Developers SENS and Callio working on hybrid BESS, pumped hydro and PV project in Finland

May 22, 2024
LinkedIn
Twitter
Reddit
Facebook
Email

Developers SENS and Callio have revealed a hybrid project in Finland which could combine a battery energy storage system (BESS), pumped hydro energy storage and solar PV technology.

The companies have struck a principal agreement to develop the project at the decommissioned Pyhäsalmi mine in Pyhäjärvi, central Finland.

The location will allow the project to utilise existing grid infrastructure and integrate with the nearby Callio Business and Olcconen Green Industrial parks, SENS (Sustainable Energy Solutions Sweden Holding) said.

SENS is primarily a BESS project developer active mostly in Sweden while Callio is owned by the Pyhäjärvi Municipality.

This article requires Premium SubscriptionBasic (FREE) Subscription

Enjoy 12 months of exclusive analysis

Not ready to commit yet?
  • Regular insight and analysis of the industry’s biggest developments
  • In-depth interviews with the industry’s leading figures
  • Annual digital subscription to the PV Tech Power journal
  • Discounts on Solar Media’s portfolio of events, in-person and virtual

Or continue reading this article for free

The BESS portion of the project is designed for a power output of 85MW and is already at the ready-to-build (RTB) stage, with commercial operation expected in 2025. It will provide frequency response services and participate in the energy arbitrage market, SENS said.

The pumped hydro energy storage (PHES) unit would be a 75MW/530MWh, 7-hour system built underground though a timeline for its development, construction or operation was not provided. The third stage of the project is a solar PV plant but details on size or timeline were not provided either.

The Pyhäsalmi mine is the deepest metal mine in Europe at 1,444 metres deep and its underground mine operation and copper and zinc processing ended in 2022, although some above-ground refining is set to continue until 2025. The underground mine is currently in the closure and decommissioning stage. It is owned by Canadian company First Quantum Minerals.

Financing for the project will be shared between SENS, Callio, the Calllio Business and Olcconon business and industrial parks, UB Corporate Finance and the Finnish government via €26.3 million (US$28.5 million) in subsidies for foreign direct investments (FDI) in renewable energy.

Axpo, a Switzerland-headquartered independent power producer (IPP) and energy trading firm, has also launched projects in neighbouring Sweden, commissioning a 20MW project in February which was acquired from SENS. A month prior SENS secured the land for another 40MW BESS project.

Sweden and Finland are leading BESS deployments in the Nordic region largely off the back of a lucrative ancillary services market.

Read Next

October 17, 2025
The New South Wales Independent Planning Commission has approved Ark Energy’s 3,148MWh Richmond Valley solar-plus-storage project in Australia.
October 15, 2025
A flurry of grid-scale BESS project progress totalling more than a combined 1.5GWh in the past week, from Renalfa in Bulgaria, Engie in Romania, Nala Renewables in Finland and Metlen in Greece.
October 14, 2025
Spanish IPP Grenergy has begun construction on a 340MW solar project with 960MWh of energy storage in El Cabrero, located in Chile’s Biobío region. 
October 13, 2025
Queensland’s Energy Roadmap 2025 suggests that by 2030, up to 4.3GW of short-duration energy storage could be operational.
October 3, 2025
WaterNSW, the state-owned water supplier to New South Wales, Australia, has selected three dams as suitable sites for pumped hydro energy storage (PHES) developments.

Most Popular

Email Newsletter