AGORA – Symbiosis: for innovative circular management of urban resources
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Symbiosis: for innovative circular management of urban resources

On the industrial wasteland of Esch and Schifflange, the new quarter being developed is based on the Symbiosis urban concept. A sustainable circular city in which all resources are managed in an interconnected way, serving each other with the aim of combating climate change.

Close your eyes and imagine a quarter powered by solar energy, distributing electricity via connected energy grids, using primarily water recovered from wastewater and taking shape around and through an urban forest. These are the outlines of the Symbiosis project, a technical solution through which all resources are constantly reused and recycled.

At the heart of the project, there are big questions. How can we create the most functional quarter possible and invent the most innovative public services while ensuring very low carbon emissions? What do we do to ensure that every source of supply necessary for the proper functioning of the city’s public services is exploited as fully as possible? How can we create a quarter in which water, waste, energy and air quality management interlock and interact in such a way as to make the most of each resource?

In response, AGORA, the city of Esch-sur-Alzette and the municipality of Schifflange have conducted an ambitious consultation exercise. Around the table were representatives of the cities and local energy companies, researchers from the University of Luxembourg as well as members of the public administrations, the Ministry of the Environment, Climate and Sustainable Development but also of Sudcal and Sudstroum.

This fruitful conversation gave rise to various scenarios. The quarter is planned as a solar city, making full use of its various water sources, but also as a forest city or indeed a circular city. AGORA is now submitting these scenarios to a design office charged with assessing their feasibility and coming up with a technical concept that emphasises innovative integrated solutions. This is the first stage of turning the dream into reality.

Thinking globally and looking to the future

“To get out of our usual habits and think more globally about the quarter’s supply services, we tried to think in global terms right from the outset through the notion of flows,” explains Yves Biwer, QAZ coordinator at AGORA.

“We thought globally about the flows of heat and cold, the management of climate extremes, then about waste, rainwater, grey water and black water. How can these flows interact? This way of thinking rapidly led us to envisage very specific mechanisms and to consider, for example, solutions such as the use of heat pumps connected to a rainwater recovery tank. This is one example among others.”

The idea behind the Symbiosis project is also to build the quarter with a view to anticipating its future development and to come up with urban structures that will make it possible to avoid any excesses so as to always remain a “low carbon city.”

“Of course, what we see in our crystal ball is imperfect but we can still rely on certain major trends to imagine the city of tomorrow,” says Jeannot Behm, energy and ecology advisor for Esch-sur-Alzette. “We know, for example, that the need for car parks will not be the same thanks to self-driving cars; we know that the emphasis will be on soft mobility. But, above all, we are trying to think of resilient and flexible infrastructures, which will be as adaptable as possible.”

Smart flows

One of the key ideas of Symbiosis is the creation of smart flows for electricity and waste. But what exactly does “smart flows” mean? “In principle, these are inflows and outflows (electricity, heat, cold, water, grey water, telecoms...) using interconnections at IT and infrastructure level,” explains Jeannot Behm.

“In our project, the grids would strictly use renewable energies, primarily a combination of heat pumps and thermal solar energy with photovoltaic panels. For example, the smart grid can save the use of the heat pump when it receives information that there is sufficient solar heat. It can also be used to store energy.”

Although artificial intelligence, digital technologies and the Internet of Things can be used in these grids, “they are not an end in themselves,” emphasises Yves Biwer. “We will also use low tech systems when they prove to be better suited to our needs and more flexible. Systems such as heat pumps, sewage treatment plants or rainwater storage are nothing new. Innovation is using them in such a fully interconnected way.”

A circular world

Symbiosis thus provides for the constant circulation and reuse of energy, water, and waste, in a principle of infinite circularity. “And this vision begins on the construction site,” says Yves Biwer. We want to ensure that we build with renewable materials and that the surplus materials can be reused elsewhere in the system.”

On a daily basis in the future quarter, this circularity will be reflected in the water management. Let’s illustrate this with a very specific example from everyday domestic life. For example, Symbiosis provides for the water used for showering to be reused immediately in the toilet, before being redirected to the water system to be filtered and reused. Circularity starts on a small scale, in your own home, before moving to the large scale.

“The watchword is to always value reuse and transformation. You have to think of each resource in terms of several uses and to meet several needs at the same time,” concludes Jeannot Behm.

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