Abstract
An analysis is performed with regards to technologically outdated heating plants operating in many areas where fossil fuels such as coal and gas are utilized, in order to consider the alternatives of their modernization. By application of a chart using a variety of alternatives, the economic feasibility of executing two types of modernization of heating plants are explored: a single-fuel gas–steam CHP plant and a coal-fired heating plant to a coal-fired CHP plant with a condensing turbine. This study demonstrates how the selection of modernization technology is affected, in terms of profitability, by the value and variability in time of the price relationships between energy carriers, rapidly growing charges related to CO2 emission allowances, and costs depending on other pollutant emissions that originate from the operation of electricity and heat sources powered by fossil fuels. In both technical cases of modernization, lower prices of energy carriers coupled with CO2 emissions allowances lead to higher prices of electricity that can be sold as additional products following this modernization, and consequently, the specific cost of heat production in the repowered heat sources is lowered. The calculations were performed by the application of models of heating plant modernization applying continuous time notations, which offer the determination of the most suitable time of initiation of this modernization. Such relationships would be difficult to describe in the case of the use of traditional discrete models. In the case of a simultaneous increase in the prices of all main factors affecting the cost of heat generation, such as the price of gas, electricity and CO2 emissions, the fastest modernization of the heating plant to single-fuel gas–steam CHP provides the possibility of the best economic performance.
Highlights
The energy policy of the European Union has for many years emphasized the importance of district heating in improving energy efficiency and reducing CO2 emissions.The current system promotes heating systems, but by imposing strict regulations it clearly emphasizes that only heating systems that ensure high efficacy can receive support [1].many heat sources are already outdated and are often characterized by low efficiency of heat production
It does not mean that the modernization is unprofitable, as the specific cost of heat generation in the modernized heat source becomes smaller with a longer time that elapses from the instant t1 when this modernization is initiated, i.e., when the modernization will take place as late as possible, and preferably not at all
The increase in coal prices and the purchase prices of CO2 emission allowances adopted in the calculations leads to the increase in the cost of heat production kh,av, irrespective of the year t1 related to the initiation of the modernization
Summary
The energy policy of the European Union has for many years emphasized the importance of district heating in improving energy efficiency and reducing CO2 emissions. The basic relationship used to determine the technical and economic effectiveness of modernization of power plants, heating plants and combined heat and power plants, taking into account the investment incurred in this modernization, is formed by the equation for Energies 2021, 14, 7426 the total NPV that is obtained from their operation throughout an interval in time T. The methodology for determining the formula for the mean specific cost, kh,av , of heat generation in a modernized heat source in a notation of continuous time was developed and discussed in detail in the study reported in [15]. This formula takes the following form [15]:. 1 − uM ρCO2 eCO bCO (bCO (i +i M )(1+ xsal,t,ins )δserv τs r h e−rt1 − e−rt2 + τzis 1 + T1 − tT1 e−rt1 − 1 + T1 − tT2 e−rt2 +
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