Climate change forces humankind to strong reduction measures for greenhouse gas (GHG) emissions. Following this scientific consensus the European Union obliged it's member states to achieve high reduction targets to almost zero emissions especially in the power generation sector - until 2050. Evidence-based strategies to implement cost-effective reduction pathways are necessary to achieve these targets. We developed a multi-regional power system model - elesplan-m - to analyze a least-cost decarbonization pathway for Europe with special focus on South-East-Europe (SEE). The analysis seeks for optimal strategies in the power sector while it neglects cross-sectoral demand shifts coming up with the electrification of transport and the use of heat pumps. Results underline both, the possibility and the enormous efforts required to achieve the intended decarbonization. SEE needs to increase its photovoltaic capacity to 120.7 GW, wind power capacity to 92.4 GW and transmission capacities to neighboring countries to 32.7 GW until 2050 to achieve the GHG emission reduction targets. The power system transformation requires annual average investments of almost one billion EUR in SEE. Resulting levelized cost of power supply of this region adds up to 12.1 ctEUR/kWh. (C) 2017 Elsevier Ltd. All rights reserved.