‘Fog City’ Catches a Few Rays

SAN FRANCISCO — A city known worldwide for its dense fog is tapping a vastly underused resource: the sun.

Construction will soon begin on San Francisco’s first major solar-power project — a $7.4 million retrofit of the Moscone Convention Center that will include the rooftop installation of 5,000 solar panels.

By Kendra Mayfield Wired.com

The Moscone project is part of the city’s effort to transform itself into a center for "green" building. In November 2001, voters approved a municipal bond measure that allows the city to issue $100 million in revenue bonds for installing renewable-energy systems, including solar panels, wind turbines and energy-efficiency measures at public facilities. The measure, created by the Vote Solar Initiative, http://www.votesolar.org/ costs taxpayers nothing, since energy savings will be used to pay off the bonds.

The city’s Public Utilities Commission, the agency responsible for providing electricity to city government operations, will handle implementation of the measure. It hopes to add 10 megawatts of solar power to the grid over the next five years.

Photovoltaic systems, which convert light energy into electricity, have been commercially available for years. But only recently has this technology become affordable and efficient enough to offer a practical alternative to conventional grid power, advocates say.

"Right now, we’re on the verge of a major technological shift," said David Hochschild, co-founder of the Vote Solar Initiative. "As costs come down and technology improves, I think we’ll see rapid growth for the installation of solar power."

Terry Peterson, manager of solar-power and green-power marketing for the Electric Power Research Institute, http://www.epri.com/ said that projects like the Moscone retrofit are one way to lower these costs.

"Solar energy captures the imagination of people, so it’s an easy sell," he said. "So far the sticky point has been the price. The Moscone project takes the sting out of the high price."

The Moscone Convention Center will install a 675-kilowatt solar system that will generate about 825,000 kilowatt-hours of electricity annually. The center will also install efficient lighting, heating and cooling systems using motion sensors and compact fluorescent light bulbs.

The retrofit is expected to provide an annual net savings of about $210,000 per year after it is completed this spring.

It will take about 6.5 years to pay back the bonds with help from the California Public Utilities Commission’s Self-Generation Incentive Program, which offers rebates for the installation and use of self-generation technologies, said Adam Browning, co-founder of the Vote Solar Initiative.

"Energy-efficiency technologies generally have a very short payback period, and are key to making projects cost-effective," he said.

In addition to the Moscone Center, the city plans to put solar panels on publicly owned structures such as schools, parking garages and covered reservoirs. The next initiative is a $2.4 million project to install panels on the roof of a wastewater treatment facility.

To help identify the sunniest sites for solar-power projects, the commission has installed 11 solar-energy-monitoring stations across the city, each collecting data to create detailed "fog maps."

While the western half of San Francisco is often enshrouded in fog, the eastern half receives about 90 percent of the annual sunshine that California’s sunny Central Valley receives, said Edward Smeloff, assistant general manager of power policy, planning and development for the San Francisco Public Utilities Commission.

San Francisco residents who want to install their own solar-energy systems can monitor a local fog map and solar data online. http://www.solarcat.com/sfsolar/main.htm

Following the state’s recent power crisis, city officials turned to renewable-energy sources like solar power to decrease reliance on fossil fuels and reduce the emission of pollutants — including those that contribute to the greenhouse effect — into the environment.

"We are trying to diversify our resource mix so that we are less dependent on nonrenewable fuels," Smeloff said.

One factor helping to speed this transformation is the declining cost of solar power. As the price goes down for photovoltaic systems, the overall cost of generating energy from the sun is also decreasing. Prices have dropped to $4 per watt, http://www.solarbuzz.com/ModulePrices.htm down from $100 per watt in 1976.

But in order to become competitive with fossil fuels on a large scale, the price of generating solar energy must come down even further, to about $1.50 per watt, Hochschild said.

A principal goal of the Vote Solar Initiative is to lower the cost of solar energy by increasing demand.

More demand will lead to greater production capacity through the creation of new solar-power systems. While those systems initially represent an added cost, they will be paid off over time with savings from lower energy bills.

And once that happens, consumers can end up spending less on electricity generated through solar power than other means.

"We are attempting to help build the solar market in California so that prices for the systems may be reduced," Smeloff said.

However, analysts say that it could be difficult to obtain the continuous, widespread demand necessary to expand solar power from a niche technology into the mainstream of the energy business.

"If demand is sustained, manufacturers may increase production," Peterson said. "But in the short term, an increase in demand can bring prices upward because there’s a limited supply of hardware."

He added, "We could see cost-competitive photovoltaic hardware within a matter of decades from now, but probably not in this decade."

Still, Vote Solar’s directors say that solar-energy costs will continue to drop if more cities implement large-scale, cost-effective projects like the Moscone Center retrofit.

"Every time the demand for solar energy doubles, costs decrease 20 percent," Hochschild said. "We’re seeing a real improvement in the efficiency of these systems, which makes them more affordable."

The Vote Solar Initiative is trying to replicate San Francisco’s model in other areas across the country. In San Diego, a solar bond initiative may be brought before the city council this spring. Meanwhile, New York and Hawaii are considering statewide solar bond initiatives.

"Global climate change is clearly the biggest challenge for this century, and the federal government is doing very little to deal with it," Browning said. "Cities can lead the fight against global warming by implementing renewable-energy projects."

Hochschild added, "If other cities see San Francisco succeeding, then they will follow."

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