By: Cate Leger, Principal, Leger Wanaselja Architecture and Commissioner, Berkeley Energy Commission
Electrify your buildings
For decades, gas has been the fuel of choice for environmental and climate conscious buildings that can’t include solar power. However to meet the goals of the Paris Agreement, not only do we need to improve energy efficiency, but building operation needs to switch entirely from gas to low-emission electricity. (1)
Even now, due to improvements in the fuel mix and technology developments, electricity is the best option for reducing greenhouse gas (GHG) emissions from our homes, apartments and commercial buildings in California.
Electricity delivered to the site is much cleaner
In the past, inefficiencies in generation and transmission of electricity meant that only about a third of the energy from the combusted fossil fuel source made it to the building. So, when drawing power from the grid, electric resistance space or water heaters had to be 3 times as efficient as gas heaters to do the job with the same amount of GHG emissions. Electric resistance, even though it is able to turn 99% of the electricity into heat, was no match for gas appliances.
Now, due to California’s requirements for renewable energy, close to a third of electricity provided by PG&E is currently generated by renewables.(2) What this means is that today in PG&E territory, the GHG emissions associated with operating conventional electric resistance appliances are close to, and in some cases lower than, those from gas appliances. Because of continuing increases in solar and wind, gas appliances will perform worse and worse by comparison over time.(3)
The Problems with Gas
New research is showing that our aging gas infrastructure in California is leaking gas that is supposed to be delivered to our buildings—the equivalent of one Aliso Canyon blowout per year.(4) There is also the risk of explosions, especially during earthquakes.
Gas also poses problems inside buildings, particularly as we improve the air tightness of the envelope. Fossil fuel combustion appliances, including gas stoves, are among the primary sources of indoor air pollution.
A Revolution in Electric Heating
While electricity is getting cleaner, widespread development of heat pump heating technologies have improved the performance of electric heaters, making them vastly more efficient. Heat pumps, the equipment used in refrigerators and air conditioners, have been deployed in space and water heaters with efficiencies as much as 3 or 4 times greater than electric resistance and gas.(5) This is accomplished because the heat pumps are using the energy not to heat the air or water but to transfer existing heat from one medium to another.
While there are still improvements to be made in the refrigerants used in most heat pumps, when heat pumps are deployed instead of gas, GHG emissions are reduced dramatically.(6)
Electric water heaters also have the added value (which can be significant) of being demand responsive–leveling out the supply/demand cycles of the electric grid. Heating water is responsible for about a quarter of the state’s residential energy use and electric water heaters can be programmed to draw energy only during peak solar generation, storing that energy through the evening when electricity demand is greatest.(7,8)
Current Barriers to Electrification
While the state has set ambitious goals for reducing GHGs, several specific energy policies are in conflict. The assumptions for title 24 energy performance analysis still favor gas space and water heating. Retail prices for gas do not reflect the GHG emissions of gas compared to electricity, or the grid benefits of flexible electric loads like electric water heaters. And finally, state regulations prevent utilities from offering rebates under the state energy efficiency program when switching from gas to electric fuel.(9) There are a variety of reasons for these conflicting policies, however they give the impression that using gas is better for the environment than electricity.
There are many challenges for energy providers to switching from fossil fuels to renewably generated electricity, such as energy storage. However, solutions are also being developed at the same dizzying pace that renewables are being added. These concerns should not obscure the significant improvements that have already been made in the electricity supply and the importance of shifting building operation from gas to electricity.
The Path Forward
Building operation accounts for approximately 40% of the greenhouse gas emissions in the United States. Shifting to all electric operation is an essential part of lowering that percentage and returning to a healthy climate.
- “Deep carbon reductions in California require electrification and integration across economic sectors,” Max Wei, etc. Environ. Res. Lett. 8 (2013) 014038 (10pp) http://iopscience.iop.org/article/10.1088/1748-9326/8/1/014038/meta
- California Renewables Portfolio Standard, Current Renewables Procurement Status, CPUC http://www.cpuc.ca.gov/renewables/
- Greenhouse Gas Emissions Factors: Guidance for PG&E Customers, November 2015 show GHG emissions per MWh of electricity dropped from 620 lbs of CO2 in 2003 to an estimated 349 in 2017. The guidance projects GHG emissions to continue to drop to 290 lbs in 2020.
- CARB and CPUC Joint Staff Report, January 2017 http://docs.cpuc.ca.gov/PublishedDocs/Efile/G000/M172/K518/172518969.PDF
- Sanden CO2 heat pump water heaters https://www.sandenwaterheater.com//
- Under the Kigali Agreement of November 2016 countries and corporations globally agreed to a phase out of all refrigerants with high global warming potential.
- Energy use: https://www.eia.gov/consumption/residential/reports/2009/state_briefs/pdf/ca.pdf
- Gurlaskie G., Duke Energy, Feb. 2017, Heat Pump Water Heaters for Demand Response http://aceee.org/sites/default/files/pdf/conferences/hwf/2017/Gurlaskie_Session7A_HWF17_2.28.17.pdf
- “The Role of Electrification in Achieving Long-term Climate Goals for the U.S.” by Rachel Golden, June 2016, UC Berkeley Energy and Resources Group