Figure 1. Tracing Valladolid heat networks. Source: SOMACYL

The COVID-19 hangover has left us with a supply crisis with long queues (not only at the supermarket) that has increased the prices of equipment and all kinds of components. In addition, the armed conflict between Russia and Ukraine has led to an energy crisis with gas prices rising steadily.

Faced with this uncertainty and the growing fear of being cold in winter, some neighbourhood communities have started to connect to district heating networks (or heat networks). In Aranda, for example, 1950 homes will be connected to a biomass thermal network. The same is happening in Valladolid, where new heat networks are being installed in the neighbourhoods of Huerta del Rey, Parquesol and Villa del Prado. In other neighbourhoods, according to RTVE, residents’ associations are deciding to turn off central heating in response to rising prices, which could lead to an increase in the number of people living in energy poverty. In this context, the latter would mean people staying cold in their homes for fear of a high energy bill.

But, what are heat networks?

Heat networks or district heating networks are heat (or cold) production facilities that supply energy to each dwelling through underground pipes. Among the major advantages, compared to individual systems (the usual household boilers), are that heat networks allow the integration of renewable energy sources to increase independence from external fossil fuels, reduce emissions and lower costs for end-users. Other benefits include the removal of individual equipment from indoor spaces, which means more usable space available inside homes, and being able to offer a supply service independent of fossil fuels (and their price rises). Their main disadvantage is that they often require extensive work to prepare for the installation of pipework, traditionally involving the construction of large production plants with tall and aesthetically unattractive chimneys, and are simply not known to the general public, nor the benefits they can provide (especially in the case of Spain).

Then, affect the urban landscape of cities?

The answer is not necessarily. The New European Bauhaus (NEB) initiative aims to improve the quality of life of citizens through the joint promotion of the principles of Beauty, Sustainability and Inclusion in our environment, which is equivalent to good, beautiful and for all.

These principles focus on reconnecting with nature, regaining a sense of belonging and fostering participation, sustainability and circularity. In the case of heat networks, this holistic approach can be achieved in different ways.

As regards the sustainability pillar, the use of renewable energy sources (geothermal, solar thermal, biomass, biogas, recovery of surplus heat from industry) can be increased in thermal networks, as is being done at a general level in the sector to reduce CO2 emissions and other pollutants, but also, for example, through the revaluation of ashes or forestry waste.

As regards the social dimension and inclusion, by integrating more sustainable alternatives and supplying heat or cooling to a large number of households, affordable, secure and flexible heat or cooling supply can be promoted, thus reducing cases of energy poverty. In addition, digitalisation and the combination of networks with energy communities promote citizen participation and inclusion in the energy transition, where they can discuss, give feedback, engage in demand-side management strategies and even encourage users to become prosumers of heat.

But how can heat networks be made beautiful? At CARTIF, we have found that, through the generation of green spaces (such as parks) or multi-purpose spaces, it is possible to make the power plants beautiful spaces integrated into the urban, cultural or educational landscape. In addition, it is possible to reduce the visual impact of heat networks by burying the installations, and thus also the possible social rejection associated with the aesthetic component of these supply networks.

A case study in Heerlen, the Netherlands.

A very illustrative example of the successful application of the New European Bauhaus principles to heat networks is the network in Heerlen (Netherlands), which supplies 350 households with heat and cold thanks to geothermal energy. This network has boreholes at different temperature levels that allow it to provide heat of around 40°C in winter and 16°C of cooling in summer. The installation uses old coal mines as underground thermal storage and also uses surplus heat from a nearby steel industry, which would otherwise be lost to the environment. This could only be promoted in Spain if the houses were first insulated in order to lower the temperature required for heating and thus lower the temperature of the district heating networks. In Heerlen, at each substation each user would have an auxiliary heating system (which could be heat pumps) to meet their thermal demand. Thus, its generation is sustainable and guarantees affordable prices for citizens.

Moreover, the network’s generation plant has a modern and innovative aesthetic that blends in with the urban environment and is part of a multifunctional building that includes a supermarket, a café, a conference room and a library. In this way, far from having a negative visual impact or provoking rejection, it has become an iconic meeting point in the city.

Figure 2. Outside design of the heat network plant in Heerlen (Netherlands). Source: Smart Cities Marketplace

All this work on heat networks towards a more sustainable, inclusive and beautiful future is possible thanks to the fact that CARTIF is participating in several projects studying heat networks from different perspectives. Among them, REUSEHEAT and REWARDHEAT, where new generation heat networks are demonstrated with the integration of heat recovery from different sources, a project together with the JRC to study the NEB perspective on heat networks in Europe, or the NetZeroCities cities mission platform, where CARTIF will support cities to promote this kind of initiatives.

If you want to know more or need help with the NEB initiative or heat networks, count on us!

CARTIF is a Cervera Excellence Centre, granted by the Ministry of Science and Innovation and the CDTI, under the file number CER201910.


Andrea Gabaldón: Energy researcher. Experince in energy modelling of district and building systems, district thermal networks, positive energy districts and energy communities. She works in european projects such as LocalRES, ATELIER and NETZEROCITIES

Carolina Pastor de Paz
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