Solar Power Goes Urban at S.F.’s Moscone Center

Over the last few months, the concrete-colored roof of the Moscone Convention Center in downtown San Francisco has turned completely black, blanketed by 30,000 square feet of photovoltaic (PV) panels. The building—which is owned by the City and County of San Francisco—is the first project to come out of Propositions B and H, two voter-backed initiatives to finance renewable-energy efforts in the city’s commercial, residential, and government-owned buildings. The Moscone Center’s adaptations mean that, for San Francisco at least, solar electricity generation is now a fact of urban life.

“We don’t consider this a demonstration project,” says Bill Kelly, an engineer with the Berkeley-based Powerlight Corporation, which manufactured the panels for the Center. “This technology is here. We’ve done over a hundred large-scale installations. Our proposal to the city was that this is something that’s a good investment.”

At their peak, these panels, which are expected to become fully operational this month, will pump out 675 kilowatts of electricity. It’s not necessarily enough to power the building, but, when combined with other newly installed energy-efficiency measures, enough to save the convention center $210,000 a year—a healthy haul for clean, solid-state energy.

San Francisco’s Propositions B and H, passed overwhelmingly by voters in November 2001 in the wake of California’s rolling blackouts, are a $100 million initiative intended to spur installation of solar, wind, and energy-efficiency technologies through the issuance of revenue bonds. By offering an easy way to finance the high up-front costs of installing alternate power sources, the city seeks to encourage adoption of the technology and provide the economies of scale necessary to lower costs.

According to Adam Browning of Vote Solar, a San Francisco-based advocacy group, measures similar to San Francisco’s are appearing across the country: on January 29, New Mexico passed a solar bond for its government buildings; New Jersey has what Browning calls a “perfect storm” of legislation in the works; and last December, the city of Austin, Texas unveiled a $5/watt rebate for solar energy, as well as passed legislation mandating that the city produce 20% of its energy needs from renewable sources by 2020.

The growing demand for solar technology promises to both decrease the costs and increase the efficiency of PV panels; the result will be more power generated from a smaller space for less money. But as Browning points out, another hurdle remains in making solar power cost-effective: it only works where energy is expensive. “It’s not how much electricity you produce, but how much that electricity costs,” he says.

Browning sees the Moscone Center as a flagship. “It’s a beautiful project to be able to hold up as an example of what is possible, and even more to the point, what should be done,” he says.

While the PV panels are not visible from the street, a kiosk—located in the center’s lobby, right next to the bust of Mayor George Moscone—shows how much energy the panels are producing. There are plans to link the gauge to the city’s Web site.

Up on the roof, the panels are tidy to the point of banality. They lay flat, rather than tilting towards the sun, to ensure greatest efficiency when it’s needed most, at noon on a summer’s day. (Tilting them requires more space, decreasing maximum output.) Metal pipes run neatly across the roof and down a level to an inverter box that contains the system’s only moving part: a fan to keep itself cool.

For Kelly, the Powerlight engineer, the panels’ most beautiful part is their silence. “You’re producing 700 kilowatts of power, and there’s not a sound,” he says, raising his voice over the din of the traffic on the street below.