A power market-based operation support model for sub-daily hydropower regulation practices

• Published in: Applied energy 2019-12, Vol.255, p.113905, Article 113905
• Main Authors: Torabi Haghighi, Ali, Ashraf, Faisal Bin, Riml, Joakim, Koskela, Jarkko, Kløve, Bjørn, Marttila, Hannu
• Format: Article
• Language: English
• Subjects: alternative energy; Commerce; Daily variations; demand analysis; Energy management; energy market; Finland; Flow regime alteration; Flow regimes; flow regulation; Hydroelectric power; hydrological regime; Hydropeaking; Kemijoki River; Land and Water Resources Engineering; Lappi [Finland]; Mark- och vattenteknik; power generation; Power market; Power markets; regulatory framework; Renewable energies; Renewable energy; Reservoirs (water); river management; River regulation; Rivers; Sub-daily variation; threshold; water budget
• ISSN: 0306-2619; 1872-9118; 1872-9118
• DOI: 10.1016/j.apenergy.2019.113905

•Investigate the impact of instant energy demand on sub-daily river regime.•Introducing power market impact index.•Introducing system efficiency ratio index.•Provides an efficient tool for sustainable river management.•Assess the interaction of power market and regulation practices. With increasing power production from renewable energy sources, sub-daily variations in energy demand need to be balanced. Today, hydropower is commonly used as balancing power. In this study, we quantified the impact of capacity constraints, in terms of reservoir volume and hydropower capacity, on the potential to comply with instant energy demand. To evaluate the impact, we developed two new metrics, power market impact and system efficiency ratio, which are based on two threshold flow regimes derived from natural flow as lower threshold release and regulated flow (based on hourly energy prices) as upper threshold release. The operation support model comprises 96 different regulation scenarios based on varying combinations of hydropower and reservoir capacities. For each scenario, an hourly water balance was simulated, to obtain the highest complying with upper threshold release based on actual energy demand. We tested the framework on the Kemijoki river with defined thresholds based on the natural flow regime (tributary river Ounasjoki) and the hourly energy price in Finland in 2017, and estimated the impact of regulation on hourly flow regime at the Taivalkoski hydropower station. The annual flow regime impact in 2013, 2014 and 2015 was estimated to be 74%, 84% and 61%, respectively, while the monthly impact varied from 27% to 100%. Our framework for evaluating interactions between the power market and sub-daily regulation practices is a useful novel tool for sustainable river management and can be easily applied to different rivers and regions and evaluated for different timescales.