Are nuclear energy and the energy transition inextricably linked?
The pathway of the energy transition is lined with conflicting objectives. In some cases, finding solutions is like squaring the circle. For instance, growing demand for electricity is likely in fields such as mobility and heating solutions, yet there is a lack of efficient new storage technologies, and existing conventional power stations are being shut down. One key question is therefore: When there is little wind and/or the skies are cloudy, where will the essential electricity for the nation’s homes and businesses be sourced from?
Annual electricity consumption in Switzerland currently stands at around 60 TWh, about a third of which stems from the four remaining Swiss nuclear power stations. Switzerland’s two largest and newest nuclear power stations – Gösgen and Leibstadt – each supply around 14 per cent of national consumption per year.
Swiss electricity production has strong seasonal fluctuations. In the warm and hot spring and summer months, Switzerland generates more than it needs, as snowmelt boosts the supply to its hydroelectric power stations. In autumn and especially winter months, however, the country relies on imported electricity. The storage capacity of the national (pumped)-storage hydroelectric power stations, which totals around 9 TWh per year according to the Swiss Federal Office of Energy, is insufficient to cover the country’s seasonal electricity needs
Both national and European demand for electricity is likely to rise sharply over the next few years on account of the envisaged electrical heating solutions (e.g. heat pumps), electric mobility and digitalisation. In the “zero-basis” scenario, the Swiss Federal Office of Energy assumes Swiss annual electricity consumption of around 75 TWh in 2035 and around 80 TWh in 2050 in its energy forecasts, while other studies arrive at even higher annual consumption levels for electricity. In these energy forecasts, the Swiss Federal Office of Energy concludes that with a service life of 50 years for Swiss nuclear power stations, winter imports will reach a maximum of around 16 TWh per year in 2034. Given the tough negotiations between our federal government and representatives from Germany and Italy for mutual assistance in the event of a gas supply emergency, as well as Switzerland’s strained relationship with the EU on energy matters, these figures are alarmingly high. The sluggish progress with installing solar panels and wind farms in Switzerland and the slow efforts to upgrade the (electricity distribution) grid for the current energy transition suggest that hopes of plugging the 16 TWh gap are optimistic.
If Switzerland were to shut down its remaining nuclear power stations by 2035 (- 20 TWh/a) and the optimistic installation targets for new renewable energy facilities were to be achieved in Switzerland, there would still be an annual national supply shortfall of around 16 TWh (about a quarter of the current annual consumption), according to the energy forecasts. Closing this electricity gap by reducing consumption is unlikely, particularly in view of the envisaged rise in electrification. Likewise, a further major expansion of hydroelectric power in Switzerland is doubtful, as suitable (good) sites are limited and it is unclear whether a large new power station could actually be built under the current landscape preservation regulations. Large-scale installation of wind turbines in Switzerland seems practically impossible due to the general lack of good wind conditions in Switzerland, public protest and the length of time taken to develop wind parks in Switzerland in the past. This just leaves a combined solution involving a large increase in solar energy, and (currently) batteries to store surplus electricity generated in the summer months for use in the winter.
According to Electrosuisse, electricity production from solar panels in Switzerland ranges from 1,000 to 1,500 kWh per m2 per year. Assuming that a solar panel generates 1.25 MWh per m2 per year on average, the required solar panels would need at least 12.8 km2 in Switzerland. However, this is contingent upon continuous availability of all solar modules, so a wider area is more realistic.
Assuming this 16 TWh of solar power would be skewed towards summer and 30% of it could be produced actually in the winter months (when its needed), it would be necessary to produce and store 11.2 TWh during the summer for use in winter.
According to figures released by Tesla, the battery capacity of a “Model 3 Long Range” is 75 kWh. Consequently, Switzerland would need around 149 million of these Teslas to store the electricity for the winter months, and even then the vehicle battery as well as the essential charging and discharging infrastructure would have to be constantly working. These vehicles are around 5 m long and 2.2 m wide, so around 1,600 km2 (around 4 per cent of the country’s surface area) would be needed as storage space. Realistically, then, we still need some new large-scale power stations in Switzerland.
Building coal-fired power stations is unlikely to find majority public support, given the implications for the environment and CO2 targets. Gas-fired power stations are also unlikely to find majority support, not only on account of their CO2 emissions. New sourcing routes of gas to Europe are making gas transport more expensive and gas prices more volatile. It is also uncertain how long the existing European natural gas infrastructure for transporting gas to Switzerland will remain available, as it is set to be converted and used for transporting hydrogen in the future.
There are promising developments with nuclear power stations. Many of the global nuclear power stations already completed, under construction or, in the planning phase have innovative “passive” safety systems. They make for example use of the natural circulation of liquids and gases at different temperatures. Unlike active safety systems, passive systems do not need motorised pumps or valves for circulation of the coolant. Hence these new safety systems work without external energy supply. In the event of a severe malfunction, reactors with passive safety systems could be left alone even for several days with no operator intervention, and no hazardous situation would arise. Even in the event of a core meltdown, it would be possible to confine the meltdown to the reactor pressure vessel and dissipate the heat in a controlled manner. This in turn substantially reduces the risk of severe core damage with harmful effects. The latest planned 4th generation nuclear reactors are being designed on a smaller1 and modular basis, meaning less fissile material in a facility – including with regard to a reactor accident. Furthermore, the modular design is also likely to significantly reduce construction costs: current Swiss nuclear power stations and many of those currently in operation abroad are custom-made with correspondingly high construction costs. The remaining difficulties with radioactive waste also should be kept in perspective. An example is Mühleberg nuclear power station, for which BKW disclosed that 8 per cent of the total mass of 200,000 t is radioactively contaminated. Most of the 8% is only “slightly” radioactive and after special cleaning can go to landfill as normal construction waste or be recycled. Just under 2% of waste is more radioactive2 and requires special disposal.
In a population survey published by Deloitte at the end of 20233, only 29 per cent of respondents stated they supported the construction of new nuclear power stations in Switzerland. However, it appears that the proportion of those in favour of new nuclear power stations in Switzerland has risen sharply in recent months. In the latest survey published by Tamedia on 24 September 2024, 53 per cent of respondents stated that they would support the construction of new nuclear power stations in Switzerland.
Our population survey in 2023 also showed that a clear majority of respondents support the use of solar energy on roofs and the expansion of national hydroelectric power ( although the potential is limited for the reasons set out above).
Conclusion
As in the past, Switzerland needs a high degree of self-sufficiency in electricity, as well as a reliable, affordable electricity mix. This is contingent upon Switzerland continuing to use hydroelectric power while also being open to new technologies, including the ongoing development of nuclear energy. As long as the two nuclear power stations in Gösgen and Leibstadt can be run safely and efficiently, they must continue operating – at least until an equivalent replacement is available.
Political acceptance of nuclear energy is picking up in many European countries as well as in Switzerland, and a revival now seems possible. A first step in Switzerland would be an examination of economic viability of new nuclear power. Thereafter would follow the lengthy approval and development process. The implication is that it may take ten years or more until new nuclear power stations could enter into service.
In the meantime, the investment planned under the Swiss “Mantelerlass”, particularly in the expansion of existing hydroelectric power stations and on roof-mounted solar panels, can be driven forward. As our earlier survey showed, these technologies enjoy wide public support and can therefore be approved more quickly than ground-mounted solar panels or new hydroelectric power stations. At the same time, an extensive debate on a secure, cost-effective electricity supply for Switzerland should be instigated, with particular consideration of the technical conditions.
Footnotes
1These days, the biggest plants have an electrical output of up to 1,600 MW – small modular reactors with an output of around 70 to 500 MW are planned.
2https://www.bkw.ch/en/energy/energy-generation/decommissioning-of-the-muehleberg-nuclear-power-plant/materials
3https://www2.deloitte.com/ch/en/pages/energy-and-resources/articles/zwischen-subsidisation of all power stations, we will not win this race or meet the climate targets.
