Alternative fuel vehicles

Alternative fuel vehicles are making big headlines these days. With more concern than ever about the environment, and roller coaster rise and fall of gas prices, more and more people are turning to vehicles that run on alternative fuel. We've gathered information on the most popular types to help you understand how different alternative fuel vehicles work and the pros and cons of each, so you can make an informed decision.

Hybrid Vehicles

How hybrid cars work
Hybrid-electric vehicles (HEVs) are the first wave of alternative fuel vehicles to hit the road. By pairing an electric motor with a gasoline engine, hybrid cars provide benefits such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools.

Some of the advanced technologies typically used by hybrid cars include:

Regenerative braking. The electric motor found in some alternative fuel vehicles applies resistance to the drivetrain, causing the wheels to slow down. In return, the energy from the wheels turns the motor, which functions as a generator, converting energy normally wasted during coasting and braking into electricity. A battery stores this electricity until needed by the electric motor.

Electric motor drive/assist. The electric motor in hybrid cars boosts power to the engine during acceleration, passing cars, or climbing hills. It augments performance when needed and allows hybrid cars to run on smaller, more efficient engines. In some hybrid cars, the motor alone provides power for low-speed driving conditions where internal combustion engines are least efficient.

Automatic start/shutoff. In some hybrid cars, the engine shuts off automatically when the vehicle comes to a stop and restarts when the accelerator is pressed. This prevents wasted energy from idling.

How hybrid cars get such great gas mileage
It is no coincidence that the most fuel-efficient vehicles in some classes for this model year are hybrid cars. Hybrid cars combine the best features of the internal combustion engine with an electric motor. Hybrid cars can be configured to achieve a variety of different objectives, such as improving fuel economy, boosting performance, or providing electrical power to auxiliary loads such as power tools.

Like conventional vehicles, hybrid cars are primarily propelled by an internal combustion engine, but hybrid cars also convert energy normally wasted during coasting and braking into electricity. This captured electricity is stored in a battery until needed by the electric motor. The electric motor assists the engine when accelerating or hill climbing and low-speed driving conditions where internal combustion engines are least efficient. To prevent wasted energy from idling, some hybrid cars also automatically shut off their engine when the vehicle comes to a stop and restart when the accelerator is pressed.

Unlike all-electric vehicles, hybrid cars now being offered do not need to be plugged into an external source of electricity to be recharged; conventional gasoline and regenerative braking provide all the energy the vehicle needs.

Three new hybrids for 2009

  • Cadillac Escalade Hybrid - Sport utility vehicle available in 2-wheel drive with an 8-cylinder engine and an automatic transmission
  • Chevrolet Silverado 15 Hybrid - Sport utility vehicle available in 2- and 4-wheel drive with an 8-cylinder engine and an automatic transmission
  • GMC Sierra 15 Hybrid - Sport utility vehicle available in 2- and 4-wheel drive with an 8-cylinder engine and an automatic transmission
Manufacturer Model Type Available
Chrysler Aspen HEMI Hybrid SUV 2008
Dodge Durango HEMI Hybrid SUV 2008
Ford Fusion Hybrid Midsize Car 2008
Mercury Milan Hybrid Midsize Car 2008
Ford Edge Hybrid SUV 2008-10
Ford Five Hundred Hybrid Large Car 2008-10
Lincoln MKX Hybrid SUV 2008-10
Mercury Montego Hybrid Large Car 2008-10
Mercedes-Benz ML450 Hybrid SUV 2009
Mercedes-Benz S400 BlueHybrid Large Car 2009-10
BMW X6 SUV 2010
Porsche Cayenne Hybrid SUV 2010
Honda Fit Hybrid Small Station Wagon 2010-15

Sources: J.D. Power-LMC; Energy & Environmental Analysis (EEA), Inc.; manufacturer web sites. Updated 9/6/2006.

All figures cited were originally gathered and reported by

New energy tax credits for hybrids
Hybrids purchased or placed into service after December 31, 2005 may be eligible for a federal income tax credit of up to $3,400.

Consumers who placed new hybrids in service before 2006 may be eligible for a "clean fuel" tax deduction of up to $2,000.

Credit amounts begin to phase out for a given manufacturer once it has sold over 60,000 eligible vehicles.

Vehicles purchased after December 31, 2010 are not eligible for this credit. The information below is provided for those filing amended tax returns for previous years.

Make & Model Full Credit 50% 25% No Credit
Toyota Jan. 1 – Sep. 30, 2006 Oct. 1, 2006 – Mar. 31, 2007 Apr. 1 – Sep. 30, 2007
Oct. 1, 2007
2005-08 Prius $3,150 $1,575 $787.50 $0
2006-08 Highlander Hybrid (2WD & 4WD) $2,600 $1,300 $650 $0
2006-08 Lexus RX400h (2WD & 4WD) $2,200 $1,100 $550 $0
2007-08 Camry Hybrid $2,600 $1,300 $650 $0
2007 Lexus GS 450h $1,500 $775 $387.50 $0
2008 Lexus LS 600h -- -- $450 $0
2008 Hybrids Certified As Tax Credit For Toyota and Lexus Comes to an End (Nov. 8, 2007)
Phase-Out of Credit for Toyota and Lexus Hybrids Continues With Reporting of First Quarter Sales (May 2, 2007)
Source: Internal Revenue Service. Updated January 17, 2008.
Make & Model Full Credit 50% 25% No Credit
Nissan Jan. 1, 2006 TBD TBD TBD
2007-08 Altima Hybrid $2,350 -- -- --
2008 Nissan Altima Certified as Qualified Hybrid Vehicle
Nissan Altima Certified As Qualified Hybrid Vehicle (Jan. 11, 2007)
Make & Model Full Credit 50% 25% No Credit
Honda Jan. 1, 2006 – Dec. 31, 2007 Jan. 1 – Jun. 30, 2008 July 1 – Dec. 31, 2008 Jan. 1, 2009
2005-06 Insight CVT $1,450 $725 $362.50 $0
2005 Accord Hybrid AT & Navi AT $650 $325 $162.50 $0
2006 Accord Hybrid AT & Navi AT (w/o updated control calibration) $650 $325 $162.50 $0
2006-07 Accord Hybrid AT & Navi AT (w/ updated control calibration) $1,300 $650 $325 $0
2005 Civic Hybrid (SULEV) MT & CVT $1,700 $850 $425 $0
2006-08 Civic Hybrid CVT $2,100 $1,050 $525 $0
AT = automatic transmission; CVT = continuously variable transmission; MT = manual transmission; SULEV = Super Low Emission Vehicle emissions rating.
Honda Hybrid Begins Phase-Out on January 1 (Nov. 19, 2007)
Additional Honda Vehicles Certified for Hybrid Tax Credits (Nov. 22, 2006)
Seven Honda Vehicles Certified for New Energy Tax Credit (June 1, 2006)
Make & Model Full Credit 50% 25% No Credit
General Motors Jan. 1, 2006 TBD TBD Jan. 1, 2009
2008 Chevrolet Malibu Hybrid -- $1,300 -- -- --
2006-07 Chevrolet Silverado Hybrid 2WD $250 -- -- --
4WD $650 -- -- --
2008 Chevrolet Tahoe Hybrid 2WD $2,200 -- -- --
4WD $2,200 -- -- --
2006-07 GMC Sierra Hybrid 2WD $250 -- -- --
4WD $650 -- -- --
2008 GMC Yukon 1500 Hybrid 2WD $2,200 -- -- --
4WD $2,200 -- -- --
2007-08 Saturn Aura Green Line -- $1,300 -- -- --
2007 Saturn Vue Green Line -- $650 -- -- --
2008 Saturn Vue Green Line -- $1,550 -- -- --
GM’s 2008 Chevrolet and Saturn Certified As Qualified Hybrid Vehicles (Sep. 6, 2007)
2007 GM Hybrids Still Qualify for Tax Credit (May 2, 2007)
Make & Model Full Credit 50% 25% No Credit
Ford Motor Company Jan. 1, 2006 Apr. 1 - Sept. 30, 2009 Oct. 1, 2009 - Mar. 31, 2010 Apr. 1, 2010
2009 Ford Escape Hybrid 2WD $3,000 $1,500 $750 $0
4WD $1,950 $975 $487.50 $0
2008 Ford Escape Hybrid 2WD $3,000 $1,500 $750 $0
4WD $2,200 $1,100 $550 $0
2005-07 Ford Escape Hybrid 2WD $2,600 $1,300 $650 $0
4WD $1,950 $975 $487.50 $0
2009 Mercury Mariner Hybrid 2WD $3,000 $1,500 $750 $0
4WD $1,950 $975 $487.50 $0
2008 Mercury Mariner Hybrid 2WD $3,000 $1,500 $750 $0
4WD $2,200 $1,100 $550 $0
2006-07 Mercury Mariner Hybrid 4WD $1,950 $975 $487.50 $0
2008 Mazda Tribute Hybrid 2WD $3,000 -- -- --
4WD $2,200 -- -- --
Purchasers of Ford Hybrids Still Qualify for Tax Credit (Aug. 7, 2007)
2009 Model Year Hybrid Vehicles (July 24, 2008)

All figures cited were originally gathered and reported by

For more information on tax incentives, please visit

Diesel & biodiesel

Diesel vehicles may be making a comeback. Diesel engines are more powerful and fuel-efficient than similar-sized gasoline engines (about 30-35% more fuel efficient). Plus, today's diesel vehicles are much improved over diesels of the past.

New diesel technologies have improved performance and efficiency, reduced tailpipe emissions, vibrations, and noise of diesel vehicles.

Ultra-low sulfur diesel (ULSD), available beginning in 2006, is cleaner burning and allows diesels to be equipped with more-effective controls for reducing particulates and smog-forming nitrogen oxide (NOx) emissions.

Biodiesel, a non-petroleum fuel produced from renewable sources, reduces tailpipe emissions and dependence on foreign oil.

Better performance
Improved fuel injection and electronic engine control technologies have

  • Increased power
  • Improved acceleration
  • Increased efficiency

New engine designs, along with noise- and vibration-damping technologies, have made them quieter and smoother. Cold-weather starting has been improved also.

Today's diesels must meet the same emissions standards as gasoline vehicles, and advances in engine technologies, ultra-low sulfur diesel fuel, and improved exhaust treatment have made this possible.

Although emissions of particulates and smog-forming nitrogen oxides (NOx) are still relatively high, new "clean" diesel fuels, such as ultra-low sulfur diesel and biodiesel, and advances in emission control technologies will reduce these pollutants also.

Diesel Emissions Device

Ultra-low sulfur diesel
Ultra-low sulfur diesel (ULSD) replaced conventional diesel fuel starting in 2006. The new fuel will contain 97% less sulfur than conventional diesel—sulfur will be reduced from 500 parts per million (ppm) to 15 ppm.

ULSD is cleaner-burning, producing less particulate emissions in both older and new engines.

It also allows the use of improved exhaust treatment devices to reduce emissions of particulates and smog-forming nitrogen oxides (NOx). These devices can be "poisoned" by the sulfur in conventional diesel fuel.

Biodiesel Tank

Biodiesel is a form of diesel fuel manufactured from vegetable oils, animal fats, or recycled restaurant greases. It is safe, biodegradable, and produces less air pollutants than petroleum-based diesel.

Biodiesel can be used in its pure form (B100) or blended with petroleum diesel. Common blends include B2 (2% biodiesel), B5, and B20. B2 and B5 can be used safely in most diesel engines. However, most vehicle manufacturers do not recommend using blends greater than 5%—using higher blends will void some engine warranties. Check with your owner's manual or vehicle manufacturer to determine the right blend for your vehicle.

Note: You should never fuel your vehicle with clean or used grease or vegetable oil that has not been converted to biodiesel. It will damage your engine.

Biodiesel compared to petroleum diesel
Advantages Disadvantages
Domestically produced from non-petroleum, renewable resources Use of blends above B5 not yet warrantied by auto makers
Can be used in most diesel engines, especially newer ones Lower fuel economy and power (10% lower for B100, 2% for B20)
Less air pollutants (other than nitrogen oxides) and greenhouse gases Currently more expensive
Biodegradable More nitrogen oxide emissions
Non-toxic B100 generally not suitable for use in low temperatures
Safer to handle Concerns about B100's impact on engine durability

All figures cited were originally gathered and reported by

Diesel Jeep

Flexible fuel vehicles (FFVs) are designed to run on gasoline or a blend of up to 85% ethanol (E85). Except for a few engine and fuel system modifications, they are identical to gasoline-only models.

FFVs have been produced since the 1980s, and dozens of models are currently available. Since FFVs look just like gasoline-only models, you may have an FFV and not even know it. To determine if your vehicle is an FFV, check the inside of your car's fuel filler door for an identification sticker or consult your owner's manual.

FFVs experience no loss in performance when operating on E85. However, since a gallon of ethanol contains less energy than a gallon of gasoline, FFVs typically get about 20-30% fewer miles per gallon when fueled with E85.

All figures cited were originally gathered and reported by


Ethanol is an alcohol-based fuel made by fermenting and distilling starch crops, such as corn. It can also be made from "cellulosic biomass" such as trees and grasses. The use of ethanol can reduce our dependence upon foreign oil and reduce greenhouse gas emissions.

E10 (gasohol)
E10 (also called “gasohol”) is a blend of 10% ethanol and 90% gasoline sold in many parts of the country. All auto manufacturers approve the use of blends of 10% ethanol or less in their gasoline vehicles.


E85, a blend of 85% ethanol and 15% gasoline, can be used in flexible fuel vehicles (FFVs), which are specially designed to run on gasoline, E85, or any mixture of the two. FFVs are offered by several vehicle manufacturers. To determine if your vehicle can use E85, consult your owner’s manual or check the inside of your car's fuel filler door for an identification sticker.

Cost varies regionally. It is cheaper than gasoline in some areas, such as the Midwest, and more expensive in others.

Several hundred filling stations in the U.S. sell E85, and that number is increasing rapidly. Visit the alternative fuel station locator for locations of service stations selling E85.

No noticeable difference in vehicle performance when E85 is used.

FFVs operating on E85 usually experience a 20-30% drop in miles per gallon due to ethanol’s lower energy content.

Advantages & disadvantages of E85
Advantages Disadvantages
Domestically produced, reducing use of imported petroleum Can only be used in flex-fuel vehicles
Lower emissions of air pollutants Lower energy content, resulting in fewer miles per gallon
More resistant to engine knock Limited availability
Added vehicle cost is very small Currently expensive to produce

All figures cited were originally gathered and reported by

Natural gas
Natural Gas

Natural gas, a fossil fuel comprised mostly of ethane, is one of the cleanest burning alternative fuels. It can be used in the form of compressed natural gas (CNG) or liquefied natural gas (LNG) to fuel cars and trucks.

Dedicated natural gas vehicles are designed to run on natural gas only, while dual-fuel or bi-fuel vehicles can also run on gasoline or diesel. Dual-fuel vehicles allow users to take advantage of the wide-spread availability of gasoline or diesel but use a cleaner, more economical alternative when natural gas is available. Since natural gas is stored in high-pressure fuel tanks, dual-fuel vehicles require two separate fueling systems, which take up passenger/cargo space.

Natural gas vehicles are not produced commercially in large numbers—the Honda GX CNG is the only new vehicle available in the U.S. However, conventional gasoline and diesel vehicles can be retrofitted for CNG.

Advantages & disadvantages of natural gas
Advantages Disadvantages
About 94% of U.S. natural gas used is domestically produced Limited vehicle availability
Roughly 20% to 45% less smog-producing pollutants Less readily available than gasoline & diesel
About 5% to 9% less greenhouse gas emissions Fewer miles on a tank of fuel
Less expensive than gasoline

All figures cited were originally gathered and reported by


Liquefied petroleum gas (LPG)
Propane or liquefied petroleum gas (LPG) is a clean-burning fossil fuel that can be used to power internal combustion engines. LPG-fueled vehicles produce fewer toxic and smog-forming air pollutants. LPG is usually less expensive than gasoline, and most LPG used in U.S. comes from domestic sources.

No LPG-fueled light-duty passenger cars or trucks have been produced commercially in the U.S. since the 2004 model year, but gasoline and diesel vehicles can be retrofitted to run on LPG in addition to conventional fuel. The LPG is stored in high-pressure fuel tanks, so separate fuel systems are needed in vehicles powered by both LPG and a conventional fuel such as gasoline.

Advantages & disadvantages of LPG
Advantages Disadvantages
90% of propane used in U.S. comes from domestic sources Limited availability (a few large trucks and vans can be special ordered from manufacturers; other vehicles can be converted by certified installers)
Potentially lower toxic, carbon dioxide (CO2), carbon monoxide (CO), and nonmethane hydrocarbon (NMHC) emissions Less readily available than gasoline & diesel
Less expensive than gasoline Fewer miles on a tank of fuel

All figures cited were originally gathered and reported by


Hydrogen (H2) is being aggressively explored as a fuel for passenger vehicles. It can be used in fuel cells to power electric motors or burned in internal combustion engines (ICEs).

It is an environmentally friendly fuel that has the potential to dramatically reduce our dependence on foreign oil, but several significant challenges must be overcome before it can be widely used.

Produced domestically. Hydrogen can be produced domestically from several sources, reducing our dependence on petroleum imports.

Environmentally friendly. Hydrogen produces no air pollutants or greenhouse gases when used in fuel cells; it produces only NOx when burned in ICEs.

Fuel cost & availability. Hydrogen is currently expensive to produce and is only available at a handful of locations, mostly in California.

Vehicle cost & availability. Fuel cell vehicles are currently far too expensive for most consumers to afford, and they are only available to a few demonstration fleets.

Onboard fuel storage. Hydrogen contains much less energy than gasoline or diesel on a per-volume basis, so it is difficult to store enough hydrogen onboard a vehicle to travel more than 200 miles.

Other challenges include fuel cell performance, customer acceptance, and hydrogen transport and bulk storage.

All figures cited were originally gathered and reported by

Electric Efficient

Electric vehicles (EVs) are propelled by an electric motor (or motors) powered by rechargeable battery packs. Electric motors have several advantages over internal combustion engines (ICEs):

  • Energy efficient. Electric motors convert 75% of the chemical energy from the batteries to power the wheels—internal combustion engines (ICEs) only convert 20% of the energy stored in gasoline.
  • Environmentally friendly. EVs emit no tailpipe pollutants, although the power plant producing the electricity may emit them. Electricity from nuclear-, hydro-,
    solar-, or wind-powered plants causes no air pollutants.
  • Reduce energy dependence. Electricity is a domestic energy source.
  • Performance benefits. Electric motors provide quiet, smooth operation and stronger acceleration and require less maintenance than ICEs.

The down side: batteries
EVs face significant battery-related challenges:

  • Driving range. Most EVs can only go 150 miles (or less) before recharging—gasoline vehicles can go over 300 miles before refueling.
  • Recharge time. Fully recharging the battery pack can take 4 to 8 hours.
  • Battery cost. The large battery packs are expensive and usually must be replaced one or more times.
  • Bulk & weight. Battery packs are heavy and take up considerable vehicle space.

Researchers are working on improved battery technologies to increase driving range and decrease recharging time, replacement frequency, weight, and cost. These factors will ultimately determine the future of EVs.

All figures cited were originally gathered and reported by

Fuel cell

Although they are not expected to reach the mass market before 2010, fuel cell vehicles (FCVs) may someday revolutionize on-road transportation.

This emerging technology has the potential to significantly reduce energy use and harmful emissions, as well as our dependence on foreign oil. FCVs will have other benefits as well.

A radical departure
FCVs represent a radical departure from vehicles with conventional internal combustion engines. Like battery-electric vehicles, FCVs are propelled by electric motors. But while battery electric vehicles use electricity from an external source (and store it in a battery), FCVs create their own electricity. Fuel cells onboard the vehicle create electricity through a chemical process using hydrogen fuel and oxygen from the air.

FCVs can be fueled with pure hydrogen gas stored onboard in high-pressure tanks. They also can be fueled with hydrogen-rich fuels; such as methanol, natural gas, or even gasoline; but these fuels must first be converted into hydrogen gas by an onboard device called a "reformer."

FCVs fueled with pure hydrogen emit no pollutants; only water and heat; while those using hydrogen-rich fuels and a reformer produce only small amounts of air pollutants. In addition, FCVs can be twice as efficient as similarly sized conventional vehicles and may also incorporate other advanced technologies to increase efficiency.

Chrysler Model

Meeting challenges together
Before FCVs make it to your local auto dealer, significant research and development is required to reduce cost and improve performance. We must also find effective and efficient ways to produce and store hydrogen and other fuels.

Automakers, fuel cell developers, component suppliers, government agencies, and others are working hard to accelerate the introduction of FCVs. Partnerships such as the DOE-led FreedomCAR initiative and the California Fuel Cell Partnership have been formed to encourage private companies and government agencies to work together to move these vehicles toward commercialization.

FreedomCAR is a new cooperative research effort between the DOE and the U.S. Council for Automotive Research (Ford, General Motors, and DaimlerChrysler) formed to promote research into advanced automotive technologies, such as FCVs, that may dramatically reduce oil consumption and environmental impacts. FreedomCAR's goal is the development of cars and trucks that are:

  • Cheaper to operate
  • Pollution-free
  • Competitively priced
  • Free from imported oil

California Fuel Cell Partnership (CaFCP)
The California Fuel Cell Partnership is a collaboration of auto companies, fuel providers, fuel cell technology companies, and government agencies demonstrating fuel cell electric vehicles in California under day-to-day driving conditions. The goals of the partnership are to test and demonstrate the viability of FCVs and related technology under real-world conditions, move them toward commercialization, and increase public awareness.

All figures cited were originally gathered and reported by