Building the Missing Link for Future Energy Systems

The world relies heavily on fossil fuels for most of its energy needs. Coal, oil and natural gas are finite resources and many important reserves are concentrated in regions of the world where there is political and economic instability, exposing energy-importing economies to an increased risk of disruption in energy supply. On a more distant horizon there is a growing concern that fossil fuel production will not meet the world's demand for energy, especially with the emergence of China and India as energy hungry super-power economies. These issues are compounded by a growing concern over the environmental impact of fossil fuels both on air quality and the broader environmental factors related to atmospheric warming by the greenhouse effect.

Fossil fuels are remarkable in that they are not only a source of energy, but also an energy store that is easily and safely transported, distributed and transformed. It is this ease of storage that is lacking with most renewable forms of energy. Without this facility there is often a mismatch between where and when renewable energy is available and when and where it is required. This is particularly true, for example, for wind and solar technologies. While these might be an environmentally friendly and economic means of harnessing "free" energy from nature, they are currently not suitable for supplying reliable base load power and even less so for powering transportation systems. Finding an economic means for storing energy, particularly electricity, is crucial to expanding the use of all renewables in mainstream society.

Electricity can be stored in physical form such as thermal, kinetic or electromagnetic energy or in chemical form such as in batteries and there are multifarious technologies that make ingenious use of these storage mechanisms. Recently, there has been increased government and industrial interest in the chemical storage of electricity in hydrogen. But, despite being the most abundant element in the universe, it does not exist freely in nature like coal, oil or natural gas. Hydrogen is an energy carrier and storage medium but it must be extracted from fossil fuels or biomass by some internal energy process, or extracted from water by supplying energy. This goes to the very heart of the problem on renewable energy systems, as the end technology is very often stranded at the end of a broken technology chain.

Energy production technologies cannot be taken in isolation but must be considered as a part of an integrated cycle. Whilst the prospect of using hydrogen, for example, to power cars via fuel cells or by internal combustion appears very appealing, the greater context of hydrogen production, storage and delivery should not be lost from sight. The transformation of biomass into bio-fuels is another promising trend for future transportation systems, but the question of sustained supply must be addressed. Can the world's farms produce sufficient biomass to power the world's transportation systems and feed us simultaneously? What will the mix of future energy systems comprise?

As the traditional carbon economy slowly winds down, the primary question is what future energy systems will deliver power with maximum economic efficiency? Secondary to this, will be the question of environmental impact.

Certainly in this short article, these questions cannot be adequately addressed, however, it is the purpose to which the Science at Stake Future Energies page is dedicated. Contributions are welcomed from all areas of research in the production, storage, transportation and use of technologies competing with petroleum or coal for energy production. Economic analysis of global energy systems would also be very much of interest. This web space is not intended for discussions on the environmental impact of the incumbent carbon economy or future energy systems, other than its potential impact on possible production systems (such as biomass).