Electricity produced by wind turbines is growing faster than any other sustainable energy source. The United States currently has about 35 GigaWatts installed capacity. With a capacity factor of .35. This means we’re producing about 100,000 GWhs per year, or over two percent of total electric production.
The history of wind power begins with sail boats over 3,000 years ago. Not long there after, the sail was adapted to the blade of a windmill to do jobs such as grinding grain and pumping water. Until rural electrification came to the midwestern U.S., a lot of ranches/farms were provide with water from the iconic Aeromotor windmill.
Current turbine technology has evolved from simply doing mechanical work to cleanly generating renewable energy in the form of electricity. Turbine capacities range from small 5 kW turbines to power a single family home to the largest which currently have a capacity of 7 megawatts. These giants stand almost 1,000 feet tall and have a blade diameter of more than 400 feet. Just one of these operating normally could supply all the electricity for around 1,500 homes.
There is some potential for wind power in virtually every state, but the midwestern states hold the highest potential. All the electricity needs of the country could be supplied by wind power from just four midwestern states:The Dakotas, Kansas and Texas, if there were sufficient transmission and storage capacity. But that is a very, very big if.
Realistically up to about 10 percent of the electricity needed in this country could be covered by wind without any changes to the infrastructure of the electrical grid. This is because power companies have to have that kind of flexibility in production capacity to meet variable demand. This means clean wind energy production can quadruple or more. Importantly, this increase in power production can be done incrementally, at lower cost that the one time construction of nuclear or coal plants.
From about 10 to 25 percent wind energy penetration, infrastructure changes will have to be made to maintain continuous power production. This can be done by a combination of a larger grid with wind forecasting which will allow for the movement of power from one locale to another. Expansion of wind power beyond 30 per cent of total needs can be done but at a higher cost. For each kilowatt of wind electric there will be a need for a kilowatt of stand by, ready reserve power. This can be provided by natural gas fired turbines, the power of which is matched with the wind field.
The biggest technological impediment to even greater expansion of wind generated electricity is the issue of storage. A robust wind system would be able to produce more power than demanded at times, but excess capacity can’t be stored. Novel storage mechanisms are being explored including compressing air in subterranean caverns or pumping water up into reservoirs. These strategies have the potential to store power over hours or possibly days. The future of wind and other clean sustainable energy sources rests in the hands of the scientists and engineers of the future who will solve the storage and transmission issues.
The only major environmental concern with wind turbines is associated with bird and bat kills. The most recent studies show that selecting sites for wind fields which avoid major migratory pathways for both birds and bats greatly reduces mortality. Regardless, bird and bat mortality from wind turbines is extremely low compared with collisions with other man made structures.