When shopping for a new car buyers are increasingly looking for the color green. Not necessarily in the color of the exterior or the number of dollars they save, but in the amount of Carbon dioxide and (CO2) other greenhouse gasses their car will contribute to global warming.

These days in the automotive industry, green is the new black. Fueled by cash-strapped commuters, nagged by environmentally-conscious drivers, and begrudgingly nudged by EPA emissions standards, manufacturers are finally jumping on the eco-bandwagon. Gasoline misers no longer bear the stigma of redheaded step-children. In fact, hybrids are the hottest trend to hit Detroit (and Tokyo) since, ironically, the SUV. For the car buyer, this means that the market is ripe with a new fleet of environmentally-friendly vehicles to choose. These tend to tread lighter on Mother Earth.

Finding the perfect shade of green for car buyers often means sorting out the various emissions standards, fuel regulations, and mileage estimates. A car’s "greenness" is measured by its tailpipe emissions – the amount of polluting gasses emitted by a car when its engine is running. However, this information typically is not available on the showroom floor. Generally speaking, the more gasoline a car burns, the more CO2 a car emits. How a car is driven and maintained, the level of engine controls installed, and the quality of fuel used are also factors that determine the amount of pollutants that a car emits.

Fueling our passion
Although global warming is at the front of many car buyers’ minds, comfort and convenience often trumps this inconvenient truth. Many shoppers are searching for the perfect combination of high fuel-economy and machismo. Grown accustom to the power, luxury, and image emblematic of the SUV-loving 90s, consumers are increasingly turning to hybrid SUVs to lessen the guilt of polluting the planet. And manufacturers are also feeling their pain.

SUVs are the cash-cows of many auto manufacturers, and they are loathed to sacrifice them to the environmental gods. The race is on to find a way to eliminate car emissions while giving customers what they want: powerful cars and trucks. While the automotive industry has yet to create the elusive zero-emissions vehicle that can meet the high expectations of today’s sophisticated car buyer, they may be getting closer.

The new green-fuel
For years E85, a blend of 15 percent gasoline and 85 percent ethanol, has been touted as the near-perfect solution to the American appetite for large vehicles and the environmentalist call for fewer carbon emissions. But due to limited compatible vehicle selection and difficulty distributing E85 fuel, adoption of this green technology has been slow to say the least. However, next generation biofuels such as butanol—an alcohol fuel with higher-energy content than ethanol that can fuel combustion engines with minimal modification--and biodiesel, which can be used in any standard diesel engine in blends up to 100 percent, may finally enable SUV drivers to fill their tanks guilt-free. Biofuels reduce carbon emissions by up to 78 percent compared to conventional diesel, and butanol nearly eliminates other polluting gases when burned. The CO2 emitted by biofuel-burning cars is absorbed by plants and trees in a environmentally clean closed-loop circle. What makes the CO2 produced by plant-based fuels such as butanol, ethanol, and biodiesels cleaner than the CO2 produced by gasoline is the origin of the carbon. Petroleum-based fuel contains carbon that has been sequestered underground. Burning gasoline introduces new carbon into the atmosphere.

How to buy a green car
The future of biofuels look bright, but their success will ultimately be decided by the appetite of the consumer. If you decide to join the bleeding-edge of eco-consumers by purchasing an E85 or biodiesel-powered car, research available fueling stations or biofuels co-op beforehand to ensure there are enough stations in your region to keep your car moving.

If you want to hedge your bet with a hybrid, consult one or more rating systems such as the EPA Green Vehicle Guide and pay attention to the car’s fuel economy. Keep in mind that fuel economy averages listed on a car’s window sticker are often higher than actual averages because the testing method the EPA uses does not mimic real-life driving scenarios. Some cars, trucks, and SUVs that implement hybrid technology may not necessarily be green, but they will certainly be greener than without. But if a hybrid or biodiesel car is not on the horizon for you, an easy way to buy green is to avoid buying a bigger car or bigger engine than you need. It goes without saying, the bigger the engine, the more fuel the car consumes.

It’s easy being green
In addition to buying a greener vehicle, properly maintaining your car is an easy way to improve gas mileage and reduce the amount of pollutants your car emits. Improperly tuned engines can reduce gas mileage by four percent, and clogged air filters by 10 percent. Approximately 1.2 million gallons of fuel are wasted each year in the United States by cars driven with under-inflated tires. By properly inflating tires, drivers can improve their fuel economy by 3.3 percent. Even the motor oil that you use can affect your gas mileage. Always use the recommended grade of motor oil or Energy Saving motor oil to improve your mileage by 1-2 percent.

Many shades of green
Hybrid: Hybrid cars are equipped with an internal combustion and an electric engine. The two engines work alternatively depending on the speed of the car. Hybrid engines implement advanced technologies, such as regenerative breaking which charges the engine each time the car break, to increase fuel efficiency. Certain hybrids meet California’s PZEV emissions standards.

Plug-in hybrid: Plug-in hybrids have larger electric engines than traditional hybrids and are equipped with a plug that can be used with a standard electrical outlet to charge the engine when the vehicle is off. The larger electric engines provide extended range for the electric engine. Certain plug-in hybrids are certified to meet California’s At PZEV standard.

Flex-fuel: Flex fuel vehicles contain engines that are able to consume E85. However, ethanol provides less energy than gasoline which means that E85 delivers 20-30 percent reduced miles per gallon.

Biofuel: Any fuel made from a biological source, including vegetable oils, animal fats, ethanol, and butanol. Diesel engines can run on biodiesel fuels (vegetable oils and animal fats). All cars can consume fuel blended with ethanol up to 10 percent with no parts modification. Early testing shows that most cars can consume gasoline blended with butanol up to 40 percent with no modification.

Natural Gas: CNG compressed natural gas or LNG light Natural Gas. Most natural gas powered vehicles on the road today are fleet vehicles due to the scarcity of natural gas fueling stations. Some examples of natural gas powered vehicles include Crowne Victoria and the Honda Civic GX.