There is a saying that the cleanest gallon of gasoline is the gallon that isn’t used. But people all over the world depend on cars and trucks for personal and business transportation. Unfortunately, when gas is combusted in a car or truck engine, the carbon in the gas combines with the oxygen in the air to form carbon dioxide, or CO2. Carbon dioxide is one of the major “greenhouse gases,” or gases that cause the overall temperature of the earth to rise.
According to the U.S. Department of energy, one gallon of gas, which weighs just over six pounds, produces up to 20 pounds of CO2 when it’s burned. You may wonder how this can be. Most of the weight of the CO2 comes from the air rather than the gasoline. Oxygen is a slightly larger atom than carbon, and in carbon dioxide, there are two oxygen atoms for every carbon atom, so six pounds of gasoline can result in more than three times that much carbon dioxide being produced.
But hybrid vehicles, which are vehicles that run partly on electric power and partly on gas, emit 30 to 50% less carbon dioxide than traditional car engines. Hybrid engines save gas by using an electric motor to power the car when it is stopped or going downhill. The gasoline engine takes over when the electric motor is not powerful enough. Hybrid cars are sometimes referred to a HEVs, or hybrid electric vehicles. Popular models like the Toyota Prius and the hybrid Honda Civic both get gas mileage of over 40 miles per gallon.
In the United States, the Energy Policy Act of 2005 allowed for generous tax credits for the purchase of fuel efficient hybrids, and some states have their own “carrots” to encourage people to use hybrid cars as well.
Now that more people are driving hybrid vehicles, the disadvantages of this type of car are becoming more apparent. Perhaps the biggest disadvantage of hybrids is that they cost much more than traditional automobiles. When gas prices are very high, the vehicle and gas costs together can weigh heavily on the consumer.
Hybrids also require more maintenance, which costs more. And because hybrids are at the cutting edge of technology, repairing these cars is a specialty that costs more than repairs on traditional cars. Additionally, studies have shown that there is a danger of hybrid cars to blind pedestrians. Hybrids are almost silent when running, with hardly any tire noise or aerodynamic noise at low speeds. This makes the vehicles too quiet for some blind people to recognize.
Global warming has no single solution. Cars, factories, and even farm livestock contribute to greenhouse gas levels. Hybrids alone won’t solve the problem, but every little bit of gas that isn’t combusted goes a little way toward making the environment cleaner and global warming less threatening.