The paper analyzes the existing fleet and the possibilities of replacing anthracite and natural gas boilers of low and medium capacity and substantiates that the reconstruction with conversion to biomass is appropriate for boilers with a thermal capacity of more than 5 MW. The main problem is the reduction of heat perception of furnace screens and increase of heat removal to the convective pass due to the increased specific yield of biomass combustion products. Based on the analysis of changes in the nature of combustion processes and redistribution of heat exchange in the boiler, it was determined the criteria for the possibility of converting boilers from fossil fuels to biomass with maximum use of available equipment and the most acceptable fuel for this - agricultural pellets and wood waste. Technical solutions for the reconstruction of a boiler with a dense bed with a steam capacity of 20 t/h on anthracite (24 t/h on natural gas) have been developed and calculated with transfer to burning of granules of biomass and/or gas coal without change of dimensions of a fire chamber and without loss of thermal power due to compensation of the lowered heat absorption of a fire chamber by increase of a surface of a water economizer with corresponding decrease in an air heater. Technical solutions were used during the reconstruction of 4 boilers "Babcock-Wilcox" of Khorostkiv Sugar Plant. Co-combustion of biofuel pellets with coal is implemented in the range of components share from 0 to 100%. When burning granules, underburning in the fly ash is almost absent, ash deposits on convective surfaces are self-cleaning for several hours of work on gas coal. The solutions developed allowed to solve the problem of renovation of old boilers with the expansion of their fuel base and improvement of environmental performance through the use of biomass. Bibl. 18, Fig. 3, Tab. 4.

The structure of electricity cost formation for consumers, including depending on the cost of TPP generation, «green» energy and other sources, is investigated, and the main conditions of the efficient regulatory function fulfillment in the power system by thermal power generation in the conditions of Ukraine's course on carbon-free energy are formulated. It is shown that excessive electricity losses in networks and, especially, accelerated increase of the share of «green» generation, much more expensive than nuclear, hydro and thermal, mainly contribute to the growth of electricity costs for non-household consumers and the need to raise tariffs for the population. This accelerated increase directly contradicts the Paris Climate Agreement, according to which plans to reduce Ukraine’s greenhouse gas emissions must be developed taking into account available energy resources and without harming its own economy. The dependences of the specific fuel consumption on the average load and the frequency of start-stops of units are found and it is shown that the increased specific fuel consumption on coal TPPs is an inevitable payment for their use as regulating capacities of UES of Ukraine. In this case, the higher the proportion of «green» generation and a smaller proportion of generating thermal power plants, especially increasing specific fuel consumption. It is proved that in the conditions of growth of the share of «green» generation in Ukraine the share of production of pulverized coal thermal power plants should be kept at the level of not less than 30 % of the total electricity generation. It is substantiated that a necessary condition for coal generation to perform a proper regulatory role in the power system is to introduce both environmental and technical measures, namely — reducing the suction of cold air to the furnace and other boiler elements, restoring condensers and cooling systems, etc. An important factor in reducing the average level of specific fuel consumption is also the reduction of coal burn-out at thermal power plants, where it still remains significant, due to the transfer of power units to the combustion of bituminous coal concentrate. Bibl. 12, Fig. 5, Tab. 5.