The impact of environmental flow constraints and energy storage on system performance and revenues in cascade hydropower

Abstract

Increasing shares of variable renewable electricity sources in the energy system extend the demand on flexibility providers, such as hydropower. More short-term regulation of hydropower plants adversely affects river ecosystems, particularly in cascades. Implementing environmental flow constraints is a well-recognised method to ensure qualitative habitat improvements. The study aims to evaluate the effects of flow constraints by modelling a national-scale energy system with a hydro cascade enhanced with hydrological details for hydropower operations. The open-source modelling framework Backbone is employed for the techno-economic simulation. Studied scenarios cover different years, a range of flow constraints, and options for additional flexibility investments to mitigate the economic impact of flow constraints. Results indicate that flow constraints reduce revenue but mitigate sub-daily ramping. In scenarios with highly volatile electricity prices, low-level flow constraints do not lead to significant reductions in electricity production. However, the simulation still reveals a revenue decrease. Moderate price levels lead to larger relative losses and require more generation from thermal power plants. Incorporating energy storage units reduces economic losses and emissions, underscoring their potential as alternative flexibility providers in the energy system. Introducing a medium-restricted scenario featuring a large energy storage unit seems viable for balancing environmental and economic impacts.

Keywords

Backbone / Cascade / Energy storage / Energy system modelling / Hydropower / River ecosystem

References

[1] Åberg SC, Korkka-Niemi K, Rautio A, Åberg AK. The effect of river regulation on groundwater flow patterns and the hydrological conditions of an aapa mire in Northern Finland. J Hydrol Reg Stud. 2022, 40. 101044

[2] Ahola M, Kerätär K, Visuri M, Hellsten S. Vedenpinnan Vaihtelun Vaikutukset vesi- Ja Rantalintujen Pesintään. 2003, Helsinki, Kirjallisuusselvitys

[3] Ajanovic A, Sayer M, Haas R. The economics and the environmental benignity of different colors of hydrogen. Int J Hydrogen Energy. 2022, 47: 24136-24154.

[4] Andrus SR, Diffely RJ, Alford TL. Theoretical analysis of green hydrogen from hydropower: a case study of the Northwest Columbia River system. Int J Hydrogen Energy. 2023, 48: 7993-8001.

[5] Anindito Y, Haas J, Olivares Met al. . A new solution to mitigate hydropeaking? Batteries versus re-regulation reservoirs. J Clean Prod. 2019, 210: 477-489.

[6] Arheimer B, Donnelly C, Lindström G. Regulation of snow-fed rivers affects flow regimes more than climate change. Nat Commun. 2017, 8: 62.

[7] Ashraf FB, Haghighi AT, Riml Jet al. . Changes in short term river flow regulation and hydropeaking in Nordic rivers. Sci Rep. 2018, 817232.

[8] Ashraf FB, Huuki H, Torabi Haghighi Aet al. . Valued peaks: sustainable water allocation for small hydropower plants in an era of explicit ecological needs. Renew Energy. 2025, 244122756.

[9] Aubin V, Helseth A, Korpås M. Do we have to choose between the ecosystems and the energy transition? Environmental trade-offs with operation of Norwegian hydropower. Renew Energy. 2025, 244. 122595

[10] Borkowski D, Cholewa D, Korzeń A. Run-of-the-river hydro-pv battery hybrid system as an energy supplier for local loads. Energies. 2021.

[11] Dantherm Power (2018) Low temperature proton exchange membrane fuel cell CHP (hydrogen). In: Technology Data - Generation of Electricity and District heating. Technology descriptions and projections for long-term energy system planning. Accessed 29 Jun 2023 https://ens.dk/sites/ens.dk/files/Analyser/technology_data_catalogue_for_el_and_dh.pdf

[12] De Vita A, Kielichowska I, Mandatowa P et al (2018) Technology pathways in decarbonisation scenarios. https://build-up.ec.europa.eu/sites/default/files/content/2018_06_27_technology_pathways_-_finalreportmain2.pdf. Accessed 15 May 2024

[13] Energiateollisuus (2023) Hourly Values of Electricity Production. In: Hourly Electricity data 2022. https://energia.fi/en/statistics/hourly-values-of-electricity-production/. Accessed 15 May 2024

[14] Fingrid (2024) Production devices. https://www.fingrid.fi/en/electricity-market-information/transactions-of-gos2/production-devices/. Accessed 29 Jan 2024

[15] Fingrid Oyj (2024) Prospects for future electricity production and consumption - Fingrid’s Forecast Q3/2024. Helsinki

[16] Gabrielli P, Garrison J, Hässig Set al. . The role of hydrogen storage in an electricity system with large hydropower resources. Energy Convers Manage. 2024, 302. 118130

[17] Gaia Consulting Oy (2024) Vesivoiman biodiversiteettivaikutukset. Helsinki

[18] Greenhouse Gas Protocol (2017) Emission factors from cross-sector tools. In: Calculation Tools and Guidance. https://ghgprotocol.org/calculation-tools-and-guidance#cross_sector_tools_id. Accessed 7 Apr 2025

[19] Guisández I, Pérez-Díaz JI, Wilhelmi JR. Assessment of the economic impact of environmental constraints on annual hydropower plant operation. Energy Policy. 2013, 611332-1343.

[20] Guisández I, Pérez-Díaz JI, Wilhelmi JR. Approximate formulae for the assessment of the long-term economic impact of environmental constraints on hydropeaking. Energy. 2016, 112: 629-641.

[21] Habel M, Mechkin K, Podgorska Ket al. . Dam and reservoir removal projects: a mix of social-ecological trends and cost-cutting attitudes. Sci Rep. 2020, 10: 19210.

[22] Helistö N, Kiviluoma J, Ikäheimo Jet al. . Backbone—an adaptable energy systems modelling framework. Energies. 2019, 12. 3388

[23] Huuki H, Karhinen S, Ashraf F, Binet al. . The economic cost of hydropower environmental constraints under decreasing price volatility. River Res Appl. 2022, 381815-1828.

[24] Huuki H, Kukkonen M, Kopsakangas-Savolainen M (2022b) Vesivoimakatsaus -. vesivoiman toimintaympäristö Suomessa ja Oulujoen vesistöalueella

[25] IEA (2024) Renewables 2024 - Analysis and forecast to 2030

[26] IEA (2023) Managing Seasonal and Interannual Variability of Renewables. Paris

[27] Ishaq H, Dincer I, Crawford C. A review on hydrogen production and utilization: challenges and opportunities. Int J Hydrogen Energy. 2022, 47: 26238-26264.

[28] Jovan DJ, Dolanc G, Pregelj B. Utilization of excess water accumulation for green hydrogen production in a run-of-river hydropower plant. Renew Energy. 2022, 195: 780-794.

[29] Kemijoki Oy (2024) Voimalaitokset. https://www.kemijoki.fi/toimintamme/voimalaitokset/. Accessed 15 May 2024

[30] Kiehle J, Lindroos TJ, Louis J-N, Pongrácz E (2024) Cascade Hydropower Integration in a Techno-Economic Power System Model: A Study of Finnish Hydropower Plants. SSRN. https://doi.org/10.2139/ssrn.4971685

[31] Kopsakangas-Savolainen M, Vehviläinen I, Belinskij A et al (2024) Vesienhoidon Toimenpiteiden Vaikutukset Säätövoimaan. Valtioneuvoston selvitys- ja tutkimustoiminnan julkaisusarja

[32] Kuriqi A, Pinheiro AN, Sordo-Ward Aet al. . Ecological impacts of run-of-river hydropower plants—current status and future prospects on the brink of energy transition. Renew Sustain Energy Rev. 2021, 142. 110833

[33] Laveneziana L, Prussi M, Chiaramonti D. Critical review of energy planning models for the sustainable development at company level. Energy Strategy Rev. 2023, 49. 101136

[34] Marttila H, Huuki H, Ashraf F, Binet al. . River systems under peaked stress. Environ Res Lett. 2024.

[35] Mathisen S, Mo B, Helseth A et al (2022) Measuring the Impact of Environmental Constraints on Hydropower Flexibility. In: 18th International Conference on the European Energy Market (EEM). IEEE, pp 1–6

[36] Mchayk A, Marttila H, Klöve B, Torabi Haghighi A. Hydropeaking mitigation with re-regulation reservoirs. River Res Appl. 2024.

[37] Mikovits C, Wetterlund E, Wehrle Set al. . Stronger together: Multi-annual variability of hydrogen production supported by wind power in Sweden. Appl Energy. 2021, 282. 116082

[38] Moreira M, Hayes DS, Boavida Iet al. . Ecologically-based criteria for hydropeaking mitigation: a review. Sci Total Environ. 2019, 657: 1508-1522.

[39] Mosbæk RR, Rao M, Chochlidakis C, Rothuizen E (2020) Hydrogen Storage. In: Technology Data - Energy storage. Technology descriptions and projections for long-term energy system planning. https://ens.dk/sites/ens.dk/files/Analyser/technology_data_catalogue_for_energy_storage.pdf. Accessed 29 Jun 2023

[40] Mosbæk RR, Hestbek Nicolaisen R, Rao M (2021) Hydrogen production via electrolysis. In: Technology Data - Renewable fuels. Technology descriptions and projections for long-term energy system planning. https://ens.dk/sites/ens.dk/files/Analyser/technology_data_for_renewable_fuels.pdf. Accessed 29 Jun 2023

[41] Pérez-Díaz JI, Wilhelmi JR. Assessment of the economic impact of environmental constraints on short-term hydropower plant operation. Energy Policy. 2010, 38: 7960-7970.

[42] Petkov I, Gabrielli P. Power-to-hydrogen as seasonal energy storage: an uncertainty analysis for optimal design of low-carbon multi-energy systems. Appl Energy. 2020, 274. 115197

[43] Pöyry (2019) Demand and Supply of Flexibility - Final report. https://www.fingrid.fi/globalassets/dokumentit/fi/sahkomarkkinat/kehityshankkeet/dalyve-fingrid_flexibility-study_final-report_v300-id-151641.pdf. Accessed 16 Mar 2023

[44] PVO-Vesivoima Oy (2024) Isohaaran Voimalaitos. https://www.pohjolanvoima.fi/wp-content/uploads/2024/01/esite-isohaara-2024.pdf. Accessed 15 May 2024

[45] Quaranta E, Georgakaki A, Letout Set al. . Clean energy technology observatory: hydropower and pumped hydropower storage in the European union – 2023 status report on technology development. 2023, Luxembourg, Trends, Value Chains and Markets

[46] Ramos A, Tuovinen M, Ala-Juusela M. Battery energy storage system (BESS) as a service in finland: business model and regulatory challenges. J Energy Storage. 2021, 40. 102720

[47] Roni M, Mosier T, Li Bet al. . Hydropower flexibility valuation tool for flow requirement evaluation. Energy Rep. 2023, 9: 217-228.

[48] Ruokamo E, Juutinen A, Ashraf F, Binet al. . Estimating the economic value of hydropeaking externalities in regulated rivers. Appl Energy. 2024, 353: 122055.

[49] Schäffer LE, Adeva-Bustos A, Bakken TH et al (2020) Modelling of Environmental Constraints for Hydropower Optimization Problems - A Review. International Conference on the European Energy Market, EEM 2020-September: https://doi.org/10.1109/EEM49802.2020.9221918

[50] Schäffer LE, Helseth A, Korpås M. A stochastic dynamic programming model for hydropower scheduling with state-dependent maximum discharge constraints. Renew Energy. 2022, 194571-581.

[51] Sridhar A, Baskar AG, Thakur J. Energy storage integration with run of river power plants to mitigate operational environmental constraints: case study of Sweden. J Energy Storage. 2022, 56. 105899

[52] Statistics Finland (2024) Electricity and heat -tables. In: Energy 2023 table service. https://pxhopea2.stat.fi/sahkoiset_julkaisut/energia2023/html/engl0002.htm. Accessed 15 Jan 2025

[53] Statistics Finland (2023) Electricity production by source and total consumption, 2000–2023. https://pxdata.stat.fi/PxWeb/pxweb/en/StatFin/StatFin__salatuo/statfin_salatuo_pxt_12b4.px/. Accessed 15 May 2024

[54] Torabi Haghighi A, Ashraf FB, Riml Jet al. . A power market-based operation support model for sub-daily hydropower regulation practices. Appl Energy. 2019, 255: 113905.

[55] van der Spek M, Banet C, Bauer Cet al. . Perspective on the hydrogen economy as a pathway to reach net-zero CO2 emissions in Europe. Energy Environ Sci. 2022, 151034-1077.

[56] Virk ZT, Ashraf FB, Bin, Haghighi ATet al. . Nordic socio-recreational ecosystem services in a hydropeaked river. Sci Total Environ. 2024, 912169385.

Funding

University of Oulu (including Oulu University Hospital)

RIGHTS & PERMISSIONS

The Author(s)