Friday, October 30, 2009
High mileage cars
Because gasoline is a limited and increasingly expensive resource, we will eventually need to switch to alternative energy sources for our automobiles. However, there is a good reason to make that switch sooner: a gallon of gasoline releases 20 pounds of CO2, contributing to the climate crisis.
The good news is that an increasing number of alternatives to the pure internal combustion engine exist: hybrid gasoline-electric cars, plug-in hybrids, pure electric powered cars, and hydrogen powered cars. Hybrid cars, running off of an electric motor and a backup gasoline engine, drive just like a standard gasoline car, but with better gas mileage. Plug-in hybrids get even better mileage because they plug into your house’s electric outlet to recharge. Pure electric cars, also plugging into the electric grid, are more efficient, but lack a gasoline engine so range is limited. Hydrogen fuel cell cars require hydrogen fueling stations, and are not yet widely available.
Today, by far, the most common alternative to the traditional engine is the hybrid gasoline-electric car. A hybrid car has a computer that switches between gas and electric power automatically as needed. At low speeds, the battery provides most of the power. The gas engine kicks in to provide extra power, so that they are generally as peppy as conventional cars. The batteries are recharged while braking, coasting, or driving at high speeds, using regenerative braking methods. Today’s nickel metal hydride batteries may soon be replaced with lighter and more powerful lithium-ion batteries. Many models of hybrids are available today in all of the car classes.
The chart to the right lists the common hybrids available. The sedans range from about $20,000 for the Honda Insight to $90,000 for the Mercedes. The SUVs range from $30,000 to $50,000. The miles per gallon (MPG) numbers are combined city/highway, from www.hybridcars.com. Models with a “hybrid” in their name also come in a standard non-hybrid version, which will cost significantly less but have lower gas mileage.
A plug-in hybrid is similar to a standard hybrid, except that it has larger battery packs that can be recharged by connecting to common household electricity. Recharging can occur at night when other electricity demand is low. Overall, this is more efficient and leads to fewer greenhouse gas emissions than running entirely off of gasoline. Running off of the electric grid costs about 1/3 the price of gasoline, and emits less than one-half of the CO2. The Chevy Volt, the first mass-produced plug-in hybrid (planned for late 2010), can run for 40 miles without using any gasoline. A plug-in Toyota Prius and Ford Escape are planned for 2012.
Many car companies world-wide are producing small “concept” electric cars. The Nissan Leaf, planned for late 2010, may be the first affordable mainstream all-electric car. It is a medium-size hatchback that seats five adults, with lithium-ion batteries and a range of 100 miles between charges. The similar Ford Focus EV is due out in late 2011. The luxurious Tesla Model S is planned for 2011.
Hydrogen (fuel cell) cars run off electricity created by combining on-board hydrogen with oxygen from the air, with only water and heat as by-products. However, fuel cell efficiency is limited because of the large amount of energy required to isolate hydrogen from natural compounds (water, natural gas, biomass), package the gas by compression or liquefaction, and transfer the gas to the user. There is then more energy lost in electrochemical conversion in the fuel cell. So, support for a fuel cell vehicle as a replacement for the internal combustion engine has dwindled. The Honda FCX will not go into mass production until at least 2018, assuming more fueling stations are available.
A lot of high mileage cars are available on the market today. Take a look at what’s available and see if there is one that meets your needs. You will not only save money in the long run, but help the planet. Keep in mind though that keeping your car running as long as possible is worthwhile, especially if it’s getting good mileage, because there are significant environmental costs to both manufacturing a new automobile and disposing of your old car. ∆
© 2009 The Carlisle Mosquito