The Chevrolet Volt is a plug-in hybrid electric vehicle, designed to run on electricity until its battery level drops. After that, a gasoline engine kicks in to power the car. According to GM, the Volt’s battery-only range would be about 40 miles, and the gasoline engine would have about 40 mpg.

How did GM reach this inflated figure? According to Motor Trend, GM used a proposed EPA measurement system that converts a vehicle’s kilowatt hours (kWh) to an equivalent in miles per gallon. Since GM predicted the Volt would consume 25 kWh per 100 miles, they calculated 230 miles per gallon. The EPA has since shied away from GM’s claims, officially rating the Volt at 37 kWh per 100 miles and announcing it had “not tested a Chevy Volt and therefore cannot confirm the fuel economy values claimed by GM.”

Journalists questioned the 230 mpg claim because the actual figure can change drastically depending on how the Volt is driven. For instance, CNN predicts that if a driver goes 300 miles with a fully charged battery, the fuel economy would actually be about 62.5 mpg. Edmunds.com found that with the battery depleted the car averaged 31.1 mpg.  Edmunds ultimately called the Volt’s performance “seriously subpar when compared to the mid-40s mpg that a standard hybrid typically provides.”

Analysts say GM’s figures also overlook recharging and initial costs. GM has said 8 kWh are needed to travel 40 miles, which the Department of Energy says will cost around 88 cents per charge. While these costs may appear modest, reviewers like Edmunds.com question the overall value since the Volt is far more expensive than other hybrids.

Ultimately, GM and other EV manufacturers need to justify the high price tag of their vehicles by providing buyers measurable fuel savings and a return on their investment. But, even the CEO of GM has questioned the Volt’s lasting value, saying it will be “an old, old technology and old news” in just five years.

PHOTO: GM-Volt.com

Feeling like you’re about to be stranded because your car runs out of juice is known as “range anxiety” in the EV business. The study at Chemnitz found drivers experienced range anxiety about once per month, and researchers proposed that feeling could worsen if there were no nearby public charging stations. EV manufacturers have long tried to dismiss consumers’ worry about insufficient mileage between charges. Then again, when new battery-electric cars like the Nissan Leaf lose power unexpectedly, range anxiety may be well founded.

The researchers discovered most drivers needlessly recharged their vehicle with 20 percent or more power left in the battery. This finding is important because frequent charging can overwhelm the electric infrastructure, which is already threatened by electric vehicles.

Experts estimate that EVs consume about a third of the power of a house, and warn that adding electric cars to a residential area could overwhelm transformers and even cause blackouts. A public charging network would ease drivers’ nerves, but would add an additional burden to the grid. EVs draw their power from a system that is not prepared to meet the increased demand.

Overcharging can also degrade EV’s battery at a higher rate. Fast charging a Nissan Leaf, for example, can decrease the battery life much faster than slow charging at home. And, replacing a dead EV battery isn’t cheap: a recent article from the UK states that a new battery pack could cost over $30,000.

With the harm overcharging can ultimately bring to their vehicles and the electric grid infrastructure, EV drivers unfortunately have more to worry about than just their range.

Image by Salvatore Vuono

Electric vehicles aren’t “zero-emissions” as advertised. Sure, EVs may have no tailpipe emissions, but when an EV plugs in, where does the energy come from? The fact is, almost 50 percent of our nation’s electricity is produced by coal. According to one new study, half of an EV’s lifecycle greenhouse gas emissions are produced during the manufacturing and shipping phase.

• Alternative vehicle fuels aren’t just better for the environment, they’re better for your health. In some states, vehicle emissions constitute the largest source of air pollution like smog and ozone, which can lead to respiratory and other health issues. That’s why the American Lung Association promotes alternative fuel use.

• Current technology cannot affordably harness enough renewable energy power to meet electricity demand. Also, while wind and hydro power are considered by some to be viable energy sources, researcher and author Vaclav Smil contends that these two sources could only supply a small portion of future energy demand. Together, all renewable energy sources only constitute 8% of current worldwide energy supply, according to Smil’s book.

• Biofuels, such as ethanol, are not feasible future energy sources. With the challenges that global food supply is currently facing, we can no longer afford to use food as vehicle fuel while other alternatives are available. Many experts have linked redirected food supply used for producing corn-based ethanol to rising tortilla and livestock feed prices. “Ethanol is taking a larger and larger share of [corn] production,” says one agricultural economist.

To learn more about the differences between alternative fuels, view our Alternative Fuel Fact Briefs online.

PHOTO SOURCE: Project Seed