Wind farm - Definition

A wind farm is a collection of wind turbines all in the same location. The wind turbines are used for the generation of electricity.

Wind farms can be positioned on land or offshore. In Europe, offshore farms are more common. In the United States, offshore farms are in the early stages of implementation.

Arguments for wind farms include:

• Wind energy is a free, inexhaustible renewable resource.
• Wind energy is a source of clean, non-polluting electricity. A single utility-scale (750 kW) wind turbine can prevent the emission of 5000 tons of carbon dioxide (CO2) into the atmosphere each year. It would take 500 acres (2 km²) of forest to absorb that much CO2.
• California wind plants effectively save the energy equivalent of 4.8 million barrels (760,000 m³) of oil per year.
• Wind power plants can help increase our nation's energy security. They are modular and can be constructed more quickly than conventional energy plants to meet emergency energy needs. Also, the energy they produce displaces imported fuels.
• Wind energy provides more jobs per dollar invested than any other energy technology.
• Wind energy can provide additional income for ranchers and farmers.
• Wind power plants may increase property tax revenues for local communities.

Arguments against wind farms include:

• Visual impact is sometimes considered undesirable, especially on otherwise undeveloped mountain ridges.
• Besides construction of towers (with substantial concrete and steel foundations), turbines, and blades, they require transformers, substations, roads, and transmission lines, further increasing their environmental impact.
• Noise might be excessive, both the hum of the blades resisting the air and the swishing sound -- including, some claim, a deep thumping felt farther away -- as the blades pass the tower. The problem is aggravated by the combined effect of many turbines together.
• Wildlife are affected, particularly birds of prey, night-migrating birds, and bats killed by the rotors.
• Impact on energy use is debated: critics note that electricity itself is only a small part of total energy use; wind is unlikely to displace oil-generated electricity (typically used for emergency backup during surges of demand); electricity produced by wind turbines may fluxuate, requiring energy to be imported or exported based on demand.
• A cost-benefit analysis which factors in these problems makes large-scale wind power on the grid less favorable.

Wind farms in the US

Numerous small and fast turning wind turbines at Altamont Pass

One of the earliest large wind farms is located at Altamont Pass in northern California. This is composed of large numbers of relatively small wind turbines of various types. They were installed after the 1970s energy crisis in response to favorable tax policies for investors. It has been said that their primary product is not electricity but rather tax write-offs. Considered largely obsolete these numerous small turbines are being gradually replaced with much larger and more cost effective units. The small turbines are dangerous to various raptors that hunt ground squirrels in the area. The larger units turn slower and being elevated higher are less hazardous to the local wildlife. An advantage of this particular site is that under hot inland (Central Valley) conditions a thermal low is developed that brings in cool coastal marine air through this pass, driving the turbines at a time of maximum need. Unfortunately this is not always reliable and with an inland high pressure condition the entire region can be both hot and windless. At this time additional power must be provided by natural gas powered gas turbine peaker plants.

Wind farms in Europe

A modern wind farm near Copenhagen using large and slow turning wind turbines.

The development of wind farms in Europe enjoys greater public acceptance and creates a larger share of energy.

Wind farms in Japan

There is no particular controversy about the sightliness or otherwise of this wind farm, as in some other countries. It is far from the scenic areas of Wakamatsu, and on windy reclaimed land. See Wakamatsu ward in Kitakyushu.