As electricity systems are becoming increasingly low carbon and more diversified, they are also more and more expensive. In most countries, electricity generation now costs USD 100 per MWh or more, particularly for low-carbon technologies. Only the long-term operation (LTO) of existing nuclear power plants, hydroelectricity and – as long as their system costs are excluded – onshore wind and solar photovoltaic technologies can provide electricity for less than USD 100.
This is one of the key findings from the latest edition of The Costs of Generating Electricity 2025, a new report providing comprehensive and internationally comparable data on the levelised costs of generating electricity (LCOE) across 21 Nuclear Energy Agency (NEA) member countries and 23 different technologies. As electricity systems face rising demand, evolving energy security concerns and efforts to reduce carbon emissions, the report offers policymakers, experts and energy system modellers a robust evidence base to support informed decision making.
The report, from the NEA and EPRI (Electric Power Research Institute), combines EPRI’s detailed engineering-based cost database with NEA expertise on system cost analyses, creating one of the most comprehensive datasets available. It provides comparable plant-level generation cost data, while also highlighting the importance of analysing technologies within the broader context of electricity systems, where reliability, flexibility, network requirements and integration costs all shape outcomes.
“There is no single technology that can meet every country's energy needs in every circumstance,” said William D. Magwood, IV, NEA Director-General. “Countries will need to make policy and investment choices that reflect their own priorities, resources and electricity systems. The data and analysis in this report can support those decisions.”
“As energy systems evolve, understanding the costs, performance characteristics and system implications of different technologies is important for informed planning,” said Steve Chengelis, EPRI Vice President, Energy Supply Nuclear Development and Fusion. “This report provides transparent, internationally comparable data and analysis to help policymakers, utilities, developers and other stakeholders evaluate options and support informed energy planning and investment decisions.”
Technologies that were once considered niche, including geothermal energy, biomass, battery storage, hydrogen-fired gas turbines and fossil-fuel plants equipped with carbon capture, utilisation and storage (CCUS), are receiving growing attention across NEA member countries. This diversity reflects the increasingly complex challenge of balancing affordability, energy security, reliability and environmental goals.
Series construction can reduce nuclear costs
The report also highlights growing interest in nuclear energy, with data submitted for large-scale reactors, small modular reactors (SMRs) and long-term operation of existing plants. One of the report's key findings is the contrast between near-term projects and more mature "Nth-of-a-kind" (NOAK) deployments. While first projects face higher costs linked to supply-chain rebuilding, workforce shortages and limited recent construction experience, costs decline significantly as designs are standardised and projects are repeated.
Figure 1: Range of levelised cost of electricity (LCOE) per technology
Renewable technologies remain competitive, but trends are diverging
The analysis confirms that utility-scale onshore wind and solar photovoltaic technologies continue to offer attractive plant-level costs in many countries. However, unlike in previous editions of this analysis, no significant further cost reductions were observed. The report also highlights contrasting trends among other low-carbon technologies. Offshore wind continues to face relatively high costs despite strong capacity factors, while geothermal energy shows promising results where suitable resources are available, offering the potential for a competitive source of low-carbon, dispatchable electricity. The interaction of variable renewables such as wind and solar photovoltaic technologies with dispatchable baseload technologies such as nuclear power, coal and gas also significantly affects the latter’s capacity factors and hence their LCOE unit costs (Figure 2).
Figure 2: Cost implications of operating coal, natural gas and nuclear power plants at different capacity factors
Implications for electricity system planning
Electricity technologies cannot be assessed solely on their plant-level LCOE costs at a given capacity factor. While LCOE with a capacity factor of 85% for baseload technologies remains a transparent and widely understood indicator of generation costs, it does not capture how technologies interact within a broader electricity system or their contribution to reliability, flexibility, security of supply and decarbonisation objectives.
Rather than relying heavily on a single technology, many countries will benefit from a diversity of complementary technologies. In many cases, combinations of nuclear energy and renewables, supported by sources of flexibility such as battery storage, hydroelectricity, gas-fired power generation, possibly with CCUS or based on hydrogen, demand response and interconnections, can provide lower-cost, more resilient electricity systems and strengthen energy security. The optimal mix, however, remains specific to each country and electricity system.
About the report series
The Costs of Generating Electricity 2025 is the 10th edition of the series of NEA reports on costs of generating electricity published since 1983.
