A sustainable vision for Tallinn
Tallinn, the capital of Estonia, aims to achieve net-zero emissions by 2050, in line with EU climate targets. As urban centers worldwide seek ways to decarbonize heating, Estonia’s largest district heating provider, Utilitas, is leading the charge with forward-thinking solutions. the Väo energy complex has taken a decisive step towards renewable and low-emission district heating with the installation of four powerful GEA heat pumps in the biomass combined heat and power (CHP) plant.
These cutting-edge heat pumps, including the first commissioned innovative GEA Grasso L XHP screw compressor, sit at the heart of this initiative. By efficiently reusing waste heat that comes from biomass CHPs, they reduce the need to use fossil fuels at peak demand, lower CO₂ emissions and provide stable, cost-effective heat to approximately 8,000 homes and businesses.
Embedded in a global approach
District heating is an essential component of urban development, integrating renewable energy and energy-efficient solutions. According to the cited IEA roadmap, district heating networks can support pathways toward lower-carbon heating and cooling. In its Roadmap for the Global Energy Sector, the IEA targets 350 million connections in cities globally by 2030.
District heating networks are also fuel-flexible, which means that the heating and cooling supply can change over time – allowing the transition to renewable energy sources over time. And that’s exactly what urban decision-makers, like the ones in Tallinn, are working on: How can we shift the supply of our district heating system to more and various renewable energy sources to accelerate our energy transition?But when we talk about supplying energy to cities, there’s more at play than sustainability alone.
The challenge: Provide reliable, affordable and low carbon heat
With 60% of Estonia’s buildings depending on district heating, reliability of the heat supply is critical. “District heating makes up more than half of the thermal energy needed in Estonia,” says Robert Kitt, CEO of Utilitas Tallinn. “We provide heat for up to 400,000 individuals, about one-third of the population. That makes our strategic challenge threefold. First, we have to secure its supply, because the heat needs to be provided in winter when it’s really cold. Secondly, we have to provide the heat at an affordable and stable price because nobody can be left behind when it comes to thermal energy or heat. And third, we have to provide energy while reducing the environmental impact for future generations.”
The Utilitas Väo energy complex uses a highly efficient biomass CHP plant and four GEA heat pumps to supply district heating to around 8,000 homes and businesses in Tallinn, Estonia.
When choosing to work with GEA, we knew we had a reliable partner who would offer an efficient and sustainable solution.
Robert Kitt
CEO, Utilitas Tallinn
The solution: GEA ammonia heat pumps at the core
A significant addition to the already highly efficient biomass CHP plant, GEA’s four heat pumps redefine energy efficiency. The system includes three GEA Grasso LT screw compressors (XB model) and the groundbreaking new 70-bar GEA Grasso L XHP screw compressor, based on decades of refined GEA Grasso technology.
“These heat pumps adjust operating temperatures dynamically to 65°C in summer, 85°C in winter and up to 95°C when required,” points out Mindaugas Lazdauskas, Director Sales Baltics at GEA Heating & Refrigeration Technologies. “With the new GEA Grasso L XHP, we’re delivering high-temperature performance and efficiency that make large-scale decarbonization projects like Tallinn’s a reality. Its unmatched efficiency and capacity at high pressure make it the ideal fit for Utilitas’ drive toward cleaner and more efficient district heating network,” adds Ron Hoffmann, Product Manager Screw Compressors at GEA Heating & Refrigeration Technologies.
GEA heat pump plant at Utilitas Väo energy complex, Tallinn, Estonia.
The natural refrigerant ammonia further enhances the energy efficiency of GEA’s heat pumps. “Ammonia has been used as an effective refrigerant for over 150 years and can be operated safely when systems are appropriately designed, installed, maintained and operated,” notes Kenneth Hoffmann, Manager Heat Pumps at GEA Heating & Refrigeration Technologies. “Its thermodynamic properties and long lifespan make it a long-term solution aligned with evolving refrigerant regulations.”
The impact: Results of first heating season
Since their installation in 2023, the GEA heat pumps have demonstrated significant environmental and economic benefits. “During the first heating season we produced approximately 80,000 MWh of heating energy,” says Sang. “Thanks to the heat pumps, we use less natural gas and cut CO₂ emissions by 20,000 tons per year.”
In addition to emissions reduction, efficiency gains have been remarkable. “We reached a coefficient of performance or COP of more than four,” adds Sang. These results provide a case study for cities assessing similar district-heating modernization projects.
We reached a coefficient of performance – or COP – of more than four.
Indrek Sang
Project Team Lead, Utilitas Tallinn
Proven success with diverse heat sources
The success of this project is not limited to Tallinn. Other European cities are also prioritizing district heating based on renewable and waste heat sources. “One of the fascinating aspects of district heating is the diversity of heat sources,” says Hoffmann. “At GEA, we’ve done district heating projects based on seawater in Copenhagen. In Malmö, sewage was used as an energy source to heat 10,000 households in the south of Sweden. In Gateshead of UK, our heat pumps are central to a project that uses energy from naturally heated mine water to supply district heating, marking the largest mine water heat recovery scheme in the country. More to the south of the U.K., the Bunhill Heat and Power Network in central London extracts waste heat from the London Underground to warm 1,350 homes, two leisure centers, and a school in Islington. GEA now has over 50 district heating projects across Europe and North America and this project here in Tallinn is among the largest.”
Heat pumps can support city net-zero strategies by reducing reliance on fossil-fuel heating, depending on electricity supply and system design.
Kenneth Hoffmann
Manager Heat Pumps, GEA Heating & Refrigeration Technologies
Cities as orchestrators of change
Heat pumps are gaining traction in policy discussions as well. The EU’s Green Deal prioritizes district heating modernization, and funding opportunities for heat pump integration are expanding. Cities that adopt heat pump-based solutions today position themselves as leaders in the future energy landscape.
“The European transition towards resource-efficient energy starts with the cities,” Hoffmann says. “As urban populations grow and energy demands rise, projects like Väo set the standard for district heating’s future and stand as a powerful example of how innovation and collaboration can drive meaningful change.” With a focus on efficiency, reliability and environmental responsibility, GEA remains a trusted partner in engineering solutions that not only heat homes but also help reduce CO2 emissions.
GEA scope of supply:
- GEA solution: 4 GEA heat pumps
- Heating capacity: 24 megawatts
- Heat source: energy from biomass boilers 2nd stage of flue gas condenser (26°C to 38°C)
- Heat sink: District heating water (60°C to 85°C)
- COP: > 4
- Compressor type: 3 GEA Grasso LT screw compressors and 1 GEA Grasso L XHP screw compressor
- Natural refrigerant: Ammonia
Award-winning GEA L XHP Compressor
The GEA Grasso L XHP compressor has been recognized as an Innovative Product of Refrigeration 2025 by the Chinese Association of Refrigeration (CAR).
This award underscores our commitment to industry-leading energy efficiency and industrial decarbonization, setting a new benchmark in high-temperature ammonia heat pump technology.
