Helsinki Energy Challenge (FI)

Helsinki’s Hot Heart is a system that uses seawater heat pumps to convert primarily carbon-free electrical energy into heat. It helps decarbonize the Helsinki district heating system while providing a beneficial balancing effect on the national grid of Finland—so that even more renewables can be used in the future.

Helsinki’s Hot Heart is a flexible system made of 10 cylindrical reservoirs of 225 m diameter filled with hot seawater (total volume approximately 10 million m3), which can receive different energy sources as input. Electric energy is converted into thermal energy using heat pumps exchanging with the sea. Alternatively, sources of heat are directly plugged into district heating. The output of Helsinki’s Hot Heart is heat that can be distributed across the existing district heating system.

Our calculations show that we are able to cover the full heating demand of the city of Helsinki, estimated at 6,000 GWh at the end of the decade, without any carbon emissions.

But there is more… In addition to providing carbon-free heating to the people of Helsinki, our system features a number of exciting benefits!

First, Helsinki’s Hot Heart will use electric energy when it is cheap, contributing to balancing the national grid as it moves toward a higher percentage of renewable energy generation.

Second, four cylinders of Helsinki’s Hot Heart, covered with tropical forests and year-long hot pools under an inflatable structure, will create a new, global attraction for the city.

Such an attraction would embody an ideal life familiar to Finnish culture: island, nature, and ‘Jokamiehen Oikeudet’ – albeit transposed into a tropical and sunny climate.

Third, Helsinki’s Hot Heart could become a model for cities around the world – cementing Helsinki as a city that always pushes the boundaries of innovation and ingenuity.