Energy transition in the South East Europe: The case of the Romanian power system

With the exception of Albania, the countries of South-Eastern Europe (SEE) have high shares of electricity generation from an ageing fleet of coal-fired power units with quite low efficiencies. Energy planning-related decision-making regarding whether to modernize or replace a significant share of this old generating capacity has to be fixed within a global clean energy transition context. At the same time, the SEE region has a huge potential for renewable energy deployment and energy efficiency implementation. This work presents a generic mixed integer linear programming model to determine the optimal energy scheduling of a multi-zonal power system following the roadmaps of its energy transition process. Through a detailed unit commitment model implementing a co-optimization of energy and reserves market with a cost minimization objective function, the developed approach determines the optimal annual energy mixes of the Romanian power system through the day by day iterative solution of all the dates of three specific time milestones (2020, 2030, and 2040), where the outputs of a specific date comprise the inputs of the next one. The model outputs highlight the impacts on the power system in terms of technical, economic, and environmental performance. The energy transition towards a renewables dominant capacity and production mix guarantees the system's security of supply, and improves noticeably its environmental performance, reporting a significant decrease in the amount of resulting CO2 emissions. With regard to the economic impacts, the wholesale price follows an increasing trend due to the parallel increase of the CO2 emission pricing, on the grounds that natural gas-fired units and electricity interconnections set the system's price during most of the hours of all dates and years. The developed optimization framework enables the provision of useful insights on the determination of the optimal energy roadmaps, by highlighting the influences and the challenges of each phase. (C) 2020 The Authors. Published by Elsevier Ltd.