Vantaan Energia Advancing District Heating with the World’s Largest Underground Thermal Energy Storage
Vantaan Energia is implementing a system-level approach to district heating electrification - combining large-scale electric boilers with the world’s largest seasonal underground thermal energy storage facility. As part of this strategy, Parat Halvorsen will deliver two 60 MW high-voltage electrode boilers, designed for operation at 20 kV and 10 barg. The boilers provide fast, efficient and emission-free heat production and are fully integrated into Vantaan Energia’s district heating network.
Customer: Vantaan Energia
Location: Vantaa, Finland
Delivery: 2 × 60 MW High Voltage Electrode boilers
Voltage: 20 kV
Pressure: 10 barg
Type: Hot water
Combining Electric Boilers and Seasonal Thermal Storage for a Resilient Heat Supply
Vantaan Energia is one of Finland’s leading energy companies, supplying district heating and electricity to the city of Vantaa. With ambitious climate targets and a clear strategy to phase out fossil fuels, the company is developing new solutions to electrify heat production while maintaining security of supply in a cold Nordic climate.
Rather than relying on a single technology, Vantaan Energia is implementing a system-level approach to district heating electrification - combining large-scale electric boilers with the world’s largest seasonal underground thermal energy storage facility. This enables efficient use of renewable electricity and stable heat delivery throughout the year, even during periods of high electricity prices and peak demand.
High-Capacity Electric Boilers as a Core Heat Production Asset
As part of this strategy, Parat Halvorsen will deliver two 60 MW high-voltage electrode boilers, designed for operation at 20 kV and 10 barg. The boilers provide fast, efficient and emission-free heat production and are fully integrated into Vantaan Energia’s district heating network.
The project builds on Vantaan Energia’s previous commissioning of a 60 MW electric boiler, also delivered by Parat Halvorsen, marking another significant step in the company’s transition towards electrified and low-emission heat production.
Electric boilers play a key role in replacing fossil-based heat sources and reducing CO₂ emissions. Their ability to respond rapidly to changes in demand and electricity market conditions makes them well suited for modern, flexible energy systems.
Seasonal Thermal Storage Unlocks Year-Round Value
A defining feature of the Vantaa project is the integration of electric boilers with large-scale seasonal thermal energy storage. Heat produced during periods of favourable electricity prices or high renewable power availability can be stored underground and utilised months later during the heating season. This approach provides several strategic advantages:
- Reduced exposure to short-term electricity price volatility
- Improved utilisation of renewable electricity
- Increased flexibility in heat production planning
- Enhanced security of supply during cold winter periods
By shifting heat across seasons, Vantaan Energia ensures that electric boilers are not limited to opportunistic use, but become more of a stable and reliable component of the district heating system year-round.
Implementation and System Integration
Parat Halvorsen’s electrode boilers are designed for demanding district heating applications, where reliability, precise control and seamless integration are essential. The delivered solution includes the boiler units and associated electrical systems, ensuring safe and efficient operation within Vantaan Energia’s existing infrastructure.
The boilers support both direct heat delivery to the network and heat production for storage, enabling flexible operation aligned with market conditions and long-term energy planning.
Enabling the Transition to Low-Emission District Heating
The Vantaa project demonstrates how electrification of district heating can be successfully implemented in cold-climate regions when supported by smart system design. By combining high-capacity electric boilers with seasonal thermal storage, Vantaan Energia is building a future-proof heating system that reduces emissions while maintaining reliability and cost control.
Parat Halvorsen is proud to support this transition by delivering proven electric boiler technology that enables industrial-scale electrification and contributes to a more sustainable energy system.
Meet us at Energia 2026!
PARAT will be present at Energia 2026 in Tampere from 20–22 October. Visit us at Stand A522 to meet our team and experience the IEH Compact, our fully integrated skid-mounted electric hot water boiler for industrial and district heating applications.
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