February 2022 – LED lighting and a rooftop photovoltaic system for Croatian Konzum supermarkets

Konzum is the leading retail chain in Croatia with more than 600 stores and 11.000 employees. Every day, more than 500,000 customers shop at 211 locations throughout Croatia. The company positions the brand with a wide range of products, an extensive network of stores and a high quality of service. The retail chain is regularly audited according to ISO 50001 (Energy Management System) and therefore constantly monitoring energy use, aiming at reducing energy consumption and reducing impact on the environment.

PV & LEDs – a smart couple

The team of Energy Scouts, Electrical engineer Mladenko Jurković and mechanical engineer Hrvoje Šarić, choose the exchange of existing lighting and the installation of a photovoltaic system on the roof of Supermarket Konzum “Dankovečka” as practical project. The primary goal was to achieve energy savings and reduce operating costs on the long run while reducing CO2 emissions at the same time. The concept is considered a pilot project to test the system and gather more experience for a possible later roll out in more locations of the company.

The first step was to replace the existing fluorescent lighting with new LED lighting. All lighting systems for the companies’ stores are standardized – defined lamps, lighting, temperature, and color of light. The main problem was the hight power consumption of the lighting and poor lighting intensity, resulting in low efficiency. After the already implemented modification, the Energy Scouts reduced the power demand from 122 kW to 41.5 kW, while doubling the light intensity. The related investment of 73.000 € for the lighting system is returned after roughly 1 year and 7 months, which is a very good indicator.

The Energy Scouts went further and asked how the supermarket could be supplied with renewable energy. Analysing economic and ecologic aspects, photovoltaic (PV) power plants as an ideal solution. Due to the large number of locations, Konzum has a unique opportunity to choose the most ideal locations to install a PV-System. With an average 2,500 hours of sunshine per year, Croatia offers very good conditions.

Mladenko and Hrvoje plan an on-grid system, where the electric installations work in parallel with the grid. The savings are realized by reducing the amount of (expensive) electricity taken from the grid. 1,900 modules with a maximum power of 385 W each add up to a power plant with 732 kWp. The expected annual energy production would amount to roughly 788,000 kWh and thus reduce CO2 emissions by 149 tons per year. Due to the steep increase in electricity prices and high likelihood of this trend to continue, the return of investment is expected to be just below 5 years.

Photovoltaics

Lighting

Energy Management

  • Industry sector: retail industry
  • Energy source: electrical energy
  • Energy saving potential: 1,198 MWh/year (LEDs: 410 MWh / PV: 788 MWh)
  • CO2 saving potential: 199.3 t/year (LEDs: 51t / PV: 149t)
  • Investment cost: LEDs: 73,000 € / PV: 474,000 €
  • Payback period: lighting 1.57 years / photovoltaics < 5 years
  • Company:
    Konzum plus d.o.o.
    Marijana Cavica 1 / a
    10000 Zagreb
    Croatia
    https://konzum.hr/
Mladenko Jurković and Hrvoje Šarić use LEDs and a pv-system to reduce electricity costs in “their” supermarket (©Konzum plus d.o.o.)
The new LEDs are much brighter as the old lighting and reduce energy costs by 66% (©Konzum plus d.o.o.)
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