Wind energy integration into future energy systems based on conventional plants – The case study of Croatia

•Eight future energy scenarios in Croatia are analyzed with EnergyPLAN model.•Future energy demand in Croatia is calculated with bottom-up model NeD.•Influence of a high share of wind on load duration curve of large combustion plants is assessed.•Influence of a high share of wind on critical excess of electricity in analyzed scenarios is assessed. Croatian energy system is currently highly import-dependent and integration of a high share of renewable energy sources needs to be considered. This paper studies eight scenarios; three proposed by the Croatian Energy Strategy, one proposed by the Indicative medium-term development plan of Croatia’s Transmission System Operator, and four alternative scenarios that propose extensive construction of hydro, wind and solar power plants in Croatia. Calculations have been conducted in the EnergyPLAN model based on modeled long term energy demand projections in the NeD model, with 2009 as the base year and a scope ranging until the year 2030. Each of the eight proposed scenarios is observed through different hydrological conditions while analyzing import dependency, economic costs and CO2 emissions. After the initial calculations, additional analysis of intensive wind power penetration has been conducted. The Results show that energy systems with a larger share of conventional and nonflexible power plants have more difficulty adjusting to wind power plants production. In case of a high share penetration of wind in a system based upon such power plants, the feasibility of investing in new large combustion plants that will spend most of the time working on minimum capacity is brought into question.