As Richard Muller points out in Energy for Future Presidents (I would highly recommend this book - - even for non-Presidents), we are addicted to gasoline automobile for some very good reasons. These include the following:
- Fill rate. When you fill up the fuel tank, you are transferring gasoline at a rate of about 2 gallons per minute. Given the energy density of gasoline, that is equivalent to an amazing 4 megawatts. However, an internal combustion engine is only 20-25% efficient (electric engines are 80%-90% efficient), so that means that useful energy is transferred at a rate of only 1 megawatt. Even so, that is a huge number - enough electricity for 1,000 small homes.
- Range. After a 10-gallon fill-up that takes only 5 minutes, you can drive 300 miles in an average US auto.
- Residue. When you've used all the energy in your tank, there is no ash, no residue, nothing to clean out.
- Cost. At $3.50 per gallon, and 35 mpg, the cost of fuel for one mile is about 10 cents. This is so cheap that many people choose to move to homes that are far from their workplace and commute large distances every day, suffering traffic jams and long travel times, but getting the benefit of a better choice of home. According to a survey of car commuters made by the market research firm TNS in 2005, the average auto commute takes 26 minutes each way to travel 16 miles. That's about a gallon of gasoline per day, or about $3.50. That's so cheap that we spend more on luxury and comfort than we do on the fuel. It's a bit different in Europe, where high taxes push fuel price to twice that in the United States.
- Emissions. The emissions from gasoline are primarily carbon dioxide and water vapor. (Soot and nitrous oxides are now largely under control in the United States.) Those are the same gases that we breathe out. And prior to our worries about global warming, carbon dioxide was considered benign - it helps plants grow.
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