Salmisaari Seawater Heat Recovery Tunnel
This overview was generated with AI from the public sources listed below and checked against them before publication. It has not had a complete human fact-check — treat it as a starting point and follow the sources.
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Helen, with alliance partners Acciona and YIT, is boring about 26km of tunnels from Salmisaari — a 17km seawater intake bore and a 9km discharge tunnel — to feed new heat pumps supplying Helsinki's district heating network. The €400m project is expected to enter service around 2029, replacing capacity lost when Helsinki closed its last coal plant, also at Salmisaari, in April 2025.
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The strongest source is the operator's or the city's own reporting — an official report, dataset or press release. It grades who did the looking — not how well the project went. All four grades →Sources
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1001 Smart Cities (2026). “Salmisaari Seawater Heat Recovery Tunnel” — Helsinki, Finland. The Smart City Atlas. https://1001smartcities.org/projects/helsinki-clean-heat/ (last verified 2026-07-24). Data: CC BY 4.0.
The underlying data is free to reuse with attribution — see the open data page.