[en] Most countries will need a shift in their energy strategies in order to limit the increase in global warming and to reduce the emissions of greenhouse gases. It is worrying that while technologies with little or no greenhouse gas emissions exist, and are used for a couple of decades now, the increase of their market share is extremely low and the investments and subsidies in fossil fuels are substantially larger on a world wide scale. For changes to accrue it is necessary to carefully plan both the energy consumption and supply. A correct and rational prediction of future energy consumption is the basic assumption for the advanced analysis and modelling of energy systems and it will, as an input, have a profound influence on them. In this paper a bottom up approach was selected because it is the most suitable methodology to describe the legal, economic or purely technical mechanisms. Scenarios for the energy supply in 100% renewable systems in 2050 and the possibility to create a low-carbon society were simulated using the EnergyPLAN model for energy system analysis. Comparison of the necessary useful energy for space heating in 2050 shows a difference greater than 16% for different rates of renovation of the existing buildings in the residential sector of 1% and 3% annually. The electrification of road transport for passenger cars in combination with increased requirements for energy efficiency of internal combustion engines can reduce the energy consumption in the transport sector by 30% in comparison to the reference scenario for 2050. It is possible to reduce the emission of greenhouse gases by 82% in the period 2030-2050 and the use of renewable energy sources and the production of synthetic fuels can enable a transition to a 100% renewable energy system in Croatia in 2050. Doing so would create 192000 jobs in plant maintenance and fuel production alone, increase the security of energy supply and reduce the expenditure for the purchase of fossil fuels by 4-5 billion EUR according to the results of the simulation.(author)