Abstract
South East Europe consists of several smaller countries in terms of energy systems and thus, integrating energy systems of the whole region has significant benefits for allthe countries included. However, as there are large differences between energy mixes of the countries included, careful energy planning needs to be carried out in order tosatisfy energy needs of all the countries of the region.Due to the significant differences in geography and the climate of different parts of the region, many different technologies need to be introduced in order to have optimal,low-carbon energy mix.In this paper, steps toward the 100% renewable energy system (RES) for the year 2050 have been presented. Novelty in this paper, compared to the similar research alreadybeing carried out, is the sustainable use of biomass in 100% RES, as this is the only way in which biomass can be considered as carbon-neutral. Smart energy systems’approach has been used in planning of 100% RES, which considers significant integration of the electrical, heating and gas sectors. Many technologies have been employedin the year 2050, but the major share is put on photovoltaics and wind energy, followed by geothermal, solar thermal, CHPs driven on biomass, hydro power and syntheticfuel technologies. Finally, it was shown that the 100% RES in the year 2050 is cheaper than the reference system, developed for the year 2012.