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Renewable Energy Report Card

  • Posted by Mitchell Flexo on May 2, 2012 in Energy
  • After our look at the major fossil fuels -- coal, oil, nuclear, and natural gas, which account for close to 90% of American energy production -- we know the pros and cons of each source of dirty energy. Now let's take a look at some renewable energy sources and see how they grade out. These sources account for about 10% of our energy production.

    Hydroelectricity

    Hydro is considered to be a renewable energy source because it relies on the water cycle. River water is pushed through turbines, usually at a dam, and the falling water creates kinetic energy that sends electricity into the grid. The water is then returned to the stream below. Hydroelectricity relies on precipitation and elevation changes, so the Pacific Northwest particularly well-suited for this type of energy creation. While there is no pollution from hydroelectricity, building dams can have negative effects on fish and wildlife, and can also displace people. It is not feasible everywhere, and should be looked at on a case by case basis.

    Grade: B- (zero pollution, negative wildlife effects)

    Biomass

    Biomass is considered a renewable energy source because it relies on burning different fuel types that are generated as waste. Some examples include corn husks, grass clippings, and trees, among many others. The plant material is burned, releasing heat that creates steam and subsequently electricity. Think of it like a coal powerplant, except that you are burning various plant wastes instead of coal. Burning biomass creates emissions of nitrogen oxides and a small amount of sulphur dioxide. It also releases some carbon dioxide, but is considered net zero since the plants absorbed CO2 while growing, then cancel it out when burned. The levels of sulphur and nitrogen are much less than coal, and it is often used as a supplement to coal to reduce the emissions. There is some water pollution from cooling the turbines and putting the water back into nature, but biomass power plants can reduce our need for landfills by creating energy out of waste.

    Grade: B (low pollution levels, recycling waste for energy)

    Geothermal

    This is a cool one. Geothermal projects tap into the earth's volcanic activities and channel the underground heat to power turbines and create electricity. This heat is constant, but does not exist everywhere in the world. Wells are drilled into the crust to access this energy -- the closer the heat is to the crust the easier this is. Much of the Western U.S. is prime geothermal real estate, and it is thought that there are great undiscovered resources that could massively increase our geothermal production. There are no emissions from geothermal since nothing is burned. Some groundwater pollution can occur from drilling the wells, but this can be easily avoided with proper management techniques.

    Grade: A (zero pollution, renewable supply)

    Wind

    Wind is everywhere. How much is classifed by a rating between 1 and 7, with 7 being the windiest. All Great Plains states and mountainous areas produce enough wind to warrant having turbines. Wind spins the blades, which are connected to the main shaft. The shaft then spins a generator and creates electricity. There are zero emissions from wind turbines but noise pollution can be a problem (although engineers are working to reduce turbine noise). They can also be a hazard to birds, but this problem is also being addressed by engineers. The turbines can be located on land or offshore. On land they can be placed on cattle ranches or farms. The technology is relatively expensive, but prices are dropping and efficiency levels are increasing.

    Grade: A (zero pollution, renewable supply)

    Solar

    The sun isn't going anywhere, and neither is the energy that it creates. Photovoltaic (PV) panels contain conductive materials that act as a catalyst for electricity creation when struck by light. Solar-thermal systems concentrate the sunlight with mirrors and use it to heat a liquid, creating steam and eventually electricity. Sunlight finds its way everywhere, although some areas are better than others. It is said that a 100-by-100-mile section of the American Southwest could meet all of the nation's electricity requirements. Solar energy creates zero emissions. Small amounts of solid waste are created from producing the conductive materials in the photovoltaic cell and they must be disposed of properly. PV systems can be placed on existing structures, minimizing space requirements. Larger installations require large amounts of land, which can have negative wildlife impacts due to the amount of required space.

    Grade: A (zero pollution, renewable supply)

    Compared with our failing non-renewable friends, it looks like we've found the answer to our energy demands. A shift towards these energy sources is the logical next step. Ten percent of energy production is not enough. We must start the transition now, even though it could mean billions of dollars in profit losses for fossil fuel companies, and job losses in their industry. It will create jobs of its own, and allow mankind to continue our existence on planet Earth. What are we waiting for?

    Photo: Toby Smith


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