Wednesday, June 3, 2009

Switch To Gallons Per 100 Miles Instead Of MPG

What you see by using gallons per 100 miles (and what scientists that study energy efficiency know) is that it is no longer worth the expense or effort to increase miles per gallon to reduce gasoline usage by automobiles. For example at 25 mpg, it takes 4 gallons to drive 100 miles. At 33 mpg, it takes 3 gallons. At 50 mpg, it takes 2 gallons. At 100 mpg, it takes one gallon. To get from 25 to 33 mpg and save one gallon of gasoline per 100 miles, it is an 8 mpg increase. To save an additional 1 gallon of gasoline and get from 33 to 50 mpg, it is a 17 mpg increase. To save another 1 gallon of gasoline and get from 50 to 100 mpg, it is a 50 mpg increase.

A car getting 25 mpg needs above a 33 percent increase in gasoline efficiency to get to 33 mpg (4 to 3 gallons per 100 miles). This reduction will have to be in weight, along with a reduction in engine power, at this point in the development of automobiles. There is very limited potential to increase an automobile's gasoline engine efficiency without making it smaller and weaker and most of the efficiency will have to come from cars getting a third lighter. To get from 33 mpg to 50 mpg, cars again will have to become a third lighter (3 gallons to 2 gallons per 100 miles). They will have to weigh half as much as a car getting 25 mpg.

The most cost effective way to make cars lighter that use weaker engines is to make cars smaller. As cars get lighter and engines get weaker, the weight of the occupants becomes a greater percentage of the weight of the car and a limiting factor. However, there is an overriding concern to reducing the weight, engine power, and size of a car. The car must be able to protect the driver and passengers in case of an accident.

We should not be even focusing on mpg and automobile engine efficiency. The concept has nothing to do with clean air or greenhouse gases. It developed as a weak political response to OPEC during the 1970s. The Clean Air Act, which has had a great effect on cleaning our air of harmful pollutants, focused on the reduction of actual emissions from automobiles. The catalytic converter, along with other emission technologies, is what improved our air. Increasing mpg did not significantly improve our air.

MPG exists because politicians pander to our paranoia about importing oil from the Middle East. In actuality, only 1-3 percent of our gasoline is from Middle East countries other than Saudi Arabia.

Most of our imported foreign oil, about a third, comes from North America, i.e. Canada and Mexico. Include South America and we are at about half of our oil imports. Add the UK, Norway, Africa, and Russia (about 4 percent) and we are at 80-85 percent. 15 to 20 percent of our imported oil comes from the Middle East and about two thirds of that from Saudi Arabia.

Additionally, a third of our oil comes from the US, which obviously does not count as an import. When the US is included, the Middle East represents about 10- 15 percent of our total oil use. Only, 3 to 5 percent of our total oil use is from the Middle East and is not from Saudi Arabia.

Furthermore, only 45-50 percent of oil is used for gasoline. The rest is used for jet fuel, petroleum products, asphalt, plastics, synthetic fabrics, etc.

Therefore, only 1-3 percent of our gasoline is from Middle East countries other than Saudi Arabia. We are paranoid about something that is inconsequential to our energy independence. Forget mpg and our worries about importing oil.

Today, our greatest concerns are about greenhouse gases such as carbon dioxide and methane. Scientists (as opposed to environmentalist who have never stopped hating the automobile) who have no bias pro or against automobiles or coal fired plants know that our best efforts at reducing carbon emissions will not be enough alone to prevent global warming as currently predicted by models. These models and their dire predictions are still subject to new knowledge and to changes in their predictions.

The most important work to prevent global warming, and probably the solution, is coming from scientists who understand that we must increase the heat outflow from the earth into outer space. If one views the earth as a bathtub that is over flowing with heat, the problem is that too little heat is escaping from the earth, i.e. going down the bathtub drain. Eliminating a small percentage of the carbon dioxide emissions from cars or reducing the carbon dioxide output from utilities and other companies is insufficient at this point to stop excessive heat capture.

There are many ideas in development. One that recently got some press was the idea to make all building roofs reflective or white. The idea is that the white roofs will reflect the sun's energy back into outer space instead of captured by the earth and converted into heat and global warming.

MPG is a political response, not a scientific response, to a geo-political paranoia and not to an environmental concern.

Also, see my previous blog:
Benefits of Higher Auto MPG Will Not Occur.

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