The Evanger hydro power scheme is located in Western Norway, close to Bergen. The main plant is the Evanger power plant, with a head of 770m. The small Askjelldalsvatn is the intake reservoir for this power plant. The higher located Holskardvatn is connected to Askjelldalsvatn via a tunnel system. It is used as a seasonal storage reservoir to provide water for the Evanger plant in winter. The energy potential between these reservoirs is not used and this thesis studies the possibilities for a hydropower plant that utilizes this potential for the production of electricity. A pump storage plant is found to be the best solution: the water is pumped up from Askjelldalsvatn to Holskardvatn in summer and utilized for energy production in winter in both the new plant and the existing Evanger plant. The high energy price in winter is the main reason for the superior economic results of a pump storage plant.