by Linda Bertelsen
scientist corner

Since the invasion of Ukraine by Putin’s Government, European countries have found themselves stuck in a painful situation. While eager to stop importing natural gas from Russia, they are simultaneously extensively reliant on Russian natural gas for their energy supply and economy. So, then what? How should European cities get started on the green transition and reduce their natural gas dependency? 

By Maëlle Caussarieu, Energy Planner, PhD

Such a critical situation is not unprecedented; crises have prompted changes in energy supply systems in the past. For example, the Fukushima nuclear disaster provoked the closing of nuclear plants in Germany, and the oil crisis of 1973 prompted the further development of district heating (DH) in Denmark. Shocks and crises can be the spark that drives energy transitions. They can provoke new understandings and uses of already-known technology, and district heating may be one of them. DH has significant potential to mitigate climate change, lower European reliance on Russian natural gas, supply low-cost heating, and improve air quality. 

In this article, I will present some findings from the DH development in Denmark and argue why these historical and contemporary examples have relevance today. I will here present two arguments also developed in my Ph.D. thesis. First, from the Danish Government’s response to the oil crisis, I show how creating a common regulatory regime was central to facilitating the large-scale deployment of DH. Second, based on the case of Albertslund municipality, I show that local parameters are essential in energy transition processes. 

Establishing and developing district heating in Denmark

District heating: a response to a crisis

Before the 1970s in Denmark, there were no dedicated energy planning procedures or regulative authorities. Municipality-owned DH companies were standard in the larger cities – and often, the DH supply was based on surplus heat from waste incineration plants. 

But when the 1973 oil crisis hit Denmark, the oil price increased by nearly 400%, seriously striking the country’s economy. With this oil embargo, Denmark realized that concerted action was needed to lower the dependency on imported oil, and an all-new Danish Energy Policy era started. Fuel diversification and energy savings became the main priorities at the national and municipal levels, and DH became the backbone of the Government’s strategy. Politicians and regulators realized the potential to exploit waste heat resources from electricity generation and waste incineration plants to increase energy efficiency. The Government thus recategorized DH from an available surplus heat source to a necessary energy infrastructure. 

Establishing such large-scale infrastructures was nonetheless not done overnight. In the following section, I expose some of the elements that made this deployment feasible in Denmark and which may provide aspects of the answer as to “how to get started.” 

The importance of national regulation for local developments

When the Danish Government realized the need to develop DH to reduce oil dependency, it established the Danish Energy Agency (DEA). This new regulative authority was tasked to create procedures, plans, and regulations to support and guide energy developments. 

The Danish Energy Agency soon signed the Heat Supply Act (1979), the first law regarding DH in Denmark. The Act holds the municipalities responsible for developing local DH infrastructures and most created municipally owned or cooperative companies to be in charge of these developments. This means that the new task of developing DH was in the hands of the local public practitioners. Yet, the DEA’s common planning practices guided this local and public task. Two regulations from the Heat Supply Act must be highlighted: the hvile-i-sig-selv principle (literally “rest upon itself”) and the socio-economic calculations. 

The “hvile-i-sig-selv” principle stipulates that no profits can be made from the production and trade of heat. It stipulates which costs can be covered in the heating price and therefore secure the customers against possible abuses. The end-users were and are thereby ensured to obtain the lowest heat prices possible and pay a fair amount for their heat supply. This principle, together with the local ownership of the infrastructure, has grounded trust between the customers and their heat suppliers over time.  

The socioeconomic calculations provided a framework for public companies to deal with the uncertainties related to energy planning. They were and still are nationally defining the references and baseline scenarios upon which practitioners are to base energy investment decisions. They assist the practitioners in assessing how to reach energy objectives in the most appropriate way for society while considering the territorial parameters. In other words, the DEA provided national guidelines while leaving enough room for the local practitioners to consider their own locality. These national calculations thus enabled the local practitioners to continually find the most cost-efficient and environmentally friendly ways of heat supply. This framework has, over time, established a sense of commitment from the public practitioners to the infrastructures at stake. 

Many say these regulations are two key elements that have enabled a fast and solid development of DH in Denmark, despite the lack of prior knowledge and plenty of uncertainties related to energy planning. These elements have, over time, grounded a sense of commitment to the task of doing something important for the good of society. It has enabled practitioners to implement new systems and technologies despite many uncertainties and provided them with enough stability to navigate their world. 

District heating is bounded to the local parameters.

DH systems are locally bounded systems, and it is, therefore, primordial to consider the territorial parameters. This section underlines this point through the example of one of my Ph.D. case studies, namely the energy transition of Albertslund municipality. This city of nearly 30,000 inhabitants 15 km from Copenhagen caught my attention as it first appeared to me as a site without subsequent resources to engage in energy system change. The municipality was said to have social and ethnic divides, a high rate of residents relying on social assistance, and a deteriorated housing fabric. Nevertheless, the city was transitioning its “traditional” DH grid into the so-called “4th Generation DH grid”. Such a transition is acknowledged in the scientific literature as requiring significant transformations such as low return temperature, low-temperature energy sources, low consumption, grid boosters, etc.  

How would and was a city with little means to engage in such an extensive transition? The answer lies in the ‘situatedness’ of the case; for the municipality, carrying out this agenda was not just a matter of energy transition but also a pragmatic way of revitalizing the city and dealing with the deteriorating housing fabric. As a matter of fact, the municipality of Albertslund was built over a little ten years – from 1963 to 1973; due to the pressing need for housing, the urban planners of the time decided to use prefabricated houses in a grid-like model to expand the city rapidly and with a standardized and affordable housing. But these prefabricated houses did not handle the wet Danish weather very well, and the problem of humidity and mold arose gradually. 

To tackle these challenges, the municipality and the DH practitioners decided that they would solve the devitalizing urban fabric. At the same time, embark the city on the green transition. They decided in 2015 that by 2025, the heat supply temperature would be decreased from 80-90oC to 60-70oC.

To achieve this target, the practitioners installed Smart Meters, used drones to identify heat losses in the grid, and developed new services ensuring the efficient operation of their customers’ heat units. Lastly, they incentivized their customers to understand (and reduce) their consumption with new tariff systems and Smartphone applications. Communication with the inhabitants was a significant part of the strategy. They spent a great deal of workforce engaging in dialogue with their inhabitants, measuring dwellings’ radiator sizes and insulation layers, all to develop interactive maps to communicate about low-temperature grids. They also made available information about energy renovation funds and good practices by creating catalogs and websites where citizens could get oriented about what to do and why it was important to reduce the temperature in the grid. The municipality is so far keeping on target, with a new milestone of having a 60oC supply temperature by 2026. 

This case emphasizes the importance of the local conditions when embarking on an energy system transition. In Albertslund, from the very local parameters have emerged ways of transforming the energy system, thereby enhancing the municipality and inhabitants’ lives. 


Getting started requires two main conditions: adequate regulation at the national level to provide a common framework of decision-making practices and considering the local parameters of the sites where the transitions are materializing. 

Energy systems are deeply influenced by how practitioners create, operate, and maintain them. These systems are bounded by how energy practitioners, city planners, engineers, system managers, and politicians operate and work with the infrastructures at hand. Deep transformations, such as getting rid of natural gas, will require new ways of working together. Urban and heat planning must be performed together to ensure space for decentral heating productions. National policy must help redirect investments from gas and other fossil fuel sources to renewable production. Communication with end-users must be improved, and heat planning must continue to be a public responsibility for the security of supply and sovereignty. In other terms, energy transitions demand a new paradigm of working together.

Maëlle Caussarieu

What makes this subject exciting to you?

I knew nothing about DH when I started my research. It is not a well-developed technology in France, where I come from. But while talking with the actors, understanding their reasonings, and witnessing how they are trying to make a difference with this degree of commitment, I became very enthusiastic about this infrastructure. DH may not sound very appealing, but it is and will become a hot topic in the coming years; I do not doubt that. 

What will your findings do for DH? 

Time will tell! I now work as an energy planner at the Copenhagen municipality and hope to contribute to developing the regional DH infrastructure. The challenges ahead of us are great, and the uncertainties are aplenty. I am curious about the system's appearance in 10, 15, and 30 years. And if I see the establishment of a few heat pumps within Copenhagen in the coming years, I could consider having somehow contributed to the field!

The author

Maëlle Caussarieu
Energy Planner, Copenhagen Municipality

“How to get started?” was published in Hot Cool, edition no. 3/2022

Hot Cool article - How to get started
Download the article from the Hot Cool magazine here
Hot Cool no. 3/2022
Hot Cool - Edition 3/2022