Increasing the integration of variable renewable energy in coal-based energy system using power to heat technologies: The case of Kosovo

The goal of this work is to identify the influence which utilization of district heating systems coupled with the power-to-heat technologies based on the flexible operation of coal-based thermal power plants and limited electricity system interconnections can have on the maximum integration of variable renewables. An hourly deterministic tool EnergyPLAN was used for modelling and simulation of Kosovo energy system. Results revealed that Wind and PV power plant capacities of 450 MW and 300 MW respectively can be installed in the actual Kosovo energy system, when operating in an isolated mode. Additional capacities around 800 MW for wind and 385 MW for PV can be integrated into this isolated energy system with the contribution of power-to-heat technologies coupled with thermal energy storage in district heating with a fixed capacity. Furthermore, it was found that separate integration of wind can contribute to decease total primary energy supply and CO2 emissions for 3.34 TWh/year and 1.08 Mt compared to the referent scenario. Total primary energy supply and CO2 emission savings for separate integration of PV power plant compared with the referent scenario were estimated 2.74 TWh/year and 0.5 Mt respectively. Finally, the combined integration of variable renewable energy sources (1MWW+1MWPV) contributed to 3.29 TWh/year total primary energy supply and 1.02 Mt CO2 emissions savings.