"They’ll Come Up With Something".
The world’s oil supply is finite and will eventually come to an end. Forecasts for this varies from 40 to 60 years, but eventually there will be no more oil. There will be no gasoline for our automobiles or oil for heating our homes or generating our electricity. Most people do not seem to be concerned, and the comment is often heard, "Oh they will come up with something". During the past century science and technology have overcome many material shortages and it is generally believed that something will be found to replace our depleted oil supply.
Unfortunately in this case it is unlikely that science or technology will be able to find an alternative fuel for our automobiles planes, ships and power stations. Our oil supply is unique and cannot be replaced. It is a wonderful gift that nature has bestowed on mankind and should be used as a source of energy only while we develop replaceable sources that will support mankind for the foreseeable future.
The following are the generally believed alternatives to the use of oil (gasoline) as a fuel for automobiles.
Electricity from batteries.
Electricity from solar cells.
Electricity from fuel cells.
Hydrogen as a fuel.
Alcohol from corn.
Let us consider each alternative in turn.
Battery powered automobiles have been with us for many years. Back in the early 1930’s the milk carts in some of our cities were all battery powered and today there are a few battery powered cars operating to provide transport for commuters to and from the rail station. These have all suffered from the same problems.
The lead/acid batteries that are commonly used are very heavy and have a limited power capacity. Their weight has a negative effect on acceleration but lighter batteries generally have a smaller power capacity. So there is a trade off between performance and driving range. The larger the battery the heavier and more expensive.
Driving range and charging time are the main limiting factors in the performance of a battery driven car. The driving range is on average around 25 to 30 miles, depending very much on the speed, the road contours, and stopping and starting. So the electric automobile is at best a vehicle for very short local trips. This would not be such a limiting factor if it was possible recharge the batteries in the same time as it takes to fill the gas tank on a normal car. Unfortunately to date no one has found a way to do this and recharging generally takes hours not minutes. Finally we have to consider the energy required not only to recharge the batteries but also to manufacture them and their routine replacements. With no oil available where will the power come from?
Battery powered cars may become more freely used if lighter more powerful batteries can be developed, but they will be expensive and cannot replace the gasoline powered automobile.
The use of solar cells to power automobiles has been a continuing technology. Unfortunately the results of all of the many experimental trials have shown quite clearly that this is not an alternative energy source that can replace gasoline. Even when the car consists of nothing a but a sheet of solar cells with only the driver as a passenger, and everything is done to minimize the weight, the performance has been totally unacceptable for everyday use even in the brilliant sunshine of Australia. Certainly the efficiency of solar cells may well be improved but it is virtually impossible for the solar powered car to become anything more than a scientific curiosity.
Electricity from fuel cells used to store hydrogen appears to be one of the more promising technologies. However the materials from which the fuel cells are made are expensive and here again the amount of power used in their construction may well not be available when the oil supply ends. It has also been pointed out that the materials are themselves not freely available and there may well not be enough of the metals available for any but a comparatively small number of vehicles. The fuel of choice for the fuel cells is hydrogen and the many difficulties in providing a readily available supply is discussed in the following section.
Hydrogen as a fuel for the automobile has been touted for several years but little advance has been made. The use of hydrogen calls for power to produce the gas, compress and refrigerate to form liquid hydrogen. Transport and storage is difficult and requires even more energy. Currently hydrogen being used in tests is obtained from the refining of oil and natural gas but eventually it will have to come from the breakdown of water. Water is a replaceable resource, but the energy required to break it down into oxygen and hydrogen may well not be available when the oil supply comes to an end. In addition hydrogen must be cooled to the very low temperature at which it liquefies and stored and transported in this form. This requires a great deal of energy to maintain the low temperatures. Precautions must also be taken to protect the stored hydrogen against any accident that might cause burning or exploding the very flammable gas. This is probably the most promising alternative fuel but there are so many problems it is unlikely that freely available reliable sources will become a reality.
Alcohol can certainly provide the energy to drive our automobiles, indeed we have seen several trials of alcohol fuels from a variety of sources such as animal and vegetable oils. The problem here is not technical, but once again the availability of the raw materials. Almost any plants can be fermented to produce alcohol, but this raises the question of land and power use. Unless we drastically reduce the world population we may well find that in the near future we will not be able to feed us all and land will have to be retained for food only. However this may well be one way that we can provide a limited amount of fuel for essential purposes. It will never replace the present supplies of oil.
While the above has discussed replacing the fuel in our automobiles it does not cover the other functions that depend on oil. Ships, airplanes and industry of almost every kind all rely on a readily available supply of oil. It is coming to an end. The slow but steady increases in price are to be expected. Perhaps when gasoline reaches $5 per gallon we will take seriously the fact that the supply is finite. It is also very obvious that what form of transport we can or cannot provide in the future depends totally on the number of people in the world. With the growing numbers it is doubtful if we will even be able to feed us all. If we can halt this insane growth we will be able to provide a reasonable life style that will depend very much on the final number of our stabilized population. If we do not take action now we may see chaos or worse when the end finally occurs.