New heat pump plant using innovative technology begins operation in Eiranranta – recovering heat from water as cold as 5°C
A new heat pump plant has begun operation in Eiranranta, Helsinki. The facility produces district heating and district cooling from waste energy contained in treated wastewater. The plant recovers heat from very low-temperature water, the energy from which has already been utilised twice in district heating production at the Katri Vala heat pump plant. Each year, the Eiranranta plant produces approximately 300 gigawatt hours of district heating, equivalent to the annual heating demand of a city the size of Rauma.
The Eiranranta heat pump plant’s three heat pump units produce district heating with a capacity of around 90 megawatts and district cooling with a capacity of around 60 megawatts. The facility also includes a 30-megawatt electric boiler.
“Electrification of district heating production is increasing the importance of heat pumps within Helsinki’s energy system. Bringing the Eiranranta heat pump plant into operation increases low-emission energy production, strengthens the self-sufficiency and security of supply of the energy system, and supports the long-term competitiveness of district heating. At the same time, it helps meet the growing demand for district cooling,” says Timo Aaltonen, Helen’s Director of Heating and Cooling.
Eiranranta harnesses waste heat in a new way
The Eiranranta heat pump plant is located in Munkkisaari in southern Helsinki, approximately 45 metres below ground. Built partly within existing underground rock caverns, the facility makes use of subterranean space to produce heating and cooling in the heart of the city.
Part of the treated wastewater utilised at Eiranranta has previously passed through the Katri Vala heat pump plant, where some of its thermal energy was already recovered. At Eiranranta, the remaining heat is extracted before the water is discharged into the sea.
The solution is based on new heat pump technology that makes it possible to recover energy from extremely low-temperature water, even at temperatures as low as 5°C. If the water in the wastewater tunnel is occasionally too cold for the heat pumps, the electric boiler can raise its temperature to a level suitable for heat pump operation. This ensures reliable production even during the coldest periods.
The three-stage heat recovery process lowers the temperature of the water discharged into the sea, reducing the thermal load on the Baltic Sea.
“At Eiranranta, we recover energy from very cool water and make use of heat that has, in part, already been utilised twice, giving it a third use. Efficient utilisation of waste heat reduces the need for other forms of heat production and supports the transition towards a low-emission energy system,” Aaltonen continues.
The experience gained at Eiranranta may support the deployment of similar solutions in Finland and elsewhere in Europe in areas where waste heat sources and district heating networks are available.
Heat pumps reduce the need for combustion-based energy production
Helen phased out the use of coal in its energy production in 2025. The Eiranranta heat pump plant forms part of the company’s investments in building an energy system based on heat pumps, electric boilers, and waste and ambient heat sources.
The goal is to achieve net-zero emissions and move away from combustion-based energy production by 2040.
The Eiranranta heat pump plant is one of the most significant investments aimed at reducing emissions from Helsinki’s heating system. The project has received energy investment support granted by the Ministry of Economic Affairs and Employment of Finland and funded through the European Union’s NextGenerationEU programme.
