A group of researchers found that “Adopting electric end-use technologies instead of fossil-fueled alternatives, known as electrification, is an important economy-wide decarbonization strategy that also reduces criteria pollutant emissions and improves air quality.”
Findings from the study conducted by nine researchers—four from EPRI, four from Ramboll, and one from the Oak Ridge National Laboratory—were published in the peer-reviewed journal Nature Communications on Nov. 5.
“We find that electrification can substantially lower CO2 and improve air quality and that decarbonization policy can amplify these trends, which yield immediate and localized benefits,” the authors wrote. “In particular, transport electrification can improve ozone and fine particulate matter (PM2.5), though the magnitude of changes varies regionally.”
To quantify the CO2 and air quality impacts of electrification, the researchers linked two models and ran scenarios that varied the extent of electrification and drivers of decarbonization. Specifically, they used a detailed energy systems model called the U.S. Regional Economy, GHG, and Energy (US-REGEN) and a photochemical air quality model known as the Comprehensive Air Quality Model with Extensions (CAMx). US-REGEN combines a state-of-the-art electric sector capacity planning and dispatch model with a uniquely capable end-use model. CAMx, meanwhile, was used for air quality modeling with a 12-kilometer (km) grid covering the entire lower 48 states and nested within a larger 36-km grid for every hour of the calendar year 2016. The meteorology for 2016 was also used for all scenarios so that the projected air quality changes could be attributed solely to emissions changes.
Significantly, the study found that commonly used short-run marginal CO2 emissions approaches underestimate reductions from electrification by 32% to 91%. “These emissions factors only capture 52 to 91% of anticipated CO2 reductions under a reference scenario and 32 to 74% of anticipated CO2 reductions under a carbon pricing scenario,” the article says. “Marginal emissions estimates implicitly assume that coal and gas generation are on the margin for large fraction of hours and do not capture changes over time. Average emissions metrics can better approximate anticipated emissions changes, especially dynamic ones based on model outputs that account for changes in the grid mix over time.”
The study also found that electrification could significantly increase electricity demand and electricity’s share of final energy consumption. Electricity currently represents about 20% of final energy usage, which grows in the “High Electrification” scenario to 31% in 2035 and 34% in 2050. (The percentages increase to 34% and 51%, respectively, if CO2 policy is added.) The growth is mainly driven by technological change, according to the researchers. Electricity demand is roughly flat over time in the “Limited Electrification” scenario, as growing service demand is offset by efficiency increases. Electrification of transport (both light- and heavy-duty vehicles) and industry (including process heat) represent the largest contributors to load growth.
Notably, the study found that electrification decreases NOx emissions across the economy by 46% to 58% by 2035. On-road and off-road fleet turnover, and a cleaner fleet mix, are major contributors to the decline, and reductions are expected even with growing population and increased economic activity. NOx emission decreases from the electric sector result mainly from declining emissions from coal generation.
Furthermore, deep NOx emission reductions lead to striking ozone reductions across the U.S. Magnitudes vary by location. The benefits are highest in the Northeast, Southeast, and Ohio Valley, with ozone reductions from 3 parts per billion (ppb) to 13 ppb expected by 2035. “Increased levels of electrification can double or even triple ozone improvement from 2016 as seen in the 2035 and 2050 with carbon pricing scenarios,” the authors wrote.
“Reducing power sector emissions and then using that low-emitting electricity to reduce end-use emissions is employed alongside energy efficiency, carbon capture and removal, other low-carbon fuels, and demand-side responses (including the lowering of energy demand through structural and societal change) to decarbonize energy systems and address climate change. Increased adoption of electric end-use technologies across buildings, industrial, and transport sectors is driven by a combination of technological change, consumer choice, and policy, especially those targeting CO2 reductions,” the article says.
The article published by Nature Communications can be found here.
—Aaron Larson is POWER’s executive editor (@AaronL_Power, @POWERmagazine).