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Responding to Global Climate Change: The Potential Contribution of Nuclear Power

The follow posistion paper was prepared by the Uranium Institute in 1998

The parties to the United Nations Framework Convention on Climate Change (UNFCCC) have adopted the long term aim of stabilising greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous changes in the climate. This has to be done in a way which is consistent with continued economic and social development. The challenge for energy supply over the next 50 years, therefore, is how to meet the rapidly growing demand for energy services from a growing population while limiting greenhouse gas emissions.

Nuclear power has the advantage of not producing carbon dioxide or other greenhouse gases. As such, it has the potential to play a vital role in meeting this challenge.

The contribution of nuclear power to electricity supplies has grown rapidly since the 1970s. As of May 1997, 436 power reactors were in operation in 32 countries. Nuclear power provided over 2300 TWh in 1996. This is about 17% of the world's total electricity, or 7% of total primary energy. This contribution avoids the emission of about 2300 million tonnes of carbon dioxide (CO2) annually, assuming it would otherwise be provided mainly by coal-fired plants. This represents nearly one-third of the CO2 presently emitted by power generation. Since electricity generation accounts for about 30% of all anthropogenic CO2 emissions, total emissions would be about 10% higher if it were not for nuclear power.

This paper sets out the background against which the future role of all energy sources must be assessed, and looks at the contribution that nuclear power could make to balanced energy supply policies for responding to global climate change.

Population and energy demand growth

The world population continues to rise rapidly and is expected to reach at least 10 billion by 2050, nearly double the present population of 5.7 billion. Most of this increase will take place in developing countries, although some developed countries will also experience rising populations.

At present, per capita energy use varies enormously between developed and developing countries. As the developing countries continue to build up their industries and infrastructure, their energy use per capita will increase. Since their populations will also be growing, total energy demand of these countries will grow rapidly. Energy demand in developed countries will grow relatively slowly, but such countries will still need to ensure adequate energy supplies.

In developed countries with high per capita levels of energy use there may be considerable scope for energy conservation measures. Nevertheless, if all the world's people are to have adequate supplies of energy by the middle of the next century then the supply of energy services will clearly need to much more than double. Even allowing for major improvements in efficiency both in the conversion and end-use of energy, it would appear that a doubling of energy supply by 2050 is the least that can be expected consistent with an acceptable level of economic and social development.

Meeting energy demand while limiting carbon dioxide emissions

Industrialisation has been achieved in the developed countries of the world almost entirely through the exploitation of fossil fuels. It is no exaggeration to say that our present global civilisation is based on fossil fuels. The fundamental product of the combustion of fossil fuels is carbon dioxide; the only way to limit CO2 emissions is to limit the use of fossil fuels.

This can only be done by making a decisive shift away from our present overwhelming dependence on fossil fuels, by making the fullest use practicable of existing and emerging non-fossil energy sources. Two such sources, hydro and nuclear, already make a significant contribution to energy supplies. Emerging non-fossil energy sources, commonly referred to collectively as renewables, include wind, wave, tidal, solar, geothermal, and biomass.

It is fortunate in this respect that nuclear and the various renewable sources will complement each other well in providing a balanced electricity supply system. Many of the renewables are by their nature variable or intermittent, or may be limited by geographical or other considerations. In contrast, nuclear power plants are best suited to steady baseload operation, to maximise their output over the year. They are concentrated energy sources, taking up little land area and able to supply densely populated urban areas.

The potential role of non-fossil energy sources

As discussed above, primary energy requirements are likely to at least double by 2050. What are the potential contributions which non-fossil energy sources could make by this time?

Nuclear power is a technically well-developed energy source, which has expanded rapidly since it was first introduced in about 1960. Several major engineering companies from different parts of the world are presently able to construct nuclear power plants with the highest standards of operation and safety. We can assume that by 2050 nuclear power could be providing about four times its present output, or 14% of the assumed total energy supply by that time.

This implies a nuclear generating capacity of just over 1200 GWe in 2050, compared with about 340 GWe in 1995. In terms of number of reactors, it implies that there would be between 800 and 1000 reactors in operation, compared with about 430 at present (assuming the typical reactor size remains similar to that of reactors presently being built, of 1200 to 1500 MWe). Over a period of more than 50 years, this represents a modest growth in nuclear capacity.

The potential contribution of renewables is much more uncertain. Forecasts range from over 50% of all primary energy by 2050 to just a few percent. Most of the renewables are at an early stage of development, and it may be several decades before large scale deployment of some of them can begin. Large questions remain about their economic viability, although it can be expected that unit costs will fall significantly as development continues. However, the siting of renewable energy generators such as large wind farms may raise public acceptance issues in densely populated regions, while biomass production may have to compete for arable land with food production.

If we make the optimistic assumption that all the renewables together (including hydro) might be providing about 40% of all primary energy by 2050, this would mean that nuclear and renewables together could reduce the role of fossil fuels from about 85% of primary energy supply at present to below half. This could allow energy supply to be doubled while keeping CO2 emissions at about the same level.

On the other hand, if we assumed that nuclear power was completely phased out by 2050, then even if we make the same optimistic assumption about the contribution from renewables, carbon dioxide emissions from energy supply would increase by up to 40% from present levels. This illustrates the potentially vital role that nuclear power can make in limiting the emissions of greenhouse gases.

In view of the above, the nuclear industry supports:

  • effective measures to conserve energy and to improve the efficiency of energy converson and end-use;
  • the development of all forms of renewable energy, and the large scale deployment of those which become economically viable;
  • the expanded use of nuclear energy.