Solutions for future district heating systems – The Helsinki Energy Challenge

The winners of Helsinki Energy Challenge are all presenting solutions tackling the challenge on how to decarbonise a district heating system. Get inspired of the winners and finalists who all created flexible and resilient systems for the future.

The City of Helsinki have arranged a year-long international Helsinki Energy Challenge to find future-proof solutions to heat the city during decades to come. The competition attracted 252 proposals from 35 countries. An international jury has selected four winners from the ten finalists in the Helsinki Energy Challenge, which were announced in March 2021. The awarded proposals illustrate the diversity of the challenge and the diversity of approaches necessary to achieve a flexible and resilient system.
Below a short presentation of the four Award winners.

• HIVE, a flexible plan, based on proven technologies and solutions, such as seawater heat pumps, electrical boilers, solar thermal fields and demand side management measures; the plan is capable of integrating new technologies if and when these emerge.
• Beyond fossils, an energy transition model based on open and technology neutral clean heating auctions, paving up the path to carbon neutral Helsinki in a flexible and innovation enabling way. According to current technology cost assumptions, the main new technologies would be heat pumps using ground, air, water and excess heat streams as heat sources.
• Smart Salt City, a solution that melds a novel thermochemical energy storage and artificial intelligence with commercially available energy technologies. We keep the existing DHS as the backbone for the city to which we link several heat sources. One of the new key sources of energy in our proposal is the utilization of waste heat. The largest one of these would be waste heat from the nearby industrial area. In addition, heat pumps utilizing sewage water, other low temperature heat sources, solar, outdoor air and sea water are expected to provide a substantial part of the heat demand.
• Helsinki’s Hot Heart, a flexible system made of 10 floating reservoirs filled with 10 million cubic meters of hot seawater that can receive different energy sources as input. Four of the cylindrical tanks that make up Helsinki’s Hot Heart would be enclosed with inflatable roof structures to create a new leisure attraction. Electric energy is converted into thermal energy using heat pumps exchanging with the sea. Alternatively, sources of heat are directly plugged into district heating.