Researchers Aim To Shed More Light on Solar's Potential

From foggy San Francisco to the Nevada desert, and to Australia's arid outback, solar-power researchers are looking at new sites and new technologies to boost emissions-free approaches to electricity generation:

• In an unlikely bid to make a notoriously un-sunny city the nation's largest municipal generator of solar power, San Francisco's Public Utilities Commission is conducting a study to determine the best neighborhoods for photocell installations. Project managers are placing a number of rooftop solar-energy monitors that are equipped with transmitters, allowing researchers to gather data and compile it into a centralized "fog map."

By targeting its sunniest areas, the city hopes to install photocell capacity of 10 MW over the next five years. This is the initial step in a long-term goal of 40 MW of capacity. The first major installation is scheduled to begin in March, when workers will cover the roof of the Moscone Convention Center with enough photovoltaic cells to generate 675 kW of electricity.

• Researchers at the University of Nevada, Las Vegas, have considerably less difficulty finding available sunlight in their work to develop efficient large-scale solar-based generating systems. The group is one year into a demonstration study of two large parabolic dishes capable of generating up to 25 kW each. The dishes feature mirrored surfaces that heat up an internal hydrogen-gas-filled tube. The heated gas then drives an attached turbine generator. Computer controls help ensure solar rays stay focused on the focal point of each dish. Organizers hope the project's success will lead to a 40-unit installation in the southern Nevada desert, an effort championed by the National Renewable Energy Laboratory.
• Perhaps the most ambitious solar effort currently under discussion is planned for the desert of New South Wales, Australia. Power company EnviroMission Ltd. hopes to build a $560 million tower capable of generating up to 200 MW of electricity. At 1,000 meters, the tower would be twice the height of Malaysia's Petronas Towers. The structure would stand in the center of a 7-kilometer glass roof. Sunlight shining through the roof would heat the air beneath. As the air rose up the tower, its heat would create an updraft powerful enough to drive 32 turbines housed within the tower itself.

The solar tower has gained both local and national government support and received clearance from Australia's Civil Aviation Safety Authority. Construction could begin before the end of 2003, with operation by early 2006.

From Pure Power, Spring 2003