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Earth Science Project: Biomass

Kinds Of Biomass
Introduction | Intro 2 | Who Uses Biomass And Who Doesn't? | What Is Biomass Energy? | Kinds Of Biomass | Wood And Wood Waste | Why Biomass? | How Does Biomass Work? | Using Biomass Energy | Biomass Economics | Advatages And Disadvantages | Website Appendix | Conclusion

What Kinds Of Biomass Do We Use?

We use four types of biomass today: 1) wood and agricultural products; 2) solid waste; 3) landfill gas; and 4) alcohol fuels.

Wood and Agricultural Biomass

Most biomass used today is home grown energy. Wood-logs, chips, bark, and sawdust-accounts for about 79 percent of biomass energy. But any organic matter can produce biomass energy. Other biomass sources include agricultural waste products like fruit pits and corn cobs.

Solid Waste

There is nothing new about people burning trash. What's new is burning trash to generate electricity. This turns waste into a usable form of energy. A ton (2,000 pounds) of garbage contains about as much heat energy, as pounds of coal. Power plants that burn garbage for energy are called waste-to-energy plants. These plants generate electricity much as coal-fired plants do except that garbage-not coal-is the fuel used to fire an industrial boiler. Making electricity from garbage costs more than making it from coal and other energy sources. The main advantage of burning solid waste is it reduces the amount of garbage dumped in landfills by 60 to 90 percent, and reduces the cost of landfill disposal.

Landfill Gas

Bacteria and fungi are not picky eaters. They eat dead plants and animals, causing them to rot or decay. Even though this natural process is slowed in the artificial environment of a landfill, a substance called methane gas is still produced as the waste decays.

New regulations require landfills to collect methane gas for safety and environmental reasons. Methane gas is colorless and odorless, but it is not harmless. The gas can cause fires or explosions if it seeps into nearby homes and is ignited. Landfills can collect the methane gas, purify it, and then use it as an energy source. Methane, which is the same thing as natural gas, is a good energy source. Most gas furnaces and gas stoves use methane supplied by natural gas utility companies. The city landfill in Florence, Alabama recovers 32 million cubic feet of methane gas a day. The city purifies the gas and then pumps it into natural gas pipelines. Today only a tiny portion of landfill gas is used to provide energy. Most is burned off at the landfill. Why? With today's low natural gas prices, this higher-priced "biogas" has a hard time competing. Wheat, corn, and other crops can be converted into a variety of liquid fuels including ethanol and methanol. Using ethanol as a motor fuel is nothing new. Its use is almost as old as the automobile. In the early 20th century, automobile pioneer Henry Ford advocated using gasohol, a mixture of ethanol and gasoline, to run his cars.

Alcohol Fuels

Today ethanol is a high cost fuel and its use has become a controversial issue. It is estimated that a barrel of oil will have to more than double in price before ethanol can compete with gasoline as a transportation fuel. In spite of this, the ethanol industry has continued to grow, mainly because the federal government exempts ethanol fuels from the federal highway tax. This exemption has been extended to the year 2000. Because ethanol is expensive, and because car engines must be modified to run on pure ethanol, ethanol is usually mixed with gasoline to produce gasohol. (Cars can run on gasohol without adjustments.) Gasohol is 10 percent ethanol and 90 percent gasoline. In 1994, 12 percent of the nation's motor fuel consisted of this ethanol and gasoline mixture. However, in some corn-growing states, gasohol use is as high as 50 percent. Gasohol does have some advantages over gasoline. It has a higher octane rating than gasoline (provides your car with more power), and it is cleaner-burning than unleaded gasoline, with one-third less carbon monoxide emissions. Gasohol may also help reduce America's dependence on foreign oil.