Goals
The Nice Cote d'Azur Metropolis (NCA) is spearheading an ambitious geothermal energy project to establish an urban heat-cold network. By integrating geothermal energy from surface water tables, heat pumps (PAC), and photovoltaic solar thermal energy, this project aims to:
- Cover 82% of the thermoelectric energy demand for 500,000 m² of buildings by the 1930s.
- Operate under a 25-year public service delegation (DSP) awarded to IDEX.
Project Context
The geothermal exploitation plan targets the aquifer of the Var alluvium near the Méridia district. The project includes:
- Well Network: 12 wells (4 producers, 8 injectors) designed to prevent thermal breakthrough and premature cooling.
- Flow Rate: A nominal cumulative flow rate of 600 m³/h, maintaining compatibility with nearby drinking (AEP) and industrial (AEI) water wells.
- Location: Lower Var Valley, a 25 km stretch characterized by ancient alluvial deposits and bordered by folded structural zones.
Modeling and Simulation
To ensure compatibility and sustainability, advanced simulations were conducted:
- Hydrothermal Interference: Evaluated interactions between planned and existing wells under seasonal cycles.
- Thermal Impacts: Seasonal temperature variations (15°C baseline) were mapped, showing limited impact on the aquifer's natural flow regime.
- Hydraulic-Dynamic Effects: Minimal interference with nearby AEP and AEI wells, with piezometric changes limited to a few centimeters.
Mining Plan Development
The project implemented a comprehensive mining strategy:
- Well Drilling: 12 wells drilled to 50 m depth, targeting the aquifer's upper alluvial fraction.
- Infrastructure: Subsurface wellheads and underground pipes ensure safety, aesthetics, and environmental harmony in the residential ecodistrict.
- Performance Testing:
- Production tests showed flow rates of 200+ m³/h and specific flow rates between 115 and 430 m³/h/m.
- Injection tests confirmed injectivities averaging 300 m³/h/m at 150 m³/h flow rates.
Innovative Design and Execution
The Nice Méridia smart grid project exemplifies sustainable urban planning:
- Energy Efficiency: A balanced integration of geothermal energy and other renewable sources.
- Environmental Impact: Minimal disruption to the natural aquifer regime and surrounding wells.
- Urban Harmony: Infrastructure designed for aesthetic and functional integration into the cityscape.
Conclusion
The first phase of the Nice Méridia geothermal smart grid has been a resounding success, thanks to the meticulous planning and execution by NCA and its partners. This project sets a benchmark for sustainable urban energy solutions, combining innovation, environmental stewardship, and operational excellence.