• Energy Research

To expand markets for plug-in electric vehicles (EVs) beyond enthusiastic early adopters, investments must be strategic. This research characterizes a segment of EV adoption that points the way toward the mainstream: EV consumers with low or no initial interest in EVs, or “EV Converts.” Logistic regression is utilized to profile EV Convert demographic, household, and regional characteristics; vehicle-transaction details; and purchase motivations—based on 2016–2017 survey data characterizing 5447 rebated California EV consumers. Explanatory factors are rank-ordered—separately for battery EVs (BEVs) and plug-in hybrid EVs (PHEVs), to inform targeted outreach and incentive design. EV Converts tend to have relatively “lower” values on factors that might have otherwise “pre-converted” them to EV interest: hours researching EVs online; motivation from environmental impacts and carpool-lane access; and solar ownership. PHEV Converts more closely resemble new-car buyers than other EV adopters, and BEV Converts actually tend to be younger and less-frequently white/Caucasian than new-car buyers. BEV Converts also tend to: lack workplace charging, be moderately motivated by energy independence, and reside in Southern California or the Central Valley. Predictors that not only help target consumers, but also help convert them, include rebates for BEV consumers and, modestly, fuel-cost savings for PHEV consumers.

This work refines and updates estimates of the fuel-cycle greenhouse-gas (GHG) emission impacts of electric vehicles (EVs) rebated in California. Emissions are estimated using disaggregated data from the start of the rebate program through August 2018 (N = 269,902 participants) and factors that characterize fuel use and fuel life-cycle carbon intensity. GHG reductions are calculated for the first year of vehicle operation and subsequently scaled to reflect various operational timeframes. GHG reduction estimates over the first year of vehicle ownership total approximately 855 thousand metric tons of CO2-equivalent emissions, or 3.2 tons per vehicle. For nonfleet individuals, 54% of reductions are associated with “Rebate-Essential” participants who were most highly influenced by the rebate to purchase/lease. Comparing the estimated warranty-life benefit of 7.9 million tons of GHG reductions to USD 603 million in corresponding rebates results in USD 76 of state incentives per metric ton reduced over the first 100,000/150,000 miles of rebated vehicle use. Uncertainty in estimates presents opportunities for further refinement using additional participant-specific, time-variant, or otherwise detailed inputs. Nevertheless, the contributions of this work increased average first-year GHG reductions per vehicle by 35–45% compared to previous work, demonstrating that use of program-derived data can enhance the understanding of EV impacts.

Accelerated market penetration of plug-in electric vehicles and deployment of grid-connected energy storage are restricted by the high cost of lithium-ion batteries. Research, development, and manufacturing are underway to lower material costs, enhance process efficiencies, and increase production volumes. A fraction of the battery cost may be recovered after vehicular service by reusing the battery where it may have sufficient performance for other energy-storage applications. By extracting post-vehicle additional services and revenue from the battery, the total lifetime value of the battery is increased. The overall cost of energy-storage solutions for both primary (automotive) and secondary (grid) customer could be decreased. This techno-economic analysis of battery second use considers effects of battery degradation in both automotive and grid service, repurposing costs, balance-of-system costs, the value of aggregated energy-storage to commercial and industrial end users, and competitive technology. Batteries from plug-in electric vehicles can economically be used to serve the power quality and reliability needs of commercial and industrial end users. However, the value to the automotive battery owner is small (e.g., $20-$100/kWh) as declining future battery costs and other factors strongly affect salvage value. Repurposed automotive battery prices may range from $38/kWh to $132/kWh.

We report on the real-world use over the course of one year of a nickel-metal-hydride plug-in hybrid—the Toyota Plug-In HV—by a set of 12 northern California households able to charge at home and work. From vehicle use data, energy and greenhouse-emissions implications are also explored. A total of 1557 trips—most using under 0.5 gallons of gasoline—ranged up to 2.4 hours and 133 miles and averaged 14 minutes and 7 miles. 399 charging events averaged 2.6 hours. The maximum lasted 4.6 hours. Most recharges added less than 1.4 kWh, with a mean charge of 0.92 kWh. The average power drawn was under one-half kilowatt. The greenhouse gas emissions from driving and charging were estimated to be 2.6 metric tons, about half of the emissions expected from a 22.4-mpg vehicle (the MY2009 fleet-wide real-world average). The findings contribute to better understanding of how plug-in hybrids might be used, their potential impact, and how potential benefits and requirements vary for different plug-in-vehicle designs. For example, based on daily driving distances, 20 miles of charge-depleting range would have been fully utilized on 81% of days driven, whereas 40 miles would not have been fully utilized on over half of travel days.

A proposed strategy for facilitating the introduction of electric-drive vehicles calls for vehicle purchasers to own the vehicle but to lease the battery from a third party to help reduce the first-cost hurdle to consumers. A further extension of this concept for all-battery electric vehicles (EVs) would include the ability for consumers to exchange their discharged batteries for charged ones at battery swap stations. This factor would extend the driving range for EV service subscribers but with increased costs to build and operate the stations. This analysis centers around a base-case scenario from 2012 to 2027 that includes a set of assumptions about subscriber membership levels, gasoline and electricity prices, corporate level expenditures, and the capital costs of batteries, charging stations, and battery swap stations. The base-case set of assumptions is then systematically varied, and a few combinations are explored to determine whether and how such a service might be economically viable. Key sensitivities include buildup of the number of subscribers, the price of gasoline, capital costs of the batteries, distribution of total annual driving mileage of subscribers, and the number of corporate employees needed to operate and manage the subscription service business. Focusing on a network in the San Francisco Bay Area, California, the analysis suggests that, with current gasoline prices and the base-case scenario assumptions, the economics of this business model are challenging.