Introduction - Wind Energy: Renewable Energy and the Environment - page 11

TABLE 1.1
Number of Small Wind Systems in the World

Application Number

Total, electric generation 600,000

Village power; wind, wind hybrid, wind-diesel 1,800?

Telecommunications 200?

Farm windmill 300,000

has increased from 25-100 kW, 10-20 m diameter, to megawatt units, 60-100 m diameter, on tow-
ers of 80 to over 100 m. Over 1 GW has been installed in offshore wind farms. Production of elec-
tricity from wind farms is the cheapest source of renewable energy and is even less expensive than
new coal and nuclear power plants. Wind power has grown at around 25% per year for the past few
years, and global installation is predicted to reach 240 GW by 2012.

1.3 SMALL SYSTEMS
Small systems (Table 1.1), in general, are wind turbines of watts to 100 kW. Most small systems are
not connected to the grid and have battery storage, and the largest percentage is in the size range of
50-300 W. However, in the United States and other parts of the developed world a fairly large mar-
ket has developed for small wind systems, 1-10 kW, connected to the grid through inverters. The
telecommunications systems need high reliability, so they are hybrid systems with wind, photovol-
taic (PV) and battery storage, and diesel. Some of these locations are only accessible by helicopter.
As one-fourth of the world's population does not have electrical power, and as costs of diesel
generation have increased, there have been a number of installations of village power systems. Most
are hybrid systems, wind/PV, and a few with only wind, and both with battery storage. Another
system is wind/diesel, where some of the wind/diesel systems have storage and other systems have
wind turbines added to an existing diesel power plant [19]. The wind/diesel systems range in size
from less than 100 kW, with one or more wind turbines, to hundreds of kilowatts, with multiple
wind turbines.

LINKS
American Wind Power Center, www.windmill.com .
Danish Wind Industry Association, www.windpower.org/en/pictures/index.htm . History of wind turbines.
Darrel Dodge, http://telosnet.com/wind . An illustrated history of wind power development. This is a very
good overview.
Erik Grove-Nielsen, www.windsofchange.dk . Winds of change, 25 years of wind power development on
planet earth. A story in photos from the years 1975 to 2000. Site also has brochures of wind turbines.
European Wind Energy Association, www.ewea.org/ileadmin/ewea_documents/documents/publications/
WD/2007_september/wd-sept-focus.pdf. Wind directions , 25th anniversary. The Road to Maturity ,
September/October 2007 .
Farm windmills, http://windmillersgazette.com/index.html .

REFERENCES
1. Vaclav Smil and William E. Knowland. 1983. Energy in the developing world . Biomass Energies,

Plenum: New York.

2. Dennis G. Sheppard. 1994. Historical development of the windmill. In Wind turbine technology, fun-

damental concepts of wind turbine engineering , ed. David A. Spera, 1. ASME Press: New York.

3. International Molinological Society. www.timsmills.info .