What Are Green Cars, and What’s Right for Me?

April 4, 2008

cars.com— Cars.com considered several factors when determining if a vehicle is ‘green’ or not. These factors including a life-cycle analyses of the energy used, the cars ability to save money, achieve a reduction in several areas including pollution emissions, greenhouse gas emissions, foreign oil consumption and allowing their manufacturers to profit on them as products.

Ethanol/E85

Ethanol or E85 fuel is made from a mixture of 85% Ethyl Alcohol harvested from corn mixed with 15% gasoline. “The money and energy that goes into its production results in only a slight improvement in pollutants and greenhouse gases and — at this point — no significant financial savings for owners of flex-fuel vehicles, which can burn E85 or gasoline or any mix thereof.” E85 has less energy by volume than regular gasoline. However, flex-fuel (cars that can run on any mixture of gasoline and ethanol) are inexpensive to produce and buy. Retro-fitting the nations fueling stations to distribute ethanol is an inexpensive but time consuming process. The main technological roadblock that is preventing wide spread ethanol use is the fact that the Ethyl Alcohol used to produce fuels like E85 can only be acquired from food crops like corn. Research and development of cellulose (plant waste/green grasses) as an alternative means of harvesting Ethyl Alcohol will likely reduce cost and life-cycle green-house gas emissions by 90%.

Diesel

As of 2006 diesel vehicles began burning “ultra-low-sulfur fuel which has resulted in a reduction of emissions and allowed the use of exhaust after treatments.” With the onset of these new technologies it is likely that diesel fuel will be as clean as gasoline within 2009. Diesel is “roughly 25 percent more efficient than equivalent gas engines.” Greater efficiency translates to fewer greenhouse gases produced during operation. However, diesel cars and fuel are often more expensive than conventional gasoline vehicles. It is likely that the cost of diesel cars and fuel will remain more expensive than conventional gasoline cars in the future.

Battery-Electric

“There is currently no mass-market electric car.” Current electric cars cost less per mile than conventional gasoline vehicles. However, the electricity used to run these cars is often manufactured by burning fossil fuels. “Still, based on the current mix, life-cycle analyses of electrical generation suggest a greenhouse gas reduction of 47 percent over the equivalent amount of gasoline.” The current state of battery technology prevents the production of Electric Cars that can run for long distances on a single charge. However, it is likely that the development of lithium-ion battery technology will make electric vehicles a viable form of transportation by 2010.

Common Hybrids

Hybrid vehicles use a gasoline motor supported by a battery pack. These vehicles typically use less gas than comparable automobile models, however, they are generally more expensive to purchase.  Hybrids are more expensive to produce because they require two drive trains as opposed to the typical single drive train in most conventional cars. Most hybrids are priced and sold for less than what it took to manufacture them. “Concerns and rumors about battery death and replacement costs have been greatly overestimated and are largely unsubstantiated.”

Plug-in Hybrids

Plug-in hybrids are not yet available for purchase. Plug-in hybrids are designed with larger batteries than conventional hybrids and can be charged off the electricity grid. “Today’s hybrids charge their own batteries using the gas engine, or by recapturing the energy of momentum in braking, which turns the drive motor and generates electricity, recharging the battery pack.”

Series Hybrids

The difference between series hybrids and Plug-in Hybrids is that series hybrids will run off of their battery pack until it deplete its charge then will turn on its gas powered generator to maintain battery pack charge. Plug-in hybrids constantly alternate between gasoline and battery throughout vehicle operation, not just when the battery becomes depleted. Series hybrid generators can run off of any fuel type including gasoline, diesel and E85. “The benefits of this include low cost, low emissions and any advantage of the fuel type used.” It is likely that the production cost of series hybrid vehicles will decrease as hybrid technology proliferates.

Compressed Natural Gas

There is only one compressed natural gas vehicle available for purchase, the Honda Civic GX. “The GX sacrifices some trunk space to accommodate the natural-gas tank, and it’s less powerful than the gasoline and hybrid Civics. It’s also the most expensive trim level, with a price tag of more than $24,000.” However, the GX is eligible for numerous federal and state incentives upon purchasing. The GX produces 28.5% less greenhouse gases than comparable gasoline vehicles. The GX can be re-filled using a home fueling station produced by Honda called “phil.” “According to Honda, a home-fueled GX costs 50 percent less than a gasoline Civic to operate, or 30 percent less when using a filling station.”

High-Mileage

The bottom line when purchasing a vehicle is to buy the smallest, lightest and most fuel efficient vehicle that serves its intended purpose.

Hydrogen

Hydrogen’s energy density by volume is low when compared to other fuel types like gasoline. “fuel-cell cars convert hydrogen gas into electricity using a component that emits only water vapor.” Because no fossil-fuels are burned during vehicle operations it is in a limited sense a zero-emissions vehicle. However, like plug-in hybrid vehicles electricity (often derived from burning fossil fuels) is required to manufacture hydrogen. “Using natural gas as a relatively clean and efficient source of hydrogen gas nets a theoretical greenhouse gas advantage of 41 percent over gasoline.” Currently the price of manufacturing hydrogen vehicles and fuel as well as retro-fitting filling stations to support Hydrogen re-fueling makes it unlikely that Hydrogen vehicles will be a viable form of transportation in the next 2-5 years.

Source: http://www.cars.com/go/crp/buyingGuides/green/article.jsp?channel=green&id=goGreen2008

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