Challenge : Reducing Energy Consumption & carbon footprint in Wastewater Treatment
Rennes Métropole, a pioneer in energy transition, embarked on an ambitious project to reduce the energy consumption of its essential yet energy-intensive wastewater treatment plants. The filtration and aeration processes crucial to wastewater treatment consume significant energy, contributing to a high carbon footprint and substantial costs for the community.
To address this challenge, Rennes Métropole launched an innovative initiative by installing solar trackers, which follow the sun’s path throughout the day to maximize energy production. The innovation also leverages artificial intelligence to optimize this installation.
Solution: Solar Trackers and Artificial Intelligence
At the Laillé site (Ille-et-Vilaine, France), photovoltaic panels equipped with trackers, controlled by advanced artificial intelligence, were installed. The facility also integrates Huawei 30/36/40 KTL inverters, enabling optimized energy conversion and management. This installation, featuring two 117 m² photovoltaic trackers provided by OKWIND and AI developed by Purecontrol (Rennes), is the first of its kind in France to power a wastewater treatment plant.
The integration of bi-axial and bifacial trackers, capable of continuously following solar radiation, represents a unique and ambitious challenge. Concurrently, Purecontrol developed an AI algorithm capable of real-time analysis of the treatment plant’s operations. This algorithm anticipates process actions to optimize energy consumption by shifting certain usages to periods of maximum photovoltaic production.
The particularly energy-intensive wastewater treatment plant greatly benefits from this energy optimization. This initiative aligns with Rennes Métropole’s energy efficiency goals, consistent with the Territorial Climate Air Energy Plan (PCAET). Through this pioneering approach, Rennes Métropole reaffirms its commitment to technological innovation and energy transition.
Benefits: Reducing energy consumption by more than 40%
Since their activation in June, the photovoltaic trackers have achieved a self-consumption rate of 68% of their production and provided 30% energy autonomy for the plant. Purecontrol’s AI has already enabled a 15 to 20% reduction in energy bills for the tested plants, with deployment across all other stations underway. Thanks to the integration of Huawei 30/36/40 KTL inverters, the system benefits from optimized energy conversion, maximizing overall energy efficiency. Annually, out of a consumption of 190,000 kWh (equivalent to 40 households), the system reduces the plant’s consumption to 108,000 kWh, a decrease of 43%.
Rennes Métropole’s commitment to energy efficiency is evident through concrete actions like improving public lighting and thermally renovating public buildings. These efforts were recently recognized with a Gold label in the European Energy Award program. Rennes Métropole’s sanitation authority, ISO 14001 certified since 2004 and noted for its exemplary actions at the Copenhagen International Water Forum in 2022, significantly contributes to this ambition.
“Huawei is a very reliable company that we have known for a long time. Their reliability and the quality of their equipment are impeccable, and the after-sales service provided by Green Power is top-notch,”
commented Louis Maurice, President of OKWind.
“The results are very positive. The technical goals we envisioned have been achieved. The integration of artificial intelligence has allowed us to exceed 40% self-consumption. We will be rolling out this solution extensively across our territory,”
concluded Boris Guéguen, Director of Sanitation at Rennes Métropole.
