Energy can be produced from mixing waters with different salinity in reverse electrodialysis (RED). Technological improvements make RED gaining momentum as a technically viable option for baseload renewable energy generation. In this paper a model is presented for three different RED applications in terms of upscale potential based on experimental data in the probabilistic software GoldSim. For a project life of 30 years (including a 5 year pilot phase), the economics and avoided CO2 emissions of such a power plant for three different price scenarios and three different feed solutions are examined. Subsequently an evaluation is carried out of the upscale potential, the economic break-even membrane price of a large scale RED power plant is quantified, identifying the most influential inputs through a sensitivity analysis. Furthermore, future performance and price developments are incorporated in the model and a comparison is made of a RED power plant with other conventional and renewable energy sources in terms of the Levelised Cost Of Electricity (LCOE) index. Brine applications seem to be closer to economic viability with the present state of technology and an optimistic membrane pricing scenario, but can only be upscaled to the order of 1 MW. River and seawater are not yet economically attractive but have an upscale potential close to 290 MW for the Dutch context. However, considering future development in membrane performance and price, the LCOE for electricity generation with river and seawater using RED is competitive to other renewable energy sources such as biomass and wind.