What is emitting the most greenhouse gas in our community?

Note: Since this data was compiled, cleaner power generation by Peninsula Clean Energy has significantly reduced the relative GHG contribution of the uses of electricity. *Vitalsigns- Greenhouse gas emissions

If the breakdown shown in the figure was not what you expected, you are not alone. Many people are surprised when they find out which sources are the largest carbon emitters.

Understanding this information is important. It can help us work together as a community to take actions that will be most effective toward reducing emissions and fighting global climate change. But there is misunderstanding about the sources of greenhouse gas (GHG).

In particular, many people underestimate the impact of transportation, which is responsible for a major share–about 55%–of the emissions in our county. On a per capita basis, this equates to about 3.4 metric tons of carbon dioxide (CO2) per person annually.* By replacing internal combustion vehicles with electric vehicles (EVs) that are powered by clean energy sources, we are helping to solve the major cause of carbon emissions in our county. To enable this, we developed programs that include education, no-obligation opportunities to easily experience and test drive EVs, incentives to purchase EVs, and will soon have programs and incentives to support installation of EV charging stations.

Other GHG sources include residences which, at the time of this study, were responsible for about 22% of the carbon emissions in San Mateo County, or about 1.3 metric tons of CO2 per person per year. Of this, about two-thirds is caused by gas appliances, including space heating, water heating, cooking and laundry. Uses of energy in non-residential accounts for the remaining 22% of emissions.*

This data was compiled in 2015, prior to the launch of Peninsula Clean Energy. Since then, our clean power has greatly reduced the amount of GHG emissions associated with residential and commercial electric uses.

We are now also working to reduce GHG caused by gas use in buildings. For new construction, Reach codes have been adopted in some municipalities, and are under consideration in others, that have more stringent carbon emission standards than those required by the state, and favor efficient all-electric designs that can be powered by clean energy. Meanwhile, for existing buildings, we are developing programs to support and incentive retrofit actions, which could include replacing gas appliances with electric heat pumps for space and water heating, and electric induction for cooking. Reducing or eliminating the use of gas will make those buildings cleaner and will reduce greenhouse gas emissions.

We will continue to update you about our programs as they are developed, and more information can be found on our website about programs for electric vehicles, building reach codes, and other pilot programs.