But it’s still not enough for the city to meet its goals.
As part of the worldwide Carbon Neutral Cities Alliance (CNCA), San Francisco has a goal to reduce its greenhouse gas emissions to 80 percent below 1990 levels by 2050. It’s among the most aggressive — but not the most aggressive — goals in the U.S., especially for a city with more residents than the entire state of North Dakota. And it will require more than renewably sourced electricity, more than transportation running on alternative fuels, more than energy efficiency.
Which is why Jessie Denver is focused on something not a lot of people are talking about: electric heat pumps.
Much of the water and air heating in buildings these days comes from natural gas, a fossil fuel that — much like oil and coal — must be pulled out of the ground and transported before it can be used. As Denver explained Sept. 8 at the Bridge SF conference, electric heat pumps offer a more efficient alternative, one that can be sourced from an ever-greener power grid.
And they hold a lot of potential to help San Francisco meet its goals, according to Denver, who is the energy program manager in the city’s Department of the Environment. If electric heat pumps replaced 80 percent of the city’s carbon-based heat sources — market saturation, in broad strokes — it would eliminate 13.6 percent of San Francisco’s total greenhouse gas emissions.
“Everybody’s done a great job on electrification of supply,” Denver said. “Rooftop solar, everyone’s focused on electric vehicles. Electric vehicles feel like solar did in 2006 right now … they’re really fun. But nobody’s focusing on natural gas, and heat pumps are a terrific solution.”
Easier said than done, perhaps. Like many technologies that can save both money and carbon — see solar panels — heat pumps can mean a big up-front cost that pays the owner back over time in the form of lower bills. For new buildings, San Francisco might be able to go the same route as it has with solar panels — simply require them in types of new construction.
But for older buildings, it’s a different story. Not that it’s something data can’t help address.
“We can look at when permits were pulled for hot water heaters across the city and aggregate a whole group of property owners who have those units coming up for replacement, because the hot water heaters only last for so long,” Denver said. “So we can target outreach to that community and say, ‘Hey, we know your hot water heaters are going to need to be replaced soon. We’d like you to look at this particular technology.’ And … we can partner that with the industry and say, ‘We have people with 10,000 permits coming up and replacement of those appliances will be needed. At what price point can you deliver that that will be effective?’”
Another potential issue is regulatory hurdles. That’s something San Francisco has run into before with water reuse systems. The city wants to encourage people to reuse water for non-potable purposes, but it also has an obligation to make sure the water quality is up to code. So it first had to come up with a developer-friendly way to ensure water quality when setting up reuse systems.
San Francisco and CNCA are trying to get a better grip on what the regulatory hurdles will be at the federal, state and local levels when it comes to electric heat pumps. But Denver said she’s confident that local government specifically will be able to help make the transition easier.
“Those policy barriers exist," she said, "and this is an area where cities can lead the way."