What is district heating?
District heating is based on centralized heating production with heat distribution to many households. The heat either comes from a heating plant, that solely produces heat or from a combined heat and power plant (CHP plant), which produces both heat and electricity. Originally, the main purpose of several CHP plants was electricity, while heat was a "by-product", then utilized for heating buildings. Because of the simultaneous heat and electricity generation, district heating is very energy efficient.
The energy mainly comes from burning either fossil fuels (primarily natural gas or coal), waste or biomass such as straw, wood chips or wood pellets. However, more and more district heating plants produce heat using solar heating during summer months. Many plants also use waste heat from companies (large stores, heavy industry, eg. cement production or steel melting).
Modern biofuel systems condense flue gases and can further utilize the residual heat via heat pumps and thus have a very high efficiency.
Why district heating?
District heating is usually an inexpensive and environmentally friendly heat source. Approximately 60% of Danish homes get their heat via district heating. On average, it is the least CO2-emitting energy form, but with great local variation, depending on which fuel is used. District heating is usually regarded as the most environmentally friendly form of heating. The price on energy and fixed expenses varies quite a lot depending on the district heat supplier, but generally, district heating is a cheap source of heat. Before converting to district heating, it is recommended to examine current prices, including the connection fee.
Is there an obligation to connect?
In large parts of Denmark, it is obligatory to be connected to the district heating supply. District heating is an efficient and economical solution, and the more buildings connected to it the more effective it is. The municipality can inform whether there is an obligation to connect in a given area. If there is an obligation to connect, it is basically unlawful to change the heat source. Exceptions are new energy-saving measures in new constructions, but they only apply to low-energy houses 2020.
Since July 1, 2016, it is no longer possible to install an oil-fired boiler in areas with district heating or natural gas and this applies to both new and existing buildings.
District heating in church. Photo: Carsten Vejborg
District heating in parish building. Photo: Carsten Vejborg