Project details



REnewable Low TEmperature District

Start date: 01.11.2017

Duration: 56 months

Coordinator: TECNALIA

Budget: 4.65 M€


District heating (DH) systems are one of the most energy efficient heating systems to deliver heat in urban environments, with proven reliability within many decades already. DHs are also identified as key systems to achieve the de-carbonization of heating energy in European Cities. Renewable and waste heat sources are foreseen at the same time as de-carbonized heat sources and the way to guarantee competitive energy costs with limited influence of fossil fuel supply price volatility. Despite this fact, district heating are serving to a market share of only 12% of the European citizens today, when studies have shown that these systems can be expanded to a market share of 50% in 2050. Such ambitious scenario requires a conversion of actual DH concept. In the forthcoming energy market, DHs need to evolve regarding:

  • The reduction of their operation temperature to integrate low-grade industrial heat sources.
  • The introduction of larger shares of renewable energy sources.
  • The introduction of distributed heat sources (reject heat from cooling equipment…).
  • To guarantee economic viability with the trend of DH heat load reduction due to the evolution of Near Zero Energy Buildings.

RELaTED has provided an innovative concept of decentralized Ultra-Low Temperature (ULT) network solution that can pave the way for expanding and modernizing existing district heating networks as well as introducing and establishing district heating in emerging EU markets. This project, funded under the European Union’s Horizon 2020 research and innovation programme, has developed a robust ultra-low temperature concept, which allow for the incorporation of low-grade heat sources with minimal constraints. Also, ULT DH reduces operational costs due to fewer heat losses, better energy performance of heat generation plants and extensive use of de-carbonized energy sources at low marginal costs. The RELaTED ULT DH concept has been demonstrated in four complementary operation environments (new and existing DH, locations, climatic conditions, dimension…) in Denmark, Estonia, Serbia and Spain.

List of achievements

Access the project results on CORDIS website.


Contact person: Roberto Garay (Project Coordinator)