Sammendrag
The solar and wind energy production in the European countries has been growing in the last years and the need of energy storage too. One of the most competitive technologies already available for large-scale balancing is pumped hydro storage with fixed operating point and one of the most promising improvements is the variable speed operation. The purpose of this research is to investigate the potential of utilizing three Norwegian revamped hydropower plants for smoothing of the offshore wind energy production in the North Sea. The investigation is carried out using two developed optimization algorithms with different time horizons and environmental constraints, managing up to seven years of wind energy production from the North Sea and seven years of reservoirs natural inflows and outflows.