Stepwise transition strategy and impact assessment for future district heating systems

Project: Other

Project Details


IEA DHC Annex XII project “Stepwise transition strategy and impact assessment for future district heating systems” (STEP) set out to study the transition to 4th generation district heating (DH) systems (4GDH) in Denmark, Sweden, Norway and Finland (later referred as the Nordic countries). It focuses on the benefit, the impact and the requirements of low distribution temperatures; arguably the most significant aspect of the 4GDH concept. The project was divided into three major aspects related to the transition; building-level actions, new enabled heat sources and the energy system impact.

Key findings

The work on building actions revealed that there is potential in the existing equipment to enable lower distribution levels and that DH companies have options to support this development. New enabled heat sources are described in a literature review, and pinch analysis is presented as a potential method in evaluation of their potential. The energy system impact analysis carried out by TIMES-VTT energy system model for the whole Nordic region showed a decreasing DH demand, an increased use of biomass in heat supply and a significant share of heat pumps. With lower DH distribution temperatures, more heat pump based heat supply was used, freeing up more biomass to be used in other sectors enabling cheaper emission reduction measures in overall.
Effective start/end date1/10/1730/09/19

Collaborative partners


  • IEA Technology Collaboration Programme