Prompted by the oil crises of the 1970s, a wind-power
industry flourished briefly in the United States. But then world oil prices dropped, and
funding for research into renewable energy was cut. By the mid 1980s US interest in wind
energy as a large-scale source of energy had almost disappeared. The development of wind
power at this time suffered not only from badly designed equipment, but also from poor
long-term planning, economic projections that were too optimistic and the difficulty of
finding suitable locations for the wind turbines.
Only now are technological advances beginning to offer
hope that wind power will come to be accepted as a reliable and important source of
electricity. There have been significant successes in California, in particular, where
wind farms now have a capacity of 1500 megawatts, comparable to a large nuclear or
fossil-fuelled power station, and produce 1.5 per cent of the state’s electricity.
Nevertheless, in the US, the image of wind power is still
distorted by early failures. One of the most persistent criticisms is that wind power is
not a significant energy resource. Researchers at the Battelle Northwest Laboratory,
however, estimate that today wind turbine technology could supply 20 per cent of the
electrical power the country needs. As a local resource, wind power has even greater
potential. Minnesota’s energy commission calculates that a wind farm on one of the
state’s south western ridges could supply almost all that state’s electricity.
North Dakota alone has enough sites suitable for wind farms to supply more than a third of
all electricity consumed in the continental US.
The prevailing notion that wind power is too costly
results largely from early research which focused on turbines with huge blades that stood
hundreds of metres tall. These machines were not designed for ease of production or
maintenance, and they were enormously expensive. Because the major factors influencing the
overall cost of wind power are the cost of the turbine and its supporting systems,
including land, as well as operating and maintenance costs, it is hardly surprising that
it was thought at the time that wind energy could not be supplied at a commercially
competitive price.
More recent developments such as those seen on California
wind farms have dramatically changed the economic picture for wind energy. These systems,
like installations in Hawaii and several European countries, have benefited from the
economies of scale that come through standardised manufacturing and purchasing. The result
has been a dramatic drop in capital costs: the installed cost of new wind turbines stood
at $1000 per kilowatt in 1993, down from about $4000 per kilowatt in 1980, and continues
to fall.
Design improvements and more efficient maintenance
programs for large numbers of turbines have reduced operating costs as well. The cost of
electricity delivered by wind farm turbines has decreased from about 30 cents per
kilowatt-hour to between 7 and 9 cents, which is generally less than the cost of
electricity from conventional power stations. Reliability has also improved dramatically.
The latest turbines run more than 95 per cent of the time, compared with around 60 per
cent in the early 1980s.
Another misconception is that improved designs are needed
to make wind power feasible. Out of the numerous wind turbine designs proposed or built by
inventors or developers, the propeller-blade type, which is based on detailed analytical
models as well as extensive experimental data, has emerged as predominant among the more
than 20,000 machines now in commercial operation world-wide. Like the gas-driven turbines
that power jet aircraft, these are sophisticated pieces of rotating machinery. They are
already highly efficient, and there is no reason to believe that other configurations will
produce major benefits.
Like other ways of generating electricity, wind power does
not leave the environment entirely unharmed. There are many potential problems, ranging
from interference with telecommunications to impact on wildlife and natural habitats. But
these effects must be balanced against those associated with other forms of electricity
generation. Conventional power stations impose hidden costs on society, such as the
control of air pollution, the management of nuclear waste and global warming.
As wind power has been ignored in the US over the past few
years, expertise and commercial exploitation in the field have shifted to Europe. The
European Union spends 10 times as much as the US government on research and development of
wind energy. It estimates that at least 10 per cent of Europe’s electrical power
could be supplied by land-based wind-turbines using current technology. Indeed, according
to the American Wind Energy Association, an independent organisation based in Washington,
Denmark, Britain, Spain and the Netherlands will each surpass the US in the generating
capacity of wind turbines installed during the rest of the decade.