Typically, CHP are either centralised or decentralised. Centralised CHP are usually much larger than decentralised CHP.

There is yet another difference between centralised and decentralised CHP. The former were originally electricity plants (generating only electricity), while the latter were originally heating plants (generating only heat). While some of the decentralised CHP are new, the main purpose of all such installations is to generate heat.

Centralised CHP are located in large cities; decentralised CHP are located in smaller centres.

16 centralised and approximately 415 decentralised plants supply public heating in Denmark, that is, the heat they produce is conveyed to customers by means of DH pipes.

Most plants produce co-generated heat and electricity whereas only a small number of the decentralised plants (approximately one-third) still produce only heat.

One in three of the decentralised DH plants and one in seven of the decentralised CHP plants use environmentally friendly fuels (straw, wood chips, wood pellets, biogas or waste). The remainder - by far the majority - use natural gas as a fuel. These CHP, owned by local authorities or co-operatives, supply heat - by means of DH pipes - to most of the households, institutions and enterprises in their areas.

BIOMASS, BIOGAS AND WASTE-DISPOSAL PLANTS: KEY FIGURES

Public-heat supply (cities):

• approximately 120 biomass-based DH plants (of which approximately are half straw-based and the other half wood-based)
• approximately 10 straw or wood-chip-fired decentralised CHP (as main fuel)DH without electricity generation: 4%
• approximately 30 waste-incineration installations (of which 18 co-produce heat and electricity and 12 are DH)
• 6 centralised CHP which use biomass, among other fuels,
• approximately 30 CHP using biogas as the main fuel

Private heat supply (enterprises, institutions):

• 200 heat and co-generating heat and electricity plants, owned by and primarily delivering heat to greenhouses, the manufacturing industry, institutions etc.

Individual heat installations (houses, farms):

• 500,000 wood-burning stoves
• 70,000 wood-burning boilers
• 30,000 wood-pellet furnaces
• 9,000 straw furnaces

Denmark has the most extensive co-generated heat and electricity system in EU. More than one-half of Danish electricity is co-generated with heat.

There is an individual natural gas supply (which is also public supply) to most of the country and the natural gas pipeline grid covers almost all of Denmark.

This is not the case, however, in South Zealand and Djursland where there are many biomass plants generating heat. Islands such as Læsø and Samsø also have public supply by means of biomass DH.

A considerable amount of coal is still used in centralised co-generated heat and electricity production.

In addition to this public heat supply, there are many plants delivering heat only to the enterprise, institution or residential block which owns them. This is the case with approximately 480 CHP and DH plants, the heat from which is used for greenhouses and the manufacturing industry or as space heat in offices, schools etc. Approximately half of these private, local plants use biomass as a fuel.

A few industries have very large plants (such as Akzo Nobel Salt and Aalborg Portland), but the vast majority of self-owned heating plants are relatively small and cover only local needs.

Denmark thus has an extensive and varied heat sector. Approximately 665 plants generate both electricity and heat and approximately 230 plants produce only heat. The vast majority of the power and heat generated is used for public supply.

NUMBER OF CHP AND DH PLANTS IN DENMARK

Public-heat supply (cities): 

• 16 centralised CHP
• 285 decentralised CHP
• 130 decentralised DH plants

  Private heat supply (enterprises, institutions):

• 380 CHP
• 100 DH plants

  In all:

• 665 CHP
• 230 DH plants