This is the largest city-owned solar power system in the United States located at San Francisco’s Convention center. Covering 60,000 square feet, equivalent to the size of a football field, it generates 826,000 kWh annually. This is equivalent to power 184 homes in San Francisco for an entire year, removing 7,000 cars from the road, or not driving 88 million miles. Over the lifetime of the project, it will reduce 35,000 tons of CO2.

What is it?

The largest city-owned solar power system in the US, which rests atop Moscone Center, San Francisco’s premier conference facility. It is a 675kW-per hour, 5,400 solar panel system.

Energy efficiency

  • Demand reduction from the lighting project will cut 800 kilowatts, for an estimated total savings of 4 million kWh per year.
  • Energy efficiency measures such as lighting upgrades and control systems have reduced facility annual energy use by 21%.
  • The PV system together and the energy efficiency measures installed produce enough electricity to power over 1,000 homes.

How does it work?

  • November 6, 2001 San Francisco voters approved two landmark propositions, B and H, which allowed the city of San Francisco to implement solar electricity and other renewable energy resources on city-owned buildings.
  • In 2004, San Francisco’s Public Utilities Commission (SFPUC), which oversees the implementation of the City’s overall energy resource plan, completed the largest city-owned solar power system in the U.S.
  • The Solar electric system was funded by the San Francisco Mayor's Energy Conservation Account (MECA). MECA has directed funding to finance solar and energy efficiency programs in City buildings and facilities since it was established in 2001.
  • The project also received rebates from the California Public Utilities Commission and California Energy Commission.
  • The system was completed by PowerLight Corporation and launched by San Francisco Mayor Gavin Newsom.
  • Moscone Center Energy project consists of two parts: 1) solar power generation and 2) energy efficiency.

1. Solar Power:

  • Solar electricity is generated by a 60,000 square foot photovoltaic array installed on the roof of Moscone Center's South Lobby and Esplanade Ballroom. Photovoltaic are solar cells that can turn light ("photo") energy into electricity ("voltaics").
  • Solar cells generate direct current (DC), which is then converted to alternating current (AC) using inverters. Solar cells are built into arrays that can be used to generate electricity on-site at facilities.
  • The solar panels also provide thermal insulation; they protects the roof from UV rays and thermal degradation, thus extending the life of the roof.

2. Energy Efficiency:Upgrades to lighting equipment and building controls. These include:

  • Replacing older, inefficient incandescent, T12 fluorescent and mercury vapor lighting throughout the building with newer energy efficient lighting technologies. This lighting includes compact fluorescent lamps, T8 fluorescents, and metal halide fixtures.


  • This is a city commission, thus financing comes from municipal government.
  • Project requires government to create incentives to enable to become cost effective.
  • City partners with private large-scale solar power systems provider such as PowerLight.