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Coal generates 2,249 pounds of carbon dioxide, 13 pounds of sulfur dioxide and 6 pounds of nitrogen oxides for every megawatt hour of energy generated.

Biomass produces nitrogen oxides and small amounts of sulfur dioxide. The amount of carbon dioxide produced does not exceed that of the Earth's normal carbon cycle and is considered negligible.

The coal powder mixes with hot air, which helps the coal burn more efficiently, and the mixture moves to the furnace. The burning coal heats water in a boiler, creating steam. Steam released from the boiler powers an engine called a turbine, transforming heat energy from burning coal into mechanical energy that spins the turbine engine. The spinning turbine is used to power a generator, a machine that turns mechanical energy into electric energy. This happens when magnets inside a copper coil in the generator spin.

Electricity-generating plants send out electricity using a transformer, which increases the voltage of the electricity based on the amount required and the distance it must travel. Voltages are often as high as 500,000 volts at this point.  Electricity flows along transmission lines to substation transformers. These transformers reduce the voltage for use in the local areas to be served.  From the substation transformers, electricity travels along distribution lines, which can be either above or below the ground, to cities and towns. Transformers once again reduce the voltage—this time to about 120 to 140 volts—for safe use inside homes and businesses. The delivery process is instantaneous. By the time you have flipped a switch to turn on a light, electricity has been delivered.

"Biofuels" are transportation fuels like ethanol and biodiesel that are made from biomass materials.

Ethanol and biodiesel are usually more expensive than the fossil fuels that they replace, but they are also cleaner-burning fuels, producing fewer air pollutants.

What Is Ethanol? Ethanol is an alcohol fuel made from the sugars found in grains, such as:

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.

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.

What is wave energy? Waves are generated by the passage of wind across the surface of the sea.  Energy is transferred from the wind to the waves.  Waves travel vast distances across the ocean and at great speed and the energy is concentrated near the water surface.  The energy within a wave is proportional to the square of the wave height.  Therefore a two-meter high wave has four times the power of a one-meter high wave. The longer and stronger the wind blows over the surface of the sea, the higher, longer, faster and more powerful the sea is.

Although wave energy is a form of concentrated wind energy, as it has often travelled over large distances it is regularly out of phase with the local wind conditions.  Wave energy can therefore help to balance output variability from other renewable sources and maximise the efficient use of the electricity networks.   Wave energy is also more predictable than many other forms of renewable energy, such as wind or solar, and can be forecast accurately up to five days in advance.

Wave energy is clean and renewable!  It is one of the last renewable energy forms which mankind has yet to harness, and its potential is huge.

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.

As gas prices rise and global warming becomes more pervasive, more people are using biofuels as a way to save money and decrease their consumption of fossil fuels.

Solar energy is an infinitely renewable resource that uses the sun's rays to generate electricity for use in your home. By going solar, you can reduce your energy costs and lower your dependence on fossil fuels, thereby making your own contribution to a cleaner environment. Generally, the solar energy systems we use work as follows:

When we get electricity from renewable energy sources like wind and solar power, we avoid the carbon dioxide emissions that would have come from burning fossil fuels like coal, oil, or natural gas.

Let’s not hide the fact that manufacturing solar panels requires resources, fossil fuels that release CO2 emissions and add to our carbon footprint. However, it’s been shown in numerous studies that solar panel production releases nowhere near as much CO2 and other greenhouse gases as electric generated from coal, oil, natural gas, etc. (And you still need to produce the equipment to generate electricity from those sources as well.)

8: One Megawatt of Wind Energy = 2,600 Fewer Tons of Carbon Dioxide So, with all the noise about clean energy, what kind of improvement are we really talking about with wind? Consider that every year 1MW of wind energy can offset approximately 2,600 tons of carbon dioxide (CO2) [source: NREL], and the interest comes into focus. The simple math is less fossil fuel consumption equals less CO2. And measuring carbon reduction has become a key benchmark for monitoring the progress of alternative energy adoption.

Wind Energy The answer is blowin’ in the wind How is man going to keep up with increasing energy demand while the amount of available fossil fuel diminishes? The answer could be wind power, the capturing of the energy contained in gusts of wind. What is wind Energy?

Man has been using wind energy for thousands of years. Windmills, sails and even kites are all devices designed to harness the awesome power produced when the wind blows. Even modern aircraft benefit from wind power. Pilots flying westward usually expend much effort trying to make sure they place themselves in the jet stream, the hundred mile per hour wind caused by the earth spinning. Now engineers are able to convert such power into electricity, pump it into grids and provide energy for homes.

What is U.S. electricity generation by energy source? In 2012, the United States generated about 4,054 billion kilowatthours of electricity.  About 68% of the electricity generated was from fossil fuel (coal, natural gas, and petroleum), with 37% attributed from coal. Energy sources and percent share of  total electricity generation in 2012 were:  Coal 37% Natural Gas 30% Nuclear 19% Hydropower 7% Other Renewable 5% Biomass 1.42% Geothermal 0.41% Solar 0.11% Wind 3.46% Petroleum 1% Other Gases < 1%

Somewhat surprisingly, the hot air that carries the heat from the earth at geothermal sites also contains carbon dioxide, CO2, the Greenhouse Gas that sends anti-technologists into a frenzy.  The suite of 20 geothermal sites from which Southern California Electric is obligated to buy electricity produces 730 tonnes of CO2 for every gigawatt-hour (GWh) of electricity produced.  Across the spectrum of all natural-gas power plants in the US, the average CO2 production is 519 tonnes per GWh.  That is, the geothermal power plants, which burn no fossil fuels whatsoever, produce 41% more CO2 than the run-of-the-mill natural gas power plant for the same amount of electrical energy produced.

Lost in the mix are the biofuels, fuels made from biological ingredients instead of fossil fuels. These starting ingredients can range from corn to soybeans to animal fat, depending on the type of fuel being made and the production method.

Photovoltaic cells are made of at least two layers of semiconducting material. The first layer has a positive charge; the next layer has a negative charge. When sunlight strikes the cell, the semiconducting material absorbs photons from the light. This process frees electrons from the negative layer, which move to the positive layer. This flow of electrons constitutes an electric current, which can be captured in a circuit connecting the two layers. The electricity generated by a photovoltaic cell can be used directly, stored in batteries or sold back to a utility company.