By Leslie D’Monte
A quieter, cleaner future is not that far away, with more automobile buyers gradually taking to electric vehicles. Despited their limited driving range, electric vehicles can successfully replace the bulk of personal cars on roads, say researchers at the Massachusetts Institute of Technology (MIT). They acknowledge, however, that users should simultaneously share internal-combustion cars to drive electrification.
“Roughly 90% of the personal vehicles on the road daily could be replaced by a low-cost electric vehicle available on the market today, even if the cars can only charge overnight,” Jessika Trancik, the Atlantic Richfield Career Development Associate Professor in Energy Studies at MIT’s Institute for Data, Systems, and Society (IDSS), said in a release on 15 August. The study has been published inNature Energy . (Read more here)
Overall, when accounting for the emissions today from the power plants that provide the electricity, this would lead to an approximately 30% reduction in emissions from transportation. Deeper emissions cuts would be realized if power plants decarbonize (reducing carbon content) over time, the MIT researchers said.
The team spent four years on the project, which included developing a way of integrating two huge datasets: one highly detailed set of second-by-second driving behaviour based on GPS (global positioning system) data, and another broader, more comprehensive set of national data based on travel surveys. 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 researchers worked out formulas to integrate the different sets of information and thereby track one-second-resolution drive cycles. They accounted for the overall cost of an electric vehicle to its owner, including the purchase and operating costs. The team also looked at once-daily charging, at home or at work, in order to study the adoption potential given today’s charging infrastructure.
Electric cars were popular in the late 19th- and early 20th century, when advances in internal combustion engines and mass production of cheaper petrol vehicles led to a decline in the use of electric vehicles. The energy crises of the 1970s and 1980s renewed interest in electric cars, but this too fizzled out till the industry got excited once again around 2008, over concerns about increasing oil prices, and the need to reduce greenhouse gas emissions.
Besides, several national and local governments now give tax credits, subsidies, and other incentives to promote electric vehicles.
For instance, India, too, has electric cars on its roads including the Mahindra e20 (formerly Reva, from the Reva Electric Car Co. that was founded in 1994) and Toyota Prius, besides hybrids such as the Toyota Camry Hybrid, BMW i8 and Maruti Suzuki Ciaz Hybrid. Some users have even booked the Tesla model.
Sales of electric vehicles in India grew 37.5% to 22,000 units in the year ended 31 March from a year ago, according to lobby group Society of Manufacturers of Electric Vehicles (SMEV). Of these, only 2,000 units were four-wheelers. Yet, India remains miles away from its objective of selling 6 million electric vehicles by 2020 (read more here )—a vision stated by the government through the National Electric Mobility Mission Plan (NEMMP) 2020 and FAME (Faster Adoption and Manufacturing of Electric Vehicles).
Electric vehicles run solely on electricity, propelled by one or more electric motors powered by rechargeable battery packs. However, the range is typically limited to 60-120 miles on a full charge, although a few models can go 200-300 miles like the Tesla Models S90D and P90D but also cost $85,000 upwards. Another problem is that fully recharging the battery pack can take 4-8 hours. Even a “fast charge” to 80% capacity can take about 30 minutes. Besides, large battery packs are expensive and may need to be replaced once or more during the life of the vehicle, not to mention that battery packs are heavy and take up considerable space—similar to how CNG (compressed natural gas) kits fill up the boot space.
The lack of available charging infrastructure in many places, and the much greater amount of time required to recharge a car compared to simply filling a gas tank have also been cited as drawbacks.
The researchers acknowledged that electric vehicles have their fair share of critics, who cite range anxiety as a barrier to transportation electrification. However, they claim in their study that the vast majority of cars on the road consume no more energy in a day than the battery energy capacity in affordable electric vehicles available today.
These numbers, the researchers said, 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, 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 electric vehicle 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 vacations, or days when an intensive need for heating or cooling would sharply curb the electric vehicle’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, according to the MIT press statement.
Even as batteries improve, there will continue to be a small number of high-energy days that exceed the range provided by electric vehicles, the researchers point out.
For these days, they advocate the use of other powertrain (those parts that transfer a vehicle’s power from the original source of energy to the surface of the road) technologies.
The study also 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.
