Building scenarios for the utilisation of the hydro storage and pumped storage potential in Norway and for the provision of balancing and storage to the European electricity market was the first major step in the HydroBalance Project. The scenarios define the scope, boundary conditions and framework for the analyses to be carried out in other work packages, and build the basis for the development of the roadmap for large-scale balancing and storage from Norwegian hydropower. We developed four scenarios for the potential future roles of Norwegian hydropower by the year 2050. The scenarios primarily differ from each other in i) the degree of integration of Norway with the power markets and grid of Central Europe and the UK, ii) the volume of balancing provided by Norwegian hydropower, and iii) the type of balancing in terms of time horizons, from seconds and minutes to days and weeks. Scenario A – Small Storage includes medium integration, small volume and balancing over all time horizons; scenario B – Big Storage high integration, large volume and all time horizons; scenario C – Niche Storage medium integration, medium volume and long time horizons only; and scenario D – Nordic Storage low integration, small volume and all time horizons.