HEP Plans 160 MW Vinodol Pumped-Storage Hydroelectric Plant
The Ministry has published HEP's environmental impact assessment request for a project that would use the existing Tribalj reservoir and a new one at Medvedak.
The Ministry has published HEP's environmental impact assessment request for a project that would use the existing Tribalj reservoir and a new one at Medvedak.
Croatian Electricity Company (HEP) has requested an environmental impact assessment for the Vinodol pumped-storage hydroelectric plant, with an installed capacity of up to 160 megawatts. The facility would be built in the Vinodol municipality in Primorje-Gorski Kotar County. The Ministry of Environmental Protection and Green Transition issued a notice of this request on August 11, 2026, and the procedure is being conducted by the Ministry itself, as it is responsible for power plants and energy facilities with a capacity exceeding 100 megawatts under the relevant regulation.
The system consists of two storage reservoirs connected by tunnels and a pipeline. The lower reservoir, Tribalj, already exists in the Vinodol Valley, covering approximately 41 hectares at an elevation of about 60 meters. The upper reservoir, Razromir, would be newly built in the Koreni Valley on the slopes of Medvedak mountain, at an elevation of about 800 meters and covering 24 hectares. The planned total volume of this reservoir is 2.1 million cubic meters, of which approximately 650,000 cubic meters would be used in daily operation.
The facility would operate on the principle of pumped storage. During periods of surplus energy in the grid, water would be pumped from the lower to the upper reservoir, and during peak demand hours, it would be released through turbines to generate electricity. For turbine operation, a flow rate of 24 cubic meters per second is planned, and for pumping, 18 cubic meters per second. With these parameters, the daily cycle would consist of ten to ten and a half hours of pumping and seven and a half to eight hours of generation.
The proposed underground powerhouse option includes two generating units with Francis turbines, with the possibility of later installing three-unit sets with Pelton turbines. The plant would be connected to the power grid via the existing 110-kilovolt transmission line, with the construction of its own switchyard.
The environmental impact study was prepared in April 2026 by the authorized company Elektroprojekt from Zagreb. The next step in the process is a public consultation, which must last at least 30 days, during which public review of the study and a public presentation of the project will be organized. The relevant authorities involved in the procedure include the administrations for nature protection, water management, spatial planning, forestry, and cultural heritage protection, along with Primorje-Gorski Kotar County and the Vinodol Municipality.
