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Resurrecting Plug-in Hybrid Cars

Category: Energy & Environment,Finance

Portland, Oregon, USA - A Toyota Prius Hybrid car is plugged in and charging at an electric vehicle charging station on the Portland State University campus.

Getty

By Scott Hardman and Dan Sperling

Plug-in hybrids are destined to face an early death, according to an emerging conventional wisdom, expressed in recent articles such as: Plug-in hybrid car hits its stride just in time to die, The death of the plug-in hybrid is inevitable, and The future of PHEVs looks bleak. GM fanned the flames with its announced termination of the award-winning Chevrolet Volt. Meanwhile, many automakers are bringing new plug-in hybrid models to market, promising greater efficiencies, improved driving ranges, and more diverse vehicle platforms (including SUVs). We recently held workshops with researchers from North America, Europe, and Asia in an effort to bring some clarify to this debate, and answer the question “what role do plug-in hybrids have in the transition to electric vehicles?”

The key difference between battery electric and plug-in hybrid electric vehicles is the combustion engine carried onboard the plug-in hybrid electric vehicle. Battery electric vehicles are driven only by their battery and electric motor and typically have ranges of 125-300 miles. Plug-in hybrids have a smaller battery that typically allows an electric range of 20-50 miles, and a gasoline combustion engine that adds another 300 to 500 miles of driving range.

It’s easy to become excited about battery electric vehicles when looking at sales. Prior to 2018 the market was split roughly 50/50 between plug-in hybrid and battery electric vehicles. However, in 2018 the market shifted to 66% battery electric vehicle and 34% plug-in hybrids.

The story is not so simple, though. If one parses out Tesla electric vehicles (as we did below), one sees that battery electric vehicle market growth was huge and entirely due to one automaker, Tesla. Sales of battery electric vehicles by all other companies actually declined, falling back to 2015 levels. Plug-in hybrids, on the other hand, are showing consistent market growth.

Some consider plug-in hybrids to be a “transitional technology,” a stepping stone on the way to “pure” battery electric vehicles. Perhaps it is better to think of them as an “enabling technology,” encouraging more consumers (and fleets) to move beyond gasoline and diesel vehicles.

As we indicate in a detailed policy report brief, plug-in hybrids offer a more flexible vehicle option for consumers, dispensing with range anxiety and concern about where to recharge. As the market moves beyond affluent house owners to apartment dwellers who do not have a personal parking space, plug-in hybrids will become more attractive and compelling. They will also be more compelling for those who frequently travel longer distances and have unpredictable use patterns—for instance car rentals and fleets.

Plug-in hybrids may also be beneficial in larger vehicles, such as most pickup trucks, SUVs, and minivans. Plug-in hybrids have fewer batteries than battery electric vehicles, and thus have less added weight and, at least for the coming years, will be more moderately priced than similarly sized battery electric vehicles. Indeed, at present, the only large battery-powered vehicles are high end luxury vehicles with prices over $70,000. Meanwhile, some large plug-in hybrids are now entering the market at prices around $35,000.

Many argue that plug-in hybrids can never match the environmental benefits of battery electric vehicles. Those advantages may be relatively small, though. Research from Nicholas et al. & Plötz et al. shows that plug-in hybrids with around 40 miles of driving range (e.g., the first generation Chevrolet Volt) operate on electricity for around 75% of their miles—and, because they are used more than battery electrics, end up traveling as many miles on electricity as a short range battery vehicle, such as a Nissan Leaf. Seen another way, it was found that households with multiple vehicles accumulate about the same number of miles on electricity with a plug-in hybrid as with a battery electric car (45% versus 43%). The explanation is simple: households with battery electric vehicles tend not to use the vehicle for longer trips, but do not worry about range with plug-in hybrids and thus use them more.

We note two caveats. Shorter range plug-in hybrids, such as those with less than 30 miles of electric range, perform considerably worse than those with ranges of 40 miles or more, usually because they are plugged in less, and longer-range battery electric vehicles which tend to be driven considerably more (on electricity) than shorter-range vehicles. For these reasons, policy should disproportionately reward plug-in hybrids with electric driving ranges over 40 miles, and battery electric vehicles with ranges over 200 miles or so. This can be done by tying incentives and regulation to the electric driving range of the vehicles; allowing easy access to charging infrastructure, especially at home and work; and by developing vehicles that drive electrically when they are fully charged (i.e. the engine does not start), giving consumers a positive, smooth, and quiet driving experience.

Let’s not give up on plug-in hybrids. Indeed, let’s encourage them. Many might see battery electric vehicles as the holy grail, but if we want to accelerate the transition from fossil energy driving to electricity driving—especially for those living in apartments and condominiums, with erratic travel patterns, and desiring larger pickups, minivans, and SUVs—then plug-in hybrids (or  perhaps hydrogen fuel cell vehicles) are essential. Don’t let the perfect be the enemy of the good.

Scott Hardman, Ph.D. is a researcher at the Plug-in Hybrid & Electric Vehicle Research Center of the Institute of Transportation Studies at the University of California Davis (ITS-Davis). His focus is on electric vehicles (EVs) and consumers, which includes understanding the buyers of EVs, their preferences and purchase motivations, how they use the vehicles, and researching incentives and policies that can increase EV adoption. See his research here.

Dan Sperling, Ph.D. is the Distinguished Blue Planet Prize Professor of Engineering and Environmental Science at the University of California, Davis, director of ITS-Davis, and lead author of Three Revolutions: Steering Automated, Shared, and Electric Vehicles to a Better Future. Follow on Twitter: @DanSperling_ITS, @ITS_UCDavis, @3Rev_ITSDavis

 

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Portland, Oregon, USA - A Toyota Prius Hybrid car is plugged in and charging at an electric vehicle charging station on the Portland State University campus.

Getty

By Scott Hardman and Dan Sperling

Plug-in hybrids are destined to face an early death, according to an emerging conventional wisdom, expressed in recent articles such as: Plug-in hybrid car hits its stride just in time to die, The death of the plug-in hybrid is inevitable, and The future of PHEVs looks bleak. GM fanned the flames with its announced termination of the award-winning Chevrolet Volt. Meanwhile, many automakers are bringing new plug-in hybrid models to market, promising greater efficiencies, improved driving ranges, and more diverse vehicle platforms (including SUVs). We recently held workshops with researchers from North America, Europe, and Asia in an effort to bring some clarify to this debate, and answer the question “what role do plug-in hybrids have in the transition to electric vehicles?”

The key difference between battery electric and plug-in hybrid electric vehicles is the combustion engine carried onboard the plug-in hybrid electric vehicle. Battery electric vehicles are driven only by their battery and electric motor and typically have ranges of 125-300 miles. Plug-in hybrids have a smaller battery that typically allows an electric range of 20-50 miles, and a gasoline combustion engine that adds another 300 to 500 miles of driving range.

It’s easy to become excited about battery electric vehicles when looking at sales. Prior to 2018 the market was split roughly 50/50 between plug-in hybrid and battery electric vehicles. However, in 2018 the market shifted to 66% battery electric vehicle and 34% plug-in hybrids.

The story is not so simple, though. If one parses out Tesla electric vehicles (as we did below), one sees that battery electric vehicle market growth was huge and entirely due to one automaker, Tesla. Sales of battery electric vehicles by all other companies actually declined, falling back to 2015 levels. Plug-in hybrids, on the other hand, are showing consistent market growth.

Some consider plug-in hybrids to be a “transitional technology,” a stepping stone on the way to “pure” battery electric vehicles. Perhaps it is better to think of them as an “enabling technology,” encouraging more consumers (and fleets) to move beyond gasoline and diesel vehicles.

As we indicate in a detailed policy report brief, plug-in hybrids offer a more flexible vehicle option for consumers, dispensing with range anxiety and concern about where to recharge. As the market moves beyond affluent house owners to apartment dwellers who do not have a personal parking space, plug-in hybrids will become more attractive and compelling. They will also be more compelling for those who frequently travel longer distances and have unpredictable use patterns—for instance car rentals and fleets.

Plug-in hybrids may also be beneficial in larger vehicles, such as most pickup trucks, SUVs, and minivans. Plug-in hybrids have fewer batteries than battery electric vehicles, and thus have less added weight and, at least for the coming years, will be more moderately priced than similarly sized battery electric vehicles. Indeed, at present, the only large battery-powered vehicles are high end luxury vehicles with prices over $70,000. Meanwhile, some large plug-in hybrids are now entering the market at prices around $35,000.

Many argue that plug-in hybrids can never match the environmental benefits of battery electric vehicles. Those advantages may be relatively small, though. Research from Nicholas et al. & Plötz et al. shows that plug-in hybrids with around 40 miles of driving range (e.g., the first generation Chevrolet Volt) operate on electricity for around 75% of their miles—and, because they are used more than battery electrics, end up traveling as many miles on electricity as a short range battery vehicle, such as a Nissan Leaf. Seen another way, it was found that households with multiple vehicles accumulate about the same number of miles on electricity with a plug-in hybrid as with a battery electric car (45% versus 43%). The explanation is simple: households with battery electric vehicles tend not to use the vehicle for longer trips, but do not worry about range with plug-in hybrids and thus use them more.

We note two caveats. Shorter range plug-in hybrids, such as those with less than 30 miles of electric range, perform considerably worse than those with ranges of 40 miles or more, usually because they are plugged in less, and longer-range battery electric vehicles which tend to be driven considerably more (on electricity) than shorter-range vehicles. For these reasons, policy should disproportionately reward plug-in hybrids with electric driving ranges over 40 miles, and battery electric vehicles with ranges over 200 miles or so. This can be done by tying incentives and regulation to the electric driving range of the vehicles; allowing easy access to charging infrastructure, especially at home and work; and by developing vehicles that drive electrically when they are fully charged (i.e. the engine does not start), giving consumers a positive, smooth, and quiet driving experience.

Let’s not give up on plug-in hybrids. Indeed, let’s encourage them. Many might see battery electric vehicles as the holy grail, but if we want to accelerate the transition from fossil energy driving to electricity driving—especially for those living in apartments and condominiums, with erratic travel patterns, and desiring larger pickups, minivans, and SUVs—then plug-in hybrids (or  perhaps hydrogen fuel cell vehicles) are essential. Don’t let the perfect be the enemy of the good.

Scott Hardman, Ph.D. is a researcher at the Plug-in Hybrid & Electric Vehicle Research Center of the Institute of Transportation Studies at the University of California Davis (ITS-Davis). His focus is on electric vehicles (EVs) and consumers, which includes understanding the buyers of EVs, their preferences and purchase motivations, how they use the vehicles, and researching incentives and policies that can increase EV adoption. See his research here.

Dan Sperling, Ph.D. is the Distinguished Blue Planet Prize Professor of Engineering and Environmental Science at the University of California, Davis, director of ITS-Davis, and lead author of Three Revolutions: Steering Automated, Shared, and Electric Vehicles to a Better Future. Follow on Twitter: @DanSperling_ITS, @ITS_UCDavis, @3Rev_ITSDavis

 


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