One of the more interesting alternative energy proposals is a SolarChimney where a giant glass inverted funnel heats the air at the base and as it rises it is forced through a chimney a kilometer high and a turbine to generate electricity. What makes it attractive is the low-tech nature of the project. It requires a lot of glass and concrete but not ceramics or microchips. A SolarChimney can be built using the resources local to underdeveloped countries instead of indebting the nation further. * http://www.gluckman.com/SolarChimney.html A 200 megawatt solar chimney is being built in Australia. It has recently been granted all necessary government approvals. At one kilometer (2/3 of a mile) high, it will be the tallest artificial structure on Earth. * http://www.wentworth.nsw.gov.au/solartower/ This follows on from a smaller 80 megawatt tower in Spain. The scale of these two projects certainly demonstrates the economic and technical feasibility of these designs. The chimney need not be glass, nor funnel shaped. It is highly probable that there are application of the solar-thermal invection principle to small-scale and homebrew projects in the tens to hundreds of watts scale. A tower could be constructed from a few meters (yards) of standard steel drainpipe, painted or galvanised black, with a small high-speed fan, such as a computer fan. An appropriately shaped vent at the top could add the effect of passing winds to the thermal updraft. Any further information on such projects would be welcomed. NB in case you were wondering, the fan can be mounted at the base of the tower to save on construction costs, by keeping the weight down low. The Australian project is configured in this way. Solar-thermal chimneys are also used to create forced-airflow ventilation in many traditional architectures, as well as in modern energy-smart home design. In remote areas of Australia, they are used to evacuate noxious odours from public restroom facilities in national parks. - by Clae http://melbourne.wireless.org.au/wiki/?Clae See AlternativeEnergy 'Hybrid Geothermal/Solar Energy Technology For Power Generation' The novel proposed schemes of hybrid Solar Chimney Power Plant (SCPP) offer a number of potential advantages and represents an innovative way to reduce cost and minimizing the environmental impact. They are based on thermal conversion, which allows hybrid operation with both solar radiation and low temperature geothermal to continue generating electricity even when sunlight is not available. New schemes of Hybrid SCPP, developed by Dr. Hussain Alrobaei, would fully exploit the potential of the geothermal/solar combination, based on the following principles: - supply solar heat to the transparent solar PV/T arrays , to achieve the highest possible conversion efficiency, - supply low temperature geothermal heat to the collector zone, to achieve the highest possible geothermal contribution, - hybrid geothermal/solar operation, to provide dispatchable full capacity at sunny and cloudy periods of operation, without solar-specific restrictions on the plant’s operation.