After the oil crisis in the seventies, Belgium (and later also Flanders) decided to make a large-scale transition to natural gas for heating houses and other buildings. During the nineties, this even led to the statutory obligation for the government to provide a gas connection in every new housing development. The outcome: no less than 90 per cent of Flanders is connected to the gas network.

Water as an energy carrier
Due to the climate change issue – and other factors such as volatile prices and security of supply – heating by means of gas (and cooling by means of electricity) is no longer a valid option. A district heating network, in which houses and buildings are supplied with water that is already warm – the water is therefore acting as an energy carrier – has numerous advantages over gas. For instance, the energy is not generated in the houses and buildings themselves, but rather in a central installation, resulting in a significant CO2 reduction. The hot water therefore feeds the district heating network, which can extend over several kilometres in an area that is ideally densely built-up.

“Over fifty per cent of our energy consumption is taken up by heating and cooling buildings”, says Ann Wouters of VITO/EnergyVille. “If you use district heating networks to do this, you have a very powerful instrument for the transition to a sustainable energy system. Ideally, district heating networks are fed with residual heat from companies or with sustainable alternatives such as geothermal energy or biomass. Another major advantage of a district heating network is that the energy source (which centrally heats the water, ed.) can easily be replaced. District heating networks are therefore compatible with changes in our energy system, that we cannot always predict.”

Starting from scratch
Other countries are much more familiar with this energy technology. For example, after the oil crisis of 1973, Sweden quickly made the decision to use district heating networks for heating. There was a similar evolution in the other Scandinavian countries, and even in our neighbouring countries. “We are taking a very close look at other countries”, says Rutger Baeten, also of VITO/EnergyVille. “In Scandinavia in particular, work has carried out on high-efficiency district heating networks in recent years. We are now implementing this knowledge here, so that the district heating networks that we create are immediately among the best in class. The advantage here, of course, is that we are starting from scratch in Flanders. We do not have to experience all the teething problems again.”

At the end of November 2018, ISVAG and VITO/EnergyVille organised an international workshop on district heating in and around Antwerp, which was also attended by the Danish District Heating Association. During the workshop, a great deal of attention was given to the large-scale urban network of Flanders, which is being built south of Antwerp.

Antwerp’s residential districts
The district heating network is to be fed by the waste incinerator of ISVAG in Wilrijk. In the first phase of implementation, the grid will be built on (or rather under) a neighbouring industrial site (Terbekehof). As a result, around ten SMEs and companies will be able to heat their buildings and generate hot water. In the second phase, the network will be rolled out to a number of neighbouring residential districts in Wilrijk, but also to a number of Antwerp’s residential districts, including its brand new district New South. The second phase coincides with the installation of a new incinerator at ISVAG in Wilrijk.

A district heating network connects a central heat source to connections in not only homes and buildings, but also various players such as the heat producer (ISVAG in this case), the heat consumers (private individuals, private companies and authorities) and the distributors. VITO/EnergyVille plays a unique role as facilitator in the implementation of this chain. “The creation of an optimal district heating network requires a lot of study work and planning”, says Baeten. “We have to research how much heat is available at the source, and how many potential consumers there are. In between, we have to map the most efficient route. It should not be too long and too complex, otherwise the heat loss would be too high and, moreover, the construction price would not be kept low. We are therefore studying the technical and economic feasibility.”

In addition, VITO/EnergyVille is helping to create a framework in which heat producers, consumers and distributors can identify one other – for the purposes of contracts, prices, etc. “The fact that we are an independent player is an advantage here,” says Wouters. “It allows us to guarantee the best solution for all actors”.

Energy broker
In the meantime, it is ensured – including at a provincial policy level – that district heating networks get every opportunity they deserve. According to Ludwig Caluwé, Deputy for Economy and Innovation, not too much new technology is involved in district heating networks per se; the challenge consists mainly in reconciling the demand and supply of heat. “This is what makes the business model work, and realisation possible. This is precisely why we have created the role of energy broker. If they wish, municipalities can play a director’s role between the various players, and thus make hay while the sun shines. After all, they have an excellent view of planned works and on supply and demand, and can therefore work on their sustainability goals. Our cooperation with VITO/EnergyVille also gives us the necessary knowledge to calculate the technical and economic feasibility. And as regional authority, we look for intermunicipal cooperation where necessary”, says Caluwé.

How does a company like ISVAG benefit from the connection of its waste-to-energy plant to a district heating network? “We are already producing sustainable electricity with our furnace, and it would be even more beneficial to also be able to supply our heat to companies and individuals”, says Kristel Moulaert, managing director of ISVAG. “District heating networks fed by sustainable sources are vital in the quest for a climate-neutral urban environment.”

Source: VITO