Dear “Earth Talk”: Aside from wind power,
which seems to be gaining in acceptance, what are some other promising
sources of nonpolluting renewable energy?
— Bianca Hoffman, Bridgeport, Conn.
Wind power certainly has been in the news lately, with
wind farms sprouting up across America from California to the Atlantic
seaboard. By the end of 2004, U.S. wind capacity neared 6,800 megawatts,
enough to power 1.5 million homes every year. And new projects in the works
will add at least 3,000 megawatts of capacity over the next five years,
according to the American Wind Energy Association.
Although wind is getting most of the headlines,
hydropower — energy generated by water flowing through turbines in
dams — is still king of the renewables. Globally, hydropower
generates 20 percent of the world’s electricity. In Canada, the
world’s largest generator of hydropower, more than 60 percent of the
electricity produced comes from the power of water. Norway gets almost 99
percent of its electricity from hydropower, and New Zealand is close behind
at 75 percent. In the United States, about 10 percent of all electricity
— enough to power 35 million homes every year — comes from
hydropower.
Although hydropower does not generate pollution, per
se, it has hurt salmon populations on both U.S. coasts and often ruins
habitat for wildlife and people. In China and India, large, controversial
dam projects have flooded huge areas of land and forced the relocation of
whole communities.
One of the world’s oldest fuel sources, biomass
— the burning of plant material for energy — is enjoying a
renaissance thanks to plentiful supplies of agricultural, forest, and wood
waste. Proponents of biomass — or “bioenergy” — say
that it could be harnessed as a clean alternative to coal in power plants.
Biomass now accounts for 7,000 megawatts of U.S. energy generation, which
puts it on equal footing with wind energy.
Solar-powered “photovoltaic” cells,
although they now account for only about 1,500 megawatts of power annually
in the United States, promise to play a larger role in our energy future.
Solar cells keep getting smaller and less costly, are highly reliable, and
don’t pollute. And fuel cells, which run on hydrogen and emit water
as the only byproduct, hold much promise not just for powering cars (all
the major carmakers are developing practical hydrogen-fueled cars) but also
for powering buildings and other stationary structures as well.
Despite the promise of renewables, though, the United
States still generates more than 90 percent of its energy from nonrenewable
and polluting sources such as coal and petroleum — and there is talk
of a nuclear revival despite the potential dire consequences of a nuclear
accident or terrorist act. Finding more efficient ways to harness solar
energy is a top priority for many environmentalists; the Earth receives
more energy from the sun in just one hour than the world uses in a whole
year.
For more information: American Wind Energy
Association, www.awea.org; National Hydropower Association, www.hydro.org;
American Bioenergy Association, www.biomass.org; U.S. Department of Energy
Renewable Fuels Program, www.eia.doe.gov/fuelrenewable.html.
Send questions to “Earth Talk” in care of
E/The Environmental Magazine, P.O. Box 5098, Westport, CT 06881, or e-mail
earthtalk@emagazine.com.
This article appears in Jun 30 – Jul 6, 2005.
