Power-modulated pumping system for the hydraulic storage of electricity generated from non-dispatchable renewable energy sources

Power-modulated pumping system for the hydraulic storage of electricity generated from non-dispatchable renewable energy sources

Electricity generation is now heavily influenced by climate change and the need to reduce greenhouse gas emissions. The rise in CO2 levels over the past 30 years necessitates a shift toward more sustainable sources, particularly renewable ones. However, the most widespread sources—photovoltaics and wind power—have a limitation: they depend on environmental conditions that vary in space and time, such as solar radiation and wind. Spatial variability affects the location of power plants, but it can be managed through high-voltage power lines, which transport energy between different areas of production and consumption. Conversely, the temporal regulation of the energy produced—that is, its storage from non-dispatchable renewable sources (NDS)—remains an open challenge in research. There are various methods of energy storage. In Italy, two complementary strategies are envisaged for energy storage: lithium-ion batteries and hydraulic pumping into reservoirs located above hydroelectric production sites. While batteries avoid the construction of new reservoirs, they present environmental challenges throughout their entire life cycle. Pumped-storage hydroelectric plants, on the other hand, maintain a strategic role, also due to the benefits they offer in terms of the stability and quality of the electric grid.

The main objective of the project is to increase the penetration into the national grid of electricity generated by small- and medium-scale FRNP plants (1–100 MW), through the use of combined pump-turbine plants, focusing primarily on solutions related to the operation of pumps with variable flow rates and constant head.

We intend to conduct a numerical study of hydraulic pumps using the commercial software Ansys-CFX to investigate the potential use of hydraulic control devices designed to maintain a constant head at a given flow rate, as is similarly done in hydraulic turbines (for example, a “slider” that adjusts the width of the turbine runner based on the flow rate).