Security of supply

Hydropower and nuclear power: a key combination for the future of energy – today and tomorrow

28.08.2026, 08:00 | Security of supply

There is a lively debate taking place on the future role of hydropower and nuclear energy in Switzerland. A key aspect of this is the question of the extent to which nuclear power plants could put hydropower under economic pressure. Alpiq has carried out its own analyses on this topic: based on our comprehensive modelling, the picture that emerges – contrary to what certain scenarios suggest – is a more balanced one: hydropower and nuclear energy are not competing technologies. They complement one another and, together, can strengthen Switzerland’s security of supply within a low-carbon electricity system.

What impact would new nuclear power stations in Switzerland have on hydropower – a renewable energy source that forms the backbone of the national electricity supply – and on its economic viability? Studies and scenarios have recently brought this issue more firmly into the spotlight of the national energy policy debate. 

This was reason enough for Alpiq to carry out its own analyses, which paint a more nuanced and balanced picture.

Our simulations were carried out using fundamental models that explicitly account for both European interconnectivity – Switzerland is at the centre of the European grid – and the technical limitations of hydropower and nuclear energy.

These analyses were carried out by two independent Alpiq teams and cover various nuclear scenarios – including that of a study by the University of Applied Sciences of Valais (+1,600 / +3,200 MW) and more realistic scenarios for Switzerland (long-term operation of Gösgen* and Leibstadt beyond 60 years, +2,280 MW, as well as a new 1,200 MW plant by 2050). The results also take meteorological variability into account and relate to the year 2050.

Our key findings

  • Additional nuclear power generation does indeed have an impact on the profitability of hydropower, but this impact is significantly more moderate than indicated, for example, in the study by the University of Applied Sciences of Valais.
  • For run-of-river and storage power stations, the decline in profitability is around four times smaller than stated in this study: Run-of-river: -4% to -11%; storage: -3% to -6%.
  • The profitability of pumped-storage power stations, on the other hand, increases (+1% to +8%), which can be explained by the combination of two cycles:
    • Absorption of surplus photovoltaic generation during the day
    • Absorption of nuclear base load at night
  • The analyses take into account only the energy market and not the other flexibility markets (system services) available to hydropower – the overall effect on profitability would be even smaller.

Conclusion: Complementarity rather than competition

Alpiq’s methodology provides a direct and realistic picture of the Swiss energy system in 2050. Our analyses show that the negative effects often cited are significantly overestimated.

In a realistic scenario up to 2050, nuclear power and hydropower prove to be complementary technologies that together contribute to security of supply and low-carbon electricity generation in Switzerland.

*Current plans envisage the Gösgen nuclear power station operating for around 60 years. From a technical and safety perspective, operation beyond 60 years is possible. Any decision to continue operation beyond 60 years – i.e. for the Gösgen nuclear power station beyond approximately 2039 – must be taken several years before the actual date for planning reasons. For the Gösgen Nuclear Power Station, this would therefore be in the early 2030s.

Disclaimer: 

For Alpiq, the construction of new nuclear power stations is not on the agenda at present. In the field of nuclear energy, we are focusing on the safe and economical long-term operation of nuclear power stations, which is necessary to ensure they continue to make a significant contribution to security of supply for many years to come and to give us the time needed to transition the energy system to renewable energy sources. Should new nuclear power stations be built in Switzerland in the future, stable political, regulatory and economic conditions would be required. State support would therefore be essential.