Environmental Engineering Reference
In-Depth Information
Generation costs for onshore wind power plants in good to excellent wind conditions
average from 5 to 10 U.S. cents (2005) per kilowatt-hour, reaching 15 U.S. cents per
kilowatt-hour in lower resource areas. Offshore wind energy has typical generation costs
ranging from 10 to more than 20 U.S. cents per kilowatt-hour. The technology is more
expensive, yet it has greater potential for cost reductions in the near future (Wiser et al.
The Potential of Wind Power
In the first decade of the twenty-first century, global installed wind power capacity
increased from 14 to 200 GW. At first, Germany, Spain, and the United States led the
way in the use of wind power, but now the big growth is in Asia, with China alone
accounting for half of all new wind power capacity in 2010 (REN21
2012
). Despite the
rapidexpansion ofwindpower,itaccounts forjustatinyfraction ofcurrent primary energy
production (0.2 per cent), and only 2-3 per cent of global electricity production (Wiser et
All experts agree that the potential of wind power is far greater than current capacity,
but they differ on how much greater. Estimates of global technical potential range from 70
exajoules per year (19,400 TWh per year) to 3,050 exajoules per year (840,000 TWh per
year), that is, from less than 10 per cent to 600 per cent of global energy production (530
EJ).
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Regardless of whether the optimistic or the pessimistic estimates are more accurate,
the main barrier to the expansion of wind power in the next few decades will not be the
strengths of the winds themselves, but rather economic constraints (such as investments
and subsidies), grid access, social acceptance and environmental impacts (Wiser et al.
4.4 Solar Thermal
As a result of the nuclear reactions occurring at its core, the sun radiates both matter and
energy; matter in the form of solar winds (a stream of highly charged electrons, protons
and neutrons), and energy in the form of electromagnetic radiation. The Earth's atmosphere
largely shields us from the effects of solar winds, though they are felt as magnetic storms
that can interfere with communications technologies, and manifest themselves visually
in the auroras (Northern and Southern Lights) and the streaking tails of comets.
Electromagnetic radiation, on the other hand, is keenly felt. In fact, without it there would
be no life on our planet. It travels through space in the form of a wave, but instead of
