Smart Integration of RENewables (SIREN)




SIREN is a three-year research project funded by the Croatian TSO - HOPS and Croatian Science Foundation. The total value of the project is 2 million kn (app. 265.000 Eur). The project has started on December 1st, 2015, and will end on November 30, 2018.
The project leader is Prof. Hrvoje Pandžić.



Large-scale integration of uncertain and intermittent renewable sources, such as wind, is a major challenge for system operators. In Croatia, the transmission system operator (HOPS) is obliged to accept the entire output of renewable generators, regardless of the time and quantity of the generated electricity. This imposition presents a large stress to the operation of the Croatian transmission system: the flexibility requirements are much higher, the congestion management needs to be refined and the system planning and operation procedures need to be updated.

One part of the project will be directed to updating the current and developing new strategies of HOPS’s system operation practices. Wind power plants’ characteristics, their expected output and effects of uncertainty will be examined. Both transmission system and generating units’ adequacy will be assessed in order to determine the flexibility requirements at different operating states of the system. This will be done for different levels of wind integration.

Another part of the project will investigate the benefits of energy storage units in transmission system. Besides the potential for construction of conventional storage units, i.e. pumped hydro power plants, the potential for utilization of battery energy storage and flywheels will be assessed as well. The usage of these storage units for arbitrage, storing energy from wind power plants, corrective actions after a contingency, voltage support, and deferment of investments in transmission lines and generators will be investigated. A price of storage at which this kind of installations become economically viable will be determined. Also, regulatory aspects of large-scale integration of storage will be investigated and proposed.


Final dissemination of project results

The final dissemination of the project results was held on the last day of the project, on November 30, 2018, at the Faculty of Electrical Engineering and Computing at the Department of Energy and Power Systems. Presentations were held by project participants in the order:

1. project manager Hrvoje Pandžić (FER): About SIREN project

2. Vladimir Valentić (HOPS): Ensuring N-1 criteria using energy storage on the island of Losinj

3. Zlatko Ofak (HOPS): Connecting of energy storage to the transmission network

4. Mateo Beus (FER): Demonstration of the Smart Grid Lab

4. Zora Luburic (FER): Optimal investments in the transmission network using the DC and AC transmission network model and Bender decomposition

5. Hrvoje Bašić (FER): Frequency control using microgrids with energy storage and demand response.

After all the presentations, a lunch and demonstration of SmartGrid Lab was held.

Photos are below the announcement.

Author: Zora Luburić

From 12.-15. November 2018 MEDPOWER international scientific conference was held in Cavtat, Croatia. At the conference articles were presented by SIREN project participants:

  1. SIPS development method and busbar splitting scheme supported by PMU technology. Zoran Zbunjak, Igor Kuzle.
  2. A Review of Energy Storage Systems Applications. Marija Miletić, Zora Luburić, Ivan Pavić, Tomislav Capuder, Hrvoje Pandžić, Ivan Andročec, Anton Marušić.
  3. Model for Defining the Potential and Value of Multi-Energy Microgrid Services to the Low Carbon Power System Operation. Ninoslav Holjevac, Tomislav Capuder, Igor Kuzle.

A special session titled SS SIREN presented the dissemination of the project results on which the lectures were held by Hrvoje Pandžić, Tomislav Plavšić, Vladimir Valentić, Zora Luburić and Hrvoje Bašić. More detailed information can be found at

Below are the photos.

Author: Zora Luburić

At the 13th Symposium on the EES Management System held in Rovinj, November 5-7, 2018, Through the papers, the symposium combined two main themes:

Theme 1 - Advanced technologies and solutions to improve the power management of the power system

Theme 2 - Changing the paradigm of the development of the power system and the market.

Zora Luburić presented the paper titled "Energy Storage in AC Power Flow Model" within theme 1, and paper "Review of existing regulatory frameworks for integration of energy storage in energy power system-advantages and barriers" within theme 2. 400 electrical engineers participated, including SIREN project participants.

Below are the photos.

Author: Zora Luburić

The International Scientific Conference INFORMS (The Institute for Operations Research and Management Sciences) was held from 4th to 7th November 2018 in Phoenix, Arizona, USA. Hrvoje Pandžić gave a lecture on "An Accurate Charging Model of Battery Energy Storage" and thus showed the results of the research within the SIREN project. Nearly 4,000 participants participated in the conference, whose research areas include mathematical optimization.

The photo is below.

Author: Zora Luburić
Workshop ‘Model Predictive Control...

From 1st to 2nd July 2018 Hrvoje Bašić attended the Tutorial ‘Model Predictive Control for PE, Drives and Grid Applications’ organized ECPE (European Centre for Power Electronics) at Haus am Dom, Frankfurt/Main, Germany.


Author: Zora Luburić
18th IEEE EEEIC conference Palermo on...

In period 12th-15th June 2018 18th IEEE EEEIC conference was held in Palermo on Sicilia, Italia.
The paper "Valuation of Energy Storage Operation in an AC Power Flow Model" was presented by Zora Luburic.
The conference hosted over 650 scientists from around the world who presented their papers  from field
of electrical engineering.


Photos are available in the remainder of this announcement.

Author: Hrvoje Bašić
9th Energy Week of Zagreb from 7th to...

During the 9th Energy Week of Zagreb from 7th to 12th May 2018, Zora Luburić held a presentation titled "Energy Storage in the Croatian Power System" at a professional meeting of students. Some of the SIREN project results were presented. The topic of Zagreb Energy Week this year was: "We have Solutions - Visions of the New Generations for Sustainable and Green Development".


Photos are available in the remainder of this announcement.

Author: Hrvoje Bašić

On the colloquium organized by the Croatian Science Foundation and the Croatian Academy of Sciences and Arts in the library of the Croatian Academy of Sciences and Arts on Wednesday, 18. April 2018, prof. Hrvoje Pandžić presented a lecture „Integretion of energy storage systems in the modern electric power system”, where projects SIREN and EVBASS (Electric Vehicle Battery Swapping Station) were presented.

Author: Hrvoje Bašić
ETIP SNET (South-Eastern Region)...

On the ETIP South-Eastern Region Workshop held on 23 & 24 November 2017. in Nicosia, Cyprus Hrvoje Pandžić presented project SIREN.

Author: Hrvoje Bašić
Smart Grid Viewed from the Regional...

On the Smart Grid Viewed from the Regional Cooperation Perspective Conference held on 28.11.2017. in the European Parliament Hrvoje Pandžić presented project SIREN to members of the European Commission, including representatives of ITRE Committee (Committee on Industry, Research and Energy) and INEA Agency (Innovation and Networks Executive Agency).

Author: Hrvoje Bašić

From 04. to 08. of October The 12th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) was held in Dubrovnik in Croatia.

Hrvoje Pandžić presented the articles written by members of project team SIREN (collaboration of FER and HOPS):

  • Zora Luburić, Hrvoje Pandžić, Tomislav Plavšić, Ljupko Teklić, and Vladimir Valentić. Role of Energy Storage in Ensuring Transmission System Adequacy and Stability
  • Zoran Zbunjak, Hrvoje Bašić, Hrvoje Pandžić and Igor Kuzle, Phase Shifting Autotransformer, Transmission Switching and Battery Energy Storage Systems to Ensure N1 Criterion of Stability
Author: Hrvoje Bašić
The fourth meeting of project SIREN

The fourth meeting of project SIREN as held on September 26, 2016 at the Department of Energy and Power System at the Faculty of Electrical Engineering and Computing. Accomplishments of the prior year were presented, and plans of work groups for the following year were defined. Alan Župan i Zlatko Ofak, are added to the project team SIREN.

Author: Hrvoje Bašić

From 11. to 14. September The 19th Conference on Power Electronics and Applications (and Exhibition) 2017 EPE’17 ECCE (Energy Conversion Congress and Expo) was held in Warsaw University of Technology, Institute of Control and Industrial Electronics, Warsaw, Poland.

Members of project team SIREN, Hrvoje Bašić and Hrvoje Pandžić in collaboration with Tomislav Dragičević and Frede Blaabjerg from Aalborg University, Denmark, presented the article "DC microgrids with energy storage systems and demand response for providing support to frequency regulation of electrical power systems".

Author: Hrvoje Bašić

Project SIREN participants, Kristina Pandžić and Hrvoje Bašić, are awarded with subventions for registration fees for 2017 IEEE PES General Meeting in USA and EPE'17 ECCE in Poland, through competition for academic mobility in 2017, University of Zagreb.

Author: Hrvoje Bašić

From 6 to 9 June 2017 IEEE International Conference on Environment and Electrical Engineering was held in Milan, Italy that gathered 500 scientists from over 70 counties from all over the world. Member of project team SIREN, Vladimir Valentić presented an article Assessment of N-1 Criterion Using Energy Storage, whose authors are Zora Luburić, Hrvoje Pandžić, Tomislav Plavšić, Ljupko Teklić, and Vladimir Valentić. 

Author: Zora Luburić

From 27. to 29. June 2017 Second IEEE International Conference on DC Microgrids was held in Nuremberg, Germany that gathered scientists from all over the world. Members of project team SIREN, Hrvoje Bašić and Hrvoje Pandžić, and Tomislav Dragičević and Frede Blaabjerg from Aalborg University, Denmark, presented the article " DC microgrids providing frequency regulation in electrical power system - imperfect communication issues".

Author: Hrvoje Bašić
Project SIREN in the Media (3)

In the issue of Jutarnji list on Sunday, 28 May 2017,  Prof. Hrvoje Pandžić gave an interview "You cannot work all your life in Croatia and be a successful in science". The article emphasizes the importance of scientific development abroad, which results are three scientific projects, including project SIREN. Also, his fields of interest include areas that will increase the chances of achievenig the goals of the low-carbon strategy for the power system in Europe. This includes integration of renewable energy sources, large battery energy storage systems, electric vehicles and electric vehicle chargers.

Article: /_news/70662/jutarnji_clanak.JPG

Author: Zora Luburić
Project SIREN in the Media (2)

In an article titled "FER-ovci krče putove do gradova budućnosti" project SIREN is highlighted as one of the most relevant research project at the Faculty of Electrical Engineering and Computing in the journal LIDER published on 7 April.

Link: /_news/70831/601 FER pr SC.PDF

Author: Zora Luburić
Project SIREN in the Media (1)

In the newspaper "Jutarnji list" on 29th February 2016, an article titled "Who will develop batteries with a cost of $ 100 per kilowatt-hour?" was published, in which the leader of project SIREN Assistant Professor Hrvoje Pandžić gave an interview to call on the importance of energy storage and the development of battery technology as a result of growth in electricity production from renewable sources.



Author: Zora Luburić
Workshop Methods for Energy System...

On 14 December 2016, a workshop was held on the theme: "Methods for Energy System Planning Under Uncertainty" in the International Centre for Mathematical Sciences (ICMS) in Edinburgh, Scotland.
Lectures were given by professors from the University of Edinburgh, Durham, Heriot-Watt and Newcastle. The workshop was attended by two members of the project team SIREN. The theme of the workshop, as well as the exchange of experiences with other doctoral students, was interesting, instructive and useful for future research.
Photos are available in the remainder of this announcement.

Author: Zora Luburić

From 14th to 16th November 2016, it was held on 12th Symposium on Power System Management in Split. The symposium brought together through the papers two main themes:
1. Application of modern technologies and solutions for the electric power system
2. Energy policy of the EU and Croatia
The study included 400 engineers in the field of electrical engineering, among which were the participants of the project SIREN. As part of the symposium was organized visit to the largest hydroelectric power plant Zakučac. The objectives of the symposium were to look at new trends in the management of the power system and possible new ideas and plans implemented in the coming period.

Below are the photos.

Author: Zora Luburić
Battery energy system Flumeri and a...

From 28th to 30th September 2016, several team members of our project SIREN visited battery energy system Flumeri in the south of Italy and held a meeting with representatives of the Italian system operator TERNA.  The battery energy system was made by NaS battery and capacity of 12 MW (10 x 1.2 MW), and was built by Japanese company "NGK Insulators" during 2015. The battery plant was put into operation in December of the same year.

Some of its applications are: primary regulation, tertiary regulation, voltage support in order to eliminate congestion in the case of large wind power generation. TERNA representatives shared their experiences gained in the management of such baterry energy system, since they have two of them in Ginestra (12 MW) and Scampitella (10.8 MW). The meeting was concluded and possibilities for potential future cooperation of TERNA, HOPS and FER were agreed.

Photos are available in the remainder of this announcement.

Author: Zora Luburić
Workshop: Mathematical Modeling in...

On Tuesday, June 28, and Wednesday, June 29, as a part of the projects SIREN (Smart Integration of RENewables), financed by the Croatian TSO HOPS and the Croatian Science Foundation HRZZ, and uGRIP (microGRId Positioning), financed by the Environmental Protection and Energy Efficiency Fund through the ERA Net Smart Grid + inictiative, we are preparing a workshop on Mathematical Modeling in Power Systems. The following lectures will take place: 

Tuesday 10-11 h: Fabio D'Andreagiovanni (Zuse Institute Berlin) - Multiband Robust Optimization: Theory and Applications

Tuesday 11-12 h: Hrvoje Pandžić (FER, Zagreb) -  Uncertainty in Unit Commitment Models

Wednesday 10-11 h: Fabio D'Andreagiovanni (Zuse Institute Berlin) - Zero-price Energy Offering by (Multiband) Robust Optimization

Wednesday 11-12 h: Matija Zidar (FER, Zagreb) - Optimal planning and operation of active distribution networks with energy storage systems

All the talks are open to general audience (everyone is welcome!). The workshop will take place in the Grey Hall at FER and will be in English.

Author: Hrvoje Pandžić
IEEE EEEIC 2016 Florence

From 07. to 10. June 2016 IEEE International Conference on Environment and Electrical Engineering was held in Florence, Italy that gathered scientists from over 50 counties from all over the world. The conference presented 480 papers, 66 oral sessions and 3 poster sessions. Members of project team SIREN, Zora Luburić, Hrvoje Pandžić and Tomislav Plavšić, presented the article "Comparison of Energy Storage Operation in Vertically Integrated and Market-Based Power System".


Photos are available in the remainder of this announcement.

Author: Hrvoje Bašić
Hrvoje Bašić awarded Erasmus+ grant

Hrvoje Bašić was awarded an Erasmus+ grant for conducting research at Aalborg University in fall 2016!

Author: Hrvoje Pandžić
Winter School 2016

In the period 13 - 17 March,  the Winter School entitled Stochastic programming in the energy sector was held in Oppdal, Norway. It was organized by the Norwegian University of Science and Technology (NTNU), and brought together 40 participants, 10 professors from prestigious universities in the world, and 30 doctoral students from universities from all over Europe.

Some of the topics were:

  • Modeling and applications for stochastic optimization
  • Multilevel models and applications
  • Models for the energy market

All doctoral students had the opportunity to present their research area.
Link: https: //

Author: Zora Luburić

A part of our team participated at Grid + Storage workshop in Rome in February 2016. The idea of the workshop was to unite the knowledge and experiences from national projects into a shared base of knowledge, so-called Knowledge Sharing Platform. Out team presented the project SIREN at the workshop. All presentations are available at

Author: Hrvoje Bašić

On February 18, 2016, Hrvoje Bašić attended the “Battery Safety Seminar” organized by Shmuel De-Leon Energy Ltd at BMZ The innovation group, Karlstein am Main.

The following topics were discussed: battery essentials, battery safety hazards, battery safety guidelines, battery safety equipment, battery safety disposal, battery safety transportation, battery safety standards and testing, EV Battery safety.


Links to announcement and program of the seminar are available in the expanded version of this announcement.

Author: Hrvoje Bašić
The first meeting of the project SIREN

On January 22, 2016, at the Department of Energy and Power System (ZVNE) at the  Faculty of Electrical Engineering and Computing, was held the first meeting of project SIREN which was attended by members of the project team (FER and HOPS). At the meeting was also established the initial phase of project development, and guidelines for the future steps of the project SIREN were set. In the second part of the meeting, members of the project team HOPS had the opportunity to visit the laboratory of ZVNE.

Photos are available in the remainder of this announcement.

Author: Zora Luburić