摘要
The latest report from the Intergovernmental Panel on Climate Change urges that global CO2 emissions from the power sector should be reduced by 90 percent or more below 2010 levels between 2040 and 2070. Such a reduction will most likely require greatly increasing the share of wind, solar, energy storage and nuclear energy in the energy mix in the next 40–50 years. This paper emphasizes the importance of developing large energy storage systems without which, wind and solar can only have a limited impact on CO2 emissions as it will depend mainly on the energy mix used during wind and solar down time. The large areas that are required would be challenging, but not unrealistic, as long as a solution for energy storage exists. Carbon capture and storage has considerable potential to reduce CO2 emissions from coal and gas power plants, but also from heavy industries such as cement and steel manufacturing. To give an idea of the scale of the required infrastructure, in the United States, coal and gas power plants emit approximately 2.4 billion tonnes of CO2 per year; whereas the US annual petroleum consumption is about 0.9 billion tonnes (6.9 billion barrels). This paper also emphasizes that uranium and thorium used in breeder reactors represent an almost infinite source of low-carbon energy. The issues associated with the management of nuclear wastes are real, but they are not the uniquely difficult issues perceived by the media, much of the public and by many politicians. Finally, the investment necessary to implement a wind and solar powered economy would very likely be higher than that necessary to implement a nuclear powered economy because of the much larger number of GWe required.