Why do we need to develop fusion power?

Energy is used partly for domestic heating and appliances, partly for transport, and partly for services, industry and commerce. Electricity production consumes a substantial share of this energy use (typically 40% worldwide in 1999) and, for reasons given below, this share is expected to increase considerably in the future.

The world's population is projected to increase substantially in this century (although the amount is in dispute). The proportion of the population living in developing regions will increase the most, and increased access to electricity in developing countries is essential to ensure an increasing quality of life. Furthermore, for international stability, nations will seek electricity supply solutions which allow them to become as far as possible independent of the possessors of scarce fuel resources.

Despite the drive towards ever-increasing efficiency in electricity use, increased individual electricity demand, particularly by the dominant population, that in developing countries, is expected to increase world electricity consumption substantially by the middle of the 21st century.

According to the Intergovernmental Panel on Climate Change (IPCC), the large increase in greenhouse gas emissions, including CO₂, over the last century has led to a considerable increase in temperature, resulting in a destabilisation of long term weather patterns. To stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous effects on the climate system, the present energy supply system needs to change considerably.

Today most of the worldwide electricity demand is satisfied by fossil fuels, basically by oil, natural gas and coal. If this pattern does not change, the conventional oil and gas resources will last for a couple of generations at present levels of consumption. Increasing scarcity will drive the prices up. At higher prices, oil and gas from unconventional sources such as oil shales and tar sands can also be supplied. Coal reserves are abundant, but their use raises local and global environmental concern. The suppliers of fossil fuels and related technologies are working on technologies to separate CO₂ from exhaust gases and to bury it, but the development, acceptability and economics of this technology are still uncertain.

Oil is also currently the major fuel for transport, and there seems to be no alternative in sight for air transport. In future, because of the increased price and reduction in oil availability, increasing interest is likely to focus on battery-powered electric vehicles and the use of hydrogen fuel generated by splitting water, recombining it to release energy in fuel cells or burning it directly. This will have the effect of increasing electricity demand, and its share in energy demand, particularly in developed countries.

Against this background, new energy sources are needed. The renewable energy technologies, namely solar, wind, tidal, wave, biomass, geothermal and hydro are already fully or in the process of being developed. Their future use is expected to grow under favourable market conditions, especially over the first half of this century. However they suffer from isolated availability and are variable in nature, are subject to sudden local climatic change, and require complex management of the electricity supply network or the additional cost of accompanying energy storage. They can make a large contribution in countries with a distributed population and lack of electricity network, but they can only cover a minor part of the energy demands at those locations where developed nations currently live.

In the past, nuclear energy based on fission has been adopted by many developed and the most advanced developing countries. Technically, the ability to deploy fission as a long-term energy source has been demonstrated, and the fuel cycle economics and environmental impact are known. A number of countries consider fission a vital element in their current and future electricity supply mix. The long term wider deployment of fission depends on a full public appreciation of the options and alternatives, allowing them to make a balanced judgement. Clearly, having developed the technology, and the infrastructure of its management, it is highly likely, to at least justify the economics of that infrastrucure, that fission will continue to have a future role alongside other electricity supply alternatives.

For the second half of this century, controlled fusion looks also to be a promising development line. Although not all is yet understood of the physics and engineering of a power station based on controlled fusion, the basic principles have been elaborated in detail, and no matters of principle have been identified to stop its development into a viable source of electricity in the future. The open questions facing fusion are rather how to optimise the process, and make it attractive and economically viable.