How Low-energy Vehicles Work

Low energy, yes...but this isn't really what we're talking about. Want to learn more? Check out these electric car pictures.
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A low-energy vehicle is a car or truck that uses less energy than a conventional gasoline-powered vehicle. Low-energy vehicles (or LEVs) most commonly take the form of gasoline-electric hybrids or plug-in electrics, but there are a few less-common alternatives.

Fans of LEVs include proponents of clean technology and renewable resources, drivers who are happy to spend less at the pump, and the environment. LEVs were designed to reduce dependency on the nonrenewable fossil fuels that are processed to make gasoline. Since they burn significantly less traditional fuel (or none at all), LEVs don't spew harmful chemicals into the air as much as regular gas-powered cars. So, they're better for a long-term sustainable energy economy, and they're better for the air we breathe.

We'd hesitate, at this point, to call LEVs a trend, which is a good thing. They're no longer particularly novel, even though the technology continues to improve in terms of becoming more efficient, more accessible and easier to use, and more like a normal car that an average person would want to buy and drive. Though alternative fuel engines were once found only in aerodynamic compact cars that were often derided as being too awkward-looking to earn mass appeal, that stigma's mostly outdated. Truck, SUV and luxury car shoppers all have LEV options...and the once-goofy-looking Prius, now an everyday sight, still brandishes its angles as a badge of honor.

We don't look at LEVs as outliers anymore; they've smoothly integrated themselves into the flow of traffic. But the underlying differences still aren't widely understood. They're worth a closer look. And all this begs the question: Are LEVs the new norm...and how will that work?

Twice the Power, Half the Burn

City officials announced in February of 2012 that 92-percent of San Francisco's taxi fleet is comprised of hybrid or CNG vehicles, making San Francisco the greenest cab city in the nation.
City officials announced in February of 2012 that 92-percent of San Francisco's taxi fleet is comprised of hybrid or CNG vehicles, making San Francisco the greenest cab city in the nation.
Justin Sullivan/Getty Images

Hybrids, one of the earliest and most consumer-friendly LEVs, are typically gasoline-electric configurations. Generally, a gas engine powers the car, and an electric motor kicks in to help out under acceleration or heavy load. Each manufacturer has tinkered with the exact ratios of gasoline and electric power to suit their target market, with some relying more heavily on the electric power, while others skew toward gasoline. For the most part, though, they work pretty much the same. This arrangement significantly cuts down on the amount of fuel that's burned, since the cars can get the job done with much smaller engines. Some hybrid models even use the electric motor for all low-speed or low-load driving.

Hybrids have a host of other features that contribute to their energy-efficient reputation. Regenerative braking was among the most innovative of the early hybrid features, and is still in use. When the driver presses the brake pedal, the electric motor acts as a brake, sending a signal through the drivetrain to tell the wheels to slow down. The wheels still have energy in them, though, so instead of that energy being lost (as it would through regular mechanical braking) it is pushed back through the drivetrain toward the motor, where it's stored until the car needs it again for acceleration. A lot of hybrids also reduce or eliminate fuel wasted at idle by shutting off the engine when the car comes to a stop, and kicking it back on when the driver hits the gas.

The Honda Insight and Toyota Prius, both launched in 2000, were the first mass-market hybrids available in the United States. They were embraced by a small but enthusiastic segment of car buyers, for their unorthodox aerodynamic design as much as their Earth-friendly reputation. Most consumers, however, were hesitant...turned off by the angular sloping hatchbacks, the up-front cost of entry, and the smug sense of superiority that seemed to envelop the hybrids like a cloud. Now, they're available from practically every manufacturer in nearly every form. So, how did hybrids eventually manage to charm the masses?

Two Million and Counting: Are hybrids the new norm?

The average consumer, faced with the task of buying a new car or SUV, has no compelling practical reason not to consider a hybrid option. Up-front price is the only barrier to entry, and carmakers have managed to pare down this difference so that it's practically negligible on a new purchase.

Assuming, of course, all other things being equal (which they never really are). Car purchases can be as emotional as they are logical, and it's understandable if someone's dead set on a model or trim that doesn't come in a hybrid... or if the growl of a V8 is just too bad-ass to ignore.

But to the average person, these things don't matter, and a hybrid will suit their needs just fine. That in itself is an achievement by the auto industry. Just a few minutes of browsing provides some compelling illustration. For example, Toyota, one of the early leaders in pushing mainstream hybrids, has six hybrid models available as of the summer of 2012 -- dead even with the car and van range.

Two million hybrids have been sold since 2012, with sales peaking just before the recession and holding fairly steady through the decline [source: Essex and Holland]. So, while a hybrid might not be the default choice for most car shoppers, they're continuing to win new converts.

Precious Plug-ins

Electric vehicles (we'll call them EVs) are in their adolescent phase, at least compared to hybrids. Electric cars run on electric motors that are powered by batteries. When the battery is drained, it can be juiced up on a public charging station or through a special adapter that runs off household current. Although EV batteries have improved considerably, they're still a weak link in the economics of owning an EV. Cost of replacement and the impact of disposal can get some people wringing their hands with anxiety. And in the early days of electric cars, critics pointed out that drivers had to be especially careful not to stray too far from a charging point. Battery range has increased and the power infrastructure has improved, but the need to charge up after each commute can still be an inconvenience.

A key theme in EVs is sustainability. For example, carmakers are looking for alternatives to the traditional electric high-powered permanent magnet-based motors that rely on rare-earth metals. They're also looking for more efficient ways to power up the cars -- even though they run clean, the electricity they use might come from dirty sources (like coal plants or fossil fuels).

Early attempts to integrate solar panels directly into cars didn't work, but a company in New Jersey has unveiled an EV charging station that uses solar energy to power up the cars' batteries. These SunStations are a lot more versatile than the existing EV infrastructure, since they don't necessarily have to tap into the power grid.

There are proposals being floated around that might make EVs even more efficient, as well as increasing cost effectiveness for their owners. A team of researchers from the University of Delaware suggests that EVs could primarily power up during off-peak times, when power is less expensive. Then, if a car is parked and plugged into its charger when there's an unexpected spike in power demand, the cars could be tapped to feed its stored energy back into the grid, and the utility company will send a rebate check or electricity credits to the owner.

On the EPA's list of top efficiency achievers, the bottom two are rated at a combined city/highway 50 miles per gallon (21.3 kilometers per liter) (both members of the Toyota Prius lineup, one edges out the other based on slightly higher city mileage). The most efficient vehicle on the list (and therefore, the most efficient vehicle available) is the electric Mitsubishi i-MiEV, which achieves the equivalent of a combined 112 miles per gallon (47.6 kilometers per liter).

Don't assume auto manufacturers are making these investments out of the goodness of their hearts. By law, they are held to emissions standards, which are usually enforced by averages. For example, BMW can offset the inefficient mileage of its performance cars by producing upscale hybrids and electrics that will appeal to BMW's target audience. Materials such as carbon fiber and other strong yet lightweight composites improve efficiency and help justify a premium price, both of which boost the brand's street cred.

Another luxury example, the Tesla Roadster (which is basically an electric drivetrain stuffed into a Lotus Elise body) would be a powerful small car by most standards, and is extra impressive for an EV. Its electric motor produces 288-horsepower and transmits 88-percent of the battery's power to the wheels [source: The Economist]. (The average car achieves about 30- to 40-percent drivetrain efficiency.) An electric sports car like this might be a mid-life-crisis car for the wealthy, but it still shows what's possible.

Will electrics ever deliver the proper charge?

Electric vehicles will only achieve mainstream acceptance if car shoppers become comfortable with their quirks -- the features and characteristics that make them seem inconvenient. Carmakers and marketers have been working hard to make some perceived drawbacks seem like benefits (for example, you'll have to plug in your EV to recharge while you're shopping...but you might score a priority parking spot at the charging-station-friendly grocery store). Coming up with terminology is a challenge with a similar goal. So, for the sake of putting electric vehicles in a context car shoppers will understand, they're rated in miles per gallon to enable comparisons with gas-powered vehicles. Of course, there are no gallons in an EV's battery, so the standard is that 33.7 kilowatt hours equals a gallon of gasoline (both produce the same amount of energy).

So far, though, EVs' sales are disappointing to some, yet inspiring to others. The Nissan Leaf and Chevy Volt, the United States' first two options, sold a combined 17,345 in 2011. These sales fall short of Nissan and GM's expectations but are more than double the Honda Insight and Toyota Prius hybrids' combined first-year sales totals of 9350 -- and look how far those have come since the year 2000 [source: Szczesny].

They're still suffering growing pains -- so far in 2012, Chevy recalled Volts to study actual battery fires, and shortly after launch, Fisker recalled all their Karmas to assess the risk of potential fires. Such problems, though, are characteristic of all vehicles -- any car can experience mechanical trouble.

There's some evidence that does suggest EVs are meeting their owners' expectations... but it's not exactly straightforward. A study of plug-in electrics in California shows that the cars there are driven an average of 26 miles (41.8 kilometers) a day, which is considerably less than Americans think they drive. Here's the catch (or, at least, one of the catches): These cars tend to be owned by people with disproportionately high incomes, like, six figures and above. That might not qualify as seriously wealthy, but it means that California EV drivers don't exactly represent the general population. They're inclined to own electric cars anyway, and can do it without too much of a cramp on the lifestyle.

By mid-2012, EV sales were ahead of 2011's pace, with more models joining the Leaf and Volt. Industry analysts predict a rise that will likely mimic the decade-long ascension of gas-electric hybrids, even if continued improvement to traditional gasoline vehicles slows growth.

And when hybrids and electrics aren't edgy enough...

A Honda FCX concept car is displayed at the 100th annual Los Angeles Auto Show on Nov. 30, 2006 in Los Angeles, Calif.
A Honda FCX concept car is displayed at the 100th annual Los Angeles Auto Show on Nov. 30, 2006 in Los Angeles, Calif.
David McNew/Getty Images

...there's always an alternative glimmering on the horizon. Like water. Or cornfields.

Two technologies that showed a lot of early promise were based on the premise of biofuels: hydrogen and ethanol. And though a lot of research is still underway to develop efficient, cost-effective methods of harvesting this energy, and determine long-term sustainability, early attempts to mass-market these fuel sources have fallen short of their potential.

Hydrogen cars run on a fuel cell that works similar to a battery in the way it stores and supplies power -- the difference is that a fuel cell depletes and needs to be refilled. The fuel cell works by splitting hydrogen into its basic parts -- an electron and a proton. The electrons come together to form electricity to power the car, which leaves behind ionized hydrogen. A quick rendezvous with some oxygen on the way down the tailpipe, and that's it -- this car's emissions consist of water.

Hydrogen is the most abundant natural element on the planet, but that doesn't mean it's easy to harness it for fuel. Hydrogen can be produced from water and natural gas, but the processes are a pain. It's up to scientists to figure out how to make it less of a pain -- more efficient and less expensive -- than producing petroleum-based gasoline from fossil fuels. There's also the sticky issue of mass-harvesting hydrogen in an environmentally friendly way. Hydrogen is also flammable, which makes it difficult to store and transport, especially in gaseous form.

Despite all that, there are a few hydrogen cars on the market, but the market itself is quite limited. More specifically, California residents can, for a hefty monthly sum, lease a hydrogen car (the Honda FCX Clarity is the most prominent, with some competition from Mercedes) -- the cost includes maintenance, insurance, and hydrogen fuel. Toyota and Hyundai hope to start selling hydrogen cars in 2015 (Toyota's target sale price is about $50,000) even though the infrastructure will still make ownership a hassle for most Americans. GM and Toyota say that they can build the cars for 10-percent of what they used to (though the cost to manufacture is still a low six figures apiece) [source: Valdes-Dapena]. But don't get too excited. They won't be available to buy, in California or anywhere else, until considerable progress is made in terms of affordability (manufacturers have to demonstrate that they can build hydrogen cars at a cost that means they'll be priced affordably for a bigger segment of the population) and infrastructure (the hydrogen fuel is reasonably available).

Though hydrogen is not a biofuel, strictly speaking, researchers in the UK recently discovered a way to produce clean biohydrogen from food waste, with no emissions. This process could even be used to make hydrogen from the byproducts of ethanol production [source: Hill].

Of course, that leads us to ethanol, the other major biofuel with potential, which has also suffered considerable setbacks. E85, one such example, is a fuel that's a blend of 85-percent ethanol (a corn-based fuel) and 15-percent gasoline. (By contrast, regular gasoline contains about 10-percent ethanol.) By diluting down the gasoline, fewer fossil fuels are used and the car spits out a smaller concentration of harmful smog-causing hydrocarbons. Some industry experts hoped E85 would help solve our energy woes, but the entire endeavor was a mess from the start.

General Motors invested heavily in developing and marketing E85-friendly flex-fuel vehicles that could run on both biofuel and gasoline (skeptics say it was to help achieve federal fuel standard averages across GM's entire lineup). Meanwhile, government subsidies encouraged farmers to grow corn for ethanol production, rather than food. Prices were kept lower than regular gasoline thanks to federal tax credits of 38 cents per gallon. Despite these efforts, the small percentage of people who'd taken the leap of faith in buying a new E85 vehicle had difficulty finding supplies of the fuel -- gas stations that sold E85 were hard to find and located only in certain regions (an estimated 2-percent of gas stations). The expiration of those corn subsides means that there's a lot less incentive to make E85, and the tax credits that expired at the beginning of 2012 means prices are considerably higher. Prices are especially volatile for E85 because the market depends on both fuel prices and corn prices.

If hydrogen and biofuels can overcome their damaged reputations, they may still have a role in the future of LEVs. It's optimistic to think that we can power our cars with renewable resources, but at least we know it's not truly impossible.

Author's Note

It's hard to deduce whether the credibility of plug-in electrics is enhanced or diminished by the California bourgeoisie. According to CleanTechnica, half of all EVs in California are owned by households with an income over $150,000 [source: Shahan].

Granted, that doesn't go far in I hear. (But I certainly wouldn't mind trading up in location and lifestyle.)

The statistic really doesn't come as a surprise. It makes sense that California's rather unique situation was studied for this article, because the state's invested so heavily in the technology and infrastructure to support electric vehicles. This is because Californians are stereotypically adopters of new tech innovations and they are stereotypically interested in environmentally-friendly pursuits. Also, California has to push these initiatives. It's huge, people drive a lot, and in some parts of the state (here's looking at you, L.A.) the air is filthy.

It seems a little hypocritical, though, that these six-figure households probably aren't using an EV as their only car (based on insinuations made by the aforementioned source article...and supported by my perhaps limited understanding of human nature). It's better, of course, to use an EV for a trip within the range limits, but when all those good-vibin' miles are offset by joyrides in the midlife-crisis-mobile, what's the point? (Unless, of course, we're talking about a Tesla.)

Maybe the disconnect is a result of thinking that an avoidance of consumerism should be a natural side effect to eco-friendliness...but neither are traits associated with the car industry. As EVs spread eastward, we'll likely see a shift in their role.

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  • Economist. "Horsepower v Cash Cows." May 17, 2011. (Aug. 27, 2012)
  • Economist. "Nikola Tesla's revenge." June 2, 2011. (Aug. 27, 2012)
  • Economist. "Revenge of the Petrolheads." Dec. 11, 2011. (Aug. 27, 2012)
  • Economist. "The iBeamer." June 14, 2012. (Aug. 27, 2012)
  • Eisenstein, Paul A. "Will E85 Vanish From the Market?" The Detroit Bureau. June 17, 2011. (Aug. 27, 2012)
  • Essex, Randy and Holland, Ben. "Why So Many Critics After 17,000 EV Sales in First Year?" Rocky Mountain Institute. Jan. 5, 2012. (Aug. 29, 2012)
  • Hill, Joshua. "Hydrogen -- Tomorrow's Biofuel?" CleanTechnica. May 17, 2012. (Aug. 28, 2012)
  • Meyers, Glenn. "The 'What Happened to the Methanol Economy?' Question." CleanTechnica. March 15, 2012. (Aug. 27, 2012)
  • Richardson, Jake. "Solar-Powered Electric Vehicle Charger Unveiled." CleanTechnica. Aug. 26, 2012. (Aug. 27, 2012)
  • Shaffer, David. "The road for E85 fuel just got rougher." Star Tribune. Jan. 7, 2012. (Aug. 28, 2012)
  • Shahan, Zachary. "California Plug-In Car Owners Driving Less & Saving Serious Money." CleanTechnica. Aug. 26, 2012. (Aug. 27, 2012)
  • Szczesny, Joseph. "Electric vehicle sales ahead of last year's pace." NBC News. March 6, 2012. (Aug. 29, 2012)
  • Toyota Motor Sales, U.S.A. "Model Selector." 2012. (Aug. 27, 2012)
  • U.S. Department of Energy. "Electric Vehicles." 2012. (Aug. 27, 2012)
  • U.S. Department of Energy. "'s Top Ten EPA-Rated Fuel Sippers (2012)." (Aug. 27, 2012)
  • U.S. Department of Energy. "How a Hybrid Works." 2012. (Aug. 29, 2012)
  • Valdes-Dapena, Peter. "Hydrogen cars: a zero-emission longshot." CNN Money. March 19, 2012. (Aug. 28, 2012)