Water Resource
In 2022, CEZ Group joined the UN CEO Water Mandate and committed to responsible water stewardship and regular reporting on water management. By endorsing the UN CEO Water Mandate, CEZ Group agrees to continuously improve in six core areas of water stewardship practice: Direct Operations, Supply Chain & Watershed Management, Collective Action, Public Policy, Community Engagement, and Transparency. Surface water is an indispensable resource in the generation of electricity for CEZ Group facilities and an indispensable cooling medium used in production processes. The water used in this way is returned to the watercourses immediately downstream of the abstraction point. Around two-thirds of the total surface water withdrawn is used for once-through cooling systems.
Water withdrawals do not pose a significant environmental risk. A material impact refers to an impact caused by mining and the disruption of the local water regime and ecosystems related to the MINING segment. This impact is being addressed through decarbonization and the development of CEZ Group’s business model and is also related to the topic of Biodiversity, where additional mitigation actions are listed (more information is provided in the chapter Biodiversity and Ecosystems of the Sustainability Report 2024).
To achieve the commitments under the Environmental Policy and meet the set targets, actions are implemented with priority on achieving climate neutrality and reducing pollution. Actions to increase the biodiversity of water resources are described in the chapter Biodiversity and Ecosystems of the Sustainability Report 2024. In addition to these actions, other actions are being implemented to mitigate environmental impacts on water resources.
- Certified Environmental Management System
- Recycling of Used Water in Generating Facilities
- Limiting the Use of Groundwater for Technological Purposes
- Use of the Energy Potential of Water
- Modernization of Hydroelectric Power Plants
Withdrawals of surface water for CEZ Group’s operations do not significantly impact the water volume of the watercourses involved. Maximum surface water withdrawal by plants with circulation cooling ranges from 0.02 to 7.66% of the natural flow capacity, and can therefore be assessed as negligible or low. An exception to this was a short-term emergency withdrawal at a level of 12.69% in one of the locations in 2024, which is assessed as medium. A significant impact on the flow is the maximum permitted surface water withdrawal for the Dukovany NPP – amounting to 28.01% of the natural flow in 2024. Surface water withdrawal is minimized by using the Dalešice water reservoir on the Jihlava River, and wastewater is discharged into the same reservoir. Furthermore, the water reservoir serves as a pumped-storage hydroelectric power plant for the generation of electricity, for long-term flow balancing, for reducing flood peaks in the lower reaches of the Jihlava River, and for recreational use. In 2024, about 34% of withdrawn surface water was used for technological purposes. There is no identified impact of surface water withdrawal on biodiversity in protected areas and on the presence of specially protected plant and animal species.
The indicator “Water Intensity”, i.e., total water consumption in m3/CZK million of operating revenue decreased from 243 m3/CZK million in 2023 to 238 m3/CZK million in 2024.
Wastewater Recycling
After use, part of the used water is recycled in the plants to minimize the amount of surface water withdrawn. In 2024, the volume of wastewater reused in power plant operations was 7.7% of process water consumption. Another method to utilize wastewater is its use in small hydroelectric power plants. For instance, wastewater from the Temelín NPP is reused to generate energy at the Kořensko II hydroelectric power plant, where 1,820 MWh was generated in 2024. Another example of harnessing the potential of water to generate electricity is the use of the wastewater discharge turbines in Ledvice and Prunéřov. CEZ Group reuses wastewater from cooling tower blowdown, sand filter and gypsum washing, seepage water, and drainage water if the quality of the wastewater is sufficient for reuse.
Generating facilities withdraw surface and ground water and generally maintain small buffer reserves of both raw water and treated surface water for their own use. These reserves rarely reach volumes of tens of thousands of cubic meters, with a total of approximately 134,000 m3 surface water stored in thermal and nuclear power plants.
A specific case of water storage is the reservoirs of pumped-storage hydroelectric plants. The total water supply reserved for energy storage during times of energy surplus is maintained at 19,431,000 m3. The retention of surface water and its storage in the reservoirs can generally be considered as an anthropogenic factor affecting water status and ecosystems by changing the morphology of watercourse channels. Simultaneously, however, reservoirs fulfill other essential complementary functions serving local communities. In order to protect against the effects of the increasingly significant climate change, reservoirs are used to buffer flood waves and to ensure minimum sanitary flows as laid down in the operational schedules approved by the local authorities. In times of drought, they provide the basic living conditions for aquatic plant and animal species in water streams. Water storage implemented by CEZ Group therefore has predominantly positive environmental impacts.