HAC builds four solar power plants along the A3 highway

Croatian Highways (HAC) plan to utilize unused areas along the highways for the installation of solar power plants and their own electricity production, aiming to reduce electricity costs, increase energy independence, and modernize highway infrastructure. Following a public tender conducted in February, a contract was signed for the development of conceptual designs for solar power plants at four locations along the stretch from Zagreb County to eastern Croatia, covering a total area of approximately 36 hectares.

The areas in question are the rest areas Zagreb (Plitvice) and Rastovica, as well as the junctions Sredanci and Ivanja Reka. The most favorable bidder selected is the Zagreb company ETS FARAGO d.o.o., with a contract value of 11,400 euros excluding VAT. The deadline for completing the complete documentation is March 2026, after which a decision on entering the investment will follow.

Four locations, 36 hectares of panels

The Plitvice solar power plant will be built in the area of the Zagreb (Plitvice) north rest area, on a gross available area of about 2.5 hectares. Near Županja, the Rastovica solar power plant is planned on the southern side of the rest area in Vukovar-Srijem County, covering about 3.1 hectares.

The Sredanci solar power plant will encompass two cadastral parcels in the area of the Sredanci junction in Brod-Posavina County, with a total gross area of about 11 hectares. The largest is planned in the zone of the Ivanja Reka junction in Zagreb County, on three cadastral parcels with a total gross area of approximately 18 hectares. Designers must ensure maximum utilization of each location.

Three scenarios

For each location, three variants of conceptual designs must be developed. The first scenario anticipates electricity production primarily for HAC’s own needs, with excess being fed into the electricity grid. The second model is the classic ‘production for the grid’, meaning the delivery of all produced energy to the operator. The third option combines self-consumption with the accumulation of excess energy in storage systems, such as battery systems.

– The contracted conceptual designs also include an assessment of investment costs and a feasibility analysis. Based on the results of these analyses, Croatian Highways will plan further steps, including the selection of a financing model, which may include own funds, applications for EU funds, or other appropriate financing models – they say from HAC.

If the analyses confirm the justification of the investment, HAC estimates that the first solar power plants could begin construction in 2027.

How much electricity?

Regarding expected production, HAC emphasizes that they currently have preliminary estimates indicating that the annual electricity production at the four observed locations could amount to approximately 6.3 GWh/a, 3.8 GWh/a, 1.3 GWh/a, and 1 GWh/a, depending on the location.

– Since the subject contract will be concluded in March 2026, we note that the conceptual designs are still in development and the values presented are of a preliminary nature. Actual and final values will be determined upon completion of the contract, i.e., in the final versions of the conceptual designs – they note from HAC.

The ultimate goal of HAC is to reduce electricity costs, increase energy independence, and contribute to a higher share of renewable sources in total energy consumption. The project, they emphasize, is aligned with key strategic documents of the Republic of Croatia, including the Energy Development Strategy, Sustainable Development Strategy, Low-Carbon Development Strategy, and Climate Change Adaptation Strategy. Their own ‘clean’ energy should ensure greater power supply security for facilities such as rest areas, parking lots, and supporting infrastructure, with the possibility of integration with future storage solutions and smart consumption management.

Financing models

The financing model has not yet been finalized. HAC emphasizes that the selection will depend on the results of the feasibility analyses, and options include investing own funds, applying for EU funds, or other financing models. In parallel with this project, Croatian Highways are already collaborating with the European Investment Bank (EIB) on a broader ‘greening’ program for their operations. The focus is on further implementation of photovoltaic systems and the development of infrastructure for sustainable mobility, including electric charging stations and future hydrogen stations. The long-term ambition is to increase the share of renewable sources in the operations and infrastructure facilities managed by HAC.

Although the framework and timeline are defined, HAC does not hide that there are risks that could affect the dynamics of realization. The greatest potential risks are related to the processes of obtaining necessary permits, movements in energy markets, and possible procedural delays in public procurement processes. Therefore, the conceptual designs and accompanying analyses are key filters, and only after they are completed in March 2026 and demonstrate that the project is financially and operationally sustainable will HAC proceed with concrete procurement and execution.

HAC also emphasizes that the company is long-term focused on increasing the share of renewable energy sources and developing solutions that contribute to energy independence, sustainability, and modernization of highway infrastructure.

Regarding EV charging stations, HAC states that this is a segment that falls under the jurisdiction of the concessionaire, therefore ‘Croatian Highways do not consider load management concepts related to this system.’

Currently, there are 74 electric charging stations in operation on the highway network managed by Croatian Highways, with another 170 contracted. By the tourist season of 2026, it is planned that 126 electric charging stations will be operational. The ultimate goal is to install 259 electric charging stations over more than a thousand kilometers of the busiest highways in the HAC network within five years.