The solar potential of Croatia from the aspect of grid integration and broader context is the title of the presentation given by dr. sc. Ninoslav Holjevac from the Faculty of Electronics and Computer Sciences in Zagreb at the recent conference ‘Sunny Days’ in Hvar as an introduction to the panel discussion on solar technologies in Croatia.
Holjevac presented an overview of the current state in Croatia, the development of the system for a better future, and solutions for a solar and green transition. “We have reached a point in time when we have to act quickly. The energy transition is undisputable, we need it, but the grid is restricted and we are currently using the one we developed many years ago and presently its capacity is reaching its limit,” Holjevac pointed out. He added that to date solar energy has not been developing as dynamically as wind energy but that is certainly changing now. “All of this indicates a significant increase of demands directed at the transmission and distribution systems. A ‘highway’ must be developed and that would enable the integration of large solars too. We must act today in order to overcome the problems in time’ Holjevac underlined.
He also emphasized the significant potential of the sun in Croatia in which there is a large number of locations with 2500 and more hours of sunshine, which up to now we have not exploited. He considers that “there are too few solars from Zadar to Dubrovnik, too few on roofs as well as an insufficient number solar collectors. There is still a lack of experience to move on to the more active implementation of projects”.
Continuing to speak of the problems and opportunities, he pointed out that summer is the critical period. Solars at the peak of the season, he clarified, contribute minimally since the problem with power supply occurs between 21.30 and 22.30h. “Solar is not the solution that will solve the grid problems from June to September. Solar energy is excellent for energy transition, it is cheap energy, but we still cannot do without the grid. We need both the grid and solar and it is not by accident that one needs the other. Batteries and similar technologies help, but it is all of a limited impact. We still cannot do with a grid. It will be necessary even if the number of solars on roofs increase.”
He also mentioned the long-term process of developing electric power grids – a 400 kW project takes 10 years and emphasized that there is an enormous amount of requests for connecting to the grid and the system must follow the requests. “The development of the electric energy grid is indispensable for the continuation of the green transition and lift-off of large solars. Solars will contribute to the problems as well as to the solution of the problem. I am convinced that from the technical aspects issues will be solvable. These are all opportunities. They also exist in regard to agricultural solars; the huge pilot project ‘Slavonia’ remains idle. Certain areas can also benefit from floating solars and polluted surfaces are not an impediment for them. In addition, hydrogen, one of the pillars of the energy transition, is also an opportunity” Holjevac went on listing all the potentials.
Ending his presentation he concluded that the development of the system, primarily of a 400kV grid, is required to further the integration of a significant share of solars, as well as the optimal use of the current capacities and possibilities effectuated on the basis of less intensive solutions in terms of capital and time and among other that changes of the existing system and legislation are a necessity.
We need to initiate a dialogue among all stakeholders and move forward towards a green and sunnier future”, Holjevac concluded.