Decarbonizing Buildings May Lower California’s Carbon Footprint

Moving the state away from natural gas use in residential and commercial buildings may be a tool in the goal of decarbonizing buildings in California.

That was the message delivered by Rachel Golden, senior campaign representative with the Sierra Club, during a talk on decarbonizing buildings at the California Energy Commission. Scientists Merrian Borgeson and Pierre Delforge from the Natural Resources Defense Council joined Golden in the talk.

Most of the natural gas used in homes in California is used for space and water heating.

California Residential Natural Gas Consumption Breakdown - 2012

The natural gas industry is an emitter of carbon dioxide and a significant source of methane emissions. Methane is a potent greenhouse gas with a global warming potential more than 25 times that of carbon dioxide.

The combined residential and commercial building sectors in California consume approximately one‐third of total natural gas usage.

California also uses a higher percentage of natural gas to heat homes compared to the rest of the United States.

Source: U.S. Energy Information Administration (2015)

Golden sees the carbon footprint of natural gas use in buildings as “significant.”



“It’s basically equivalent to that of all in-state power plants,” Golden said. “And those emissions don’t even include the methane leakage that happens on a distribution level.”

She said natural gas use in buildings is incompatible with the state’s long-term climate goals.

“If we don’t make progress in decarbonizing buildings emissions from the building sector, mostly from heating fuels, it could take up most of the allowable carbon budget by 2050,” said Golden.

Decarbonizing buildings will demand comprehensive policy, investment, market transformation and workforce training, she said.

“We have very strong climate and energy policies in California but nothing that specifically focuses on heating fuels,” said Golden. “We need to begin to plan now.”

Borgeson said combining clean electricity, efficient appliances and sustainable fuels – like biogas and synthetic gas – holds promise.

A possible tool for wresting residential buildings off natural gas is the heat pump for home heating. That technology works like a refrigerator in reverse. Instead of burning fuel to create heat, the pumps use electricity to take heat from ambient air for use inside a home.

“They’re two to four times as efficient as electric heaters,” said Borgeson. “The efficiencies are quite high – you’re looking at around 250 percent efficiency for many regions in California.”