Rennes Métropole has just implemented an experiment at the Laillé wastewater treatment plant to limit energy consumption and develop renewable energy production. Two photovoltaic trackers have been installed and the treatment plant will be controlled by artificial intelligence.
Context: long-standing energy conservation policies
As part of the Territorial Climate Air and Energy Plan (PCAET), which aims to reduce energy consumption by 40% by 2030 and 60% by 2050, Rennes Métropole is deploying a global strategy to reduce its energy consumption and to commit the region to a sustainable ecological transition. For example, it concerns public lighting, for which the actions carried out by Rennes Métropole will have made it possible to reduce energy consumption by 40% by 2030, or the thermal renovation of public buildings.
This metropolitan ambition was recently recognized with the Gold label (the highest distinction) in the European Energy Award program for its policy in favor of energy transition.
Rennes Métropole’s sanitation authority is making a significant contribution to this ambition:
- ISO 14001 environmental management certification since 2004
- Recognized as an exemplary local authority in its actions to combat and adapt to global warming in the context of its sanitation responsibilities, at the international water forum in Copenhagen in 2022.
A conclusive experiment
The installation of two 117 m2 photovoltaic trackers by OKwind (35) and the artificial intelligence proposed by Purecontrol (Rennes) is a first in France to power a wastewater treatment plant.
Photovoltaic technology is now well known. By associating this technology with a system of intelligent and connected trackers, capable of following the sun’s rays in an optimal way, the photovoltaic trackers make it possible to obtain an optimized production of renewable energy all day long.
Purecontrol has developed an algorithm capable of analyzing in real time the functioning of the treatment plant process. From the data collected, the algorithm will be able to anticipate the actions of the process to optimize energy consumption, the goal, consume better and consume less.
This solution has already been tested at two of the city’s wastewater treatment plants and has resulted in savings of 15 to 20% on the energy bill. It is currently being deployed at all other wastewater treatment plants.
In operation since June, the trackers have so far achieved 68% self-consumption of their production and 30% energy autonomy for the plant.
The innovation lies in the combination of these two technical solutions. Indeed, the artificial intelligence developed by Purecontrol will allow to shift certain consumptions during the periods when the photovoltaic trackers produce the most. This will increase self-consumption and reduce the station’s electricity consumption by a further 12%.
In total, on an annual consumption of 190 000 kWh (equivalent to 40 households), the device will reduce the consumption of the equipment to 108 000 KWh, a reduction of 43%.
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