Prague Water’s roadmap to carbon neutrality by 2035
In 2019, the city of Prague set out a plan for becoming a carbon-neutral metropolis. Following the example of other leading European cities, Prague adopted a ground-breaking city council decision with a goal of reducing CO2 emissions in the entire municipal area by 45% before 2030. It has been estimated that water-related energy use is equivalent to 13% of the nation’s electricity consumption. CO2 embedded in the nation’s water is 5% of all carbon produced nationwide (an estimation based on research conducted in the USA). Pražské vodovody a kanalizace a.s. (PVK) as the largest water and waste-water utility in the Czech Republic supplies drinking water for Prague and part of the Central Bohemian Region. Together with Pražská vodohospodářská společnost a.s. (PVS), we are looking for ways to minimise impact on the environment and improve water management, with resilient water infrastructure, less water loss, and using wastewater and resource recovery.
Adapting to climate change
To improve water management and further adapt to climate change, Prague Water diversified its portfolio by investing in an extensive modernisation of one of its treatment plants (Podoli) which until 2018 only served as a substitute plant. The utility also included in their treatment process another layer of filtration through granular activated carbon which enhances the removal of pesticides and their metabolites to supply drinking water of the highest standards.
Prague Water, in its pursuit of reducing water loss within the water distribution network, has implemented innovative technologies such as satellite leak detection or Enigma 3M – an advanced fault detection system that uses noise sensors. In 2021, Prague Water launched a new leak detection project which uses an extension of the SWIM (Smart Water Integrated Management) system. This system detects leakages using artificial intelligence. Thanks to this, Prague Water managed to reduce water loss from 34% in 2000 down to 12% in 2021.
The utility is committed to reducing water consumption and continues to explore other sources of water for non-portable use. We are currently working on an EU-funded project ‘Wider Uptake’ to evaluate opportunities for treated wastewater use for non-drinking purposes such as irrigation and maintenance of urban greenery, surface washing and cooling the capital territory during the hottest summer days.
The utility’s efforts to minimise its impact on the environment also include resource recovery. Currently, the most valuable resource recovered by Prague water is biogas generated from sludge in thermophilic anaerobic digesters, which is used to produce electricity and heat for the operation of the Wastewater Treatment Plant. However, studies are currently being carried out to evaluate other resource recovery opportunities, such as heat recovery from wastewater.
In 2022, Prague Water launched a company-wide project with the main goal of achieving net operational carbon neutrality by 2035.
To achieve this target, ISO Standard ČSN ISO 14064-1 was chosen as the most suitable method since the utility has been certified according to other ISO standards. Following this, Prague Water has developed the method for Scope 1, Scope 2 and Scope 3 (as defined by the GHG Protocol). These documents include a detailed description of data that need to be collected and methods of carbon footprint calculation. To ensure the most accurate results taking into consideration the local conditions, the utility has also set up a partnership with the Department of Sustainability and Product Ecology (DSPE) – under the University of Chemistry and Technology – to share knowledge on carbon footprint calculation.
Prague Water has identified several fields of operational activity with great potential for GHG emission reduction. A GHG emission reduction action plan to reduce the utility’s carbon footprint has been prepared. The utility recognised that the largest percentage of its emissions is represented by process emissions generated during wastewater treatment. We plan to launch a measurement campaign targeted at N2O escaping from biological lines into the atmosphere and by using mathematical modelling based on data to adjust the aeration regime and minimise emissions. GHG emissions related to electricity consumption from the grid ranked second. To minimise energy-related emissions, the utility will consider primary measures aimed at maximising energy efficiency. Currently, we are exploring the possibility of using energy stored in wastewater – residual heat from treated wastewater and blowers, energy recovery from digested sludge and screenings and maximisation of biogas yields. Prague water has also begun installing photovoltaic power plants in selected buildings. An additional step of Prague Water’s net zero journey is the reduction of the carbon footprint of its vehicle fleet; since 2017, Prague Water has been systematically transitioning to CNG vehicles with its goal to operate 122 CNG vehicles by 2025.
Communication with citizens
Prague water is committed to creating value for all their stakeholders by actively participating in sustainable urban projects of the city of Prague. Awareness and education are our core objectives. Activities such as guided tours for the public, regular open days of the water treatment plant, and competitions focused on water and the environment for schools are an important aspect of our awareness-raising campaigns.
As active contributors to conferences within the Czech Republic and internationally, Prague Water has been actively expressing its passion and vision for carbon neutrality and sharing ideas on how to calculate and mitigate its carbon footprint. We have published the first detailed data about operational carbon in the Czech Republic at local conferences and magazines.
Carbon footprint mitigation is like any other new great challenge – the hardest part is the beginning. At the start of the project, Prague water did not have any idea of how to calculate the carbon footprint, where to start, what method to use, or mitigation measures. Through the knowledge gained from the IWA Climate Smart Utilities Recognition Programme, they have been able to develop and implement methodologies and strategies and we are happy to be able to share it with the community of water professionals in the Czech Republic and around the world. The planet is in a climate crisis, and it is our duty to act and motivate others to do the same.
For more information on this climate smart story, contact: Martin Srb
Useful Links and References
The Capital City of Prague. Prague 2030 Climate Plan. Prague’s mission towards zero emissions. [Online] 2021. [Citace: 14. 12 2021.] https://klima.praha.eu/en/the-climate-plan-at-a-glance.html.
Griffiths-Sattenspiel, Bevan a Wilson, Wendy. The Carbon Footprint of Water. Portland : River Network, 2009.
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