March 17, 2021

Ramboll among the winners of the Helsinki Energy Challenge

Hot Heart – a series of islands with the dual function of storing thermal energy storage and serving as a hub for recreational activities – has won the Helsinki Energy Challenge, which aims to decarbonize the heating system of the Finnish capital by 2030. Ramboll was part of the project coordinated by CRA-Carlo Ratti Associati in collaboration with Transsolar, Danfoss Leanheat®, Schneider Electric, OP Financial Group, schlaich bergermann partner and Squint/Opera.

Hot Heart was developed as part of the Helsinki Energy Challenge organized by the municipality of Helsinki to accelerate the city’s transition towards carbon-neutrality in heating by 2030. The competition was attended by 252 teams from around the world and the 10 best entries were selected for the final. Ramboll delivered the technical ideation and design of the proposed solution as part of the team led by the Italian design and innovation agency Carlo Ratti Associati.
Hot Heart is based on an archipelago of heat-storing basins with the dual function of storing thermal energy and serving as a hub for recreational activities. The “islands” will also be home to tropical forests and ecosystems from around the world, giving the Finnish capital additional public space and a new educational attraction. The project is highly adaptable and could be replicated by other cities with similar climatic characteristics pursuing sustainable heating solutions.
Located off the coast of Helsinki, Hot Heart will be the largest infrastructural facility of its kind. The project consists of a set of 10 cylindrical basins, each measuring 225 meters in diameter. They collectively can hold up to 10 million cubic meters of water. The system functions like a giant thermal battery: low- or negative-cost renewable energy is converted into heat, stored in the tanks, and withdrawn into the city’s heat distribution channels during the winter.
“There are excellent conditions for wind power generation Finland. Wind power generation has evolved in recent years and is, in fact, the cheapest way to generate electricity. Further, electricity generated by wind power using heat pumps is also the cheapest way to produce district heat”, says Jouni Laukkanen, Director at Ramboll Finland and continues:
“However, it is not always windy. Thanks to the proposed huge heat storage, the use of electricity in district heating production can be timed to windy times and the annual variation in heat demand can be significantly balanced. A similar solution would be applicable to all district heating networks”.
The system, operated by artificial intelligence, synchronizes the production and consumption of thermal energy, which helps stabilize the national energy grid in relation to fluctuating supply. The whole system is expected to cover the entire heating needs of Helsinki, estimated at 6,000 GWh, by the end of the decade, all without any carbon emissions and at an estimated cost 10% lower than today.
In addition to its thermal storage properties, Hot Heart doubles as an accessible recreational venue. Four of the 10 hot water reservoirs are enclosed in transparent domes containing the “Floating Forests” – tropical ecosystems from the world’s key rainforest zones naturally heated by the basins underneath. The “Floating Forests” provide visitors with a place to socialize and enjoy the sunlight, even in the harsh Nordic winter, thanks to the use of powerful Sun-like LED Technology. They create a unique public space for residents and provide an attraction to international travelers.
Hot Heart is planned to enter the master planning phase in 2021 and projected to be fully implemented in 2028.
Watch a video presentation of Helsinki’s Hot Heart (Credit: Squint/Opera)
More information about the proposal
CRA-Carlo Ratti Associati (Design)
Ramboll (General Engineering) – Jouni Laukkanen, Mika Kovanen, Kreetta Manninen
Transsolar (Climate Engineering) – Monika Schulz, Thomas Auer
Danfoss Leanheat® (Demand Management Engineering) – Oddgeir Gudmundsson, Jukka Aho, Juho Nermes, Lauri Leppä, Nico Klecka
Schneider Electric (Technology Partner for Sustainability and Energy Efficiency) – Jani Vahvanen
OP Financial Group (Financial Analysis)
schlaich bergermann partner (Lightweight Structural Engineering) – Mike Schlaich, Boris Reyher
Squint/Opera (Communications Partner)