Honda Motor Company's hydrogen-fueled FCX fuel cell vehicle is now in the hands of customers. The FCX, powered by Ballard's latest generation Mark 902 fuel cell, seats four, has a range of 170 miles (270km) and can reach speeds of 93 mph (150km/h). Having made its commercial debut in December 2002, Honda is leasing five FCX vehicles to the City of Los Angeles and will market others by lease arrangement to customers in the Tokyo Metropolitan Area. Over the next two to three years, Honda plans to lease about 30 FCX cars in Japan and California.

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Hydrogen is a highly flammable chemical element which occurs in great abundance throughout the universe. In fact, hydrogen makes up approximately 75% of the universe, by volume, and it appears in a very large number of compounds, especially those which make up various organic materials.

Biofuels have been around as long as cars have. At the start of the 20th century, Henry Ford planned to fuel his Model Ts with ethanol, and early diesel engines were shown to run on peanut oil.

Think of them as big batteries, but ones that only operate when fuel—in this case, pure hydrogen—is supplied to them.

The hydrogen fuel cell operates similar to a battery. It has two electrodes, an anode and a cathode, separated by a membrane. Oxygen passes over one electrode and hydrogen over the other. The hydrogen reacts to a catalyst on the electrode anode that converts the hydrogen gas into negatively charged electrons (e-) and positively charged ions (H+).

Biofuels are produced from living organisms or from metabolic by-products (organic or food waste products). In order to be considered a biofuel the fuel must contain over 80 percent renewable materials

It is plenty in nature although it doesn’t occur freely but in association with other compounds.

It does not produce greenhouse gases that are damaging to the surroundings.

Most transportation fuels are liquids, because vehicles usually require high energy density, as occurs in liquids and solids.

First generation biofuels 'First-generation' or conventional biofuels are biofuels made from sugar, starch, and vegetable oil.

All winds are caused by differences in air pressure, which are usually caused by the sun. When high air pressure flow into low air pressure, it creates wind.Our planet turns around the Sun on an axis with a 23 degree tilt towards the North Star. The difference of heating on the surface of the Earth (between the equator and the pole) causes a mass of hot air to go up and to displace colder air toward the bottom - this all causes movement in the mass of air that is contain in our atmosphere.

"But if we could harness 0.1 percent of the energy in the ocean, we could support the energy needs of 15 billion people.