Martinlaakso’s electric boiler and thermal battery for Vantaan Energia (EPCM)

Rejlers was responsible for the full EPCM delivery (Engineering, Procurement and Construction Management) and acted as the principal contractor at the construction site. Our experts were in charge of project management, procurement, detailed engineering, construction management, site supervision and commissioning coordination.

Implemented between 2024 and 2025, the project was delivered in close collaboration with multiple stakeholders. Approximately 50 suppliers and contractors were involved, and including subcontracting chains, more than 500 professionals worked on-site over the course of the project.

– The Martinlaakso project was delivered using the EPCM model. EPCM offers flexibility, particularly when construction is carried out in connection with an existing plant. At the same time, it requires close cooperation between the client and the EPCM consultant. Collaboration with Rejlers worked very well, and we are satisfied with the final outcome, says Juuso Pulkkinen, Project Manager at Vantaan Energia.

The 60-megawatt electric boiler completed at Martinlaakso marks the beginning of a new era in Vantaan Energia’s heat production. Heat generation based on emission-free electricity enables district heat to be produced when electricity prices are low. The generated heat can either be supplied directly to the district heating network or stored in a 700-megawatt-hour thermal battery – the volume of stored water corresponds to approximately six Olympic-sized swimming pools.

The electric boiler has sufficient capacity to heat around 6,000 detached houses, replacing the use of solid biofuels while delivering improved cost efficiency and lower emissions. Thanks to the thermal energy storage, Vantaan Energia can further optimise heat production and make more effective use of periods of low electricity prices. The system also improves security of supply by reducing dependence on fuel availability and price volatility.

Together, the electric boiler and district heating battery form a core component of Vantaa’s emerging flexible and electrified heat production system. In addition to electric heat generation, the system is based on utilising excess heat, energy storage and waste heat recovered from the thermal treatment of non‑recyclable waste.

– The Martinlaakso project is an excellent example of how the EPCM model creates clear added value for the client. We were able to combine best practices from industrial project delivery, strong technical expertise and close cooperation with Vantaan Energia. The result is a solution that not only improves the efficiency of district heating production but also accelerates the entire sector’s transition towards a low‑emission and flexible energy system says Jussi Likitalo, VP Energy & Utilities, Industry division at Rejlers Finland.

Photos: Vantaan Energia