Pumped storage and new solar container are developing rapidly

Global hydropower development is entering a new phase, with the latest IEA Renewables 2025 report forecasting both steady growth in conventional capacity and a sharp rise in pumped storage installations as systems adapt to record levels of variable renewable generation. From underground caverns in Austria to record-speed builds in China and long-duration storage studies in the US, pumped storage hydropower is re-emerging as the backbone of renewable integration. A wave of projects in 2025 shows how engineers are adapting old principles to new system needs. It’s called pumped storage and it’s the largest and oldest form of energy storage in the country, and it’s the most efficient form of large-scale energy storage. Pumped storage hydropower has grown rapidly over the last fifty years, first to store energy produced by thermal and nuclear stations during off-peak hours when demand is low, and since the turn of the century to deal with the intermittency of wind and solar power generation.