Sustainable Energy Solutions Sweden Holding AB announced a principal agreement with Callio, a Finnish multidisciplinary development company, to initially develop an underground pumped hydro storage and battery energy storage system at the town of Pyhajarvi, Finland. SENS also sees opportunities to expand the project with a solar plant that would further increase the grid capacity in the region. The integration of BESS with UPHS, and PV, at the Callio Business park and Olcconen Green Industrial park aims to enhance energy management efficiency and profitability, offering substantial financial returns while supporting sustainable development.

One of the Pyhasalmi mine's core strengths is its strategic geographical location, which provides direct access to the established electrical grid, ensuring seamless integration and optimal functionality. There are three separate projects within the scope of the total project, being the follow: With all necessary permits already secured, including agreements on grid connections, the BESS is in a ready-to-build phase, with battery systems expected to be operational within a year, ready to deliver 85 MW capacity to the grid, the frequency market or the arbitrage market, and enabling immediate revenue generation using existing infrastructure. The full project is slated to commence in 2025.

The underground pumped storage hydro (UPHS) system has an estimated storage capacity of 530 MWh and a maximum output of initially 75 MW. Its primary objective is to balance energy supply and demand using the existing mine infrastructure, thereby contributing to grid stability, and reducing carbon emissions. The third aspect of the project is the establishment of PV's in the area, which would further enhance sustainable energy production and increase the total capacity of the project.

The project involves a consortium consisting of SENS, which offers the BESS and UPHS solutions; Callio, developer Callio Business park andOlcconen green industrial park areas; UB Corporate Finance Ltd. who will act as financial partners for this development, while Axpo is considered to be responsible for energy trading in relation to the assets. In addition to this, The Finnish government has also allocated funds of EUR 26.3 million linked to foreign direct investments for initiatives within renewable energy.