Mapping the potential for pumped storage using existing lower reservoirs

The increasing utilization of wind and solar power sources to lower CO2 emissions in the electric sector is causing a growing disparity between electricity supply and demand. Consequently, there is a heightened interest in affordable energy storage solutions to address this issue. Pumped Hydropower Storage (PHS) emerges as a promising option, capable of providing both short and long-term energy storage at a reasonable cost, while also offering the advantage of freshwater storage. To identify potential PHS locations in Brazil existing hydroelectric reservoirs as the lower reservoirs, we employed an innovative methodology that combines (i) plant-siting model that leverages high-resolution topographical and hydrological data to identify the most promising sites for further studies. (ii) An economic methodology was applied to configure PSH projects identified by the plant-siting model in terms of their installed capacity and discharge time, and to select the most attractive projects. (iii) A comprehensive analysis of the socio-environmental impacts of the projects was carried out, which enables the elimination of projects with severe impacts. Results created a ranking of 5600 mutually exclusive projects by net present value (NPV). The highest NPV is 2145 USD which refers to a PHS plant in the Doce Basin and Salto Grande dam as the lower reservoir. The upper reservoir stores 0.36 km3 of water and a 75 m high dam, the PHS has a 2 km tunnel, a 1 GW power capacity and discharge rate of 220 h. The paper shows a vast potential for weekly, monthly, and seasonal PHS with existing lower reservoirs in Brazil.