Aquatic centers: transforming energy constraints into levers for territorial transition

At the heart of the concerns are aquatic centers, essential educational and social infrastructures, caught between an aging stock, soaring energy costs and strengthened regulatory obligations, notably by the Tertiary Decree and the recent "mega-decree" for simplification of February 2026. How to sustain these facilities without increasing deficits?

Aquatic centers under pressure: decarbonizing to control costs: how to break free from the volatility of fossil fuels?

Aquatic centers, iconic buildings in their communities, are also among the most complex public facilities to operate. Operating year-round, they have significant requirements for heating, ventilation, water treatment, and indoor air quality. In a context of sustained increases in energy costs and severe budgetary constraints for local authorities, the challenge is no longer simply to renovate, but to ensure long-term operational viability.

And with a building stock largely dating from the 1960s-1980s, their dependence on fossil fuels directly exposes local budgets to price volatility. Decarbonization is therefore no longer an option, but an economic necessity.

Cost control begins with a comprehensive approach to the building: precise management of facilities, enhanced preventive maintenance, continuous monitoring of energy consumption, and anticipation of equipment aging. This approach not only helps to contain operating expenses but also avoids costly and disruptive technical shutdowns for users.

Finally, aquatic centers represent a prime testing ground for decarbonizing their uses. Their stable and predictable consumption profile lends itself to the integration of local or contract-based renewable energy solutions.

The most effective solution is to mobilize local resources: shallow geothermal energy, particularly suited to the continuous thermal needs of the basins, hybridization of energies (heat networks, recovery of waste heat, heat pumps), photovoltaics in self-consumption or via green electricity purchase contracts (Green PPA), water sobriety, with the recovery and reuse of water.

These solutions are not mutually exclusive: they can be combined, on a case-by-case basis, depending on the site and the territory.

All these solutions make it possible to overcome market fluctuations and stabilize costs, as demonstrated by Caux Seine Agglo, where a comprehensive approach integrating operation and modernization generated 10 to 15% energy savings on the heating and cooling needs of five aquatic centers. Similarly, in the COBAS (South Arcachon Basin) region, the effectiveness of hybridization is demonstrated by the choice of an energy mix combining wood, solar thermal, and electricity to power three swimming pools, transforming a cost center into an asset for the region's energy transition.

The Performance Contract: the tool to guarantee savings and achieve the objectives of the Tertiary Decree?

Implementing a decarbonization strategy is one thing, securing its results is another. This is the crux of the contractual framework, especially since local authorities are subject to the Tertiary Decree, which mandates a 40% reduction in their energy consumption by 2030.

To address these challenges, local authorities now have several contractual arrangements that allow them to combine commitment to results with objective performance monitoring.

Energy Performance Contracts (EPCs) are based on a simple principle: the operator commits to measurable consumption levels, verified according to recognized protocols. Global Performance Contracts (GPCs/GPCs) expand on this approach by integrating design, construction, operation, and maintenance within a single contractual framework. Other models also exist, such as optimized management by the public authority or Public Service Delegation, depending on the project's maturity and the local authority's asset management strategy.

Beyond the installation itself, the credibility of the system relies on the ability to measure, verify, and adjust. Monitoring indicators (energy, water, facility availability) then becomes a lever for management and continuous dialogue between the operator and the local authority.

The effectiveness of this model has been proven in Lyon, where the city opted for a Global Performance Public Contract for the renovation of the Vaise swimming pool. This engaging framework, which included the renovation of the ventilation and heating systems, made it possible to achieve 25% energy savings, transforming a regulatory obligation into a shared and controlled performance project.

Indoor air quality: beyond energy, how to address health and air quality challenges?

The performance of an aquatic center is not measured solely in kilowatt-hours. While energy is often at the heart of discussions, indoor air quality is an equally critical public health issue, recently reinforced by Decree No. 2026-118, which entrusts the operator with full responsibility for monitoring water quality.

The culprit: trichloramines, byproducts of the reaction between chlorine and organic matter brought in by bathers. Highly volatile, they concentrate in the air and can cause irritation, respiratory problems, and accelerated deterioration of buildings.

To address this, building operators are now relying on solutions that combine smart ventilation, humidity control, and continuous monitoring of trichloramine concentrations. The goal is to precisely adjust fresh air flow rates according to actual usage, rather than systematically over-ventilating. This ensures healthier air while optimizing energy consumption.

This synergy between health and sobriety is visible on the Royan Atlantique swimming pool park, where the optimization of regulations has allowed a measurable improvement in indoor air quality while generating between 10 and 20% energy savings on thermal and ventilation uses.

The ELENA Piscines solution exemplifies this evolution. Compatible with existing installations, it allows for real-time ventilation control, improving user comfort and simultaneously reducing electricity consumption. Within this precise monitoring system, the installation of trichloramine probes provides reliable, real-time measurement of a critical pollutant, contributing to the modern, responsible, and efficient operation of the aquatic center. Air quality thus becomes a monitored, objective, and shared indicator.

At the crossroads of energy, health, and budgetary challenges, aquatic centers are undergoing a transformation. Far from being a mere burden, their modernization represents a significant opportunity for local communities. By addressing the energy mix, the contractual framework, and the precise management of the facilities, local authorities can transform these facilities into exemplary infrastructures of the ecological transition: more energy-efficient, healthier, and more resilient.

Opinion piece by Peio Maisonnave, aquatic center expert at ENGIE (LinkedIn).