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5th-Background Information for Teachers





Alternative Energy Sources

Most of this information is from By Jeffrey Orloff 's article available at http://saveenergy.about.com/od/alternativeenergysources/a/altenergysource.htm

  • Across the globe, humans burn fossil fuels to provide the majority of their domestic, transportation and industrial energy needs. These fossil fuels have increased the levels of CO2 and other gases in the atmosphere causing pollution and health problems.
  • Sources of energy that do not come from fossil fuels are called alternative energy sources. Some, like wind and hydro power, have been used for years, and some new ones are being discovered and developed. These alternative sources of energy, like fossil fuels, have benefits and problems. The major benefit is that these are renewable and usually cause less pollution than fossil fuels.
  • Texas has been a leader in the use of wind energy and solar energy for domestic and industrial use. So far, these sources are not used successfully for the nation's transportation needs.

There are many reasons we are looking towards alternative energy sources. Efforts to reduce pollutants and greenhouse gases are a primary focus in today's culture. Alternative or renewable energy sources show significant promise in helping to reduce the amount of toxins that are by-products of energy use. Not only do they protect against harmful by-products, but using alternative energy helps to preserve many of the natural resources that we currently use as sources of energy.

Wind Power

Wind energy harnesses the power of the wind to propel the blades of wind turbines. The rotation of turbine blades is converted into electrical current by means of an electrical generator. In older windmills, wind energy was used to turn mechanical machinery to do physical work, like crushing grain or pumping water. Wind towers are usually located together on wind farms.
    Large scale wind farms generate electricity that is sent to electrical grids. Small or individual turbines provide electricity to isolated locations or individual homes.

Pros

  • In wind power generation, no chemical processes take place, like in the burning of fossil fuels so, there are no harmful by-products left over.
  • Since wind generation is a renewable source of energy, we will never run out of it.
  • Farming and grazing can still take place on land occupied by wind turbines.
  • Wind farms can be built off-shore.

Cons

  • Wind power is intermittent. Consistent wind is needed for continuous power generation. If wind speed decreases, the turbine lingers and less electricity is generated.
  • Large wind farms can have a negative effect on the scenery and on migratory species.

Solar Power

Solar energy is used commonly for heating, cooking, the production of electricity, and even in the desalination of seawater. Solar power works by trapping the sun's rays into solar cells where this sunlight is then converted into electricity. Additionally, solar power uses sunlight that hits solar thermal panels to convert sunlight to heat water or air. Other methods include using sunlight that hits parabolic mirrors to heat water (producing steam), or passive solar use such as opening blinds or window shades to allow entering sunlight to passively heat a room.

Pros

  • Solar power is a renewable resource. As long as the sun exists, its energy will reach Earth.
  • Solar power generation releases no water or air pollution because there is no chemical reaction from the combustion of fuels.
  • Solar energy can be used very efficiently for practical uses such as heating and lighting.

Cons

  • Solar power does not produce energy if the sun is not shining. Nighttime and cloudy days seriously limit the amount of energy produced.
  • Solar power stations can be very expensive to build, and the production has an environmental impact.
  • Efficient and accessible storage batteries have not been developed.

Biofuels

(Information from Wikipedia)

The energy in a biofuel is derived from biological carbon fixation. Biofuels include fuels derived from biomass conversion, as well as solid biomass, liquid fuels and various biogases. Biofuels are gaining increased public and scientific attention, driven by factors such as oil price hikes and the need for increased energy security.

Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as corn or sugarcane. Cellulosic biomass, derived from non-food sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the USA and in Brazil.

Bodiesel is made from vegetable oils and animal fats. Biodiesel can be used as a fuel for vehicle in its pure form, but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using trans esterification and is the most common biofuel.

Biodiesel is of interest because:

  • It is a renewable fuel which can help reduce our dependence on imported fossil fuels.
  • It has a lower carbon footprint than petro-diesel, and so can help reduce greenhouse gas emissions.
  • It produces less air pollution than conventional diesel.
  • It can provide an additional source of income to farmers who grow oilseed crops.

According to the EPA's Renewable Fuel Standards Program Regulatory Impact Analysis, released in February 2010, biodiesel from soy oil results, on average, in a 57% reduction in greenhouse gases compared to fossil diesel. Biodiesel produced from waste grease results in an 86% reduction.

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