Wind Energy

 Wind Energy

 

1. Introduction

Wind has considerable potential as a global clean energy source, being both widely available,
though diffuse, and producing no pollution during power generation. Wind energy has been one
of humanity’s primary energy sources for transporting goods, milling grain, and pumping water
for several millennia. From windmills used in China, India and Persia over 2000 years ago to the
generation of electricity in the early 20th century in Europe and North America wind energy has
played an important part in our recorded history. As industrialization took place in Europe and
then in America, wind power generation declined, first gradually as the use of petroleum and
coal, both cheaper and more reliable energy sources, became widespread, and then more sharply
as power transmission lines were extended into most rural areas of industrialized countries. The
oil crises of the 70’s, however, triggered renewed interest in wind energy technology for gridconnected
electricity production, water pumping, and power supply in remote areas, promoting
the industry’s rebirth.

This impetus prompted countries; notably Denmark and the United States, to establish
government research and development (R&D) programs to improve wind turbine technology. In
conjunction with private industry research this lead to a reemergence in the 1980’s of wind
energy in the United States and Europe, when the first modern grid-connected wind turbines
were installed. In the 1990’s this development accelerated, with wind becoming the fastest
growing energy technology in the world developing into a commercially competitive global
power generation industry. While in 1990 only about 2000 MW of grid-connected wind power
was in operation worldwide by 1999 this figure had surpassed 10,000 MW, not including the
over one million water-pumping wind turbines located in remote areas.
Since 1990 the average annual growth rate in world wind generating capacity has been 24
percent, with rates of over 30 percent in the last two years. Today there is more than 13,000 MW
of installed wind power, double the capacity that was in place just three years earlier (Figure 3).
This dramatic growth rate in wind power has created one of the most rapidly expanding
industries in the world, with sales of roughly $2 billion in 1998, and predictions of tenfold
growth over the next decade. Most 2000 forecasts for installed capacity are being quickly
eclipsed with wind power having already passed the 10,000 MW mark in early 1999.

2. Economics of Wind Energy

Larger turbines, more efficient manufacturing, and careful siting of wind machines have brought
wind power costs down precipitously from $2600 per kilowatt in 1981 to $800 per kilowatt in
1998. New wind farms in some areas have now reached economic parity with new coal-based
power plants. And as the technology continues to improve, further cost declines are projected,

which could make wind power the most economical source of electricity in some countries.
Market growth, particularly in Europe, has been stimulated by a combination of favorable
governmental policies, lower costs, improved technology (compared to wind turbines built in
1981, modern turbines generate 56 times the energy at only 9 times the cost), and concern over
environmental impacts of energy use.
Wind energy is currently one of the most cost-competitive renewable energy technologies.
Worldwide, the cost of generating electricity from wind has fallen by more than 80 percent, from
about 38 US cents in the early1980s to a current range of 3-6 UScents/kWh levelized over a
plant's lifetime, and analysts forecast that costs will drop an additional 20-30 percent in the next
five years. Consequently, in the not-too-distant future, analysts believe, wind energy costs could
fall lower than most conventional fossil fuel generators, reaching a cost of 2.5 UScents/kWh

Wind technology does not have fuel requirements as do coal, gas, and petroleum generating
technologies. However, both the equipment costs and the costs of accommodating special
characteristics such as intermittence, resource variability, competing demands for land use, and
transmission and distribution availability can add substantially to the costs of generating
electricity from wind. For wind resources to be useful for electricity generation, the site must (1)
have sufficiently powerful winds, (2) be located near existing transmission networks, and (3) beeconomically competitive with respect to alternative energy sources. While the technical
potential of wind energy to fulfill our need for energy services is substantial the economic
potential of wind energy remains dependent on the cost of wind turbine systems as well as the
economics of alternative options.

3.Conclusions

For the first time, we are seeing one of the emerging renewable energy generating options—wind
power—in a position to compete with the generation technologies of the last century. A variety
of players are engaged in pushing forward wind projects worldwide. Enron Wind Corporation
acquired German turbine manufacturer Tacke; NEG Micon of Denmark has built manufacturing
facilities in the U.S., Vestas of Denmark has built factories in Spain and India and many
manufacturers have developed joint ventures in various countries around the world. This
globalization trend is likely to continue as financial institutions are beginning to view the wind
industry as a promising investment opportunity. As more countries are added to the wind energy
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roster, uneven development focusing on a half-dozen key markets will most likely be replaced by
more balanced growth. During the next couple of years, large-scale projects are expected to be
developed in Egypt, Nicaragua, Costa Rica, Brazil, Turkey, Philippines, and several other
countries, totaling thousands of MW of new installed capacity, and expanding the number of
countries using their wind resources.
Yet, as land constraints, lower average wind speeds in future projects, as well as possibly lower
energy prices impact the economics of future projects wind penetration will likely begin to
saturate and the growth rates quoted above slow. This trend may be offset, however, by the use
of larger, more efficient turbines, where the average size per turbine installed has already
increased from 630 kW in 1997 to megawatt size systems in 1999, allowing operators to lower
generation costs. The increase in capacity factor (annual energy output/output based on full time
operation at rated power) from 20 percent to 25 percent also reflects improved efficiency and
siting of projects. In addition, the future development of offshore wind farms will open up new
frontiers in wind energy development.
The issue of wind power opportunity is likely to become increasingly relevant in determining its
future use in world electricity supply. Understanding wind prospects is important in expected
“normal” energy futures as well as for possible exceptional ones. As wind turbine costs decline
and their performance improves, the extent to which wind resources, transmission and
distribution networks, and market forces complement or offset these improvements becomes all
the more pertinent for near and mid-term electricity supply. If these additional factors have little
influence, then improved wind technologies may enjoy fairly rapid penetration into electricity
markets. To the extent that economically accessible wind resources are soon exhausted, networks
are full, or markets are resistant, however, wind power may find itself still a marginal source of
electric power supply.