REPLICABILITY AND STANDARDISATION TO FACILITATE TIME-EFFECTIVE DECARBONISATION

Europe’s district heating systems face a complex, urgent transition away from fossil fuels. The SET_HEAT project addresses this challenge by promoting replicable, standardised solutions that save time, reduce costs, and lower risks. Using a multi-criteria assessment, SET_HEAT identified six model investment projects, from sewage heat recovery to large-scale heat pumps, complete with pre-feasibility studies and technical guidelines. These ready-to-use blueprints will aim to accelerate planning and spark widespread adoption, helping DH companies meet climate targets while building resilient, low-carbon heat networks.

By Jacek Kalina, Coordinator of the LIFE22-CET-SET_HEAT project, Silesian University of Technology

Published in Hot Cool, edition no. 5/2025 | ISSN 0904 9681 |

European decarbonisation challenge

In many European countries, District Heating (DH) is still largely based on the combustion of fossil fuels. The accelerating global climate change and the growing problem of primary energy availability have caused an unprecedented change in the approach to energy planning and the evolution of DH systems.

The ambitious EU climate and energy policy – setting targets and pushing towards decarbonization and climate neutrality in 2050 – has placed DH systems at the forefront of urban, green energy transition. These systems play a pivotal role in mitigating climate change, ensuring energy security and affordability for citizens. This is because DH offers a unique opportunity to integrate local renewable and waste energy sources and improve energy efficiency at the city level.

On the other hand, since DH is deeply embedded in the socio-economic system and built environment, the energy transition and decarbonisation of DH assets at the local level trigger serious technical, economic, and social challenges. Considering the scale of the required change, the relatively short timeline, the current state of play, technological and infrastructural constraints, socio-cultural factors, and the scarcity of capital and other resources, it can be concluded that in many EU member states, achieving the goals may be challenging.

‘The energy transition and decarbonisation of DH assets at the local level trigger a serious technical, economic and social challenges.’

State of play

In countries such as Croatia, Lithuania, Poland, and Romania, the transition has progressed very slowly. Since the European strategy for district heating and cooling (DHC) was announced in 2016, no major changes have occurred in the sector. Although many DH companies have recently initiated investment projects focused on renewables and waste heat, the decarbonisation potential is largely untapped, and the share of clean technologies in heat production is still relatively small.

‘The complexity and multidimensionality of the transformation process and the uncertainty of the data slow down the pace of change.’

The main reasons for this are the complexity and multidimensionality of the energy system planning process. It is also important that the tactics to achieve the strategic targets, which the EU policymakers have left to individual decision-makers at the company and municipality levels, must overcome existing barriers, look for opportunities, and address threats to devise future-proof solutions under uncertain boundary conditions.

Multidimensional, holistic strategic planning is a must.

To effectively address the DH decarbonisation challenge, municipalities and DH companies should consider the MultiD approach, which is typical for transitioning into the 4th Generation District Heating Network (4G DHN) [1]. Moreover, transition planning requires considering many projects simultaneously and deciding the sequence of their implementation.

Capital-intensive projects, which usually require public financial support and bank loans, must meet the requirements of financing institutions, including minimised risks. The economic viability of many projects depends on electricity prices, which are unknown in the long term. The market is changing at an unprecedented rate regarding products, services, mechanisms of operations, and trade rules. What is incomprehensible today may be a standard soon.

‘The MultiD approach to redesign of existing DH systems should simultaneously take into consideration such aspects as territorial expansion, decomposition, reconfiguration, distributed sources, multiple sources, cogeneration, zero-emission sources, intermittent sources, heat storage, digitisation, low-temperature heating networks, sector integration, electrification, decarbonised fuels, adjustments of heat sink installations, improved energy efficiency in buildings, large-scale investments in municipal energy infrastructure, active consumers, optimisation, flexibility, resilience, integrated businesses and value stacking, democratisation, and disruption as a usual factor.’

Eventually, the transition plans should be goal-oriented, which in this case is not profit, but rather meeting regulatory requirements and achieving a given environmental impact at minimum cost. Overall, it’s not an easy task to find new resources to replace traditional fossil fuel-based production assets. The issues are significant, and in many European countries, the transition is currently in a learning phase. In many cases, this is learning by doing and learning from mistakes. The bigger the system, the bigger the issues.

Energy harvesting is a common feature of transition plans.

An effective energy transition and decarbonisation of DH systems requires a significant shift from fossil fuels to local resources. Depending on local conditions, the structure of the primary energy mix of a given DH system can vary greatly.

The announced strategies of cities such as Berlin, Amsterdam, Copenhagen, Vienna, and several others reveal that future primary energy mixes will be highly diversified, and DH systems will become increasingly complex structures. This is mainly due to the scarcity of resources such as renewable and waste heat, as well as land or other space, such as suitable parcels or building rooftops, in dense built urban environments.

In general, an energy harvesting strategy must be implemented in each case. On the other hand, the number of potential types of heat sources is relatively small, and projects for individual kinds are usually multiplied by implementing them in various locations. Examples include the implementation of solar collectors, air source heat pumps, heat recovery from supermarkets, or shallow geothermal systems.

Current projects tend to focus on large sources such as waste-to-energy plants, sewage treatment facilities, solar thermal installations, and large industrial sites. Smaller, distributed heat sources, especially low-temperature ones, receive less attention.

These sources are often used onsite, reducing consumers’ reliance on DH systems. However, integrating small-capacity sources may be essential to achieve and maintain the status of an efficient DH company, as defined by the revised Energy Efficiency Directive. Large-scale heat storage, including seasonal storage, will also play a vital role.

Harnessing similarities may help.

Despite similarities among systems and projects, new strategies and investments are often planned as unique, tailor-made solutions. This siloed approach demands considerable time and financial resources, which many municipalities and DH companies lack. A coordinated approach to large-scale DH energy transition planning is needed.

Such an approach should prioritise collaboration, knowledge exchange, and implementation of replicable technical and non-technical solutions. Replication and standardisation can streamline planning, reduce costs, improve quality, facilitate communication, and ultimately accelerate investment and transition processes.

The replicability of a project, process, or approach is defined as the ability to reproduce it across different contexts. It ensures that proven solutions can be adapted and implemented in various locations with minimal modifications. Standardisation entails the establishment and execution of consistent procedures and criteria. In principle, a wide range of elements within the domain of DH are conducive to standardisation and replication.