One of the questions most often asked about wind power
is ‘what happens when the wind doesn’t blow’. In the big picture wind
is a vast untapped resource capable of supplying the world’s electricity
needs many times over.
In practical terms, in an optimum, clean
energy future, wind will be an important part of a mix of renewable
energy technologies, playing a more dominant role in some regions than
in others. However, it is worthwhile to step back for a minute and
consider the enormity of the resource.
Researchers at Stanford
University’s Global Climate and Energy Project recently did an
evaluation of the global potential of wind power, using five years of
data from the US National Climatic Data Center and the Forecasts Systems
Laboratory 1). They estimated that the world’s wind resources can
generate more than enough power to satisfy total global energy demand.
Using
only 20% of this potential resource for power generation, the report
concluded that wind energy could satisfy the world’s electricity demand
in the year 2000 seven times over.
After collecting measurements
from 7,500 surface and 500 balloon-launch monitoring stations to
determine global wind speeds at 80 meters above ground level, they found
that nearly 13% had an average wind speed above 6.9 meters per second
(Class 3), sufficient for economical wind power generation.
Offshore Resources
North
America was found to have the greatest wind power potential, although
some of the strongest winds were observed in Northern Europe, while the
southern tip of South America and the Australian island of Tasmania also
recorded significant and sustained strong winds. To be clear, however,
there are extraordinarily large untapped wind resources on all
continents, and in most countries; and while this study included some
island observation points, it did not include offshore resources, which are enormous.
Scale of large wind turbines |
For
example, looking at the resource potential in the shallow waters on the
continental shelf off the densely populated east coast of the US , from
Massachusetts to North Carolina, the average potential resource was
found to be approximately four times the total energy demand in what is
one of the most urbanized, densely populated and highest-electricity
consuming regions of the world 2).
The
WBGU calculations of the technical potential were based on average
values of wind speeds from meteorological data collected over a 14 year
period (1979–1992). They also assumed that advanced multi-megawatt wind
energy converters would be used. Limitations to the potential came
through excluding all urban areas and natural features such as forests,
wetlands, nature reserves, glaciers and sand dunes. Agriculture, on the
other hand, was not regarded as competition for wind energy in terms of
land use.
Looking in more detail at the solar and wind resource in 13 developing countries, the SWERA (Solar and Wind Energy Resource Assessment)
project, supported by the United Nations Environment Programme, has
found the potential, for instance, for 7,000 MW of wind capacity in
Guatemala and 26,000 MW in Sri Lanka. Neither country has yet started to
seriously exploit this large resource.
After this initial pilot
programme, SWERA has expanded since 2006 into a larger programme with
the aim of providing high quality information on renewable energy
resources for countries and regions around the world, along with the
tools needed to apply this data in ways that facilitate renewable energy
policies and investments. The private sector is also getting into the
resource-mapping business, with Seattle based 3Tier launching its
‘mapping the world’ programme in 2008, with the goal of making
accessible resource assessments available for the entire world by 2010.
In
summary, wind power is a practically unlimited, clean and emissions
free power source, of which only a tiny fraction is currently being
exploited.
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