With extreme drought in the Western U.S. causing water levels in the Colorado River to fall to historic lows and the Northeast also experiencing an extraordinarily dry summer, it’s a good time to explore recent research about electric vehicles — long touted as a key way to turn back the clock on climate change.
Carbon emissions increase the likelihood of extreme weather events, such as drought and wildfires. Electric vehicles “have large potential to reduce land-based transport [greenhouse gas] emissions,” according to a 2022 report from the Intergovernmental Panel on Climate Change, a scientific analysis organization headquartered in Geneva and endorsed by the United Nations.
The first electric cars date to the 1830s, though they weren’t ready for everyday use until the 1870s. By the early 1900s, electric vehicles made up one-third of all vehicles in America, according to the U.S. Department of Energy. The rise of Henry Ford’s gas-fueled Model T in the early 1910s spelled an end to the electric car for decades. The 1970s oil crisis renewed interest in electric vehicles. In 1996 General Motors released the EV1, a mass-produced all-electric car. In 2000 Toyota announced the U.S. launch of its Prius, the first mass produced hybrid vehicle, running on both gas and electric power. Tesla began delivering its first electric car, a sports car called the Roadster, in 2009, followed by the Model S luxury sedan in 2012.
Electric vehicles make up a small fraction of the roughly 261 million light-duty vehicles, including motorcycles, on U.S. roads. The Environmental Protection Agency defines light-duty vehicles as those weighing less than 8,500 pounds. Most passenger cars, SUVs, motorcycles and pickup trucks are considered light duty. Passenger cars and light-duty trucks account for 68% of U.S. road vehicle emissions and the transportation sector as a whole is the biggest greenhouse gas polluter, according to the latest federal government data.
There were about 2 million registered hybrid and fully electric vehicles in the U.S. in 2021, according to a 2022 report from the International Energy Agency, an independent intergovernmental organization based in Paris. “Some of the main drivers underpinning growth in the United States in 2021 were the increased production of Tesla models and the availability of new generation electric models by incumbent automakers,” according to the report. Combined sales of fully and partially electric vehicles doubled from 295,000 in 2020 to 631,000 last year — representing 5% of new vehicle sales, according to the agency.
Globally, hybrid and fully electric vehicles make up less than 1% of the 1.3 billion light-duty vehicles on the road today, according to the U.S. Energy Information Administration, which collects and publishes energy statistics and analysis. The administration projects that by 2050, there will be 672 million plug-in vehicles around the world, making up about one-third of the global vehicle fleet.
One barrier to widespread electric vehicle adoption is fleet turnover, which simply means new vehicles replacing old ones. New gas-powered cars can last years, even decades, before they are replaced by lower- or no-emissions vehicles. As the authors of one of the papers included below write, “even if [electric vehicle] market share jumped dramatically, it would take decades to replace the existing vehicle fleet, during which time vehicle [greenhouse gas] emissions would continue, worsening climate change.”
To reduce electric vehicle costs and speed production, the Inflation Reduction Act, which President Joe Biden signed into law on Aug. 16, provides tax credits to battery makers, potentially bringing down battery production costs by about one-third. Some states are also attempting to accelerate fleet turnover through policy action. California, for example, by 2035 will ban sales of new cars that run solely on gasoline.
The five studies featured here explore innovative ways to spur electric vehicle purchases, such as a revamped cash-for-clunkers program, which originally made national headlines in the U.S. during the Great Recession. Other topics include overviews of current charging infrastructure needs, considerations related to social and economic inequality, and the prospect of reusing car batteries to store solar power.
Inequality and the Future of Electric Mobility in 36 U.S. Cities: An Innovative Methodology and Comparative Assessment
Patricia Romero-Lankao, Alana Wilson and Daniel Zimny-Schmitt. Energy Research & Social Science, September 2022.
The study: The authors explore social and economic inequalities in 36 U.S. cities, then discuss how those inequities can inform the rollout of transportation technologies, such as electric vehicles, so the broadest number of people can take advantage of them. They specifically explore how inequities play out for “wealthy, urban disadvantaged, urban renters, middle-class homeowners, and rural/exurban” groups.
The findings: The authors focus on 20 large metropolitan areas — each with a population of more than 1.5 million people — and 16 medium metropolitan areas — each with 500,000 to 1.5 million people — in California, Colorado, Illinois, Missouri, New York, Ohio, Oregon, Pennsylvania, Texas and the District of Columbia. They conclude that in order for electric vehicle rollouts to be successful, government policies will need to be tailored to the specific needs of each group. “For instance, rural/exurban populations might require electric carpooling,” the authors write. City dwellers, however, especially renters and households with lower incomes, would benefit more from electrified transit options rather than individually owned electric vehicles.
In the authors’ words: “Offering a variety of electrified options would provide benefits to the largest percentage of people and have more potential to sustainably decrease greenhouse gas emissions, reduce tailpipe emissions, and improve the health of people and ecosystems.”
Accelerating Vehicle Fleet Turnover to Achieve Sustainable Mobility Goals
Sergey Naumov, David Keith and John Sterman. Journal of Operations Management, March 2022.
The study: The authors examine potential designs for cash-for-clunkers programs that would help turn over more of the nation’s vehicle fleet to low- or no-emissions vehicles. The most notable cash-for-clunkers program in the U.S., called the Car Allowance Rebate System, ran during the summer of 2009 with $3 billion in congressional allocations. People with eligible gas-guzzling cars received a credit to purchase newer, more fuel efficient vehicles. Engines in the old cars were disabled and the cars scrapped. The authors use a model of light duty vehicle turnover in the U.S., developed as part of prior research from two of the authors, and simulate cash-for-clunkers policies that would achieve significant vehicle turnover by 2050.
The findings: Despite thousands of dollars in existing tax credits at the federal level and in some states for people buying zero-emissions vehicles, “alternative fuel vehicles have only achieved low single-digit market share in the United States to date,” the authors write. Their model assumes that patterns of car turnover will remain largely the same in the coming decades — with the average light vehicle having a useful life of 17 to 30 years — though they acknowledge that technological advances, like self-driving cars, could change those patterns. They explore several different program designs, including those in which people can get a cash credit for the purchase of an electric vehicle or traditional combustion engine vehicle; an electric or hybrid; or electric only. The authors find the design that would work best at turning over the existing vehicle fleet and reducing emissions is one that makes all gas-powered vehicles eligible, regardless of their age or fuel efficiency, and the credit reserved for those who replace their old car with a fully electric one. Government vehicle fleets being made fully electric would further spur the no-emissions vehicle market, they add.
In the authors’ words: “[Cash-for-clunkers] programs will also primarily benefit more affluent individuals who buy the majority of new cars, while low-income individuals tend to purchase used vehicles or forgo car ownership altogether, instead relying on public transportation. However, by accelerating fleet turnover, [cash-for-clunkers] policies speed reductions in harmful tailpipe emissions. The adverse health impacts of these emissions are disproportionately borne by the poor and especially by people of color.”
The State of Play in Electric Vehicle Charging Services — A Review of Infrastructure Provision, Players, and Policies
Sarah LaMonaca and Lisa Ryan. Renewable and Sustainable Energy Reviews, February 2022.
The study: The authors explore current charging options for electric vehicle owners and policies that could spur the development of more charging infrastructure. They also discuss whether charging infrastructure is “a public good or private asset,” considering that “both the public and private sectors have been involved in the provision of charging stations and it is timely to consider the roles of the different actors in this market.”
The findings: Charging services have different cost structures, which make it hard for consumers to compare whether it’s cheaper to charge at home or at a public charging station. Some charging services charge by the minute, the hour, by energy used, or even offer subscriptions. The authors suggest that legislation could standardize how charging pricing is presented and “could help to improve the customer experience when searching out charging services.” To promote electric vehicle usage, federal and state governments could subsidize charging infrastructure, which is still expensive to build and maintain. Better data is needed on how and when people use public chargers, which federal or state governments could compel private providers to make public.
In the authors’ words: “Because the likely social benefits are not limited to those who can pay, decisions about this infrastructure are an important public policy concern and should not be just a matter for private firms and investors; it is therefore rarely fully privately-funded or owned.”
Quantifying the Emissions Impact of Repurposed Electric Vehicle Battery Packs in Residential Settings
Alizer Khowaja, Matthew Dean and Kara Kockelman. Journal of Energy Storage, November 2021.
The study: The authors use detailed electrical grid generation data and electricity demand data from homes with solar power in Austin, Texas, to explore the potential emissions benefits of adding the storage power of old electric vehicle batteries to energy efficient homes. Based on previous environmental research, the authors note that drawbacks crop up throughout the life of an electric vehicle battery, including “the depletion of water tables during mining, high [greenhouse gas] emissions during battery manufacturing, e-waste due to a small percentage of batteries being recycled after operation, and contamination or exposure of toxic chemicals after disposal.”
The findings: Used electric vehicle batteries can hold from 60% to 80% of their original capacity, “which under favorable conditions could provide up to 10 years of second-life stationary [battery storage systems] at an economic savings of up to 60% compared to new storage systems,” the authors write. Assuming processes are in place to distribute and install old electric vehicle batteries to store solar power for homes, the authors find that such setups could reduce carbon emissions by one ton each year for each equipped house. By comparison, the average car emits roughly 4.6 tons of carbon per year, according to the Environmental Protection Agency.
In the authors’ words: “While the [greenhouse gas] savings for each household may appear negligible, the power of scale and rising social cost of CO2 may allow communities to considerably reduce their carbon footprint and transition both the power and transportation sector away from traditional fuel sources.”
There’s No Place like Home: Residential Parking, Electrical Access, and Implications for the Future of Electric Vehicle Charging Infrastructure
Yanbo Ge, Christina Simeone, Andrew Duvall, and Eric Wood. National Renewable Energy Laboratory Technical Report, October 2021.
The report: The authors examine the types of homes that currently have charging access, noting that “there is uncertainty about how effectively home charging can scale as the primary charging location for electric vehicle owners.” They conducted an online survey from May 13 to May 31, 2020, asking 5,250 adults across the U.S. about their access to parking and electrical outlets. The authors use the survey results to project what the future of charging infrastructure might look like.
The findings: The authors find that one quarter of those surveyed have driveways or garages with electrical access, with another quarter reporting they could have such access installed. In one future scenario, the authors project that if every car on the road were electric, about one quarter of vehicles would lack at-home charging. They note that for electric vehicle ownership to extend beyond “high-income, single-family homes that have access to off-street parking,” city planners will need to consider how to provide charging infrastructure for people living in multi-family housing, such as apartment buildings, where overnight, off-street parking may not be easily available.
In the authors’ words: “In situations where residential off-street charging access is unattainable, a portfolio of solutions may be possible, including providing access to public charging in residential neighborhoods (on street), at workplaces, at commonly visited public locations, and (when necessary) at centralized locations via high power fast charging infrastructure (similar to existing gas stations).”