When fossil fuels are burned, they release large amounts of carbon dioxide, a greenhouse gas, into the air. Greenhouse gases trap heat in our atmosphere, causing global warming.

On Earth, human activities are changing the natural greenhouse. Over the last century the burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2). This happens because the coal or oil burning process combines carbon with oxygen in the air to make CO2.

Carbon dioxide is added to the atmosphere naturally when organisms respire or decompose (decay), carbonate rocks are weathered, forest fires occur, and volcanoes erupt. Carbon dioxide is also added to the atmosphere through human activities, such as the burning of fossil fuels and forests and the production of cement.

Fossil fuels produce large quantities of carbon dioxide when burned. Carbon emissions trap heat in the atmosphere and lead to climate change. In the United States, the burning of fossil fuels, particularly for the power and transportation sectors, accounts for about three-quarters of our carbon emissions.

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Alternative fuels are derived from sources other than petroleum. Most are produced domestically, reducing our dependence on imported oil, and some are derived from renewable sources. Often, they produce less pollution than gasoline or diesel. Ethanol is produced domestically from corn and other crops.

Here is our Top Eight list of alternative fuels.

• Ethanol. An alcohol-based alternative fuel made by fermenting and distilling crops such as corn, barley or wheat.
• Natural Gas.
• Electricity.
• Hydrogen.
• Propane.
• Biodiesel.
• Methanol.
• P-Series Fuels.

But diesel and gasoline fuels are of environmental concern because burning the fuel emits carbon dioxide, nitrous oxide and methane. Alternative fuels are meant to reduce greenhouse gases, which include water vapor, carbon dioxide, methane, nitrous oxide and ozone. Biodiesel is used in standard diesel engines.

Alternative Fuel Options

• Alcohols, e.g., ethanol and methanol.
• Biomass-based diesel fuels. Biodiesel (fatty acid methyl esters, FAME) Renewable hydrocarbon diesel.
• Methane, e.g., natural gas, biogas and synthetic natural gas (SNG)
• Hydrogen.
• Synthetic fuels.
• Dimethyl ether (DME) and other heavier ethers.
• Ammonia.

The Best Examples of Alternative Energy Sources

• Wave Energy.
• Biofuels.
• Natural Gas.
• Geothermal Power.
• Wind Energy.
• Biomass Energy.
• Tidal Energy.
• Hydrogen Gas. Unlike other forms of natural gas, hydrogen is a completely clean burning fuel.

Plant-based fuels come from renewable sources, can be grown anywhere and have lower carbon emissions as compared to fossil fuels. Biofuels not only help a struggling economy by providing jobs but also helps in reducing greenhouse gases up to much extent by emitting less pollution.