Rise of the Machines
A modern wind farm, when installed on agricultural land, has one of the lowest environmental impacts of all energy sources:
It occupies less land area per kilowatt-hour (kWh) of electricity generated than any other energy conversion system, apart from rooftop solar energy, and is compatible with grazing and crops.
It generates the energy used in its construction within just months of operation.
Greenhouse gas emissions and air pollution produced by its construction are small and declining. There are no emissions or pollution produced by its operation.
The construction of offshore wind turbines has vastly increased the market.
Modern wind turbines rotate so slowly (in terms of revolutions per minute) that they are rarely a hazard to birds.
Modern wind turbines have sound power levels between 100 and 110dBA, about the same as a heavy lorry travelling along a motorway. Although they appear to rotate slowly the tip speed is about 75m/s (170mph) and it is the blade passing through the air at this speed that generates most of the sound.--Allprogress (talk) 06:35, 10 May 2008 (UTC)