Slashing Emissions from Fossil Fuels Burned in Buildings

The “decarbonization” of America’s building is critical to reducing carbon emissions by at least 80 percent below 1990 levels by 2050, the amount scientists believe is necessary to avoid the worst effects of climate change. California, long a national and world leader in fighting climate change, is already beginning to take a look at how to reduce the carbon pollution from fuels burned inside buildings for space and water heating.

Just last week, California’s Governor Brown signed two landmark bills that commit the state to decreasing climate-disrupting carbon emissions to 40 percent below 1990 levels by 2030, putting California on a pathway toward an 80 percent reduction by 2050. This is huge progress, but there is much more for California—and the United States as a whole—to do to meet our long-term climate goals.

Progress will require action on all fronts: reducing emissions from transportation, industry, power plants, and from fuels like natural gas burned in buildings. While the amount of pollution from burning fuel in homes and commercial buildings is a relatively small part of total emissions today—just 11 percent of U.S. energy-related emissions—it is a roadblock to reaching our 2050 climate targets, according to long-term climate mitigation analyses.

Emissions from Fossil Fuels Burned in Buildings Cannot Be Ignored

When asked to identify sources of climate pollution, most people probably imagine a coal power plant spewing smoke, or exhaust billowing out behind an 18-wheeler. They likely don’t realize it also can come from the furnace or hot water heater tucked away in a closet or in the basement quietly burning natural gas, heating oil, or propane.

To cut emissions by 80 percent economy-wide and offset the challenges of reductions from industry and transportation, we must slash emissions from buildings by around 95 percent. Energy efficiency is the foundation for these reductions, for example through building energy codes and appliance efficiency standards including the new proposed federal furnace standards. However, hitting 2050 targets requires deeper reductions than building energy efficiency can achieve alone.

Once again, California is leading the way in tackling this topic. Governor Jerry Brown called out the need for cleaner heating fuels in his State of the State address last year. And more recently, several top California energy leaders launched a public discussion on this critical issue. The California Air Resources Board has also flagged this issue as part of their scoping plan update to meet 2030 climate targets, and is examining options for “zero carbon” buildings.

The need to reduce direct emissions from buildings is more obvious in states with relatively clean electricity, such as California. For example, emissions from California’s residential and commercial buildings create roughly as much climate pollution as all of its in-state power plants, and the majority of this is from natural gas burned for space and water heating. The graphic below shows that while fuels burned onsite account for 28 percent of U.S. emissions associated with building operations, the number is a whopping 41 percent in California. This is because California has cleaner electricity than most states, thanks to its bold renewable energy targets, so direct fuel use in buildings represents a bigger piece of its emissions pie.

We Need Policies that Drastically Cut Emissions from Buildings

To meet our 2050 climate goals, we’ll need a scale-up in the deployment of energy efficiency (including vehicle efficiency), renewable electricity, and electric vehicles–these are the climate policies most commonly discussed and they are vital. But to get all the way, we must also tackle the carbon pollution from fossil fuels in buildings.

To illustrate, today’s emissions from fossil fuels burned in buildings would represent almost 80 percent of the entire energy sector’s 2050 “carbon budget” to avoid the worst effects of climate change. This 2050 carbon budget includes building emissions plus all power plants, industrial energy use, and transportation.

In addition to increasing energy efficiency and the amount of electricity from renewable sources, there are two primary strategies to significantly cut emissions from burning fuels in buildings:

1. Electrification – We’ll need to move a large share of our buildings from natural gas and other fossil fuels to electric space and water heating. This includes using highly efficient electric equipment, such as heat pump technology, that is powered by low- or zero-carbon electricity. Electrification should be a priority in areas where low emissions from the existing electric supply makes it the cleanest and most affordable option to achieve 2050 emissions targets.

2. Decarbonized fuels – We also need to replace fossil fuels, such as conventional natural gas and heating oil, with fuels produced from renewable sources that release no net greenhouse gases over their lifecycle, such as sustainably produced biogas (e.g. gas produced from landfills, wastewater treatment plants, or farms) and synthetic natural gas produced by electrolyzing water using renewable electricity. Decarbonized fuels should be developed sustainably and at the level needed to affordably help achieve 2050 targets.

These strategies will be challenging, and we still have a lot to learn about the potential of these options. Success will surely require a combination of strategies depending on local resources and infrastructure, and how the technologies develop and economics improve over time. 

Even in places like California, where top policymakers are starting to address this issue, a significant amount of additional action is needed. The initial steps that California needs to take include: 1) Remove regulatory barriers like outdated building code and efficiency program rules that hinder the choice of heating fuel that can best achieve 2050 emissions targets in new construction and retrofit building projects; 2) Invest in research and development to reduce the cost and increase the performance of low-carbon space and water heating technologies; 3) Develop the market so that low-carbon alternatives are available to residents and businesses throughout California.

It is important that both California and U.S. policymakers act now to develop more aggressive low-carbon building policies. While 2050 seems a long way off, decisions made today and in the decades to come about long-lived investments like buildings and energy infrastructure will define our future options, for better or worse. It will also take time to understand the viability and economics of these strategies, as well as to develop the market for efficient electric heating systems and decarbonized fuels. 

NRDC will be working closely with others to examine these questions, and supporting the policies, pilot programs, and research needed to speed up this necessary transition.