Keeping the city warm efficiently
District heating is one of the most carbon efficient and flexible ways to produce and supply energy locally, because it cuts out much of the waste products associated with centralised production of power. With the integration of renewable energy like biomass, wind energy and geothermal energy as replacements for fossil fuels in the system, further reductions of carbon emissions have been achieved.
The district heating system was originally established in the mid 1920s and since developed in the 1970s as a way of protecting the citizens and the economy from the dramatic rise in fossil fuel prices. This was during a time when the city of Copenhagen was overly dependent on increasingly scarce and expensive fossil fuels, experienced air quality concerns do to the burning of coal and oil within a city environment, and low efficiency in energy distribution in the existing district heating network. The solution was a reduction in the city’s reliance on fossil fuels by maximising energy generated from waste, biomass and other fuel sources.
Step by step expansion of the network
District heating does not necessarily require complete replacements of the existing energy systems. It can be implemented over a period of time. A steam network was originally hospitals and industry with energy, and once a steam pipe was established, offices, day care centres and private homes nearby were also connected.
This network is now replaced by water-based district heating which is more energy efficient and can be stored in thermal storages.
Regional co-operation in Greater Copenhagen: The entire integrated district heating system spanning more than 20 municipalities in the region is developed and operated through regional co-operation and partnerships.
Decarbonising the heating system
Strategy: The short-term goal of the city is to convert all remaining coal-fired CHP to biomass. As a long-term strategy the City of Copenhagen is now also using geothermal energy in the district heating network.
Renewable energy supply
The use of CHP units allows highly efficient use of the energy in the fuels (up to 94%) and results in lower carbon dioxide emission.
Biogas is being made an operational part of the city’s gas grid by extracting gas from sludge produced in wastewater treatment processes. Biomass is planned to replace coal and provide 100% renewable energy from the CHP plant. One plant has already been converted to 100% biomass.