How much confidence do we have in the science?
Researchers use the scientific method to search for cause and effect relationships. This method requires that a
hypothesis be constructed. Scientists then design an appropriate well-controlled experiment to test that hypothesis. The results must be statistically significant and reproducible in order to be considered valid. There are a number of techniques that can be used to enhance the objectivity of a study as well as increase its statistical reliability.
In prospective medical research for example, we often use double blind, placebo controlled studies so that neither the researcher nor the patient knows if they are receiving the active drug or a placebo. This eliminates observer bias. Some times we cross the patient's over, so that the same patient takes both the active…
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Coal-fired plants produce approximately 50% of the electricity in the United States and 82% of power generated carbon dioxide
emissions. If electric vehicles are charged exclusively by coal-fired electricity they produce more green house gases than a traditional gasoline-powered combustion engine car. In the future, electricity must be generated cleanly, if we expect automotive electric-drive technologies to reduce our carbon dioxide burden.
Wind and
solar will probably make a significant contribution to clean energy generation, but realistically, we cannot count on these two sources for more than 20-30% of our electricity needs in the next 20 years. Even reaching these modest goals will require a major investment in energy infrastructure and fundamental advances in technology. Nuclear power may be the only clean alternative.
In the United States…
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Only one industrial country in the world has significantly reduced its carbon footprint, and that country is France. France, the sixth largest economy in the world, ranks 15th in
carbon dioxide emissions, behind pre-industrial economies like Iran and Indonesia. France has simultaneously, reduced its dependence on foreign sources of fossil fuels, coal, natural gas and oil. While we dither with small-scale experimental intermittent technologies like
solar and
wind in the United States, France has gone nuclear and clean. In 2008
wind and solar accounted for 1.1% of US energy needs and even if we meet President Obama's objective of doubling the amount by 2012, its contribution will still be inconsequential. In the best-case scenario for wind and solar, they might together generate 20%-25% of our clean…
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Hydroelectricity is the most widely used form of
clean renewable energy in the world, generating over 19% of the world's electricity. It requires no fuel and produces no direct emissions or by-products. The United Nations estimates that the technically exploitable potential for
hydropower is 15 trillion kilowatt-hours per year, amounting to half of the total projected global electricity needed in 2030. In the United States, hydropower has fallen to 10% of the electricity supply mix down from14%, 20 years ago. In terms of electricity production, hydropower accounts for only 7% of America's current power needs.
Source US Department of Energy
In theory, the mechanics of a
hydropower plant
There are two basic types of
solar electricity plants:
Solar thermal, also called Concentrating Solar Power (CSP), and
Photovoltaic. CSP generates high-temperature heat through the use of various mirror configurations, which is then used to make electricity utilizing traditional heat-conversion technology. Photovoltaic solar power in contrast, converts sunlight directly into electricity.
Concentrating Solar Power
Solar thermal electricity is an attractive renewable energy option in the southwestern United States and other Sunbelt regions.
Concentrating Solar Power (CPS) systems can be sized at a capacity for village power (10 kilowatts), or a number of smaller systems can be connected to a larger grid. According to the
Solar Energy Industries Association, solar thermal electric systems operating in the U.S. today using parabolic trough design meet the needs of over 350,000…
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