By Norbert Jardin, Ruhrverband, Germany
The Ruhrverband ensures water supply to 4.6 million people through eight major reservoirs and operates wastewater treatment plants for 60 municipalities. However, the utility faces significant climate change-related challenges that impact its core operations. To address these, Ruhrverband has, among other things, implemented legal changes to reservoir operations in the Ruhrverband Act (RuhrVG) and expanded the use of renewable energy sources, including solar power. Despite these efforts, energy neutrality has so far been achieved ‘only’ on an annual basis and remains difficult to maintain at a quarter-hourly resolution throughout the year. Furthermore, it poses a challenge in achieving a consistently balanced greenhouse gas (GHG) footprint. To close this gap, Ruhrverband is developing a comprehensive roadmap and implementing targeted measures aimed at reducing its GHG emissions by approximately 60% by 2030.
Problem
The Ruhrverband’s actions are driven by its legal mandate under the Ruhrverband Act (RuhrVG). However, with the onset of climate change, this will become an even greater challenge, especially for the reservoir system. The utility’s reservoir operation is highly affected by climate change. Since 2018, the Ruhrverband has observed long dry periods with less-than-average rainfalls and increasing temperatures. Furthermore, climate modelling projections undertaken indicate, these situations will become more frequent in the next decades.
In 2023, the Ruhrverband achieved a historic milestone by generating more electricity from renewable energies than it consumed over the course of the year. However, seasonal fluctuations remained a challenge. During summer, some electricity must be purchased, as electricity production from hydropower is generally not high in these months. Instead, a surplus was generated in the winter months, which was then fed into the grid. This, therefore, informed the next goal of the Ruhrverband to achieve energy neutrality during every single quarter of an hour throughout the year, followed by the goal of achieving a balanced carbon footprint.
The reduction of greenhouse gas (GHG) emissions presupposes that the current emissions and potentials are known. The Ruhrverband has compiled a GHG balance sheet covering the years 2013 to 2024, identifying the major emitters and summarising the mitigation measures as part of a feasibility study. This study has now been translated into a roadmap for achieving the goal of ‘a balanced carbon footprint by 2030’. The actual GHG balance shows the following results for the year 2024: Scope 1: 33,800 t CO2e, Scope 2: 1,300 t CO2e, Scope 3: 66,800 t CO2e. The positive equivalents from climate protection measures, e.g., management of own forests, totalled 26,600 t CO2e in 2024.
Adapting to climate change
In the past years, the Ruhrverband and others have advocated for the legislative body of what they believe to be an urgently needed step towards increasing the climate resilience of their reservoir system. As a result, in December 2024, the parliament of the State of North Rhine-Westphalia agreed to a reduction of the minimum flows required by the Ruhrverband Act. This important step helped them to preserve the water stored in reservoirs for longer periods, thus providing a secure drinking water supply for 4.6 million people.
The change of the Ruhrverband Act was accompanied by an agreement outlining several measures for water quantity and water quality improvement. The measures included:
- Establishment of year-round, runoff-dependent powder-activated carbon-dosing at two WWTPs as an immediate and temporary solution
- Upgrading of ten WWTPs with an advanced treatment stage to reduce micropollutants
- Measures to ensure the coherence of the Natura 2000 network
- Monitoring to record the possible effects of reduced minimum outflows and to assess the effectiveness of the coherence assurance measures
- Implementing an operational flood forecasting model and provision of the forecast to stakeholders and the public
- Potential analysis of flood retention areas
- Analysis of pre-relief options in the event of flooding
- Carrying out a ‘hydrological stress test’
Additionally, the Ruhrverband supports municipalities in planning preventive flood protection measures such as flow delay, flow reduction and/or retention space management. To further these efforts, the Ruhrverband will develop an initial overarching concept for one catchment area.
Finally, the Ruhrverband, in collaboration with another public utility and support from the state ministry for the environment, has launched a project worth 250 million euros to further expand the blue-green infrastructure in one of Europe’s most densely populated areas, the Ruhr Region. This initiative aims to enhance climate resilience and sustainable water management.
Mitigation actions
The Ruhrverband’s GHG inventory identifies potential opportunities for reducing GHG emissions. An estimate revealed an overall reduction potential of 61% across different scopes (Scope 1: 44%, Scope 2: 68%, Scope 3: 69%). A major initiative includes the construction of a solar sludge drying plant at the company’s sewage sludge combustion plant. The operation of such a facility would enable the Ruhrverband to use dried sewage sludge instead of coal in the auxiliary firing, reducing GHG emissions significantly and advancing sustainability goals.
In addition, the Ruhrverband has identified a strong collaboration between nitrous oxide emissions and the wastewater treatment plant’s ability to remove nitrogen. To better understand and manage these emissions, the company plans to advance measurement techniques to verify and assess the correlation between operational parameters and emissions. Another potential project being explored by the Ruhrverband is aimed at reducing methane emissions from the sludge of the wastewater treatment plants. This involves the use of vacuum degassing technology to improve methane separation. Currently, the company is evaluating the feasibility of this new approach.
Lastly, the Ruhrverband is currently in the planning and authorisation phase for the construction of further solar power plants (PV) with a total capacity of about 14,000 kWp advancing its goal of being energy-neutral every quarter of an hour. The first building permits have been submitted and construction of the first plants is expected to start in 2025.
The Ruhrverband addresses the challenges of climate change in its core business with the increased expansion of renewable energy generation plants (pictured: photovoltaic plant at the Essen-Kettwig wastewater treatment plant). Photo credit: Ruhrverband.
Communication with citizens
As a water association under public law, the Ruhrverband is strongly committed to the climate agenda at its leadership level. This is particularly evident in the corporate mission statement and strategic framework. Based on the vision, ‘Ruhrverband – The best water for people and nature today and in the future’ and the mission ‘Holistic water management for the Ruhr: efficient – sustainable – climate neutral’, the corporate strategy comprises five fields of action, one of which focuses completely on sustainability.
In addition, the RV involves its stakeholder groups at various levels in planning and decision-making processes. One example in which the RV cooperates closely with its municipal members is the funding project KRiS (‘Climate-Resilient Region with International Appeal’). The dissemination of experience to stakeholders also takes place in the integral drainage planning programme, as all urban water management measures are planned in close collaboration with the city or municipality concerned.
The project ‘Gießkannenheld:innen’ (‘Pouring Can Heroes’) aims directly at citizens, encouraging them to act climate-smart in their immediate environment, whereas the recently launched Schwammwaldinitiative (‘Sponge Forest Initiative’) brings together organisations and authorities in their pursuit to establish a sustainable forest management for the largest contiguous forest area in North-Rhine Westphalia.
With a strong learning culture being part of the corporate DNA, the Ruhrverband’s pioneering role within the German water and wastewater treatment community comes as no surprise. Employees who give lectures and presentations at conferences enjoy unconditional support, as do Ruhrverband’s representatives who engage themselves in committee work on either the national or international level. In 2023, the Ruhrverband played a key role in the development of the ‘Roadmap 2030’. The joint DVGW and DWA project offers an action agenda for the future of water management and lists over 50 specific measures that address the challenges of climate change and social change.
Lessons learned
- Our efforts to adapt the Ruhr Association Act have shown that legislative changes take time and can only be influenced to a limited extent, although the necessity and possible risks have been comprehensively explained.
- With regard to both ‘energy neutrality’ and ‘GHG neutrality’, it is clear that it is a question of definition and system boundaries. Furthermore, literature values (for balancing) should be underpinned by own measurements. So far literature data are insufficient to draw up a reliable balance sheet.
- We are already well advanced in the area of ‘energy neutrality’ in comparison within the industry.
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