ČEZ Distribuce as a European Distribution System Operator (DSO) with more than 3.6 million customers prepares for the expected future development of renewables and charging stations in the Czech Republic. The official government document called Czech National Action Plan for Smart Grids published in 2015 by the Czech Ministry of Industry and Trade presents a reference scenario of the expected future development of renewables where PV installations have a major share. In order to find a cost-effective solution for renewable energy integration, reliable power supply and high power quality for customers, ČEZ Distribuce focused on testing innovative smart solutions with a strong potential for large scale development under the InterFlex project. The Czech demonstration project was located in several areas in the Czech Republic where ČEZ Distribuce operates its distribution grids. The demonstration was focused not only on one area in order to prove replicability and interoperability of designed solutions and was divided into 4 use cases:

  • UC1: Increase the hosting capacity for renewables in LV distribution grids through smart PV inverters equipped with autonomous Q (V) and P (V) functions
  • UC2: Increase the hosting capacity for renewables in MV grids through Volt/VAr control (control of reactive power based on voltage set points)
  • UC3: Smart EV charging (autonomous charging power curtailment in case of under voltage or under frequency)
  • UC4: Smart energy storage (autonomous discharging of batteries in case of under voltage or under frequency)

The Czech demonstrator focused on the implementation of solutions which are not yet common in distribution grids, but which have a strong potential for future roll out. The tested solutions cover the most urgent challenges for DSOs: increasing the renewable energy hosting capacity of the grid and implementing EV charging stations and energy storage. Beyond the technical developments, the Czech demonstrator also aimed to propose grid codes and standard updates in order to secure future smoother integration of selected smart grid solutions. The demonstration confirmed the expected increase of the DER hosting capacity in LV and MV grids, as well as the added value of Smart EV charging and Smart energy storage concepts to introduce increasing flexibility in the distribution grids.


Various areas in the Czech Republic


  • 2 areas with residential PV systems
  • 5 large DERs connected to MV grids (2 x small hydro, PV, Wind park, CHP unit)
  • 4 areas with smart charging EV stations
  • 1 area with residential PVs + energy storage systems


  • ČEZ Distribuce – demo leader
  • Austrian Institute of Technology
  • ČEZ Solarni
  • Fronius
  • Schneider Electric
  • Siemens


  • Increase the DER hosting capacity of LV distribution networks by smart PV inverters
  • Increase the DER hosting capacity in MV networks by Volt/VAr control
  • Smart EV charging
  • Smart energy storage


The DER hosting capacity in the demonstration areas increased up to:

  • 76% in LV grids
  • 92%in MV grids

Czech Demonstrator

Testimonial of the Czech project team


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