Applicability of pumped storage power in Finland

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Journal Title
Journal ISSN
Volume Title
School of Engineering |
Date
2013
Major/Subject
Vesitalous ja vesirakennus
Mcode
Yhd-12
Degree programme
Language
en
Pages
98
Series
Abstract
The discrepancy between electricity production and consumption asks for regulation power and energy storage capacities. In Finland regulation power is produced comparatively expensively by thermal reserve power plants and is imported. In future Finland has an increasing regulation power demand due to focus on nuclear and on wind power. Pumped storage power is up to date the only economically sound and environmentally compatible technology for large scale energy storage. Although this technology is largely used in other countries Finland has not any single pumped storage power plant in operation. The aim of this study is to evaluate applicability of pumped storage power for Finnish conditions. The built up PSP operation simulation model uses price spreads referred to a moving average energy price. With price series of Nord Pool for Finland in hourly resolution as input the model generates site specific turbining and pumping decision series determing operation benefit. As applicability of pumped storage power depends on site specific conditions possible pumped storage sites are identified and feasibility is evaluated in case studies. In iterative procedure operation scheme, design flow rate as well as hydraulically and electromechanical design 1S optimized. The plants are predesigned in conceptual and feasibility studies. Thereby technical, economic and environmental aspects are respected. The predesigned feasible PSP Tampere between large lakes has an installed power of 12 MW. Simulated annual performance is characterized by an increasing trend with large annual fluctuations. In Pyhäsalmi mine the pre-dimensioned PSP with 1400 m head and an installed power of 660 MW is highly feasible with a direct payback time of 5 years. The power is provided by two reversible multistage pump turbine units and by two dual units with Pelton turbine and multistage pumps. The dual units enable regulation within seconds and input power adjustment by hydraulic shortcut operation. The hourly resolution of the in the model used regulation energy price data leads herewith to an underestimation of pumped storage operation benefit. Average stable hardrock conditions in mine Pyhäsalmi allow drilling of penstock directly into hardrock. Detailed geological conditions have to be investigated in further studies. With good geological conditions and deep ore mines of large storage volume Finland has optimal conditions for underground pumped storage. Due to straight waterways high hydraulic efficiencies can be achieved in mines. On the other hand electromechanical efficiencies get reduced for deep mines due to the need for multistage pump turbines or pumps. Constructing of pumped storage power plants between large lakes requires large design flow rates due to usually low heads. Hydraulic losses are thereby considerable. Using large natural lakes environmental impacts of pumped storage is small with lake level fluctuations of some centimetres. The use of mines does not consume new surface areas. Compared to alternative technologies pumped storage power is free of greenhouse gas emissions. Sustainability requires energy storage capacities and the necessary infrastructure can also in Finland be realized by large scale pumped storage.
Description
Supervisor
Järvelä, Juha
Boes, R.
Thesis advisor
Aalto, A.
Ziller, A.
Keywords
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Citation