The recycling of process and cooling water is implemented throughout the Group, where appropriate.
In order to reduce the impact on freshwater withdrawal, the possibilities of using water from wastewater treatment plants and rainwater as a source of complementary water are studied as early as the design stage of new nuclear reactors. Moreover and by way of example, it is planned to pool the existing demineralisation plant between Penly 1/2 and the two future EPR2 units for the production of industrial water and demineralised water using wastewater from the treatment plant, rainwater collected via stormwater basins and water from a drain at the foot of the cliff.
EDF’s thermal power plants in Cordemais and Martigues recover rainwater and recycle their effluents. The Blénod thermal power plant has also studied a system for recycling rainwater and process effluents to be implemented by 2023.
At West Burton A, effluent from the sewage treatment plant is no longer discharged into the river but is diverted for reuse in the cooling water circuit. As a result, up to 100,000m3 of water is no longer taken from the River Trent each year.
In China, the ultra-supercritical power plant of Fuzhou reuses all its process water sequentially and depending on the quality of water (from cooling to watering ash to gardens).
In Dalkia’s large biomass combustion facilities, process wastewater is used to cool bottom ash to limit the volume of liquid effluent to be treated.
In Flamanville, a desalination unit has been in operation since 2016 to produce demineralised water. EDF is also conducting several desalination experiments for process water at its sites:
According to the World Meteorological Organization (WMO), the period from 2015 to 2022 corresponds to the eight warmest years ever recorded in the world (1). In France, 2022 was the hottest year ever recorded and the second hottest (meteorological) summer after 2003, with an average of +2.3°C compared to the average for the 1991-2020 period, and a record 33 days of heatwave (in 3 waves). Locally, it was even the hottest summer (in Chamonix for example). Moreover, 2022 was one of the years with the least amount of water, with a 22% rainfall deficit compared to normal. Some months even broke records, such as May (-60% deficit) and July (-85%), which were the driest since measurements began in 1959. These temperatures combined with the significant hydrological deficit led to a drought that was more intense and more extensive than those of 1976 and 2003, the most intense ever recorded in France, with surface soil moisture values breaking records for low humidity. This underscores the importance of balanced and sustainable water management.
The early drought of 2022 affected hydropower generation in France. The summer of 2022 broke the 1976 record, with a summer hydraulic deliverability coefficient of 0.59 (1 being the 1960-2022 average) and a 20% drop in production over the year (to be confirmed at the end of the year) compared with 2021 (but no historical minimum). Many reservoirs were under exceptional management throughout the summer, up to 23 simultaneously, and 10 were still under exceptional management. In contrast to Metropolitan France, French Guiana and Reunion experienced surplus regimes (even experiencing flooding) and reached high production levels.
The heat waves with 3 successive heat waves and severe low water levels had no impact on nuclear safety and had a limited impact on the production of the nuclear fleet (500GWh, i.e. less than 0.2% of the annual production in 2022). Due to the extreme weather situation and tensions on the energy market, temporary modifications to the thermal discharge limits were granted to the Blayais, Bugey, Golfech, Saint Alban and Tricastin nuclear power plants to maintain the security of the power grid (as requested by RTE), and then to preserve natural gas and water reserves for the winter.
In total, about 400GWh were saved through temporary changes to the thermal discharge limits:
The initial feedback from the enhanced environmental monitoring implemented by the operator as part of the temporary modifications does not show any significant changes in physico-chemical and microbiological parameters and no unusual fish mortality has been observed.
Studies of water consumption are underway for all the thermal sites in order to refine the procedures to be followed in the event of a drought alert in 2023 (2).
EDF does not own the water stored in its dams; it uses it as part of a public service mission to generate energy on the basis of the available resource while incorporating other uses as best as possible.
The water in these reservoirs is not only used to generate hydropower, but depending on the reservoir, it can be used for drinking water supply, irrigation, navigation, tourism, recreation and the preservation of biodiversity. This availability of water for other uses can have an impact on hydropower generation, a renewable and carbon-free energy that contributes to climate change mitigation.
A balance must therefore be sought through close and continuous consultation with local stakeholders, including governmental services, which are the last resort in the event of arbitration on the prioritisation of water uses.
EDF constantly ensures that its hydraulic facilities are managed in consultation with the stakeholders (the French government, local authorities, water agencies, associations, etc.). As such, EDF plays a part in national and local water governance and management bodies (national water committee, basin committees, local water commissions, etc.).
In France, EDF is represented by the French Electricity Union (3) at meetings of each of the river basin water governing authorities.
(3) Union française de l’électricité (i.e. French electricity union).
