Massive solar-chimney project takes steps toward launch

by Ryan Randazzo - Dec. 10, 2010 05:30 PM

The Arizona Republic

The ambitious plans to build two of the tallest manmade structures on Earth in western Arizona are progressing, according to EnviroMission Ltd. CEO Roger Davey, who recently visited Phoenix from Australia.

EnviroMission is developing two solar-power plants in La Paz County that would be the first of their kind.

EnviroMission has an agreement to sell power from its first solar tower to the 10 municipal utilities in the Southern California Public Power Authority, including the Los Angeles Department of Water and Power. The power plant would use a 4-square-mile greenhouse to heat air and direct the heated air to a 2,400-foot-tall concrete chimney.

Hot air rising through the chimney will spin turbines to make electricity, just as turbines in hydroelectric dams on rivers make electricity as water pours over them.

The greenhouse and chimney concept was tested in the 1980s in Spain on a smaller scale.

EnviroMission's plans are for each tower to have a capacity of 200 megawatts, which would be enough electricity for about 50,000 houses at once.

Unlike most solar projects, they would generate power after dark because the land under the clear plastic ceiling on the greenhouse would stay warm and continue to make hot air after sunset, Davey said.

The numbers are intimidating, but Davey said that the benefits of making power without using water or creating pollution should attract investors to fund the estimated $750 million construction cost of the first tower.

Davey downplayed the size and scope of the chimney, which would be nearly as tall as the recently opened Burj Khalifa in Dubai, which is the tallest manmade structure ever built, at more than 2,700 feet.

Because engineering work is still under way, the exact height of the chimney could change. And building a concrete cylinder without windows or doors is much simpler than a skyscraper with plumbing, electrical and other features for people to occupy the building, he said.

EnviroMission has engaged global engineering firm Arup, known for its "Water Cube" at the 2008 Beijing Olympics, to finalize the construction plans for the solar tower.

Before construction, EnviroMission will apply for project approval with the state's Power Plant and Transmission Line Siting Committee and is soon to announce financing that will carry the project through the design phase up to construction, he said. Davey said that he had been raising capital investment in waves to fund one portion of development at a time.

He said he was not concerned about raising the needed funds, even as other big Arizona solar projects using better-known technologies and designs have struggled to attract capital.

Before launching EnviroMission, he was a director of Australia's largest stock-broking firm, McIntosh Risk Management Ltd., now Merrill Lynch, according to his company biography.

Davey and his son, Christopher, who is engaged in business development for EnviroMission, have much bigger plans for solar towers than the Arizona projects. Once they prove the concept, they want to develop them globally.

EnviroMission shares are traded on the Australian stock exchange and on the over-the-counter market in the U.S.