Climate change is widely recognized as a major threat to humanity and much of the natural world. According to the Intergovernmental Panel on Climate Change (IPCC), in order to limit the average global temperature increase to 1.5°C, global energy production and use need to be fully decarbonized by around 2050, with rapid reductions in emissions starting immediately.
There are many ways to decarbonize energy production. From its competence in the field of nuclear energy, the International Atomic Energy Agency wants to deliver its share in providing information on the contribution of nuclear power to climate change mitigation: on the role it already has been playing as well on its future potential.
Nuclear power is a 24/7 available, large-scale, concentrated energy source yet flexible enough to contribute effectively to a low carbon energy system with larger shares of variable renewable energy sources like wind and solar. Its greenhouse gas emissions per kilowatthour are less than 40 times those of an efficient gas-fired power plant.
From 2000, the IAEA has been publishing the report Climate Change and Nuclear Power annually or bi-annually. Building on energy statistics and scenarios from organizations like IEA and IPCC, the contribution of nuclear power to the avoided greenhouse gas emissions in the past, as well as the expected contribution in the future is elaborated. Also challenges and concerns on the production of nuclear power are discussed, like nuclear plant safety, waste management and investment costs, as well as the nuclear technology development potential to address these challenges.
The 2020 Edition
The focus of the 2020 edition is on the significant role of nuclear energy in climate change mitigation scenarios and the challenges of realizing this role in a low carbon energy system. Many organizations are analysing the decarbonization of the energy system and many of their scenarios, including all four illustrative scenarios described by the IPCC in its 2018 Special Report on Global Warming of 1.5°C, call for a substantial increase in global nuclear power capacity. This publication elaborates on how this energy source could be optimally enabled to take its place in an integrated decarbonized energy system and outlines the developments needed to realize a large scale capacity increase to rapidly decarbonize the global energy system in line with limiting global warming to 1.5°C. To that effect, the role of nuclear power includes maintaining existing low carbon capacity by extending the operational life of the current nuclear fleet as well as expanding low carbon capacity through the construction of new facilities.
Key Takeaways
A synthesis of over 400 recent long term scenarios of energy demand from international, governmental, non-governmental, private sector and scientific organizations, including the IPCC, illustrates the challenges and opportunities of reducing emissions while simultaneously supplying energy for economic and social development. Several scenarios identify an opportunity to reduce final energy consumption by 2050. All project an increase in electricity consumption, ranging from 20% to 330%. In scenarios in which ambitious mitigation targets are achieved, electricity generally plays a larger role to support decarbonization of other energy uses (e.g. by electrifying transportation and industry).
Low carbon electricity generation technologies are estimated to have reduced direct power sector CO2 emissions by up to one third over the period 1971–2018 by avoiding the use of significant quantities of fossil fuels. After expanding rapidly from the early 1970s onwards, nuclear power has contributed substantially to reducing emissions, supplying close to 50% of low carbon electricity in the 1990s. Annual emissions would have been around 2 gigatonnes (Gt) of CO2 higher over the past decade if electricity from nuclear power plants had instead been supplied using the average global fossil fuel generation mix.
The potential future contribution of nuclear energy to climate change mitigation has been analysed across 400 recently published scenarios, presenting a wide range of future estimates reflecting many uncertain technical, economic, social and policy factors. An increasing role for nuclear power compared with its present role is seen across many of the scenarios, particularly in those with lower CO2 emissions that achieve more stringent mitigation targets. Compared with the IAEA's projections of nuclear electricity generation to 2050, higher levels of nuclear generation are seen in other scenarios, including the IPCC's four illustrative pathways, implying significant additional market and policy action beyond the current trends reflected in the IAEA projections.
The characteristics and assumptions of the four IPCC illustrative pathways and other scenarios projecting a strong increase in nuclear capacity highlight several potentially important enabling factors for capitalizing on nuclear power's mitigation potential: (a) a strong mitigation target, and related consistent policy signals; (b) control of nuclear costs and, implicitly, access to finance; (c) a moderate degree of social acceptance; and (d) recognition of the value of nuclear power to the stable operation and management of the electricity system or grid.
In the period 1999–2019, net nuclear electrical capacity increased by a modest 14%. At the start of 2020, there were 52 reactors under construction in 19 countries, equating to over 13% of current global nuclear capacity. This includes projects in countries with established nuclear power programmes as well as in 'newcomer' countries constructing their first NPPs, such as Bangladesh, Belarus, Turkey and the United Arab Emirates, illustrating the potential for nuclear power to provide low carbon energy to emerging economies.
A key impediment to a rapid transition to a low carbon energy system is the lack of incentives provided by existing policy and regulatory frameworks, including the current design of power markets in many countries. In addition to a firm political commitment to full decarbonization in the long run, several elements can support the transition to a reliable, low carbon energy system in liberalized markets: (a) competitive short term electricity markets for efficient dispatch; (b) frameworks for the adequate provision of capacity, flexibility and infrastructures for transmission and distribution; (c) measures to foster long term investment in low carbon technologies; (d) internalizing system costs; and (e) carbon pricing.
Robust supply chains, capable of delivering equipment, systems and services with the highest quality levels, are vital to the success of nuclear new build projects. In some parts of the world, declining orders for new nuclear power stations have led to a general weakening of the subcontractor network and to a relative increase in construction costs and delivery times. In comparison, successful nuclear projects are generally backed by vendors and supply chains built up across a steady series of projects, enabling subcontractors to develop and retain experienced and skilled teams.
Complementing new nuclear projects, extending the operational lifetimes of existing NPPs is expected to continue to deliver significant short to medium term contributions to climate change mitigation, while reducing air pollution and enhancing security of supply. Experience shows that this can be realized with a modest investment to replace and refurbish major components to ensure plant operation in line with current expectations. Compared with a new nuclear build, lifetime extension projects are less capital intensive, feature significantly shorter construction and payback times, and have a good track record in terms of cost control and limiting construction delays.
Policy and investment incentives will also need to deliver an energy system that is resilient to the impacts of climate change. While the vulnerability of different electricity generating technologies varies, NPPs have shown themselves to be relatively resistant to weather events, with limited forced outages in most cases despite a high frequency of extreme weather events in some regions.
