Preliminary design and environmental impact assessment for Estonia’s first pumped storage hydroelectric plant is underway under the guidance of Estonian energy company Eesti Energia.
The pumped hydro plant, planned for the industrial area of the Estonia mine in Ida-Virumaa, is a large-scale circular economy project, the construction of which uses limestone rubble and closed tunnels created during the mining of oil shale. It will have a capacity of up to 225MW.
The pre-design work is intended to specify the size and profitability of the investment. During the pre-assessment of the environmental effects, it will become clear which environmental requirements and conditions must be taken into account during its construction, Eesti Energia said.
The upper reservoir will be built on a tailings structure, and a closed mine will be used as the lower reservoir. The station is slated to begin operating in 2026.
The project is unique because, as far as Eesti Energia is aware, oil shale or coal mines have not been used as water reservoirs for hydroelectric power plants. In addition, the pressure head of the pumped hydroelectric plant is increased by reusing the tailings from the enrichment of the rock mass of the Estonian oil shale mine.
According to Margus Vals, a member of the board of Eesti Energia, the pumped hydroelectric power plant can offer various services to the energy markets, which makes it an important asset not only for the company, but also for the country.
Image credit: Eesti Energia
“Ensuring Estonia’s energy security and energy independence with our own assets is more important than ever before,” said Vals. “In light of the connection to the continental European electricity system, which is planned for 2026 at the latest, it is extremely important that the necessary energy markets and production or storage assets are created in the Baltic States, with which security of supply can be ensured in the greenest and most affordable way possible.
“The pumped hydroelectric power plant offers a solution to several challenges at the same time, because in addition to ensuring security of supply, it promotes the introduction of renewable energy, helps to achieve zero-waste production, and reuses industrial territory.”
“Renewable energy production is inherently variable, and the production forecast can differ widely from what wind and solar farms actually produce,” Vals noted. “Even two hours before the moment of production, the production forecast can differ significantly from the actual production. To cope with this, the power system must have generation assets that can respond as quickly to ensure the balance and frequency of consumption and production. One of the technologies that enables such a quick response is a modern pumped hydroelectric power station, which is able to load itself up and down in a matter of minutes.”