Conference programme

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Delegates are invited to meet and discuss with the poster presenters during the poster presentation sessions between 10:30-11:30 and 16:00-17:00 on Thursday, 19 November 2015.

Lead Session Chair:
Stephan Barth, ForWind - Center for Wind Energy Research, Germany
Laszlo Horvath Energy Institute Hrvoje Pozar, Croatia
Nikola Karadza (1) F Goran Majstrovic (1) Laszlo Horvath (1) Hrvoje Keko (1) Sinisa Knezevic (1)
(1) Energy Institute Hrvoje Pozar, Zagreb, Croatia

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Presenter's biography

Biographies are supplied directly by presenters at EWEA 2015 and are published here unedited

László Horváth has 18 years of experience in the renewable energy industry, particularly wind energy. László has extensive experience in site selection, wind measurement, wind resource modelling and assessment, wind turbine selection, wind farm design and optimisation. He also has experience in wind farm planning and development, economics, and regulatory issues related to renewable energy. He has been involved in many national and international wind energy projects and education campaigns for private and public clients.


Poster Download poster (11.80 MB)


Wind Variability and Wind Power Integration Challenges - The Case of Croatia


In the recent years Croatia has experienced a notable increase in the installed wind power capacity. This is especially the case if the size of Croatian power system is taken into account. The total installed wind power at the end of 2014 reached 346 MW, which suffices to satisfy 5.5% of national yearly electricity consumption. More wind farms are underway in the construction phase, totalling in 81 MW of new wind power. Following their completion, Croatia will reach 427 MW of installed power in early 2016. Further wind projects are being developed however due to the grid integration challenges, these are considered on hold. A considerably vast wind resource in Croatia would remain untapped unless these grid integration issues are not solved. The work describes the challenges along with suggested measures on how to deal with them.


Besides the operational wind power plants and the projects being constructed, more wind projects are being developed in Croatia: there is 1627 MW of wind projects registered with the national Renewable Energy and Cogeneration Registry. Among these, 315 MW already have a signed Power Purchase Agreement and are classified as advanced projects at the time. However, these are currently considered on hold due to unsolved grid integration issues.
The minimum load consumption in Croatia during 2014 was slightly lower than 1200 MW. On a windy day in November 2014, the currently operating wind power plants contributed as much as 22.5% (on an hourly basis). After the commissioning of the remaining capacity being constructed, the wind power share is expected to increase to 30%.
Previous wind integration studies performed by Energy Institute Hrvoje Požar for the Croatian Transmission System Operator concluded that, on the safe side with no measures taken, the maximum wind power integration limit in Croatia is around 400 MW of installed capacity. In other words, Croatia is already reaching its limits and is entering a challenging period regarding further increases of wind capacity. To be able to accommodate additional wind power plants on the grid, additional measures are required. The aforementioned grid integration studies analyse in detail the available measures in Croatia, depending on the desired wind targets in the future, and the economic implications (i.e. the costs) of these measures were estimated as well.

Main body of abstract

The first part of the paper aims to describe the existing experience with wind farms already operating in Croatia, in terms of various generation indicators. A special focus is on the hourly production variability under a very specific wind regime in Croatia dominated by strong and gusty bora winds. The production variability represents a challenge per se, as most of the Croatian wind farms are located in a region exposed to similar wind regime, thus the spatial smoothing effect is very limited.
In the second part of the paper, the characteristics of the existing balancing system will be described. Cost-effective measures for short- and mid-term increase of integration limits in Croatia will be discussed in detail.
Finally, the issue we address in the above defined context of wind integration is related to wind power forecasting. While forecasting is one of the most cost effective measures, in Croatia it is associated with higher uncertainty, due to complex wind regime and challenging predictability in the Croatian complex terrain. The proposals for the most promising directions for further improvements of the existing forecasting system will be discussed, according to our recent research results.


In this work, the current situation of wind power integration in Croatia will be depicted through several indicators. The operational wind power plants are almost reaching the previously established safe-side limits of wind power integration, so the challenges of further wind power deployment are described along with the measures specifically appropriate for the Croatian situation.

Learning objectives
This work showcases the current wind integration situation in Croatia from an analytical viewpoint, and illustrates the challenges of future wind integration in Croatian power system.