European electricity prices are set through a merit‑order system, where power plants are dispatched from the lowest to the highest marginal cost. Renewables such as wind and solar usually come first because their variablecost is close to zero. Nuclear and coal follow, while gas‑fired plants are typically last, as they are the most expensive to operate.
The final plant needed to meet demand sets the market‑clearing price for all electricity in that hour. This is why electricity prices rise when gas prices rise, even if most electricity comes from cheaper sources. However only 20–30% of electricity is traded on the day‑to day market,the remaining 70–80% is sold through mid‑ and long‑term contracts (PPAs, bilateral agreements, hedging products, and regulated contracts). These contracts are typically indexed to expected future prices rather than real‑time gas costs.
Nuclear plants have very low variable costs, so once they are running, they tend to push wholesale prices downward. Countries with large nuclear fleets—France, Finland, Sweden—generally experience lower average prices, fewer spikes, and reduced exposure to gas volatility. Increasing nuclear capacity strengthens these stabilizing effects by reducing the number of hours in which gas sets the price.
Nuclear plants operate almost continuously at high-capacity factors, the flexibility is in the range of 10% of the fleet. Every hour they run, they push gas further down the merit- order. Gas plants therefore run fewer hours and become variable price setters less often. Nuclear does not replace entirely gas in terms of flexibility, but it does replace gas in terms of market share. Gas still sets the price during peak hours, but those hours become fewer—exactly what we see in France and Finland. Electricity markets ultimately respond to marginal cost, not flexibility, which is why nuclear reduces volatility even without ramping capability.
Italy tends to pay more for electricity because it relies heavily on gas, imports a significant share of its power, faces structural grid constraints, and carries higher system charges. Even when renewables are strong, gas often remains the marginal technology. Germany, by contrast, enjoys low prices when wind and solar output is high, but experiences sharp spikes when renewable production drops. France typically has the lowest wholesale prices—except in years when nuclear availability is reduced.
Energy storage is emerging as the third major force in Europe’s electricity system, complementing renewables and nuclear. Storage, in the form of short term storage, hydro and hydrogen in the future, provides the flexibility that nuclear lacks and helps stabilize prices by absorbing surplus renewable generation and releasing it during high‑demand periods. This does not replace nuclear; it enhances its role. In such a system, nuclear becomes the stable backbone, renewables supply cheap bulk energy, and storage provides the flexibility that gas used to deliver. The combined effect is lower and more stable prices, reduced dependency, on gas, and improved economics for both nuclear and renewables. Europe’s future grid is not “nuclear versus renewables” but nuclear + renewables + storage, each contributing its strengths.
Today, storage is still more expensive than gas for providing flexibility. However, Europe should not try to replace gas with storage immediately. Instead, it is building the conditions for storage to become cheaper, more scalable, and more valuable over the next decade. Storage acts as a hedge against gas price volatility, not an instant substitute. Gig Battery costs for instance will fall by more than 40 % by 2030 according to IEA, BNEF,Fraunhofer and RMI , and unlike gas plants—which earn money only when they run—storage assets can earn revenue even when idle through grid services.
Finally, CO2 prices are becoming one of the strongest forces reshaping Europe’s energy system. Carbon pricing steadily pushes gas out of the market and strengthens the economic case for nuclear, renewables, and storage. In a future where these three form the core of the system, European electricity prices will depend far less on gas and geopolitical shocks, and far more on capital‑intensive, low‑carbon assets that deliver cheaper and more stable electricity over time—though this requires higher upfront investment and smarter system design.