Public Utility Company ‘Waterworks and Sewerage’ Novi Sad in Serbia needed to improve its water supply system in light of the country’s changing energy market. Together with the Regional Centre for Energy Policy Research (REKK), DHI’s engineers used hydraulic modelling to identify energy saving interventions, forecast energy use and provide a cost-benefit analysis to determine the best operational scenarios. The partnership provided a much-needed solution for the water utility, which has not yet developed a hydraulic model for Srem area—the most complex part of the water system—to this day.

*This project has been co-financed by the Western Balkan Green Center of the Ministry of Innovation and Technology of Hungary.

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The majority of the water supply in the project area is based on pumping water. With about 45 pumps in the vicinity, the water utility was dealing with significant energy requirements and associated costs. A calibrated hydraulic model would best help them determine ways to lower the pumps’ energy use. The intention was also to use the model results to calculate how to reduce CO2 emissions. Due to the water system’s complexity, no hydraulic model has been developed.


DHI developed a hydraulic sub-model of the Novi Sad water network consisting of 210 km of pipelines of diameter 100-900 mm (excluding service pipes), primarily made of AC, PE, PVC, and Cl/CLS. The Srem area water network consists of over 15 pressure zones, a high number of pumping stations (about 45 pumps) and 14 storage tanks.

The model represented about 25% of the water system involving 8,800 customer connections. It was carefully modelled to ensure a good match between simulated and observed data; calibration plots were developed for 54 comparison points, 21 flows and 33 pressures or water levels. Energy optimisation measures included a pump operations efficiency review and system-wide energy audit.

DHI’s solutions were to:

  • Create a calibrated hydraulic model of the highly complex water system
  • Link the energy market forecast model to the hydraulic model
  • Provide cost-benefit analysis and suggestions for better operations
  • Analyse potential CO2 savings to support climate change mitigation

Electricity price forecast and cost calculations

Using the European Power Market Model that provides wholesale electricity prices for each hour and each country, DHI’s partner REKK helped ViKNS calculate average energy prices to estimate retail price points. REKK derived these conclusions:

  • Energy prices are increasing yearly
  • Daytime prices are now higher than nighttime because of electricity demand
  • When more and more solar energy is used during the day (8am-8pm), daytime prices will become cheaper. This is particularly true during summer months, thus price differences between winter and summer increases further.


Complex part of the water system now well represented in hydraulic model

Hydraulic model linked to energy market forecast model for more accurate pricing estimates

Energy savings measures discovered through comparison of energy optimisation scenarios

‘We are happy to cooperate with DHI. The hydraulic model they developed for the complex Srem area will help us improve and optimise the water system. Thanks to the DHI team, our work is now easier thanks to the energy-efficient and sustainable solutions proposed.’

Zlatko Arvaji MSc
Civil Engineer of Hydrotechnics
Senior Engineer, Development Department
PUC ‘Waterworks and Sewerage’ Novi Sad, Serbia

About the client

PUC ‘Waterworks and Sewerage’ Novi Sad, Serbia is a public utility that produces and distributes quality drinking water to 135,000 households in Novi Sad and its surrounding settlements. The company also performs wastewater as one of its basic functions and activities.

The project has been co-financed by the Western Balkan Green Center of the Ministry of Innovation and Technology of Hungary.

About our partner

The Regional Centre for Energy Policy Research (REKK) provides professional analysis and advice on networked energy markets that are both commercially and environmentally sustainable. Since 2004, they have performed comprehensive research, consulting and teaching activities in the electricity, gas and carbon-dioxide markets. REKK’s analyses range from the impact assessments of regulatory measures to the preparation of individual companies’ investment decisions.

Software used

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