Europe | It’s all a balancing act
Balancing environmental flows and the country’s power grid have become hot topics for discussion across the Swedish hydropower industry
DESPITE ITS IMPORTANT ROLE for the future energy system, limited focus has been placed on how increasing hydropower capacity can help Sweden achieve a valuable balancing act within its power grid. With hydropower currently accounting for around 40% of electricity across the country, its 2000 plants generated 66TWh in 2023 with an installed capacity of 16.4GW. Large scale plants above 10MW account for around 94% of this.
Above: Swedish hydropower accounts for around 40% of electricity across the country
By 2045, Swedish electricity demand is expected to double and the share of intermittent power, mainly wind, is also expected to increase. And this is where problems may arise. Between 2010 and 2023 total installed capacity in Sweden increased by 14.5GW and although wind and solar power also increased, hydropower capacity has remained largely unchanged. With higher levels of intermittent renewables in its energy system, Sweden is in growing need of a good balancing act. To help resolve this, the Swedish Association of Engineers commissioned AFRY Management Consulting to carry out research during the summer of 2024. As Swedish hydropower is considered to be ‘built-out’ with limited potential for new plants, its aim was to identify ways in which existing hydropower plants can meet growing electricity demand. The study encompassed a literature review, expert
Above: Vattenfalls’s 125MW Älvkarleby hydro project in Sweden © Alexanderstock23 /
Shutterstock.com
interviews, and quantitative analysis. It discovered that existing Swedish hydropower plants could increase capacity by 4000MW, a boost of 24% on current levels. The greatest potential is in northern Sweden due to 82% of current hydropower being sited in the northernmost areas of the country. And this enhanced capacity could also support an additional 800-1200MW of wind power integration, but challenges do exist. For example there are major obstacles in the form
of hydropower permit reassessments, with ambiguity concerning the implementation of a national plan as initial benchmarks for acceptable production loss are reported to have created great uncertainty. In addition altered flow approvals and financial viability for plant owners are also a cause for concern. The report highlighted three main measures that can
be taken to increase hydropower expansion across Sweden. These are:
Full or partial turbine upgrades to improve flow rate and efficiency.
Upgrading power units by replacing generators, turbines and related equipment to increase capacity. Installing additional power units in stations prepared for future capacity expansion. In conclusion the study calls for further investigation into regulatory and financial barriers to unlocking hydropower’s full potential in Sweden.
Go with the flow Other research focusing on Sweden analysed the
complex balancing act that needs to be played out between hydro production and ecosystem rehabilitation, when looking at environmental flows in a future climate. In their research published in Science of the
1. Abelvattnet Hydropower Station 2. Bleriken-Gejmån Hydropower Station 3. Överum an-Klippen Hydropower Station 4. Ajaure Hydropower Station 5. Gardiken Hydropower Station 6. Stenselet Hydropower Station 7. Grundfors Hydropower Station 8. Rusfors Hydropower Station 9. Bålfors Hydropower Station
10. Betsele Hydropower Station 11. Hällfors Hydropower Station 12. Tuggen Hydropower Station 13. Bjurfors Övre Hydropower Station 14. Bjurfors Nedre Hydropower Station 15. Harrsele Hydropower Station 16. Pengfors Hydropower Station 17. Stornofffors Hydropower Station 18. Storuman Hydropower Station 19. Storjuktan Hydropower Station Reservoir Tunnel from Storjuktan to Storuman
Above: Maps showing the position of dams and hydropower stations in the Ume River catchment. Names of hydropower stations are also used for the impoundment/reservoir affected by the dam at the station throughout the paper. Inset map shows the major catchments in Sweden with the Ume River in blue. Source Widen et al in https://doi. org/10.1016/
j.scitotenv.2024.176622
20 | October 2025 |
www.waterpowermagazine.com
Total Environment, Widen et al hope their work contributes in shedding light on an increasing interest in environmental flow assessments, and the need to consider the effects of climate change and potential climate-change consequences for environmental flow versus hydropower conflicts. In an effort to improve ecological conditions while ensuring a continued national supply of hydropower, all permits are in the process of being relicensed, with environmental flows being designed to help meet the demands of this dual challenge. As the authors explain, to avoid implementing ineffective measures and enabling mitigation of extreme events, environmental flows need to be viewed ‘through the lens of climate warming and changing hydrological regimes’, and require a time perspective of at least a decade to consider among-year variability in hydrological conditions. Widen et al’s study focuses on an entire regulated river system. Located in the north of Sweden and flowing from the Scandinavian mountain range to the Gulf of Bothnia, hydropower production on the Ume River developed during the 1950s and 1960s with 19 dams and hydropower stations. Six dams are storage reservoirs and the remaining 13 are impoundments with hydropeaking. Impacts on the ecosystem have included the replacement of lotic fish communities with lentic ones, with a reduction in fauna diversity and abundance as a result of loss of rapids, flow diversions and hydropeaking. The researchers used the Intergovernmental Panel on Climate Change’s climate change projections for up to 2040, and modelled the consequences for
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