One of the world’s largest and most advanced district heating systems turns 100 today. HOFOR’s network in Copenhagen has evolved from coal-fired steam to large-scale heat pumps and renewable energy – and now supplies heat to almost every household in the city.
25 September 2025 | HOFOR A/S | Press Release
From a brilliant idea to a world-class system
It all began in 1925, when engineers at the Gothersgade power plant decided to use surplus heat from electricity production to warm nearby buildings. That idea laid the foundation for Copenhagen’s district heating system – today among the most extensive and efficient anywhere in the world.
HOFOR’s Director of Energy, Gorm Elikofer, at the new Tietgensgade heat pump, which recycles surplus cooling heat to supply 3,000 homes. Photo: HOFOR
HOFOR (Greater Copenhagen Utility) now operates nearly 3,000 kilometers of district heating pipes under the capital – the equivalent of the distance from Copenhagen to Portugal – ensuring reliable and affordable heat for residents.
“In the past, people carried petroleum and coke up the stairs. Thanks to district heating, we can simply turn the thermostat,” says Gorm Elikofer, Director of Energy at HOFOR. “We were among the first cities to phase out coal, and today 85% of our district heating is CO2-neutral. Our goal is to reach 100% in the early 2030s.”
Investing in electrification
To reduce biomass use and further decarbonize, HOFOR is investing DKK 3–5 billion in electrification. Plans include up to 300 MW of large-scale heat pumps, 550 MW of electric boilers, and new heat storage facilities by 2033.
“We are electrifying district heating to make it cleaner, more flexible, and more resilient – while tapping into wind and solar power when it’s available,” Elikofer explains. “This is about securing affordable heat for Copenhageners, protecting the environment, and ensuring high supply security for the next 100 years.”
Challenges to overcome
Scaling up requires both technical and urban planning solutions.
“Large heat pumps are still a relatively new technology at this scale,” says Elikofer. “Buildings must also adapt to lower supply temperatures, which means owners need to invest – but they will save both money and CO2 in the long run. And of course, space in the city is limited, so new facilities must be carefully integrated into the urban landscape.”
Another key challenge is access to the electricity grid. HOFOR is working with partners CTR, VEKS, and Energinet to secure the green electricity needed for its transition.
Fact Box:
HOFOR’s electrification roadmap
- First of ten planned large-scale heat pumps came online in 2024 at Tietgensgade (15 MW).
- Next in line: a 30 MW wastewater heat pump at Kløvermarken Pump Station and a 20 MW seawater heat pump in Nordhavn.
- The new Svanemøllen Energy Center will feature a 30–50 MW seawater heat pump, a large electric boiler, and heat storage facilities.
- Together with Ørsted and CTR, HOFOR is exploring the addition of 30 MW of heat pumps, 200 MW of electric boilers, and heat storage at the H.C. Ørsted Power Plant.
- Heat storage facilities are planned across several sites, enabling better use of renewable electricity when wind and solar production peaks.
Read more about HOFOR here.
Fact Box:
Heat pumps and electric boilers
- Electric boilers convert electricity directly into heat with nearly 100% efficiency.
- Heat pumps extract thermal energy from sources such as seawater, wastewater, geothermal energy, or surplus heat from data centers and supermarkets. They typically deliver 3–4 units of heat per unit of electricity consumed.
- Together, these technologies make it possible to produce low-cost, electricity-based heat when renewable power is abundant – and store it for later use.
You can find all our district energy news here.