Some recent European projects have indeed suffered from cost overruns and delays. In many cases this was linked to first-of-a-kind designs, lost industrial know-how after long construction gaps, and to political or local opposition that prolonged licensing and court processes.

Experience from countries such as France in the 1980s-1990s and South Korea more recently shows that standardised designs, stable regulation, and consistent political support tend to shorten schedules and reduce costs for nuclear fleets.

Production costs (LCOE) for solar, wind and nuclear power cannot be compared in isolation, because an electricity system must remain balanced every hour of the year.. What matters for consumers and industry is the total system cost – generation, flexibility, backup capacity and grids together. When examining total system costs, several European analyses in 2025 from, among others, the European Commission and the International Energy Agency (IEA) find that in systems with high shares of variable renewables, a combination of renewables and firm low-carbon capacity such as nuclear can be cost-competitive, and often cheaper than trying to rely on wind and solar plus storage and backup alone.

Nuclear power provides stable, dispatchable output and ancillary services, which can complement renewable energy and help keep overall system costs under control. Scenarios from the IEA and others show that systems including nuclear typically require less backup capacity and lower grid-reinforcement needs than systems that must compensate variable renewables exclusively with storage, flexible fossil plants and long-distance transmission.

The International Energy Agency (IEA) estimates that grid costs account for 10 to 30 percent of electricity system costs and increase significantly as the share of solar and wind increases. The higher the share, the faster the costs increase, especially due to the need for new connections and network reinforcements.

Today, nuclear power supplies roughly 25 percent of the EU’s electricity and is the single largest low-carbon source in the European power mix, alongside hydropower and rapidly growing wind and solar. In a decarbonised power system consistent with EU climate targets and the EU Taxonomy Regulation, nuclear can act as a firm, low-carbon backbone that, together with renewables, enables a competitive and reliable European energy system.