Questions and Answers on Electric Vehicles
What are electric vehicles or electric-drive vehicles?
Since the invention of the automobile, the vast majority of US transportation has been fueled by oil that has been turned into gasoline, diesel, or other fuels. “Conventional” cars burn gasoline or diesel in an internal combustion engine to turn the wheels and get you where you need to go.
In contrast, electric-drive vehicles use electric motors, more advanced versions of the ones that power your refrigerator or washing machine, to partially or entirely replace the internal combustion engine. And instead of supplying all the fuel from a gas tank, electric-drive vehicles rely on batteries or fuel cells to supply electricity for the motor. Batteries used in electric cars have a lot in common with those found in your average laptop or power tool, and fuel cells combine hydrogen and the oxygen from air into electricity.
The first electric-drive vehicles were actually developed in the 1830s with non-rechargeable batteries and limited range. The first car to ever exceed 100 kilometers per hour (65.7 miles per hour) and set the world land speed in 1899 was an electric car called the La Jamais Contente, meaning "the never satisfied." Electric-drive vehicles have developed and matured considerably since then.
What kind of electric vehicle technologies are available today and how do they differ from "conventional" cars?
“Conventional” cars run by converting energy released from burning gasoline or diesel in an internal combustion engine to turn the wheels and get you where you need to go. In contrast, electric-drive vehicles use electric motors and batteries or fuel cells to partially or entirely replace the internal combustion engine.
Electric-drive vehicles offer many benefits that conventional combustion engine-only vehicles cannot. For example, all of the Model E vehicles are designed to temporarily operate their motors as generators to slow down and stop the car while recharging their battery packs at the same time—a feature called regenerative braking. Plug-in hybrid and battery electric cars, and potentially fuel cell electric cars, can also be recharged at home. Electric-drive vehicles are also far quieter than conventional vehicles, both because electric motors are quieter than internal combustion engines, and hybrids (both conventional and plug-in) don’t let their engines idle.
- Battery electric and fuel cell electric cars are considered pure, or all-electric cars because they do not have gasoline engines. Instead, they rely on a motor fed by electricity from a battery pack or from a fuel cell that converts onboard hydrogen and oxygen from air into electricity. Because pure electric cars do not use gasoline, they do not produce harmful emissions directly from a tailpipe, though there are emissions associated with making the electricity or hydrogen.
Electricity used to charge battery electric cars, or to produce hydrogen for fuel cells, can be produced using solar, wind, or other sources of renewable American-made energy. Electricity and hydrogen can also be made from natural gas, coal, or other fossil fuels, leaving a significant environmental footprint.
Even accounting for the energy needed to make the electricity or hydrogen, all-electric vehicles can be two-and-a-half to three times more energy-efficient than today’s conventional vehicles, which only turn 15 to 20 percent of the energy in a gallon of gasoline into energy to drive the wheels.
- Hybrid and plug-in hybrid electric cars still require some gasoline to power their internal combustion engines, and represent an important bridge between conventional and all-electric cars. Hybrids are closest to conventional cars because they rely exclusively on gasoline for all of their fuel. If used well, the electric motor and battery pack in a hybrid car can keep the engine operating more efficiently by avoiding idling and providing extra power so a smaller engine can be used.
Plug-in hybrids are closer to battery electric cars because they use a bigger battery pack and have the ability to drive somewhere in the range of 15 to 50 miles exclusively on electricity from the grid. If the technology is used with efficiency in mind, both hybrid and plug-in hybrid electric cars can use significantly less gasoline and produce fewer tailpipe emissions than conventional vehicles.
Learn more about these technologies in the Model E Vehicle Technology Center:
- Battery Electric Vehicle (BEV)
- Fuel Cell Electric Vehicles (FCEV)
- Hybrid Electric Vehicle (HEV)
- Plug-in Hybrid Electric Vehicle (PHEV)
How do I recharge, refuel, or ‘fill up’ an electric-drive vehicle?
Drivers can plug a number of electric cars or plug-in hybrids into any conventional 120 volt electrical socket, just like you do with your cell phone. The more limited range vehicles, such as the upcoming plug-in Toyota Prius (projected all electric range of about 15 miles), can fully charge the battery system in approximately three hours with a 120 volt charger.
Battery electric vehicles can take several hours to fully recharge, though it depends on the rating of the outlet and how much driving the vehicle did that day (less driving means a quicker charge and a lower environmental footprint). Most battery cars also have the capacity to be charged by 240 volt (the level for larger home equipment like a clothes dryer) outlets for faster charging. Plug-in hybrids, because of their smaller battery packs, can rely on 120 volts, but can also use the higher level for a quicker charge. In a number of cases, home wiring can be upgraded to support chargers that can handle more electric current, lowering the time required to charge the battery.
In addition to charging at home, an infrastructure of commercial electric charging stations is developing in some parts of the country. Some of these stations have higher currents and can fully recharge an electric car in as little as thirty minutes, depending on the voltage and the battery. Car and charging station manufacturers have agreed on standard plugs and outlets, so all electric vehicles should be compatible with all charging stations, though it may take time for this to be true everywhere. Some companies are either considering or moving ahead with carports and charging stations outside their buildings to allow their employees and customers to charge while at work or while shopping. This network of charging stations is still in its very early stages.
While Honda tested a home refueling system for a short time, hydrogen fuel cell vehicles currently cannot be filled up at home. Fuel cell cars can be filled up at hydrogen refueling stations. There are currently about 60 of these stations as they are currently in their very early stages of growth and are regionally concentrated, with a number of them in Southern California, and several on the East Coast. Honda and others are researching ways commercialize a system for FCEV owners to produce fuel for their vehicles at home.
Check the Department of Energy's Alternative Fuels & Advanced Vehicles Data Center for hydrogen fuel cell and commercial electric charging stations near you.
How far can plug-in hybrid and all-electric vehicles go on a single charge/refill? Do I have to worry about running out of “juice” when I’m driving an electric vehicle?
The range—the distance an electric car can travel on a single charge or fill up—is constantly evolving with technological improvements. The range of battery electric cars on the market today varies from about 60 to more than 200 miles. Greater range for battery cars tends to come with higher costs because the vehicle requires a larger battery pack.
The Chevy Volt, the first plug-in hybrid on the U.S. market, gets about 35 miles on electricity alone, and can travel up to 375 additional miles on its gas tank before being recharged and/or refueled. The Honda Clarity fuel cell vehicle has an estimated range of 240 miles on a single tank of hydrogen, and most automakers are expecting to reach a range of about 400 miles with fuel cell electric vehicles to be introduced in 2015.
For comparison, the average American drives about 30 miles per day, according to the Bureau of Transportation Statistics. This is well under the maximum range of the battery and plug-in electric cars on the market today. And according to data from the Department of Transportation, the typical household has two cars, leaving most battery electric vehicle drivers with another option for longer trips. The range of conventional gasoline vehicles today is around 400 miles.
Temperature and driving style can also significantly affect how far the electric car can go on a single charge. A driver who speeds or who needs heat to stay warm or air conditioning to cool off will experience a smaller range.
Many new BEVs or PHEVs have additional features and driving modes to extend the range of the car while attempting to maximize the range of the battery, with pre-heating systems that warm the car while charging and before you leave for work and heated seats to warm you instead of the air. Volvo has been testing its PHEV V60 family sedan in the Arctic Circle in temperatures of -40 degrees Fahrenheit to ensure that the battery can withstand harsh temperatures in an effort to calm consumer fears.
What is the lifespan of an electric-drive vehicle compared to a "conventional" car? Are there special maintenance issues?
In order for electric-drive vehicles to be a commercial success they will have to last just as long as today’s conventional gasoline vehicles (an average of about 15 years, 180,000 miles or more) and all automakers have that goal within their sights. Because there are not a lot of electric-drive vehicles on the road, data on lifetimes are limited, but anecdotal evidence points to hybrid vehicle batteries having lasted since the technology was brought to the US in 1999. Some battery electric vehicles sold more than a decade ago are still on the road.
Electric-drive vehicles have many components that will likely last even longer than a typical gasoline car, both because they have fewer moving parts and because they don’t operate at the high temperatures of an internal combustion engine. Expectations are that maintenance should end up simpler for all-electric vehicles like battery and fuel cell electric cars.
Will an electric-drive vehicle still be “fun" to drive? How does the handling of these cars compare to "conventional" cars?
Electric-drive vehicles can deliver great acceleration, especially from a stop, and can have improved handling over today’s gasoline cars.
One of the benefits of using an electric motor to drive the wheels is that it delivers its maximum torque (the force applied to get the wheels turning and the car moving) even when the car is just getting rolling. In contrast, gasoline engines don’t reach peak torque until the engine revs up to higher speeds, so electric-drive vehicles will typically beat their gasoline counterparts’ accelerating around town.
Electric motors can also deliver very high torque over short periods of time, providing good acceleration on the highway. And unless an automaker is really going for high-end acceleration, electric-drive vehicles won’t have to down-shift to get plenty of torque for passing.
Electric-drive vehicles have two features that can lead to improved handling: a lower center of mass and the flexibility to reach a near ideal weight distribution. Because of their size and shape, the gasoline engine and transmission in a car are typically placed under the hood, but in an electric-drive vehicle, automakers have a lot more flexibility.
Components like batteries, fuel cells, and hydrogen tanks can be placed near the bottom of the vehicle, so electric-drive vehicles can have a lower center of mass than typical gasoline vehicles. A lower center of mass is a key feature of sports cars because it helps the car hug the road during turns and helps avoid rollovers.
Removing some of the weight from under the hood and spreading out electric-drive components around the vehicle also gives automakers the ability to more easily customize the weight distribution between the front and rear wheels, potentially improving safety and driver control during cornering.
Are certain technologies better suited for certain geographic areas?
Automakers are developing and testing electric-drive vehicles to make sure they can operate well from the extremes of Death Valley, California to those of Alaska, but depending on where you live there will be pros and cons of different technologies.
- Battery Electric Vehicles:
Areas of the country that rely heavily on natural gas or renewables to generate electricity will be the best places to plug-in to minimize pollution—that includes the western United States from California to Washington, and Montana, New York, and the North East. Areas of the country that rely heavily on coal will be the worst places to plug-in when it comes to pollution—including much of the Plains states, Midwest, Mid Atlantic, and the South-Central United States.
Battery electric drive vehicles really shine in areas with a lot of stop-and-go traffic due to a feature called regenerative braking which captures the energy normally lost during braking and instead uses it to run the motor as a generator and recharge the batteries, improving efficiency and lowering energy use.
While they can be used anywhere, the more limited range of battery electric vehicles means that they are best suited to denser urban areas where you can drive to work, do your shopping and other daily activities in under 100 miles a day. This is no significant drawback, however, since a 100 mile range covers over 80 percent of Americans’ daily travel.
Other than regional differences in pollution from electricity, the biggest geographic challenges facing battery electric vehicles are temperature extremes. Battery electric vehicles face diminished range when it is very cold outside both because the batteries can’t deliver as much energy when they are cold and because electricity from the battery is needed to keep passengers warm—any electricity that goes into heating passengers can’s be used to drive the vehicle. In very hot weather, extra electricity is needed to keep passengers—and sometimes the batteries themselves—cool, reducing range.
- Plug-in Hybrid Electric Vehicles:
Plug-in hybrids, because they also use batteries also benefit from or are impacted by many of the same geographic issues. Areas of the country with cleaner electric grids deliver the best environmental benefits from plug-in hybrids and areas with a lot of stop and go traffic are also attractive.
Because their refueling time is comparable to a gasoline vehicle and they have even better range, plug-in hybrids don’t necessarily favor denser urban areas, though environmental and petroleum displacement benefits are enhanced in these areas if the plug-in hybrids are mainly run on electricity made from natural gas.
Both cold and hot weather also impact the all-electric range of plug-in hybrids, but the flexibility of still having a gasoline engine means their overall range is not compromised.
- Fuel Cell Electric Vehicles: Fuel cell electric vehicles won’t see differences in environmental performance as long as the hydrogen they run on is generated from natural gas or renewables. Producing hydrogen from electricity is a poor environmental choice unless the vehicle is operated in a region where significant electricity is generated from sustainable biomass, wind, or solar power.
Most, if not all, fuel cell vehicles will be hybridized in much the same way as a conventional hybrid electric vehicle, providing the ability to avoid idling and to capture and store braking energy in a small battery pack. This means they will also benefit in areas of the country with a lot of stop-and-go traffic and therefore access to a lot of regenerative braking opportunities.
The range and refueling time of fuel cell vehicles is comparable to gasoline vehicles, so they can be used anywhere a gasoline vehicle can be used, provided the infrastructure is available for hydrogen fueling.
Fuel cell vehicles can operate well in both cold and hot regions, but, like battery electric vehicles, their range will be reduced in hot and cold weather due to the energy demand to cool or heat passengers. Their relatively quick refueling time means this won’t really impact vehicle utility, despite these heating or cooling needs.
Are certain technologies better for different sized vehicles?
Battery, fuel cell, and plug-in hybrid electric powertrains can be used in all sizes of vehicles, from buses and big-rigs to compact cars, but some technologies stand out more for different applications.
Because doubling range requires about double the batteries, battery electric powertrains are best positioned for smaller vehicles, where a smaller, less expensive, battery can be used to deliver significant range.
Battery electric powertrains are also well suited for fleet vehicles of all sizes that need only limited range and operate under stop-and-go conditions. Good examples include mail or utility trucks, garbage trucks and local delivery trucks which today spend a lot of time wasting fuel from idling and operating within a relatively short range. Battery electric vehicles don’t waste energy when they are idling, and they recover energy during the braking portion of stop and go travel.
Fuel cell vehicles are best suited to larger cars and trucks, especially those that need longer range, because their most expensive component, the fuel cell system, doesn’t have to increase in size to deliver more range in the way batteries do. More range is still more expensive because hydrogen storage still costs money, but it is less expensive to increase the hydrogen storage capacity of a FCEV than it is to add a larger battery to extend a BEV’s range. In the near term, while hydrogen infrastructure is limited, fuel cell vehicles are well suited to centrally refueled fleet vehicles. In the long term, when there is a more extensive hydrogen infrastructure, fuel cells could work well in any size, and might be the best alternative to replace diesel engines in long haul trucks.
Plug-in hybrids can be used in all sizes of vehicles, but, like battery electric vehicles, larger applications require more expensive batteries, limiting either their application or effectiveness. Plug-in hybrids may make the most sense for medium-sized cars and SUVs, where they can fill a sweet spot where battery-only powertrains are increasingly expensive and fuel cells are not quite sufficiently cost effective yet.
What are the environmental impacts of electric drive technologies?
Electric-drive vehicles have the potential to dramatically reduce global warming, smog-forming, and toxic pollution from cars and trucks. If the electricity or hydrogen on which they run is produced by renewable energy such as solar or wind power, little or no smog-forming, global warming pollution, or toxic pollution is associated with operating an electric-drive vehicle.
However, 45 percent of electricity today is generated from coal, leading to significant emissions of global warming, smog-forming, and toxic pollution—in addition to the related impacts of strip mining and the health and safety of coal miners. Another 25 percent of U.S. electricity is generated by natural gas, which has a lower, but still significant impact on public health and the environment.
If an electric-drive vehicle is recharged primarily using electricity generated from coal, its global warming pollution footprint is only a little better than the average gasoline vehicle today and is significantly worse than a good hybrid—based on emissions from generating, transporting, and using electricity or gasoline. Recharging from electricity generated using natural gas, however, leads to a global warming footprint that is even better than a good hybrid.
Natural gas is also a good resource for generating hydrogen, leading to a global warming foot print that is as good as or better than recharging batteries from a natural gas powered grid. Electricity, on the other hand, is not a good resource for generating hydrogen today, leading to a global warming footprint that is not much better, or even worse, than today’s conventional vehicles unless that electricity is made using wind or solar power.
How is a battery or plug-in hybrid electric vehicle running on coal-fired electric grid any better than a "conventional" gasoline vehicle?
If an electric-drive vehicle is recharged primarily using electricity generated from coal, its global warming pollution footprint is only a little better than the average gasoline vehicle today and is significantly worse than a good hybrid—based on emissions from generating, transporting, and using electricity or gasoline.
And while pollution controls on powerplants should keep the problem in check, there are risks that some pollutants, such as sulfur or toxic particulates, could be increased, at least in the areas around the powerplants.
At the end of the day, consumers living in areas with a lot of coal should either focus on buying a good hybrid or should look for ways to support increased use of renewables, both directly through their purchases and by advocating for increases renewable generating capacity.
Should I buy one of the electric-drive vehicles now, or should I wait for these technologies to mature?
Early production will be limited, but if you live in an area of the country where much of the electricity is generated from renewables or natural gas and can afford a battery electric or plug-in hybrid electric vehicle, then you should seriously consider buying one. This useful map shows what global warming pollution from electricity looks like by region.
Not only will you be helping to cut down on global warming pollution and oil use, but you will also show the auto industry that there is an early market for these vehicles. Building up that early market is important to help drive up production volumes and research to get costs down so that electric-drive vehicles can become an environmental, energy security, and market success.
Production of fuel cell vehicles today is even more limited, with only Honda offering some version of a commercial lease to a few people each year. Daimler-Benz, Ford, GM, Honda, Hyundai, Nissan, and Toyota are among the automakers that have vehicles being tested on U.S. roads today and have said that, buy at least 2015 they expect fuel cell vehicles will enter the commercial market in volumes similar to today’s battery and plug-in hybrid vehicles.
If you can’t purchase a battery, fuel cell, or plug-in electric vehicle, then your next best bet is a good hybrid. There are many excellent hybrids on the market, but there are also some that fail to live up to the promise of the technology. You can get a lot more information with our hybrid scorecard at hybridcenter.org. And if you can’t find a hybrid that meets your needs, purchase the highest fuel economy conventional car that does.
Of course, don’t forget to save yourself some money and keep a lower environmental footprint by choosing a car or truck based on your daily driving, not the few times a year when you need to haul a heavy load or a lot of people. Between rental cars and car sharing, you can get whatever kind of vehicle you need in those circumstances. If you do that, your car will tend to cost less up front and will be a lot less expensive to fuel.
Are there tax breaks or subsidies available for hybrid and electric vehicles?
Federal and State governments often offer a number of incentives for clean vehicle consumers. The details of the tax credits and subsidies depend on the type of technology purchased, the auto manufacturer, where you live, and when you buy. These incentives can help cover the cost of electric-drive vehicles and the electricity or hydrogen infrastructure they require.
Some states offer other perks for advanced vehicle drivers, like access to the carpool lane and reduced fares on toll roads.
For more information about available federal and state incentives, go to the Department of Energy's Alternative Fuels & Advanced Vehicles Data Center.
Why are electric-drive technologies important to our transportation future?
Our current oil dependence leads to myriad problems—environmental, security, and economic. Reliance on oil leaves America vulnerable to fluctuations in oil prices and gas price shocks and creates significant challenges for our foreign policy due to our reliance on resources from unstable regions or unfriendly governments. Oil and other petroleum products are also the biggest source of global warming pollution in the United States—just edging out coal.
Transportation is almost exclusively dependent on oil and represents over two-thirds of U.S. petroleum demand. Transportation is also the largest single source of many air pollutants in the United States. It causes more than half of the carbon monoxide, more than a third of the nitrogen oxides, and almost a quarter of the hydrocarbons in our atmosphere.
Motor vehicles also emit pollutants, such as carbon dioxide, that contribute to global climate change. The transportation sector currently is responsible for about 30 percent of all U.S. greenhouse gas emissions.
If Americans were to do nothing to improve energy efficiency, or to invest in clean alternative fuels, and nothing to change the travel choices we make every day, our dependence could rise to more than 25 million barrels of oil each day by 2030.
While vehicle electrification is not a “silver bullet” solution to our addiction to oil, an increased portfolio of electric-drive cars and light trucks is a key segment of an oil savings plan that can cut America’s projected oil use in half by 2030. Expanding this sector of the automobile market will be crucial to effectively ending our reliance of oil for transportation by 2050.
What is the Union of Concerned Scientists’ stance on electric-drive technology?
For more than 40 years, the United States has shifted its financial and policy support from one promising energy technology to another, making it difficult for industry and venture capitalists to make long-term investments of their own. Each of the last eight presidents have acknowledged the need to curb U.S. oil dependence, but instead of building on the work of his predecessors, each chose to highlight and incentivize one among a variety of promising technologies.
Developing a new fleet of clean vehicles depends on creating an opportunity for many technologies, not focusing on one “winning” one. U.S. policy toward electric-drive vehicles and clean technology more broadly has suffered from a chronic problem along these lines—the “silver bullet” syndrome.
It is vital that we avoid prejudging the science and picking winners and losers at this stage. Instead we should pursue multiple options to see what technology mixture will work best in the long term.
UCS will continue to remind lawmakers that the typical two- to four-year political cycle is not enough time to deliver big results, and that we have to invest in technologies with some risk if we are to succeed.
Considering that our nation has relied on one basic engine technology and one fuel for more than a century, the switch to electric-drive vehicles may feel more like evolution than a revolution—but it is high time we face the challenges of climate change and America’s oil dependence by moving our transportation system into the twenty-first century.