Fossil fuels and other energy resources in the 21st century

We study the changing volumes and costs of the energy resources available in the coming century as a result of exploration, technical progress, and consumption. The most reliable and well-documented information involves fossil fuels, which account for nearly 80 percent of the energy mix today. Known and presumed resources are fairly well ranked by cost, and we can estimate future developments. We present two consumption scenarios: the more contrasted reference case and the ecologically driven case presented by the World Energy Council at its last congress (1992). Our scenarios take into account the twofold goal set forth at the Rio summit: to achieve sustainable development and to minimize the climatic effects of pollutant emissions.We show that the most cost-effective mineral resources, including uranium, will run out only gradually in the next century according to these hypotheses. As a result, marginal cost will grow relatively slowly. However, we presuppose a tough policy on curbing consumption and using renewable sources of energy.We point out the need for better cost ranking of energy saving and energy switch possibilities. Additionally, the ecological impact and cost of corrective measures will have to be evaluated. We believe that the medium- and long-term difficulties will stem chiefly from the contradiction between low energy prices and the commitments required. The danger of geopolitical tension will remain a serious concern.