The duration of the exploitation of oil resources can also be extended by increasing the efficiency of their use. Energy utilization systems have greatly improved over the past three decades, a process that began in 1973, with the first oil shock. For example, the consumption per kilometer driven by cars fell by more than half because cars are lighter (due to the greater use of plastics and aluminum) and engines are more efficient. The same can be said for the production of electricity, because the advent of gas has brought about a strong technological improvement (with combined cycle power plants).

Energy Efficiency

Possible further developments in energy efficiency are in themselves a factor in the longer life of oil. Moreover, the result of this trend can already be seen in the consumption data of recent years: many large developed countries, such as Europe or Japan, report relatively small increases in their consumption of crude oil, around 1% per year. The only countries that are increasing the demand for energy sources at very high rates are the developing countries and, albeit to a lesser extent, the United States. The sharp increase in the demand for oil in certain areas multiplies consumption on a planetary level. In countries like China and India, per capital consumption of petroleum products is around 10 % of that of Europe, and there is therefore ample room to increase it; however it is unlikely that these countries will reach levels of consumption similar to that for example of the United States, also due to the too high price of oil.

All these considerations support the hypothesis of a depletion of oil reserves in a fairly long period of time, of the order of about three quarters of a century, which however could also be further prolonged.

Sustainability

A model based on the consumption of energy sources, for mobility or for heat, produces a certain level of air and water pollution. Hydrocarbons pollute less than previously used energy sources, especially coal, but their widespread – and ever increasing – use is equally a threat to the overall order of planet Earth. The hydrocarbon model is very flexible, but it is still based on combustion, and therefore on emissions that can hardly be reduced to zero.

The problem of how long the oil system can last cannot therefore be considered only from the point of view of the physical duration of hydrocarbons. The other, much more important point of view concerns environmental sustainability. It seems certain (on this point the general consensus of the scientific world is now well defined and stable) that the oil system as it is now is not sustainable, as it produces environmental damage capable of permanently altering the balance of the planet. However, at present neither private oil companies nor, in reality, consumers have substantially changed their behavior: as already highlighted, the sharp rise in price has led to a reduction in demand growth, but only in mature countries, and not in developing ones. Therefore it will perhaps be necessary to induce a radical change in the oil system politically.

It is difficult to say what form such a change could take, which would have an epochal character. However, it can be foreseen that only the transport sector will be reserved for oil, already its main use today. Increasing the efficiency of electrical vehicles could therefore reduce their consumption, pollution and emissions.

Given the level of urban congestion (and not only in developed countries), such a measure seems inevitable, also in order to continue to guarantee consumers the fundamental advantage of the oil system, namely mobility. However, it can be foreseen that only the transport sector will be reserved for oil, which is already its main use today. Increasing the efficiency of vehicles could therefore reduce their consumption, pollution and emissions.

The problem of urban air pollution cannot be solved except with one of these two hypotheses: o the transformation of cities with the creation of rail transport networks (based on the nineteenth-century model, still fully functional today, for example in the city of London); o the use of motors wholly or largely driven by electricity. Of the two hypotheses, the second seems more probable, but the first could also be effectively pursued, given the competition that fast trains already have to medium-haul air transport.

However, this prospect would require the total replacement of oil with some other fuel for the production of electricity and for industrial uses, an option that is bound to solutions (not yet feasible) to the problem of capture (or, better, utilization) of CO2 and that of greater acceptability of nuclear energy. In thermal uses, oil has already been largely replaced by natural gas, which however also produces CO2, albeit in reduced quantities. It is very likely that this set of measures will not be sufficient, even if the reduction of emissions, both in electricity generation and in transport, could still be very relevant.

Further forecasts are conditioned by a fundamental question: how would it be possible to stop increasing emissions and possibly reduce them to zero without decisively diminishing the role of oil in the economic system, and therefore mobility in the daily life of modern cities? Strong physical restrictions on the consumption of crude oil seem inevitable, with the possible favor of the new leaders of the oil scene, the producing countries, which have an interest in extending the life of oil as much as possible, to which, at least for the moment, the their economic well-being. Restrictive regulations have already been applied in many European cities, but they do not appear to have reduced either mobility or consumption of petroleum products.

Questioning about the fate of the oil system, that is, about the end of the oil era, it requires decisive answers on this complex of problems which has taken on the terms of urgency. In any case, it should be borne in mind that technological progress will in all probability be able to radically change the current framework.