TABLE OF CONTENTS Energy conservation has often been referred to as the Fifth Fue , the other four being the so-called primary or fossi fuels of coal (solid), oil (liquid), gas and nuclear/hydro-electricity. This emphasizes the importance of reducing the amount of energy used, not only nationally but also internationally.
The simple fact is that the world's reserves of fossil fuels will eventually run out, depending on the rate of use, and therefore, if the consumption of these forms of energy are reduced, the existing reserves will last longer. Research and experimentation could lead to those reserves currently available but uneconomic to recover and use being rendered economic, thus extending further the number of years before these non-renewable sources of energy do eventually run out.
The amount of worldwide energy reserves and life is variable according to the source of information used, but the position is of the order shown in Table 36.1.
| Oil | 4,105 Million tonnes. |
| Gas | 3,105 Billion cubic metres. |
The estimates of remaining reserves has been roughly the same over the last ten years despite the large increase in oil and gas extracted. This is due to new discoveries being made and new technology allowing the exploitation of previously unviable discoveries.
No mention is made of coal for which there are still vast amounts available, probably sufficient for some one thousand years, so that if oil...
