A circular district at every level, from energy supply to water and waste recovery: this is the essence of the Symbiosis project. After drawing up the initial plans with the town of Esch-sur-Alzette and the municipality of Schifflange, the AGORA team embarked on a fruitful technical study phase with six partners with a wide range of expertise, including energy, biodiversity and water treatment. We spoke to four of these partners, who are keen engineers, have contributed to the brainstorming and have their heads full of ingenious solutions.
AGORA (represented here by Jean-Claude Huberty, Project Manager, and Alexandre Londot, Director of Operations) brought together: engineers from the Schroeder & Associés design office, including our interviewee Philippe Genot; sustainable energy specialists from IDES Engineering, such as our interviewee Jean-Philippe Lemaire; biodiversity experts from WEO; specialists in black and grey water treatment from the Swiss firm AFRY; collaborators from the collaborative innovation consultancy The Impact Lab and, finally, methodology enthusiasts from the EXCEPT consultancy. Inventing a district that is almost entirely circular is a highly complex undertaking, and one that is unprecedented on this scale, on a site of almost 61 hectares. An interdisciplinary approach and the constant cross-fertilisation of different technical expertise are essential. It is exciting!
On paper, the Symbiosis project may seem utopian. From an engineering point of view, and based on the current state of your research, can it already be considered technically feasible?
Jean-Claude Huberty, AGORA project manager: “The idea behind Symbiosis is to put everything into intelligent networks to create a neighbourhood in which, for example, rainwater is recovered and treated for reuse in toilet bowls, or in which waste becomes material for biomass, which in turn is a source of energy. It’s true that this is a pioneering project and that there are few existing models to rely on to determine technical feasibility. Symbiosis requires a paradigm shift: we need to consider resources in their entirety and imagine them at the heart of a network of interrelationships. For example, at this stage of the adventure, you don’t choose to do a study on water, then a study on energy, then a study on biodiversity; instead, you have to think about where these different resources might intersect. We’re not yet at the stage of testing whether all our ideas are feasible, but the current study phase has enabled us to identify and consider a range of ingenious solutions.”
Jean-Philippe Lemaire, Founder of IDES Engineering: “We used a method called Symbiosis in Development (SID), and it’s a nice coincidence that this process, in which EXCEPT is a specialist, bears the same name as our project for Metzeschmelz! The method enabled us to organise all the data to produce an initial map of possible solutions, taking into account all the links between resources. In practical terms, the Symbiosis project aims first and foremost to make the most of natural elements such as the sun, the air and the ground, for example by using photovoltaic panels, aerothermal energy and geothermal technologies. We combine these techniques so that they complement each other and there is no waste of resources, in particular by implementing what we call systemic energy balancing, which is based on a fine distribution of resources according to supply and demand in real time, coupled with techniques for storing resources for later use. We’re also trying to think about an open system that can incorporate other techniques in the future. For example, the technologies for using hydrogen as an energy source are not sufficiently developed at the moment, but they will certainly be so over the next decade.
Can you describe in more detail the solutions envisaged for creating a circular energy supply network?
Jean-Philippe Lemaire, Founder of IDES Engineering: “We’ve already talked about aerothermal, solar, geothermal, possibly wind and hydrogen. These are known solutions. The innovation lies in combining them in line with the main principle of “smart” networking, to achieve balanced management of both heat and electricity flows. There are several ways of achieving this balance, including heat pumps that we could group together on a mobility hub or on a multi-unit building. In the case of geothermal energy, probes need to be spread out over the area to use the ground as a thermal storage system, and then a solution needs to be put in place for networking and balancing with other energy sources. The idea would also be to recover heat wherever possible, particularly that rejected by air conditioning systems. Ultimately, we hope that Metzeschmelz will be supplied solely with renewable energy, with no reliance on fossil fuels.
How could water circulation be set up in “smart networks”?
Philippe Genot: “First of all, let’s remember that we’re going to be facing a water crisis in the near future, so the site needs to be resilient in the event of very dry summers or torrential rain. It will be essential to recover as much of this rainwater as possible and run it for as long as possible in different cycles on the site. As for the intelligent networking of grey, black and yellow water, the aim of Symbiosis is to encourage an autonomous supply of non-potable water. In other words, drinking water should only be used for human consumption, and all other uses of water, such as toilets, showers or cleaning, would benefit from non-drinking water being reused several times. We therefore propose a grey water cycle. For example, shower water would no longer be diverted directly into a pipe to an evaporation plant, but would instead be sent to a water treatment plant before being returned to the home for other uses. This solution involves building a complex network of pipes, but it’s worth it because it drastically reduces the amount of water used.
Symbiosis also aims to transform all waste into sources of energy or other resources. How do we get there ?
Alexandre Londot, Director of Operations, AGORA: “Firstly, we are looking at the waste produced during the site clean-up and deconstruction phase, and then during the major infrastructure and building construction work. Ideally, what is destroyed on the current site could be used for future construction, or at least we will recover anything that can be reused – for example, concrete that can be crushed and used to make the road box, or metal frames that can be used to build new structures. To do this, an inventory of reusable materials must be drawn up. Secondly, the Symbiosis project is effectively based on the idea of transforming everyday waste into resources, for example by using this waste to make biomass, as mentioned above, or to use it as fertiliser in local urban agriculture. The technologies needed to carry out these transformations exist – it would be laborious to describe them here – but our research phase has enabled us to identify them.
Does the current regulatory framework in Luxembourg allow Symbiosis to achieve all its objectives?
Jean-Claude Huberty: ” Not yet. The grey water cycle, for example, would not be entirely feasible under current regulations. But, in collaboration with the government, a site like Metzeschmelz could serve as a pilot project to reassess and transform the legal and regulatory framework. Luxembourg is in a fertile period of legislative change to adapt to a world in climate transition. We know that the various ministries involved are very open. It is essential to see this as a collective opportunity to evolve and innovate in our consumption patterns, because it is together, by embracing these new practices, that we will be able to build a sustainable and harmonious future”.
Philippe Genot: “The laws have to change. As a country sensitive to the problems of our time, Luxembourg has no choice. I think that a space for experimentation and dialogue will naturally be created between the developers of new districts and the State and local authorities, and that this will quickly lead to changes in the regulatory framework. Metzeschmelz gives us a rare opportunity to build from scratch and experiment. It’s precious. We know that our country will seize this opportunity. »
