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The most important advantage of using liquid as fuel is that they can be easily pumped and can also be handled easily.

Biofuels are the best way of reducing the emission of the greenhouse gases.

Some of the major producers and users of biogases are Asia, Europe and America. Theoretically, biofuel can be easily produced through any carbon source; making the photosynthetic plants the most commonly used material for production. Almost all types of materials derived from the plants are used for manufacturing biogas. One of the greatest problems that is being faced by the researchers in the field is how to covert the biomass energy into the liquid fuel

the world’s fastest growing renewable energy source for more than a decade with an average annual growth rate of over 20%.

increasing generating capacity by 50%. With more than 25,170 MW of wind energy

ind energy in the United States could provide as much as 10,777 billion kWh annually

global potential is enormous: over 400 billion liters annually, well more than double the amount of diesel the US burns every year.

Hydrogen is colorless, odorless, tasteless and non-toxic. It is a gas at temperatures above -423° F and is highly diffuse, having a density approximately 14 times less than that of air. Because it is buoyant and diffusive, hydrogen dissipates quickly in open areas and can move through small spaces, which makes it difficult to store. Hydrogen is flammable over a broad range of gas concentration (from 4 to 74 percent), although its lower flammability limit – that is, the lowest temperature and pressure at which it will combust – is higher than those for some common fuels such as gasoline, propane or diesel.1 Hydrogen has been described as “the fuel of the future.” On Earth, hydrogen is found in combination with other elements such as carbon (hydrocarbons), oxygen (water) and nitrogen (ammonia). Although hydrogen may sometimes be used as a fuel, it is most often used as an energy carrier, such as electricity, and not an energy source. To make hydrogen a usable, stand-alone fuel, it must be separated from these other elements by chemical, thermal or electrochemical processes.

History British scientist Henry Cavendish identified hydrogen as a distinct element in 1766. Subsequent experiments by British and French scientists resulted in the first flight of a hydrogen balloon and the discovery that applying electricity to water can produce hydrogen and oxygen.

In the 1960s, NASA space capsules used hydrogen fuel cells for onboard electric power, heat and water.

Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover. This wind flow, or motion energy, when "harvested" by modern wind turbines, can be used to generate electricity.

The terms "wind energy" or "wind power" describe the process by which the wind is used to generate mechanical power or electricity

The terms "wind energy" or "wind power" describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power

The fuel cell is being considered as an eventual replacement for the internal combustion engine for cars, trucks and buses. Major car manufacturers have teamed up with fuel cell research centers or are doing their own development. There are plans for mass-producing cars running on fuel cells. Because of the low operating cost of the combustion engine, and some unresolved technical challenges of the fuel cell, however, experts predict that a large scale implementation of the fuel cell to power cars will not occur before 2015, or even 2020.

Most fuel cells are still handmade and are used for experimental purposes. Fuel cell promoters remind the public that the cost will come down once the cells are mass-produced and lower cost material are found. While an internal combustion engine requires an investment of $35 to $50 to produce one kilowatt (kW) of power, the equivalent cost in a fuel cells is still a whopping $3,000 to $7,500. The goal is a fuel cell that would cost equal or less than diesel engines.

Fuel cell system costs have decreased significantly over the past several years but are still nearly twice as high as those for internal combustion engines. Likewise, onboard hydrogen storage costs are currently $15–$18/kWh for high-pressure gaseous storage, while the commercialization target is $2/kWh. There is potential to reduce this cost using lower-cost carbon fiber tanks or materials-based storage technologies, such as metal hydrides.

FCVs will have to offer consumers a viable alternative, especially in terms of performance, durability, and cost, to survive in this ultra-competitive market.

The sun delivers about 7000 times more energy than we currently consume globally. However, we cannot cover the whole surface of the Earth with solar energy collectors. How much of this energy can we collect? Will it be enough to replace fossil fuels?

Our global consumption of electricity in 2005 was 15,182 TWh/y (see The Little Green Handbook). However, 9,541 TWh/y of electricity was produced by fossil fuels and 2,555 TWh/y by nuclear power, or the total 12,096 TWh/y. Assuming the lowest solar potential and the lowest efficiency of solar cells we can calculate that we could produce 35 times more electricity than produced by fossil fuels and nuclear power. The additional advantage is that solar power is clean and last practically forever.

Even if we used only 1% of unused land area we could produce nearly 4 times more electricity than we produce using fossil fuels and nuclear power.

Figuring out an inexpensive and carbon-neutral way to produce an abundant amount of hydrogen will be key to the success of fuel cell vehicles

The dirty secret of clean energy is that while generating it is getting easier, moving it to market is not.

While the United States today gets barely 1 percent of its electricity from wind turbines, many experts are starting to think that figure could hit 20 percent.

Achieving that would require moving large amounts of power over long distances, from the windy, lightly populated plains in the middle of the country to the coasts where many people live.

Challenges Wind power must compete with conventional generation sources on a cost basis. Depending on how energetic a wind site is, the wind farm may or may not be cost competitive. Even though the cost of wind power has decreased dramatically in the past 10 years, the technology requires a higher initial investment than fossil-fueled generators. Good wind sites are often located in remote locations, far from cities where the electricity is needed. Transmission lines must be built to bring the electricity from the wind farm to the city. Wind resource development may compete with other uses for the land and those alternative uses may be more highly valued than electricity generation. Although wind power plants have relatively little impact on the environment compared to other conventional power plants, there is some concern over the noise produced by the rotor blades, aesthetic (visual) impacts, and sometimes birds have been killed by flying into the rotors. Most of these problems have been resolved or greatly reduced through technological development or by properly siting wind plants.

Like electricity, hydrogen is a secondary source of energy. It stores and carries energy produced from other resources (fossil fuels, water, and biomass).

ydrogen is the simplest element. Each atom of hydrogen has only one proton. It is also the most plentiful gas in the universe. Stars like the sun are made primarily of hydrogen. The sun is basically a giant ball of hydrogen and helium gases. In the sun's core, hydrogen atoms combine to form helium atoms. This process — called fusion — gives off radiant energy.

Hydrogen gas is so much lighter than air that it rises fast and is quickly ejected from the atmosphere. This is why hydrogen as a gas (H2) is not found by itself on Earth. It is found only in compound form with other elements. Hydrogen combined with oxygen, is water (H2O). Hydrogen combined with carbon forms different compounds, including methane (CH4), coal, and petroleum.

In the hydrogen economy, there is no storehouse to tap into. We have to actually create the e­nergy in real-time.

There are two possible sources for the hydrogen: Electrolysis of water - Using electricity, it is easy to split water molecules to create pure hydrogen and oxygen. One big advantage of this process is that you can do it anywhere. For example, you could have a box in your garage producing hydrogen from tap water, and you could fuel your car with that hydrogen. Reforming fossil fuels - Oil and natural gas contain hydrocarbons -- molecules consisting of hydrogen and carbon. Using a device called a fuel processor or a reformer, you can split the hydrogen off the carbon in a hydrocarbon relatively easily and then use the hydrogen. You discard the leftover carbon to the atmosphere as carbon dioxide.

To have a pure hydrogen economy, the hydrogen must be derived from renewable sources rather than fossil fuels so that we stop releasing carbon into the atmosphere. Having enough electricity to separate hydrogen from water, and generating that electricity without using fossil fuels, will be the biggest change that we see in creating the hydrogen economy.

Advantages by Application Telecoms CHP Fuel Cell Generators Electric Vehicles - APU's and Range Extenders Fuel Cell Forklifts Marine Power Portable Power

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

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

Enhanced geothermal systems (EGS), also sometimes called engineered geothermal systems, offer great potential for more than 100 GW of geothermal power which 40 times more than present geothermal power.

ultimately geothermal global resources amount to 50,000 times the energy of all oil and gas resources in the world.

Enhanced Geothermal Systems (EGS) – Often categorized under the antiquated term‘Hot Dry Rock,’ EGS is thought by several experts to refer to any resource that requires artificial stimulation. This includes resources that have to be fully engineered, or ones that produce hydrothermal fluid, but sub-commercially. Regarding the latter, one expert states that, ‘As we go further, there might be projects that require more and more stimulation.’ Although EGS technology is still young and many aspects remain unproven, several projects are currently underway. If EGS technology proves commercially successful, it is expected to allow significantly increased extension of and production from existing fields, as well as utilization of geothermal energy in previously implausible locations.

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.