Sunday, November 7, 2010

Arizona Solar Tower Will be Largest Building in World

The first large-sized solar tower in the world will be developed in Arizona in the US, following the Southern California Public Power Authority (SCPPA) approval of the purchase agreement for power from the plant.

The tower will be three times as high as the Eiffel Tower, and will be the tallest building in the world when built.

The next-generation plant, proposed by Australian company EnviroMission, will employ a new technology to build a one-kilometre-high, 130-metre-wide cylindrical tower, heating air which will be used to power 200 MW wind turbines.

A solar tower combines the power of both solar and wind, also known as solar updraft technology, to generate as much energy as possible.

According to Enviromission, the structure generates energy by using the sun’s radiation to heat a large body of air stored under a large collector zone. Since hot air rises, it is forced by physics to move as a hot wind through a shaft lined with large turbines, which generate electricity.

The air temperature beneath the tower will be raised by the sun’s heat to more than 70°C, forming hot drafts that can power thirty-two 6.5MW wind turbines. The facility would be able to operate at full capacity for 12 hours a day.

GetSolar comments that the ‘green’ credentials of the solar tower “might be in doubt once one considers the massive energy cost of erecting such a structure. But by entering into a Project Performance Analysis (PPA) with SCPPA, EnviroMission has taken a first step that allows it to begin planning and trying to get funding for its sky-high ambitions, since it has a definite customer for a plant that could generate as much as 200 MW of renewable solar energy without the use of silicon or water.”

EnviroMission CE Roger Davey said: “Finalisation of this PPA with SCPPA is an important milestone that will allow project finance to be secured and the front end engineering and design necessary to break ground at the earmarked Arizona site to commence.”

Melbourne-based EnviroMission, which has a US subsidiary in Phoenix, Arizona, offers a solar generating technology it says can operate without water, which is often used in cooling systems for solar thermal plants though scarce in many areas with a high solar potential.

A small pilot facility using similar technology was run in Spain during the 1980s, producing about 50 kW of power, but the technology has not yet been deployed at the scale planned for Arizona.

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