A look back at the day dedicated to heating and cooling grids: a key to decarbonise cities!

A look back at the day dedicated to heating and cooling grids: a key to decarbonise cities!

The day of 19 April 2023, dedicated to heating and cooling networks and co-organised by Construction21, ADEME, Fedene, FNCCR, Euroheat & Power and the European project D2Grids, highlighted their latest innovations in decarbonisation on the French, European and global energy scene!

The day of 19 April 2023, dedicated to heating and cooling grids and co-organised by Construction21, ADEME, Fedene, FNCCR, Euroheat & Power and the European D2Grids project, highlighted their latest innovations in decarbonisation on the French, European and global energy scene! The event included a number of announcements.

"On average, heating and cooling grids are 63% green." says Paulo Cameijo, a member of the board of the National Union of District Heating and Urban Air Cooling (SNCU) and of the Fedene board of directors. Biomass, solar thermal energy, cogeneration, waste heat recovery, geothermal energy... their varied sources of supply make it possible to produce heating and cooling with less carbon emissions.

These low-carbon grids therefore contribute to reduce carbon emissions from buildings such as housing and offices the most efficient way. This is an important issue considering that the heating and cooling sector accounts for 50% of the energy consumption of buildings and industry.
These grids are therefore key to decarbonise. However, they account for only 5% of heating in France. In 2020, there were about 833 heating grids, with a length of 6200 km grids, 44,000 buildings connected (2.5 million housing equivalents). The French government has also set the objective of doubling the supply of renewable heat by 2028 through the greening of grids, but above all through the creation, extension and densification.

So how can these installations be massively expanded? What feedback has been received? What benefits? What contractualisation models? These are some of the questions addressed during the various round tables, conferences and debates at the heating and cooling Day on 19 April.

On the road to 5th generation for heating and cooling grids!

The morning session was dedicated to 5th generation heating and cooling grids. More specifically, it focused on the lessons learned from the six years of research and development conducted by the D2Grids project of the European Interreg NWE programme to develop low-temperature heating and cooling grids in urban neighbourhoods.

As a reminder, the European D2Grids programme, supported by 60% of the European Union, is part of the European energy strategy. It has made it possible to monitor the deployment of five pilot sites for the latest generation of district heating and cooling grids: Bochum in Germany, Brunssum in the Netherlands, Glasgow in Scotland, Paris-Saclay in France and Plymouth in England. This first phase of experimentation has been completed and the initial results are very positive. The various sources of energy, thermal flexibility and renewable electricity, and the various pieces of feedback have shown the capacity of these innovative grids to be both reliable and decarbonised.

Frans Drummen, D2Grids project manager at Mijnwater in the Netherlands, explained that the 5th generation grids fully meets the current challenges of a more sustainable development: "the energy transition is the desire to move from a fossil fuel system to renewables while reducing needs to reduce energy production. We are now facing an X-curve: the old regime replaced by a new regime. There is not just one process, but two that work at the same time, with the old regime falling and the new regime rising."

Among the five European projects involved in the programme, the Paris-Saclay science and technology cluster extends over 27 municipalities in Essonne and Yvelines. A total of 25 km of underground grids connects 650,000 m² of buildings, i.e. more than 50 MW of combined heating and cooling capacity. Thanks to geothermal energy in particular, more than 50% of renewable and recovered energy supplies the grid. The next developments will consist of making the installation even greener: "two networks still run on gas, we are looking to reuse the waste heat from the IT networks, but also to pool the boiler room on the Saclay plateau in order to maximise its use" says Antoine Latreille, Vice President of the University of Paris-Saclay's Heritage Department. Other project examples are those in Heerlen and Bochum, whose 5th generation heating and cooling grids use geothermal energy from old abandoned mines.

For more information on these projects: https://bit.ly/41xWdNb

After experimentation, capitalisation. A "toolbox" has been developed by the D2Grids project to enable stakeholders to embark on 5GDHC. Models, technical documents, customised feasibility studies and online courses are also available. Finally, an industrial alliance has been created to develop a "collective intelligence of 5GDHC" - to be found on the D2Grids website and the 5GDHC platform. The second phase of the Interreg NWE programme, due to end in 2027, was announced in conclusion by Eugenia Bueno Martinez, project coordinator at Open Universiteit: "Seven regions have been identified as having interesting potential for further research: Flanders in Belgium, Luxembourg, the north-east of France, the Ruhr in Germany, the East Midlands in England and the province of Limburg in the Netherlands. One of the major challenges of this new phase will be to continue to improve the sustainable supply of heat and cooling networks." To be continued...

Managing a heating and cooling grid project

The afternoon was more "macro", with a particular focus on France. The first round table of the afternoon"What energy for the city of tomorrow?" began with an urgent observation: "France is the only European country that has not reached its objective of 23% of renewable energy in its energy mix" said Paulo Cameijo by way of introduction.
Despite this, there are many examples of innovative district heating and cooling grids. André Santini, mayor of Issy-Les-Moulineaux, and Pascal Thévenot, mayor of Vélizy-Villacoublay, were able to show that the grids of their respective cities could rely heavily on geothermal energy to guarantee low-carbon and economical energy for their inhabitants. "We expected to reach 60% of geothermal energy in the supply of the heating grid, but with the energy crisis and the reinforcement of the sobriety of uses, this share has exceeded 70%", testifies Pascal Thévenot.

Also, the implementation of a technological breakthrough (multi-drain geothermal energy) in Vélizy-Villacoublay has enabled the geothermal installations to exceed 600 metres in depth. "It took a year to adapt the mathematical models and the settings of the heat pumps connected to the heating network. The temperature of the water still needs to be increased" says the mayor. In Issy-les-Moulineaux, Mayor André Santini has a cursed number: "14...", the number of years he has been working to see this project come to fruition. Inaugurated in 2023, the project now provides 70% of the heat for its new district "Issy Cœur de Ville". And what if he had to do it again? The mayor confides: "I would go even faster! To succeed in this type of project, one of the key points is to have a population that wants to move forward and is confident". Determination, then!

For Paulo Cameijo, another key to success is the need to set up genuine "territorial cooperation". Yannick Jacquemart, Director of new flexibilities for the Electricity System at RTE, emphasised the importance of being aware of the electricity issue in a decentralised system, a system in which heat pumps must be continuously supplied with electricity. Finally, Benoît Ricard, Managing Director and co-founder of E-nergy, emphasised the benefits of heat and cold networks "to withstand rising energy prices such as the one observed since 2022." 
The role of "heat made in France" was then at the heart of the discussions between Baptiste Perrissin-Fabert, Executive Director of Expertise and Programmes at ADEME, and Serge Burtin, Technical and Operations Director at Dalkia. As a result, Baptiste Perrissin-Fabert announced an increase in the amount of the ADEME's Heat Fund from €520 million (2022) to €950 million for 2023. As a reminder, the aid allocated in 2022 will enable the construction of more than 900 new installations (geothermal, biomass heating, waste heat recovery equipment, etc.) which will produce 3.68 TWh of renewable and recovered heat.