In a new policy brief, the Regulatory Assistance Project (RAP) recommends several ways that the U.S. Environmental Protection Agency (EPA) and states can ensure that energy efficiency is utilized to meet air quality standards. Driving Energy Efficiency: Applying a Mobile Source Analogy to Quantify Avoided Emissions suggests that the same approaches used to quantify emissions from the country’s cars, buses, and trucks can also be used to quantify the emissions avoided by energy efficiency programs.

“Energy efficiency is cost-effective, reduces multiple pollutants at once, and provides numerous co-benefits to society,” said Rich Sedano, principal and director of US programs at RAP. “States invest more than $6 billion in energy efficiency every year, but they don’t get credit for the emissions reductions associated with that investment. The proposed Clean Power Plan offers a unique opportunity for EPA to support new approaches to quantifying those avoided emissions in a way that will help realize the full potential of energy efficiency as an air quality control strategy. ”

Mobile sources of pollution—cars, trucks, and buses—are numerous, dispersed, and decentralized. Individual drivers decide when, where, and how to operate their vehicles. The authors argue that the same characteristics apply to energy efficiency. Lights and appliances are decentralized too, and homeowners decide how often to turn on their lights and when to run the dishwasher.

“EPA already uses statistical assessments and assumptions about how and when vehicles are driven to estimate the impact they have on air quality. We think they can do the same thing with energy efficiency,” added Ken Colburn, coauthor of the brief and senior associate at RAP. “We call this approach the ‘mobile source analogy’.”

State and utility energy efficiency programs are subject to rigorous evaluation, measurement, and verification processes to determine the amount of energy saved, but calculating the emissions avoided by these energy savings adds additional complexity. The authors believe that by applying a mobile source analogy, states and EPA already have many of the tools they need to quantify the emissions impact of energy efficiency programs across the country. The missing piece is clear approval from EPA of this analogous methodology.

“Although a few states measure the impact of their efficiency programs on air quality, almost none have asked EPA for credit under the Clean Air Act, because of uncertainty regarding the level of rigor needed in these analyses,” said Mr. Colburn. “EPA must provide specific guidance to state air regulators on how to estimate the impact of energy efficiency programs on air quality. We believe that methods similar to those already approved for mobile sources provide sufficient rigor.”

The authors offer three complementary approaches EPA could take to connect the dots between energy saved and emissions avoided. A “deemed emissions approach” may be the quickest and easiest way for regulators to estimate the avoided emissions resulting from energy efficiency. Under this approach, EPA would establish default emissions reductions for a host of well-established efficiency measures with well-documented outcomes. A second approach suggests that EPA extend its existing AP-42 approach for establishing acceptable emission factors to include acceptable emissions reductions from energy efficiency measures. A third, more arduous approach would utilize modeling to determine location-specific emissions reductions when important for meeting ambient air quality standards.