The near-constant temperatures in San Francisco Bay and in its soil would be used to heat and cool new homes in planned mega-developments under separate energy-saving strategies being assessed.
Pipes are expected to channel liquid between planned high-rise residential buildings near the proposed Ferry Quay at Treasure Island and the Bay, which averages from 55 degrees to 65 degrees, Wilson Meany Sullivan developer Kheay Lok said.
In the summer, liquid in the pipes would be cooled by the Bay and pumped back to the units as a coolant, Lok said recently. In the winter, the system would heat the homes.
Separately, the San Francisco Department of Environment is investigating whether ground-source heat pumps could heat and cool homes on Treasure Island, Renewable Energy Project Manager Johanna Partin said.
The technology pumps liquid from homes through pipes below the ground’s surface, where temperatures are relatively unaffected by the air’s temperature.
Partin said the technology also would be considered for the thousands of homes planned at the Hunters Point Shipyard and Candlestick Point area, Visitacion Valley and around the proposed downtown Transbay Transit Center.
The system is an offshoot of geothermal energy technology, described by Partin as a “key renewable energy technology missing from The City’s efforts” to fight global warming.
Ground-source heat pumps are useful for new developments, said Marilyn Nemzer, executive director of the Tiburon-based Geothermal Education Office. She said it’s nearly impossible to lay pipes below existing homes.
Multihome residential developments are prime candidates for the technology in San Francisco, where subsoil temperatures hover around 50 degrees to 55 degrees, UC Institute for Energy and Environment researcher Bill Glassley said.
A grant application to investigate whether geothermal energy could be harvested from below San Francisco Public Utilities Commission
SFPUC spokesman Tony Winnicker said the agency would continue to explore opportunities to harness the technology.