December 2024 – Croatian Energy Scouts cover a quarter of the electricity needs of a swimming pool with a photovoltaic system, Čakovec, Croatia

Čakovec is a town with around 27,000 inhabitants and the administrative center of Međimurje County in the far north of Croatia. The company GP-Ekom d.o.o. is the town’s company for the management of some sports facilities such as sports fields and swimming pools. Due to their high heat and energy requirements, swimming pools are one of the largest energy consumers among public facilities. Uncovering the unused energy efficiency potential there would save the tight municipal coffers and benefit the whole community.

Thanks to the short amortization period and the “convincing” Croatian sun, the financial requirements were quickly met. The large rooftop photovoltaic system went into operation as early as December 2023. A total of 653 PV modules with a maximum peak output of 375 W each were installed, which corresponds to a total installed direct current output of 244,875 kWpeak or an alternating current output of 220 kW.

The electricity is mainly used to cover the company’s own requirements, is fed into the grid in full and is billed at the end of the month. The PV system utilizes almost the entire suitable roof area, leaving only roof areas facing north or shaded in winter free. The PV modules were mounted on the supporting surface of the roof panels. If only the electricity demand were taken into account, the system could be even larger. However, the direct power consumption at any time of day (and position of the sun) results in financial advantages because a battery is not required for storage.  This results in a very short amortization period of just over three years, while the entire system is designed for a term of 25 years.

The annual analysis shows: in 2024 (excluding December), a total of 1,263 MWh of electricity was consumed, 272 MWh were generated by the PV-system , thus covering around 22 % of the electricity demand.

Photovoltaics

  • Industry sector: Municipal swimming pool
  • Energy source: electricity
  • Electricity savings potential: 272.3 MWh/year
  • CO2 emissions savings potential: 64.1 t of CO2/year (electricity)
  • Potential cost reduction: approx. 22 % of electricity costs
  • Investment costs: 210,000 € (net)
  • Payback period: 6 years
  • Company:
    GP-Ekom d.o.o.
    Športska 2
    40000 Čakovec
    Croatia
    www.ekom.hr
Indoor swimming pool area with multiple pools, lounge chairs, plants, and decorative elements.
Indoor swimming pool with multiple lanes, tiled deck, large windows, and a ceiling supported by wooden beams.
Outdoor swimming pool complex with several pools, surrounded by buildings, fields, and trees.

The swimming pool has an outdoor and indoor area (©GP-Ekom).

Industrial area with large filtration units connected by pipes and valves; clean and well-organized environment.
The water in the outdoor pools is treated with ultrafiltration modules so that it is clean (©GP-Ekom).
Bar chart showing the ratio of consumed and generated electricity in 2024, with monthly data for grid electricity, generated electricity, and total consumption.
Annual overview of electricity consumption. In the summer, most of the electricity is used for cooling and air conditioning, in the winter, it is used for heating. Heat pumps can do both. Maintenance is due every year in September, making it the month with the fewest visitors in the year, along with February (©GP-Ekom).
Bar chart showing electricity consumption from 2007 to 2024 in kilowatt-hours.
The annual analysis of costs shows a sharp reduction of 22% in electricity costs from 2023 to 2024 (©GP-Ekom).
Two aerial views of a building with solar panels on the roof – one wide view and one close-up.
The roof surface is valuable - the PV-system installed on the roof of the “Marija Ružić” indoor swimming pool in Čakovec (©GP-Ekom).
wo people in yellow safety vests standing in front of a modern building with glass windows and a slanted roof; a swing set is visible on the right.
Energy Scouts Miodrag Novosel and Saša Končić in front of their project (©GP-Ekom).
Two people in yellow safety vests standing in front of a building with a grey facade, blue doors, and white electrical boxes.
The inverters convert the direct current from the PV modules into alternating current as used in the electricity grid (©GP-Ekom).
Photovoltaics
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