The fossil fuels in use today (oil, gas, coal, oil sand and oil shale) are hydrocarbon compounds that have been formed from dead organic material through geological transformation processes that take place over millions of years. Since it will not be possible for new fossil fuels to be formed in the period of relevance to human beings, fossil fuel reserves are not classified as renewable energy forms.
In view of the fact that projections concerning supply and demand, as well as reserves that have yet to be discovered, are very unreliable, it is difficult to make precise predictions regarding the existing reserves of fossil fuels. One thing, however, is clear: as supplies become increasingly scarce, prices will inevitably rise. As a consequence, the exploitation of reserves that have been little utilised to date (e.g. oil shale) could well become more economically viable. Nonetheless, it is generally assumed today that, if consumption levels remain the same, the remaining oil reserves will suffice for another 40 to 50 years, gas reserves will last another 70 years, and there should be enough coal for more than 200 years. However, it is highly unlikely that consumption levels will stagnate: rapidly growing economies like China and India will inevitably bring about a constant increase in global demand. In the view of the International Energy Agency (IEA), of which Switzerland is a member, fossil fuels will continue to play a major role in the foreseeable future. According to the reference scenario in the IEA 2006 energy perspectives, the proportion of fossil fuel to global energy consumption could even increase in the period up to 2030.
Apart from the fact that their reserves are not infinite, the second major drawback with fossil fuels is that their use results in the emission of pollutants. In view of this, the stabilisation of consumption, reduction of energy-related CO2 emissions and the substitution of fossil fuels with renewable forms of energy represent major challenges for policy-makers, trade and industry, and researchers.
Fossil fuels will continue to meet a major proportion of our energy demand for many years to come. In the transport sector, the importance of synthetic motor fuels produced from gas and coal (gas-to-liquid, coal-to-liquid) is increasing, but in the foreseeable future these will increasingly be substituted by biomass and by combustibles and motor fuels produced from biomass (biomass-to-liquid). Hydrogen – which is not an actual energy source, but merely an energy carrier – could also play an increasingly important role if it proves possible to produce it economically, in sufficiently large quantities and without CO2 emissions (e.g. through the use of solar or nuclear energy). But regardless of the type of fuel that is used, combustion technology will remain the predominant form of consumption for many years. And even with a changed fuel spectrum in the future, increasing efficient energy use and reducing emissions of pollutants will remain the principle objectives of combustion research, and the same reduction paths will remain applicable. The Combustion research programme sets out to contribute towards the improvement of the energy efficiency of combustion systems and the reduction of emissions.