2.1 A lesson from the past
One famous example of forecasting was Marion King Hubbert's prediction of US oil production, published in 1956. Hubbert, a respected geophysicist, predicted that US oil production would peak in the early 1970s — an extraordinary statement at a time when oil production was rising steadily, with plenty of spare capacity. Hubbert recognised that the rate of consumption had exceeded the rate of discovery of new reserves, and the result would be a decline in production that mirrored the growth over the previous century. As Figure 6 shows, his forecast has proved remarkably accurate, even down to the total ultimate production (represented by the area under each curve). Hubbert's figure for this, 2.7×1010 t, is remarkably close to modern estimates (2.9-3.0×1010 t).
The Hubbert example is relatively simple — considering a single energy source in a single, politically and economically stable country. Any attempt to forecast global energy demand must consider a variety of influences, including:
- availability and suitability of different energy sources
- technological advances in energy production and use
- economic factors
- political trends, tensions and timescales
- environmental pressures.
These points raise several important questions. For example, what proportions of fossil fuels will generate electricity in power stations that are only 30-50% efficient? What proportions will drive transport? If oil is to be used as a fuel, for how long can it also continue to supply the petrochemicals industry — another important role? Can we actually locate and extract the necessary reserves in the amounts required? To what extent can we reduce our dependence on environmentally damaging fossil fuels, either by conserving energy, or substituting alternative sources of power? These are just some of the questions to bear in mind as you read on.
One way of trying to visualise how energy resources might be used is by building 'scenarios', or imagined pictures of the future, which try to account for the factors listed above.