Energy in Switzerland in numbers

In 2004, energy use was composed of 31.3% motor fuels; 25.7% combustibles; 23.1% electricity; 12.1% gas; and 7.8% other. In Switzerland, water power covers about 60% of the demand for electricity or 1/8 of the entire energy demand . Nuclear power plants produce about 40% of the Swiss electricity demand. In 2020, the first nuclear power plants will reach the end of their operating time. Swiss production capacities will decline strongly thereafter. If measured by electricity production in 2003, the proportion of wind power would amount to 1.8% (12).

Electricity consumption is likely to further increase in the future. If the linear trend continues, the electricity demand will be about 33% higher by 2050 compared to 2003 (12).

Vulnerabilities Switzerland

Hydropower

A 20% of the gross electricity production worldwide comes from hydropower plants; in Austria and Switzerland hydropower accounts for more than 50% of the national electrical power production (15). Water resources in mountain regions are particularly sensitive to climatic forcing as glacier retreat is already affecting hydropower production across the Alps (16). This is particularly the case in Switzerland, where reservoirs are frequently glacier fed (17).

The main effects of climate change in the Alps are changes in seasonal snow cover duration and spatial extent on the short term (22) and glacier retreat on the middle and long term (23). These are expected to modify the Alpine hydrological regime substantially, ultimately impacting hydropower productivity (24). Moreover, the projected hydrological shift from low-frequency processes, that is, snow and ice melt, to high-frequency rainfall-driven streamflow patterns, will accelerate the catchment response to precipitation events, enhance the variability of reservoir inflows, thus calling for a modification of the current hydropower system operations (25). Current traditional reservoir operating strategies may prove inadequate (26), and hydropower system operators will likely be forced to change their current operating strategies in favor of higher flexibility and reliability in order to cope with changed water availability and price structure (21).

The impact of climate change on hydropower production in the Swiss Alps during the 21st century has been assessed by combining climate projections, dynamic glacier modeling, and hydrological modeling accounting for water storage in reservoirs and river diversion (18). Climate projections are based on seven different combinations of global and regional climate models, and the A1B scenario (rapid economic growth, quick spreading of new and efficient technologies, and a global population that reaches 9 billion by the midcentury and then gradually declines). The main conclusions of this assesment are (18):

• Glaciers will continuously decrease until they almost disappear by the end of the 21st century. While temperature and global radiation are expected to increase throughout the entire year, it is difficult to define distinct trends in precipitation patterns.
• Based on the presented projections, total runoff generation for hydropower production will decrease during the 21st century by about one third due to the massive retreat of the glaciers. The reduction of ice melt will not be compensated by the potential increase of precipitation.
• In the future the melt season will start earlier in the year, but in the second half of the melt season water runoff will be drastically reduced because of the glacier retreat and the advanced snow melt in the spring months.
• By midcentury, high water events due to heavy precipitation events are expected to become more frequent than today, leading to an increase of water loss due to overflow at some water intakes during fall. While today most water is lost during strong melt periods in summer, the future dynamics of hydrology will lead to overflows in particular during heavy precipitation events in fall. This represents new challenges for hydropower companies to adapt their infrastructures accordingly.
• While the increased snow and ice melt in spring will lead to enhanced runoff in spring, runoff in the second half of the year will be significantly lower. Subsequently, this seasonal shift will impact hydropower production, which is expected to decrease by over half by the end of the century during the summer months.

Previously, hydropower production was expected to decrease by a few percent in the coming decades due to the overall reduction of surface run-off (11). According to a more recent estimate for one of the largest hydropower reservoirs in Switzerland, based on a moderate scenario of climate change (the so-called emission scenario A1B), water availability will significantly reduce due to ice melt and this will translate in a loss in electricity production down to −27% by 2050 (21). 

Glacier retreat and permafrost degradation will substantially increase the sediment transport in rivers, which will have implications for the management of reservoirs, and ultimately affect hydropower production as well (1).

Peak runoff is projected to shift to earlier in the season (20), and hydropower electricity production can be increased during the winter season, but will be reduced in summer. This may be advantageous for hydropower production: runoff may become more consistent throughout the year (19).

Other power plants

The production in nuclear and other thermal power plants will also be affected by climate change. Due to increasing water temperatures and decreasing discharge, they will not be able to obtain as much cooling capacity from the water as today. In the summer 2003, the performance of nuclear power plants had to be curbed by 25% for two months. This reduced the electricity production for the year by 4% (12).

Renewable energy

The direct impacts of climate change on power production from renewable energy are classified as being between neutral and slightly positive. While the growth of biomass will tend to be favoured and solar radiation will increase slightly, extreme events will have a potentially negative impact. However, more important than these direct influences is the fact that increasing energy prices and climate protection strategies will improve the general conditions for the promotion and introduction of renewable energy (12).

The contribution of new renewable energy to the Swiss electricity supply could increase from 3% today to 10% (5500 GWh/a) by 2050. Wind energy will contribute to this. By expanding all wind farm locations to the maximum, the total potential of 1150 GWh/a could be tapped by 2050. Individual plants have an additional potential of 2850 GWh/a. With an increase in mean wind speed due to climate change, an increase in mean wind power production can be expected (12).

Wood energy will also profit from the improved competitiveness of new renewable energy. Forest areas will expand as a result of climate change and the potential for wood energy will continue to grow (12).

At present, changes in the European energy market (liberalisation, increasing importance of wind power) are considered to have much stronger influence on the management of hydropower production than the relatively slow climatic changes. In the long run, it will be essential to fill the gap between decreasing hydropower production and increasing electricity demand by improving the efficient use of energy and by establishing new sources of renewable energy (10).

Demand

As a result of climate change, less heating energy will be used in winter and more cooling energy used in summer. Fuel consumption will thereby decrease and electricity consumption increase (12). Due to warmer winters, the heating demand for the service sector, for instance, will have decreased by 13% by 2035 and by 18% by 2050, compared with 1984-2004. The electricity demand for the service sector for air conditioning will have increased by 115% by 2035 and by 170-200% by 2050, compared with 1984-2004. For private households these numbers are (much) lower (12).

Vulnerabilities Europe

Supply

The current key renewable energy sources in Europe are hydropower (19.8% of electricity generated) and wind. By the 2070s, hydropower potential for the whole of Europe is expected to decline by 6%, translated into a 20 to 50% decrease around the Mediterranean, a 15 to 30% increase in northern and eastern Europe and a stable hydropower pattern for western and central Europe (1,3,4). In areas with increased precipitation and runoff, dam safety may become a problem due to more frequent and intensive flooding events (5).

It has become apparent during recent heat waves and drought periods that electricity generation in thermal power plants may be affected by increases in water temperature and water scarcity. In the case of higher water temperatures the discharge of warm cooling water into the river may be restricted if limit values for temperature are exceeded. Electricity production has already had to be reduced in various locations in Europe during very warm summers (e.g. 2003, 2005 and 2006) (5,8).

Extreme heat waves can pose a serious threat to uninterrupted electricity supplies, mainly because cooling air may be too warm and cooling water may be both scarce and too warm (9).

Climate change will impact thermoelectric power production in Europe through a combination of increased water temperatures and reduced river flow, especially during summer. In particular, thermoelectric power plants in southern and south-eastern Europe will be affected by climate change. Using a physically based hydrological and water temperature modelling framework in combination with an electricity production model, a summer average decrease in capacity of power plants of 6.3–19% in Europe was shown for 2031–2060 compared with 1971-2000, depending on cooling system type and climate scenario (SRES B1 and A2) (14).

Overall, a decrease in low flows (10th percentile of daily distribution) for Europe (except Scandinavia) is projected with an average decrease of 13-15% for 2031–2060 and 16-23% for 2071-2100,compared with 1971-2000. Increases in mean summer (21 June - 20 September) water temperatures are projected of 0.8-1.0°C for 2031–2060 and 1.4-2.3°C for 2071-2100, compared with 1971-2000. Projected water temperature increases are highest in the south-western and south-eastern parts of Europe (14).

By the 22nd century, land area devoted to biofuels may increase by a factor of two to three in all parts of Europe (2).

Demand

It may become more challenging to meet energy demands during peak times due to more frequent heat waves and drought conditions (1). Strong distributional patterns are expected across Europe — with rising cooling (electricity) demand in summer in southern Europe, compared with reduced heating (energy) demand in winter in northern Europe (7).

Climate change impacts on electricity markets in Western Europe

The expected climate changes in the 21st century are likely to have a small impact on electricity prices and production for the energy markets of Western Europe. This has been estimated by modelling three climatic effects (13):

• changes in demand for electricity due to changes in the need for heating and cooling,
• changes in supply of hydropower due to changes in precipitation and temperature, and
• changes in thermal power supply due to warmer cooling water and therefore lower plant efficiency.

According to the model results each of these three partial effects changes the average electricity producer price by less than 2%, while the net effect is an increase in the average producer price of only 1%. Similarly, the partial effects on total electricity production are small, and the net effect is a decrease of 4%.

The greatest effects of climate change are found for those Nordic countries with a large market share for reservoir hydro. In these countries total annual production increases by 8%, reflecting an expected increase in inflow of water. A substantial part of the increase in Nordic production is exported; climate change doubles net exports of electricity from the Nordic countries, while the optimal reservoir capacity is radically reduced (13).

Adaptation strategies

Considering the projected decreases in cooling-water availability during summer in combination with the long design life of power plant infrastructure, adaptation options should be included in today's planning and strategies to meet the growing electricity demand in the 21st century (14).

The seasonal shift of the hydrological cycle and the reduced ice melt generation will very likely force hydropower companies to adapt new water management strategies. The new strategies have to take into account that ice melt in summer will be drastically reduced, but the frequency of heavy precipitation events during fall will increase. Accordingly, the current practice of hydropower companies, of producing maximum energy during winter and relying on ice melt to fill the reservoirs, might be jeopardized by the end of the century (18).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Switzerland.

1. Lehner et al. (2005), in: Alcamo et al. (2007)
2. Metzger et al. (2004), in: Alcamo et al. (2007)
3. Kirkinen et al. (2005), in: Anderson (ed.) (2007)
4. Veijalainen and Vehviläinen (2006); Andréasson et al. (2006), in: Anderson (ed.) (2007)
5. Anderson (ed.) (2007)
6. Rothstein et al. (2006), in: Anderson (ed.) (2007)
7. Alcamo et al., 2007
8. EEA, JRC and WHO (2008)
9. Behrens et al. (2010)
10. Federal Office for the Environment FOEN (Ed.) (2009)
11. Piot (2005), in: Federal Office for the Environment FOEN (Ed.) (2009)
12. OcCC/ProClim- (2007)
13. Golombek et al. (2012)
14. Van Vliet et al. (2012)
15. Zimmermann (2001), in: Finger et al. (2012)
16. Hock (2005), in: Finger et al. (2012)
17. Hauenstein (2005), in: Finger et al. (2012)
18. Finger et al. (2012), in: Finger et al. (2012)
19. Schmucki et al. (2017)
20. Addor et al. (2014); Bavay et al. (2009); Köplin et al. (2014), all in: Schmucki et al. (2017)
21. Anghileri et al. (2018)
22. Barnett et al. (2005); Magnusson et al. (2010); Steger et al. (2013), all in: Anghileri et al. (2018)
23. Huss (2011); Huss et al. (2008); Zemp et al. (2006), all in: Anghileri et al. (2018)
24. Beniston (2003); Farinotti et al. (2012); Fatichi et al. (2015); Hänggi and Weingartner (2012); Viviroli et al. (2011), all in: Anghileri et al. (2018)
25. Brekke et al. (2009); Gobiet et al. (2014); Haguma et al. (2014), all in: Anghileri et al. (2018)
26. Mateus and Tullos (2016); Palmer et al. (2008); Watts et al. (2011), all in: Anghileri et al. (2018)