District Heating and the Energy Transition

How does a district heating network work?

In a district heating system, heat from a centralised or decentralised source is supplied to a network. Hot water is transported through insulated pipes to a residential area or business district. In homes and buildings, a heat transfer unit replaces the central heating boiler or gas-fired water heater. Within the heat transfer unit, a heat exchanger transfers heat from the district heating network to the building’s internal heating system. The cooled water then returns to the source, where it is reheated and recirculated.District heating networks offer both advantages and disadvantages.

Why are heat networks important for the energy transition?

District heating networks are not a solution for every situation, but together with heat pumps and green gas they form an important part of the Netherlands’ sustainable heating mix. District heating is an important building block of the energy transition for several reasons:

• Efficiency and economies of scale: In densely populated areas, collective heating is often more efficient than individual solutions. District heating networks make optimal use of local heat sources and reduce the number of installations required in individual buildings.
• Reducing pressure on the electricity grid: The energy transition places increasing demands on the electricity system. District heating networks reduce the need for electric heating and help limit grid congestion. This also helps keep the overall energy transition more affordable.
• Suitable for Existing Buildings: A large proportion of Dutch homes were not built to current insulation standards, or do not have sufficient space for a heat pump. For many existing buildings, district heating is therefore a more practical option than fully electric alternatives.

In addition to these benefits, district heating networks support energy security and reduce geopolitical dependence by making use of local heat sources. The process of making heat demand more sustainable is also referred to as the heat transition.

Can district heating be used everywhere to replace natural gas?

District heating networks are not suitable everywhere, but together with heat pumps and green gas they form an important part of the overall sustainable heating solution for the Netherlands. Within the built environment, district heating networks are particularly well suited to urban areas with high-density housing, including apartment buildings. A suitable heat source must also be available near these neighbourhoods. In historic city centres, green gas may sometimes be a more appropriate solution than district heating.

The sustainability of a district heating network ultimately depends on the heat source or combination of heat sources that it uses. Existing district heating systems already deliver significant CO₂ reductions compared with conventional gas boilers. Replacing fossil-based heat sources with geothermal energy, aquathermal energy, or heat recovered from data centres can further improve their sustainability. New district heating networks are increasingly designed around fossil-free heat sources from the outset.