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MIT analysis finds current EVs could replace ~90% of personal vehicles now on the road based on driver’s energy consumption

A study by a team at MIT has concluded that roughly 90% of the personal vehicles on the road in the US could be replaced by an electric vehicle available on the market today, even if the cars can only charge overnight. MIT Associate Professor Jessika Trancik, corresponding author of the paper published in Nature Climate, noted that this would more than meet near-term US climate targets for personal vehicle travel.

The team spent four years on the project, which included developing a way of integrating two large datasets—one highly detailed set of second-by-second driving behavior based on GPS data, and another broader, more comprehensive set of national data based on travel surveys—to estimate the energy requirements of personal vehicle trips across the US. Together, the two datasets encompass millions of trips made by drivers all around the country.

The detailed GPS data was collected by state agencies in Texas, Georgia, and California, using special data loggers installed in cars to assess statewide driving patterns. The more comprehensive, but less detailed, nationwide data came from a national household transportation survey, which studied households across the country to learn about how and where people actually do their driving.

By working out formulas to integrate the different sets of information and thereby track one-second-resolution drive cycles, the MIT researchers were able to demonstrate that the daily energy requirements of 87% of personal cars on the road in the US could be met by today’s EVs, with their current ranges, at an overall cost to their owners—including both purchase and operating costs—that would be no greater than that of conventional internal-combustion vehicles. The team looked at once-daily charging, at home or at work, in order to study the adoption potential given today’s charging infrastructure.

Such a large-scale replacement would be sufficient to meet the nation’s stated near-term emissions-reduction targets for personal vehicles’ share of the transportation sector—a sector that accounts for about a third of the nation’s overall greenhouse gas emissions, with a majority of emissions from privately owned, light-duty vehicles.

While EVs have many devotees, they also have a large number of critics who cite range anxiety as a barrier to transportation electrification.

This is an issue where common sense can lead to strongly opposing views. Many seem to feel strongly that the potential is small, and the rest are convinced that is it large. Developing the concepts and mathematical models required for a testable, quantitative analysis is helpful in these situations, where so much is at stake.

—Jessika Trancik

The team found that the vast majority of cars on the road consume no more energy in a day than the battery energy capacity in affordable EVs available today. These numbers represent a scenario in which people would do most of their recharging overnight at home, or during the day at work, so for such trips the lack of infrastructure was not really a concern.

Vehicles such as the Ford Focus Electric or the Nissan Leaf—whose sticker prices are still higher than those of conventional cars, but whose overall lifetime costs end up being comparable because of lower maintenance and operating costs—would be adequate to meet the needs of the vast majority of US drivers.

The study cautions that for EV ownership to rise to high levels, the needs of drivers have to be met on all days. For days on which energy consumption is higher, such as for vacations, or days when an intensive need for heating or cooling would sharply curb the EV’s distance range, driving needs could be met by using a different car (in a two-car home), or by renting, or using a car-sharing service.

The study highlights the important role that car sharing of internal combustion engine vehicles could play in driving electrification. Car sharing should be very convenient for this to work, Trancik says, and requires further business model innovation. Additionally, the days on which alternatives are needed should be known to drivers in advance—information that the team’s model “TripEnergy” is able to provide.

Even as batteries improve, there will continue to be a small number of high-energy days that exceed the range provided by electric vehicles. For these days, other powertrain technologies will likely be needed. The study helps policy-makers to quantify the “returns” to improving batteries through investing in research, for example, and the gap that will need to be filled by other kinds of cars, such as those fueled by low-emissions biofuels or hydrogen, to reach very low emissions levels for the transportation sector.

Another important finding from the study was that the potential for shifting to EVs is fairly uniform for different parts of the country.

Jeremy J. Michalek, a professor of engineering and public policy at Carnegie Mellon University who was not involved in this study, says the MIT team’s integration of the GPS and national survey data is a new approach “highlighting the novel idea that regional differences in range requirements are minor for most vehicle-day trips but increase as we move into higher-range trips.” The study, he says, is both “interesting and useful.”

The work was supported by the New England University Transportation Center at MIT, the MIT Leading Technology and Policy Initiative, the Singapore-MIT Alliance for Research and Technology, the Charles E. Reed Faculty Initiatives Fund, and the MIT Energy Initiative.

Resources

  • Zachary A. Needell, James McNerney, Michael T. Chang & Jessika E. Trancik (2016) “Potential for widespread electrification of personal vehicle travel in the United States” Nature Energy 1, Article number: 16112 doi: 10.1038/nenergy.2016.112

Comments

Calgarygary

Rentable/ exchangeable range extenders in the form of aux battery packs, fuel cells or ice could be developed and vehicles could be designed to easily adapt to the RE's. I envision small trailers that can carry extra cargo as well. If you are going on a long journey you are going to be on highway where towing a small trailer shouldn't be too much of a burden.

mahonj

An obvious solution to the range problem is car sharing / swapping (as they clearly point out). If you had that, you could use a Leaf for 87% of your journeys and an ICE for the rest.
The problem is that people are attached to their cars and do not want to swap / share cars.
IMO, what you want is a "valet" car swap service where you book an ICE for a certain umber of days and a guy turns up at your house with it, and drives off in your EV. Thus, there is no painful "drive to the rental place and get your car". Obviously, this would cost more that doing it yourself, but it could be offered.
You could get (say) 15 ICE days / year and 1 "valet swap". The rest you have to do yourself, or pay for them.
On an informal view, one of my neighbours has a leaf and there are dozens of ICEs parked nearby. "All" he needs is a swap agreement with one or two of their owners (and suitable insurance) and he is away with it.
[ The government could mandate simple "car swap" insurance ]

JMartin

@ mahonj: Valet Car swap would be just one more Uber or Lyft service. I like it. I would not be surprised to see a VRBO or AirBNB type online service pop up in the near future. When it does it will be overnight.

Brian P

Did they consider the large number of urban dwellers who live in apartment buildings, condominium units, downtown properties without access to recharging? It sounds plausible that 90% of trips are within the capability of current EVs but it doesn't sound plausible that that 90% of people have access to charging. Infrastructure needs some work to make this happen.

Every trailer that I've ever towed increases fuel consumption by 30% - 50% because it buggers the aerodynamics of the tow vehicle. If you're going to have a range extender it needs to be on-board to avoid this. If it's going to be on-board then the space needs to be allocated in the vehicle for it. If the space needs to be allocated in the vehicle for it then it might as well be there all the time.

Car sharing means you're sharing the previous owner's detritus left in the car unless someone's being paid to clean it after every use, just like normal car rentals ... up goes the cost ... Like it or not, lots of people are pigs. Car sharing also means I can't leave my hard hat, safety vest, tool box, etc in the car. It might work for some people but it won't work for all people ...

electric-car-insider.com

Long range PHEVs solve the car sharing problems. Well managed car share programs like Zipcar could fill in a significant gap for BEVs.

EV charging for multi-tenant dwellings are being rolled out on scale in California now. Curbside charging for street parkers is in pilot programs and have a clear path forward.

If a city can provide street lights and parking meters, they are capable of providing public charging infrastructure.

ai_vin

This is not news. They came to the same conclusions when they built the EV 1. And it was BECAUSE of those conclusions that they scrapped the EV 1.

Trees

By 2021 Ford will have a ride sharing technology available. So, why would anyone own a battery car? The battery car will seldom occupy the status of primary car as this article attempts to sway readers into believing. Watch the videos of Paul Elio explaining the 2rd car market and that consumers aren't stupid as this article attempts to infer. Consumers have a need for big vehicles or a desire for them. They need all season operation with maximum range and dependability. They tow stuff, haul stuff, and carry many people. They like to sit up high with powerful 4x4 equipment underneath. They carry a lot of luggage on trips or cargo when shopping. This vehicle is the primary vehicle.

Where does the battery car fit in? Inner city, short hop, extreme light duty, self driving, single passenger with cargo or two if not. These vehicles easily calculate their energy use and recharge stations. They work night and day to keep investment cost per mile to the minimum. They replace all public transportation and make car ownership for light duty user worthless. These vehicles will be extremely light with no safety equipment other than computing power and sensors. They will make metro transit a pleasure.

Brian P

There is zero chance that a vehicle like this would be granted an exemption from collision standards in the foreseeable future ... unless it is a motorcycle.

HarveyD

Smaller families with 3+ large vehicles is deeply ingrained in the American way of life and is quickly spreading to other countries and continents.

More effective, faster, lower cost public electric transport systems are neglected and/or inefficient in many cities, towns and countries.

With due regards to above, private and public vehicles will be electrified in the next 20-25 years but the ratio may stay about the same as today, in USA and most industrialized countries.

gorr

Does the volt resolve these problems. It is already available but not selling a lot because not everybody can charge it at home and it cost way more and it's unsustainable to gm because they are losing money on it because it cost more to build than the price they are selling it.

Thomas Lankester

@Trees
"The battery car will seldom occupy the status of primary car"
Seems a bizarre statement. If you have a BEV, you want to maximise its use to maximise return on investment (+drive experience, smoothness of ride, quietness).
In our household we have a simple rule on who get the BEV. Whoever is going further, gets first dibs to minimise fuel costs on the HEV. Indeed, the secondary car, the HEV Honda Jazz, is only used for:
-exceptional long journeys
-2 cars needed simultaneously
-awkward loads (due to its 'magic seats' and bike carrier)
-son's driving experience (only insured on Jazz).

Hence: 9000 miles per annum in primary (BEV Zoe) car vs. 4000 miles pa for the Jazz secondary car.

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