Energy and fusion: challenges of the future
Modern society depends on access to an abundant and reliable supply of energy for transport, heating, lighting, industry and agriculture. Our energy demands are currently supplied by fossil fuels, nuclear fission, hydroelectricity and a small amount from other renewable sources, in particular biomass and wind.
How does fusion work?
It is highly likely that global energy demand will double over the next 50 years due to a rise in population and higher per-capita consumption. The greatest increase in demand will come from developing countries where, with rapid urbanisation, large-scale electricity generation will be required. Environmental requirements favour low or zero CO2 emission sources. Europe, like other industrialised world regions, has only limited indigenous resources which do not have green house gas emissions. New and cleaner sources of energy supply must be developed to halt a growing dependence on energy imports.
Fusion will be available as a future energy option by the middle of this century, and should be able to acquire a significant role in providing a sustainable, secure and safe solution in answer to European and global energy needs.
Why fusion? Fusion has some significant advantages in terms of environmental, operational and safety issues:
- The basic fuel resources (deuterium and lithium) for fusion are abundant and can be found practically everywhere on Earth;
- The ash from the fusion burn is helium. Like the basic fuels, it is non radioactive;
- The intermediate fuel (tritium) is produced from lithium in the mantle of the reactor. Transportation of radioactive materials is not required for the day-to-day operation of a fusion power station;
- Fusion power stations will have inherent safety aspects – runaway or meltdown accidents are impossible;
- With a suitable choice of materials for the fusion device itself, any waste from fusion power will not be a long-term burden on future generations;
- Generating fusion power will not create greenhouse gas emissions; and
- Fusion power offers a sustainable, large-scale power source independent of climatic conditions and available for an around-the-clock baseload supply of power.
Atoms of light elements – such as hydrogen – collide and fuse at the extremely high temperatures (about 15 million Celsius) and pressures that exist in the centre of the Sun. Because of the huge size of the sun, this process releases large amounts of energy.
On Earth, scientists have built devices able to produce temperatures more than ten times higher than those in the Sun. This increases the rate of fusion energy production to a level that makes its use as an energy source on Earth a practical proposition. At high temperatures, atoms become completely ionised – i.e. the electrons and atomic nuclei are separated to form a state of matter known as a plasma. For energy production this plasma has to be confined, and controlled using powerful magnetic fields while being heated to temperatures above 150 million degrees Celsius. The challenge is to employ this advanced science and technology to provide reliable, safe and environmentally friendly power production on a large scale.