5.1.2 Key Events

Year
644	Earliest possible mention of a Persian windmill
950	First record of a windmill, in Sistan, Eastern Persia (vertical axis)
1185	Horizontal axis windmill developed in England
1219	Chinese reference to windmills in Samarkand
1270	English post mill illustrated in a manuscript
1390	Tower mills recorded in Europe
1745	Invention of fantail (automatic yaw turbine) by Edmund Lee
1759	First scientific paper on wind rotor performance (John Smeaton)
1854	American wind pump (Halladay Standard)
1888	Electricity generated by wind (Brush, USA)
1895	Wind tunnel for wind rotor design (LaCour, Denmark)
1925	Propeller type rotor (2.5 kW, Jacobs, USA)
1925	Darrieus vertical axis rotor invented (France)
1926	Maximum energy conversion formulated (Betz limit, Germany)
1931	100 kW AC wind generator (Russia)
1941	1.25 MW generator (Smith-Putnam, USA)
1980	Wind farms in California
1991	First UK wind farm

 

5.1.3 Electricity generation

Windmills and windpumps continued to be used until displaced by electric motors during the 20th century. But by that time the wind was already being used to generate electricity. Commercial success was initially confined to local battery chargers for remote locations not served by an electricity grid, typically with 2 or 3 bladed propeller type rotors derived from aircraft engine technology. Several projects in Russia, USA and Britain demonstrated the feasibility of increasingly large individual aero-generators, but could not compete with the decreasing costs of electricity from fossil fuels.

Only after oil supplies were first threatened by the Arab-Israeli war of 1973 did the USA adopt tax credit legislation to stimulate alternatives, particularly wind turbine construction. This was mainly taken up in California, where for the first time a large number of small wind turbines were installed on a common windy site to form a wind farm. A few such wind farms effectively became development sites for manufacturers from both USA and Europe (notably Denmark which had been at the forefront of wind turbine development). Although it was initially expected that economies of scale would favour very large machines (e.g. 4 MW), in practice, as with the windpump, series production of smaller machines has been found to be more effective commercially. The new vertical axis rotor (earlier invented by Darrieus) has been well represented but has not proved as competitive as first supposed. By 1985, California had installed over 1200 MW of wind powered generators, considerably more than the whole of the rest of the world. More recently, however, incentives have waned in USA but been taken up in Europe to much greater effect.