Of all the solutions being considered for the future of heating in Brussels, heat networks could play an important role.
In the future, heat networks could be part of the solution to the gradual phase-out of fossil fuels, including natural gas.
By integrating heat networks into our energy systems, we can not only reduce our carbon footprint but also bolster our long-term energy security.
Sustainable and efficient
The principle is quite simple: heat is generated centrally, ideally from renewable energy sources, or recovered from industrial processes such as waste incineration. This heat is then transported in the form of hot water through a network of insulated pipes to the buildings that need heating. This system not only heats the buildings, but also provides domestic hot water.
Heat networks have the capacity to use a variety of primary energy sources, sustainable or otherwise. This flexibility means that they have a certain agility in the face of market developments. The ratio of final energy to primary energy can also be more efficient than that for gas, depending on the technologies used.
However, installing heat networks requires major infrastructure works. As a result, they cannot be installed in all roads, due to a lack of sufficient space in the subsoil.
An economic opportunity
Installing heat networks involves considerable investment. They are therefore best suited to supplying large consumers (hospitals, swimming pools, etc.) or above a certain population density, such as as apartment buildings in city centres.
As collective infrastructure, they can offer economies of scale that help alleviate the economic impact of the energy transition, notably on the most vulnerable customers.
What is more, these networks make it possible to use waste heat that would otherwise be lost. Producing heat from various renewable energy sources (alternative gases, geothermal or riothermal energy, renewable electricity, etc.) can also be considered if this makes sense at the time.
Heat as a service
What are the implications if I connected to a heat network tomorrow? In concrete terms, a heat exchanger would be installed at your home, between the heating circuit there and the heat network, and this would take up very little space.
Heat production would no longer be individual but centralised. Energy would be purchased 'as a service', meaning that you would only pay for the hot water and would not have to take care of the installation. This offers a number of advantages, such as access to decarbonized energy at an affordable, stable price, as well as relief from the responsibility of maintaining and ensuring the proper operation of the installation.
But we need to remain vigilant. Connecting to a heating network is a long-term commitment. It's essential to choose a reliable partner capable of operating the network optimally, while keeping operational risks and prices under control.
High or low temperature
There are 2 main types of heat network.
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High-temperature networks (above 90°C): these require heavily insulated pipes, meaning that they are larger and more expensive. However, they are suitable for older, less well-insulated buildings.
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Low-temperature networks (from 20-30°C) or "5th generation" networks: these do not require heavily insulated pipes, and are therefore less expensive to install. Low-temperature networks can also be used to generate cooling and balance exchanges between different buildings locally. However, in order to work, the buildings in which they are installed need to be well-insulated.
What role will heat networks play in the future energy mix?
Given the cost of installation and the lack of long-term visibility on the energy market, it is still difficult to obtain finance for heat networks. This is why the development of support measures such as Renolution grants or European subsidies is essential. It is important to maintain this trajectory in order to give district heat networks the place they deserve in the future energy mix.
What is the potential for Brussels?
Heat networks could play a significant role in the future of heating in Brussels. This will depend mainly on the state of the energy landscape by 2050.
If a heat network proves to be the most logical energy solution, it could be imposed in certain neighbourhoods. This will depend on the characteristics of each area, such as the level of building insulation, ease of access and proximity to sources of residual or renewable heat.
'High-temperature' heat networks require large-diameter pipes (up to 550 mm), which may lead to issues due to the limited underground space. These pipes of course need to be routed, which is only possible on roads and not on pavements. 'Low-temperature' networks, with their narrower pipes, could be an advantageous solution in new neighbourhoods that are well-insulated, and could also meet cooling needs.
Heat networks could therefore make a significant contribution to the goal of being a carbon-neutral society by 2050. Brussels Environment has already drawn up a subsoil map for geothermal networks. The creation of individual studies based on consumption density per neighbourhood and the existing soil cadastre could further facilitate their implementation.
Sibelga: an agent of change
With 6,500 km of electricity network and almost 3,000 km of gas network managed in Brussels, Sibelga has built up extensive expertise in operating energy networks on public roads. To achieve this, we have highly-qualified staff, technical resources, metering equipment and IT management tools, among other things.
We also took part with the VUB in a study subsidised by Innoviris on the potential of heat networks in Brussels. In collaboration with Brugel and Bruxelles Environnement, we are also participating in the Task Force Energie to to establish a common vision for the heating of tomorrow.
Thanks to our local knowledge and our experience of coordinating with other players, we can also identify the best locations for these networks and facilitate their implementation and operation.
Given its core business, Sibelga has a natural role to play in the development of heating networks in Brussels. As a public company, we act and seek solutions in the general interest of the community, so that all Brussels residents have access to sustainable and affordable heating.