JET 51 JET Volume 16 (2023), p.p. 1 - 10 Issue 1, 2023 Type of article: 1.01 http://www.fe.um.si/si/jet.html 1 ANALYSIS OF REVITALISATION MODEL BEHAVIOUR FOR THERMAL POWER PLANTS IN DIFFERENT GEOGRAPHICAL AREAS ANALIZA ODZIVANJA REVITALIZACIJSKEGA MODELA TERMOENERGETSKA POSTROJENJA NA RAZLIČNIH GEOGRAFSKIH LOKACIJAH Martin Bricl  , Jurij Avsec 1 Keywords: revitalisation model, solar tower, heliostat field, solar irradiance, geographical location Abstract The implementation of renewable sources for electricity production into the energy portfolio of European countries has been a priority in recent years, especially taking into account the current geo-political changes. Even though coal is the fuel of the past, its use cannot be put aside that easily; firstly, because of the high fluctuation of electricity production from renewable sources, and secondly because of the possible negative economic impact on the economy resulting from a change in electricity prices when exiting coal. Based on the Rankine process, the authors of this paper designed a solar tower installation with a heliostat field, which enables electricity production based on solar irradiation. This combination also foresees an additional installation for flue gas desulphurisation. This combination of three processes is named the ‘revitalisation model’ for thermal power plants (TPPs). Based on the computer model and energy market parameters, the authors tested the ‘revitalisation model’ for pessimistic and optimistic scenarios. In the scope of the paper, the authors analyse the performance of the proposed ‘revitalisation model’ for three different  Corresponding author: Martin Bricl, Rudis d.o.o. Trbovlje, Trg revolucije 25b 1420 Trbovlje, Tel: +386 3 56 12 409, E-mail address: martin.bricl@rudis.si 1 University of Maribor, Faculty of Energy Technology, Hočevarjev trg 1, SI-8270 Krško, Slovenia JET Volume 14 (2021)Issue 1, 2023 p.p. 51-66 Issue 1, 2023 Type of article: 1.01 http://www.fe.um.si/si/jet.htm 52 JET geographical locations – Berlin in Germany, Wuwei in China, and Hyderabad in India. The results of the analysis are described and shown graphically. Povzetek Uvajanje obnovljivih virov za proizvodnjo električne energije v energetski portfelj evropskih držav je v zadnjih letih postala prednostna naloga, še posebej zaradi spreminjajočih se geopolitičnih razmer. Premog je gorivo preteklosti, vendar ga ne moremo tako zlahka opustiti. Vodila razloga za to sta veliko nihanje proizvodnje električne energije iz obnovljivih virov in negativni ekonomski vpliv na gospodarstvo, ki bi ga lahko povzročila sprememba cen električne energije s prenehanjem uporabe premoga. Zraven obstoječega procesa Rankine smo zasnovali instalacijo solarnega stolpa s heliostatskim poljem, ki omogoča proizvodnjo električne energije na osnovi sončnega obsevanja. V tej kombinaciji smo tudi predvideli dodatno napravo za razžveplanje dimnih plinov. Ta tri-fazni proces smo poimenovali revitalizacijski model termoenergetskih postrojenj. Na podlagi računalniškega modela in parametrov energetskega trga smo preizkusili model revitalizacije za pesimistični in optimistični scenarij. V članku bomo analizirali uspešnost predlaganega modela revitalizacije za tri različne geografske lokacije – Berlin v Nemčiji, Wuwei na Kitajskem in Hyderabad v Indiji – ter prikazali rezultate analize v pisni in grafični obliki. 1 INTRODUCTION The proposed ‘revitalisation model’ comprises three main elements that make up the entire proposed plant. The first component is the Rankine process [1], which represents an existing thermal power plant and has a certain operational energy and exergy efficiency in the process [2]. Coal is the primary fuel of the Rankine process (or steam process). The combustion of coal in a steam boiler releases heat, which generates steam, which is fed into a steam turbine where a shaft drives a generator for electricity production. The second component is the solar power plant, which consists of a solar tower on which the concentrated sunbeam receiver is located, and a field in which heliostatic mirrors are arranged to direct the sun’s rays to a common point on the concentrated sunbeam receiver [3-5]. All the absorbed solar energy is concentrated at a certain point, thus obtaining a high temperature and consequently a high concentration of energy at a point on the solar radiation receiver. The working medium in a solar tower plant is a salt solution, which can be heated to a higher temperature than the evaporation temperature of the water. This energy (heat) is used in the evaporator to produce steam, which is conducted from the solar process back to the steam process [6]. This reduces the amount of steam that the steam boiler needs to produce to be able to run the high-pressure and low-pressure steam turbines, which rotate the generator shaft to produce electricity. This enables the energy of solar radiation [7-8] to be used to produce steam, and the load of the steam boiler in the production of steam during solar radiation can be reduced proportionally [9-13] by the amount of steam that can be produced from the solar process. Due to the lower load and production of steam from the steam boiler, the consumption of coal – a fossil fuel – is also reduced, which also reduces the required amount of carbon emission coupons, as the amount of flue gases and greenhouse gas emissions is lower at the lower load of the steam boiler in the steam process. JET Volume 16 (2023) Issue 1, 2023 Martin Bricl, Jurij Avsec JET 53 Analysis of revitalisation model behaviour for thermal power plants in different geographical areas Analysis of revitalisation model behaviour for thermal power plants in different geographical areas 3 ---------- Figure 1: The proposed ‘revitalisation model’ combines the traditional Rankine cycle with a solar central receiver system The third component of the proposed model of the revitalisation of TPPs is a plant for flue gas cleaning using the wet calcite process, which is most often identified as the best solution based on the guidelines for selecting the best possible technology. The purpose of the plant is primarily to reduce the acidic components in the flue gases and consequently reduce the impact on the environment and living beings. The advantage of the wet process is the cheap and easily accessible reagent as well as the integrity for the environment of the flue gas cleaning by-product and the specimen in it. Properly designed desulphurisation technology can achieve both high levels of purification of acidic components – sulphur dioxide as well as other air pollutants such as dust and some heavy metals [14-15]. As a by-product of flue gas cleaning, gypsum is formed, which can be used for commercial purposes (possible purchase from cement plants and gypsum board manufacturers), or it can be used to stabilise fly ash from the bottom of the steam boiler. 2 OPTIMISTIC AND PESSIMISTIC OPERATION SCENARIOS FOR THE CHOSEN GEOGRAPHICAL LOCATIONS 2.1 Geographical location Velenje, Slovenia Figure 2, shown below, illustrates the economic performance of the proposed model. As can be seen, with the help of solar energy [16-18], the proposed model is profitable when taking into consideration the optimistic scenario, which covers all the costs of fossil fuels, the flue gas cleaning process, infrastructure maintenance and other regular maintenance costs. In this case, the proposed model would still generate EUR 1,075,400.00 in annual profit. In the figure below, the optimistic scenario is represented by the deletion-related dots and the corresponding right y-axis. The sum of monthly net profits from electricity sales is the annual economic result of the considered scenario. Figure 1: The proposed ‘revitalisation model’ combines the traditional Rankine cycle with a solar central receiver system The third component of the proposed model of the revitalisation of TPPs is a plant for flue gas cleaning using the wet calcite process, which is most often identified as the best solution based on the guidelines for selecting the best possible technology. The purpose of the plant is primarily to reduce the acidic components in the flue gases and consequently reduce the impact on the environment and living beings. The advantage of the wet process is the cheap and easily accessible reagent as well as the integrity for the environment of the flue gas cleaning by-product and the specimen in it. Properly designed desulphurisation technology can achieve both high levels of purification of acidic components – sulphur dioxide as well as other air pollutants such as dust and some heavy metals [14-15]. As a by-product of flue gas cleaning, gypsum is formed, which can be used for commercial purposes (possible purchase from cement plants and gypsum board manufacturers), or it can be used to stabilise fly ash from the bottom of the steam boiler. 2 OPTIMISTIC AND PESSIMISTIC OPERATION SCENARIOS FOR THE CHOSEN GEOGRAPHICAL LOCATIONS 2.1 Geographical location Velenje, Slovenia Figure 2, shown below, illustrates the economic performance of the proposed model. As can be seen, with the help of solar energy [16-18], the proposed model is profitable when taking into consideration the optimistic scenario, which covers all the costs of fossil fuels, the flue gas cleaning process, infrastructure maintenance and other regular maintenance costs. In this case, the proposed model would still generate EUR 1,075,400.00 in annual profit. In the figure below, the optimistic scenario is represented by the deletion-related dots and the corresponding right y-axis. The sum of monthly net profits from electricity sales is the annual economic result of the considered scenario. 54 JET JET Volume 16 (2023) Issue 1, 2023 Martin Bricl, Jurij Avsec 4 Martin Bricl, Jurij Avsec JET Vol. 16 (2023) Issue 1 ---------- Figure 2: Economic behaviour of the proposed ‘revitalisation model’ for the geographical location of Velenje, Slovenia Taking into account the pessimistic scenario, the costs of allowances for CO2 emissions must be added to all the aforementioned costs, as they are a form of taxation for the operation of TPPs. In the case of the pessimistic scenario, assuming that the price of CO2 emission allowances is expected to be higher with each additional year that a TPP operates, the model would generate EUR 353,050.00 in losses per year. This is not a bad achievement, as, without a central solar tower system, the annual loss of a TPP would be even greater. As illustrated in Figure 2, the pessimistic scenario is shown with columns and the corresponding left y-axis. The sum of monthly net profits from electricity sales is the annual economic result of the pessimistic scenario under consideration. The proposed model and its economic benefits will play an important role in the transition from conventional fossil fuels to renewable energy sources (RES), as it would allow the simultaneous production of electricity from thermal power and renewable sources – a central solar power plant, thus maintaining a stable electricity distribution network and reducing the consumption of, and dependence on, fossil fuels. 2.2 Geographical location Wuwei, China For the location of the city of Wuwei, China, effective solar irradiance is shown in Figure 3. Figure 4 illustrates the pessimistic and optimistic scenarios for the chosen location. Table 1 represents the income per corresponding month for the optimistic and pessimistic scenarios. Figure 2: Economic behaviour of the proposed ‘revitalisation model’ for the geographical location of Velenje, Slovenia Taking into account the pessimistic scenario, the costs of allowances for CO 2 emissions must be added to all the aforementioned costs, as they are a form of taxation for the operation of TPPs. In the case of the pessimistic scenario, assuming that the price of CO 2 emission allowances is expected to be higher with each additional year that a TPP operates, the model would generate EUR 353,050.00 in losses per year. This is not a bad achievement, as, without a central solar tower system, the annual loss of a TPP would be even greater. As illustrated in Figure 2, the pessimistic scenario is shown with columns and the corresponding left y-axis. The sum of monthly net profits from electricity sales is the annual economic result of the pessimistic scenario under consideration. The proposed model and its economic benefits will play an important role in the transition from conventional fossil fuels to renewable energy sources (RES), as it would allow the simultaneous production of electricity from thermal power and renewable sources – a central solar power plant, thus maintaining a stable electricity distribution network and reducing the consumption of, and dependence on, fossil fuels. 2.2 Geographical location Wuwei, China For the location of the city of Wuwei, China, effective solar irradiance is shown in Figure 3. Figure 4 illustrates the pessimistic and optimistic scenarios for the chosen location. Table 1 represents the income per corresponding month for the optimistic and pessimistic scenarios. JET 55 Analysis of revitalisation model behaviour for thermal power plants in different geographical areas Analysis of revitalisation model behaviour for thermal power plants in different geographical areas 5 ---------- Figure 3: Effective solar irradiance by month for the geographical location of Wuwei, China [19] In Figure 3, it can be seen that the effective sun irradiance expressed in hours per month is equally spread across the whole year. In Figure 4, where the realisation of the model is presented (pessimistic and optimistic scenarios) the operation of the model in the summer months is not that promising, due to the regular monsoon periods during the summer months. Figure 4: Economic behaviour of the proposed ‘revitalisation model’ for the geographical location of Wuwei, China Figure 3: Effective solar irradiance by month for the geographical location of Wuwei, China [19] In Figure 3, it can be seen that the effective sun irradiance expressed in hours per month is equally spread across the whole year. In Figure 4, where the realisation of the model is presented (pessimistic and optimistic scenarios) the operation of the model in the summer months is not that promising, due to the regular monsoon periods during the summer months. Analysis of revitalisation model behaviour for thermal power plants in different geographical areas 5 ---------- Figure 3: Effective solar irradiance by month for the geographical location of Wuwei, China [19] In Figure 3, it can be seen that the effective sun irradiance expressed in hours per month is equally spread across the whole year. In Figure 4, where the realisation of the model is presented (pessimistic and optimistic scenarios) the operation of the model in the summer months is not that promising, due to the regular monsoon periods during the summer months. Figure 4: Economic behaviour of the proposed ‘revitalisation model’ for the geographical location of Wuwei, China Figure 4: Economic behaviour of the proposed ‘revitalisation model’ for the geographical location of Wuwei, China 56 JET Martin Bricl, Jurij Avsec JET Volume 16 (2023) Issue 1, 2023 Table 1: Economic values of model operation for an individual month in the case of optimistic or pessimistic scenarios Month Optimistic scenario [€] Pessimistic scenario [€] January 171,020.00 54,138.00 February 78,180.00 -31,591.00 March 80,020.00 -37,073.00 April 77,160.00 -37,709.00 May 70,310.00 -48,579.00 June 84,280.00 -31,960.00 July 108,230.00 -11,227.00 August 92,710.00 -26,416.00 September 98,430.00 -18,101.00 October 151,820.00 33,619.00 November 140,403.00 30,524.00 December 141,340.00 24,256.00 TOTAL: 1,293,903.00 -100,119.00 2.3 Geographical location Berlin, Germany For the location of the city of Berlin, Germany, effective solar irradiance is shown in Figure 5. Figure 6 illustrates the pessimistic and optimistic scenarios for the chosen location. Table 2 shows the income per corresponding month for the optimistic and pessimistic scenarios. 6 Martin Bricl, Jurij Avsec JET Vol. 16 (2023) Issue 1 ---------- Table 1: Economic values of model operation for an individual month in the case of optimistic or pessimistic scenarios Month Optimistic scenario [€] Pessimistic scenario [€] January 171,020.00 54,138.00 February 78,180.00 -31,591.00 March 80,020.00 -37,073.00 April 77,160.00 -37,709.00 May 70,310.00 -48,579.00 June 84,280.00 -31,960.00 July 108,230.00 -11,227.00 August 92,710.00 -26,416.00 September 98,430.00 -18,101.00 October 151,820.00 33,619.00 November 140,403.00 30,524.00 December 141,340.00 24,256.00 TOTAL: 1,293,903.00 -100,119.00 2.3 Geographical location Berlin, Germany For the location of the city of Berlin, Germany, effective solar irradiance is shown in Figure 5. Figure 6 illustrates the pessimistic and optimistic scenarios for the chosen location. Table 2 shows the income per corresponding month for the optimistic and pessimistic scenarios. Figure 5: Display of the time of effective solar radiation for the city of Berlin, Germany [20] Figure 5: Display of the time of effective solar radiation for the city of Berlin, Germany [20] JET 57 Analysis of revitalisation model behaviour for thermal power plants in different geographical areas Analysis of revitalisation model behaviour for thermal power plants in different geographical areas 7 ---------- Figure 6: Optimistic and pessimistic operating scenarios for the city of Berlin Table 2: Economic values of model operation for an individual month in the case of optimistic or pessimistic scenarios Month Optimistic scenario [€] Pessimistic scenario [€] January 12,650.00 -120,500.00 February 6,100.00 -115,350.00 March 36,780.00 -87,510.00 April 81,600.00 -32,580.00 May 79,940.00 -37,360.00 June 110,730.00 -1,840.00 July 125,020.00 7,630.00 August 96,470.00 -20,220.00 September 92,610.00 -24,610.00 October 63,230.00 -63,650.00 November 8,570.00 -119,490.00 December -5,490.00 -139,640.00 TOTAL: 708,210.00 -755,120.00 Figure 6: Optimistic and pessimistic operating scenarios for the city of Berlin Table 2: Economic values of model operation for an individual month in the case of optimistic or pessimistic scenarios Month Optimistic scenario [€] Pessimistic scenario [€] January 12,650.00 -120,500.00 February 6,100.00 -115,350.00 March 36,780.00 -87,510.00 April 81,600.00 -32,580.00 May 79,940.00 -37,360.00 June 110,730.00 -1,840.00 July 125,020.00 7,630.00 August 96,470.00 -20,220.00 September 92,610.00 -24,610.00 October 63,230.00 -63,650.00 November 8,570.00 -119,490.00 December -5,490.00 -139,640.00 TOTAL: 708,210.00 -755,120.00 2.4 Geographical location Hyderabad, India For the location of the city of Hyderabad, India, effective solar irradiance is shown in Figure 7. Figure 8 illustrates the pessimistic and optimistic scenarios for the chosen location. Table 3 represents the income per corresponding month for the optimistic and pessimistic scenarios. 58 JET Martin Bricl, Jurij Avsec JET Volume 16 (2023) Issue 1, 2023 8 Martin Bricl, Jurij Avsec JET Vol. 16 (2023) Issue 1 ---------- 2.4 Geographical location Hyderabad, India For the location of the city of Hyderabad, India, effective solar irradiance is shown in Figure 7. Figure 8 illustrates the pessimistic and optimistic scenarios for the chosen location. Table 3 represents the income per corresponding month for the optimistic and pessimistic scenarios. Figure 7: Display of the time of effective solar radiation for the city of Hyderabad, India [21] Figure 8: Optimistic and pessimistic operating scenario of the model for the Hyderabad site Table 3: Economic values of model operation for an individual month in the case of optimistic or pessimistic scenarios Month Optimistic scenario [€] Pessimistic scenario [€] January 230,010.00 119,330.00 February 114,300.00 10,380.00 March 107,820.00 -5,170.00 April 95,180.00 -16,890.00 May 74,370.00 -43,860.00 June 76,250.00 -41,120.00 July 85,690.00 -36,570.00 JET 59 Analysis of revitalisation model behaviour for thermal power plants in different geographical areas August 79,260.00 -41,720.00 September 108,340.00 -6,990.00 October 181,880.00 66,610.00 November 181,270.00 71,178.00 December 192,150.00 80,940.00 TOTAL: 1,526,520.00 156,118.00 3 REVITALISATION MODEL RESPONSE FOR CHANGED MARKET PARAMETERS The designed model was further analysed by considering the following parameters for the geographical location of the cities of Berlin, Hyderabad and Wuwei: • number of hours of effective solar radiation • local coal price • the price of electricity for the country in which the selected geographical location is located • the price of carbon dioxide emissions if such a taxation scheme is located in the country of the selected geographical location 3.1 Geographical location Wuwei, China For the geographical location of Wuwei, China, when analysing the behaviour of the model, the authors considered the change in parameters that depend on local regulations and limits, as shown in Table 4. Table 4: Display of considered changed parameters for the location of Wuwei, China Parameter Quantity Unit Coal price 60.00 [€ / t] CO 2 emission coupon price / [€ / t] Salaries 9.50 [€ / h] Electricity price 82.00 [€ / MWh] Figure 9 and Table 5 show the graphically and numerically expected realisation of the considered model for the selected location of Wuwei. 60 JET Martin Bricl, Jurij Avsec JET Volume 16 (2023) Issue 1, 2023 10 Martin Bricl, Jurij Avsec JET Vol. 16 (2023) Issue 1 ---------- Table 4: Display of considered changed parameters for the location of Wuwei, China Parameter Quantity Unit Coal price 60.00 [€ / t] CO2 emission coupon price / [€ / t] Salaries 9.50 [€ / h] Electricity price 82.00 [€ / MWh] Figure 9 and Table 5 show the graphically and numerically expected realisation of the considered model for the selected location of Wuwei. Figure 9: Display of the expected realisation of the model based on the changed entry parameters for the location of Wuwei Table 5: Numerical representation of the expected realisation of the realistic scenario according to the changed entry parameters for the location of Wuwei Month Realistic scenario [€] January 375,650.00 February 343,480.00 March 370,990.00 April 332,130.00 May 339,600.00 June 307,160.00 July 325,540.00 August 329,490.00 September 294,720.00 Figure 9: Display of the expected realisation of the model based on the changed entry parameters for the location of Wuwei Table 5: Numerical representation of the expected realisation of the realistic scenario according to the changed entry parameters for the location of Wuwei Month Realistic scenario [€] January 375,650.00 February 343,480.00 March 370,990.00 April 332,130.00 May 339,600.00 June 307,160.00 July 325,540.00 August 329,490.00 September 294,720.00 October 332,680.00 November 346,000.00 December 360,770.00 TOTAL 4,058,210.00 3.2 Geographical location Berlin, Germany For the geographical location of Berlin, the analysis of the model behaviour took into account the change in parameters that depend on local regulations and limits, as shown in Table 6. JET 61 Analysis of revitalisation model behaviour for thermal power plants in different geographical areas Table 6: Display of considered changed parameters for Berlin, Germany Parameter Quantity Unit Coal price 51.00 – 85.00 [€ / t] CO 2 emission coupon price 25.00 [€ / t] Salaries 30.00 [€ / h] Electricity price 120.00 [€ / MWh] Analysis of revitalisation model behaviour for thermal power plants in different geographical areas 11 ---------- October 332,680.00 November 346,000.00 December 360,770.00 TOTAL 4,058,210.00 3.2 Geographical location Berlin, Germany For the geographical location of Berlin, the analysis of the model behaviour took into account the change in parameters that depend on local regulations and limits, as shown in Table 6. Table 6: Display of considered changed parameters for Berlin, Germany Parameter Quantity Unit Coal price 51.00 – 85.00 [€ / t] CO2 emission coupon price 25.00 [€ / t] Salaries 30.00 [€ / h] Electricity price 120.00 [€ / MWh] Figure 10: Illustration of the expected realisation of the model with changed input parameters for the location of Berlin Figure 10: Illustration of the expected realisation of the model with changed input parameters for the location of Berlin Table 7: Numerical representation of the expected realisation of the realistic scenario according to the changed entry parameters for the location of Berlin Month Realistic scenario [€] January -507,000.00 February -362,090.00 March -217,830.00 April -19,180.00 May 320.00 June 31,700.00 July 530.00 August -39,210.00 September -110,040.00 October -289,830.00 November -441,730.00 December -510,920.00 TOTAL -2.465,280.00 62 JET Martin Bricl, Jurij Avsec JET Volume 16 (2023) Issue 1, 2023 3.3 Geographical location Hyderabad, India For the geographical location of Hyderabad, the analysis of model behaviour took into account the change in parameters that depend on local regulations and constraints, as shown in Table 8. Table 8: Display of considered changed parameters for Hyderabad, India Parameter Quantity Unit Coal price 70.00 [€ / t] CO 2 emission coupon price / [€ / t] Salaries 8,35 [€ / h] Electricity price 95.00 [€ / MWh] Analysis of revitalisation model behaviour for thermal power plants in different geographical areas 13 ---------- Figure 11: Illustration of the expected realisation of the model with changed input parameters for the location of Hyderabad Table 9: Numerical representation of the expected realisation of the realistic scenario according to the changed entry parameters for the location of Hyderabad Month Realistic scenario [€] January 252,980.00 February 145,090.00 March 139,520.00 April 128,810.00 May 110,130.00 June 108,970.00 July 120,440.00 August 117,770.00 September 144,400.00 October 223,240.00 November 215,090.00 December 221,840.00 TOTAL 1,928,280.00 Figure 11: Illustration of the expected realisation of the model with changed input parameters for the location of Hyderabad JET 63 Analysis of revitalisation model behaviour for thermal power plants in different geographical areas Table 9: Numerical representation of the expected realisation of the realistic scenario according to the changed entry parameters for the location of Hyderabad Month Realistic scenario [€] January 252,980.00 February 145,090.00 March 139,520.00 April 128,810.00 May 110,130.00 June 108,970.00 July 120,440.00 August 117,770.00 September 144,400.00 October 223,240.00 November 215,090.00 December 221,840.00 TOTAL 1,928,280.00 3 CONCLUSION Table 10 summarises the results of the considered model for different geographical locations and parameters. The results for two different cases are summarised and shown for three additional locations – Wuwei, Berlin and Hyderabad,. The first example takes into account the change of geographical location only and the consequent change of hours of effective solar radiation. The second example involves changing several parameters. In addition to changes in geographical location, local fuel (coal) prices, local electricity prices, and local labour or personnel prices are also taken into account. When analysing the operation of the plant, it was found that due to high fuel costs, the production of electricity exclusively from steam generated by a steam boiler is unprofitable. Thus, the contribution of the central receiver system (CRS) is essential for the cost-effective operation of the assumed model. As demonstrated by the positive operating scenario, the proposed system would achieve positive market results in the current market situation. In the case of the pessimistic scenario, the system would only operate profitably for four months a year, which is a low amount, however, it should be noted that most TPPs operate at a loss and the state provides financial assistance for uninterrupted electricity production. The pessimistic scenario shows a positive impact of upgrading the CRS system, as the loss at the annual level of operations is reduced almost 10-fold. 64 JET Table 10: Results of the considered model for different geographical locations and parameters 14 Martin Bricl, Jurij Avsec JET Vol. 16 (2023) Issue 1 ---------- 3 CONCLUSION Table 10 summarises the results of the considered model for different geographical locations and parameters. The results for two different cases are summarised and shown for three additional locations – Wuwei, Berlin and Hyderabad,. The first example takes into account the change of geographical location only and the consequent change of hours of effective solar radiation. The second example involves changing several parameters. In addition to changes in geographical location, local fuel (coal) prices, local electricity prices, and local labour or personnel prices are also taken into account. When analysing the operation of the plant, it was found that due to high fuel costs, the production of electricity exclusively from steam generated by a steam boiler is unprofitable. Thus, the contribution of the central receiver system (CRS) is essential for the cost-effective operation of the assumed model. As demonstrated by the positive operating scenario, the proposed system would achieve positive market results in the current market situation. In the case of the pessimistic scenario, the system would only operate profitably for four months a year, which is a low amount, however, it should be noted that most TPPs operate at a loss and the state provides financial assistance for uninterrupted electricity production. The pessimistic scenario shows a positive impact of upgrading the CRS system, as the loss at the annual level of operations is reduced almost 10-fold. Table 10: Results of the considered model for different geographical locations and parameters PARAMETER Location Velenje Wuwei Berlin Hyderabad ① ② ① ② ① ② Effective sun irradiance [h] 1,112.3 1,267.9 1.267,9 912.7 912.7 1,427.5 1,427.5 Coal savings [t] 25,227 28,984 28.982 20,742 20.701 32,377 32,375 Amount of emitted CO2 [t] 266,508 260,000 260.757 273,300 273.441 255,500 255,538 Amount of cleaned SO2 [t] 111.8 109 109,3 114 114.6 107 107.2 Optimistic scenario [mio €] 1.07 1.29 4,05 0.71 -2.46 1.52 1.92 Pessimistic scenario [mio €] -0.35 -0.10 / -0.75 / 0.15 / * ① - Results of the considered model at the changed geographical locations (number of hours of effective solar radiation) * ② - The results of the considered model with the following parameters changed: • Number of hours of effective solar radiation • Number of hours of effective solar radiation • Consideration of the local coal price • Observance of the local electricity price • Taking into account the local price of labour or employees The model represents a possible upgrade and modernisation of conventional TPPs to ensure an uninterrupted supply of electricity even in the event of an increased disruption in the thermal power system due to the production of electricity from renewable sources. Rising fossil fuel prices, and limiting them, will increase interest in the implementation of the model described and similar solutions. Martin Bricl, Jurij Avsec JET Volume 16 (2023) Issue 1, 2023 JET 65 Analysis of revitalisation model behaviour for thermal power plants in different geographical areas 15 ---------- • Consideration of the local coal price • Observance of the local electricity price • Taking into account the local price of labour or employees The model represents a possible upgrade and modernisation of conventional TPPs to ensure an uninterrupted supply of electricity even in the event of an increased disruption in the thermal power system due to the production of electricity from renewable sources. Rising fossil fuel prices, and limiting them, will increase interest in the implementation of the model described and similar solutions. References [1] J. Oman: Generatorji toplote, Univerza v Ljubljani, Fakulteta za strojništvo, Ljubljana 2005 [2] M. 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Mango: Evaluation of a solar-powered organic Rankine cycle using dry organic working fluids, Cogent Engineering, Vol.2, 2015 – Issue 1 [18] Povprečno trajanje sončnega obsevanja. (n.d.). V Meteo. Pridobljeno s www.meteo.si [19] Efektivno sončno obsevanje za mesto Wuwei. (n.d.). V Photovoltaic geographical information system. Pridobljeno s https://re.jrc.ec.europa.eu/pvg_tools/en/#MR [20] Efektivno sončno obsevanje za mesto Berlin. (n.d.). V Photovoltaic geographical information system. Pridobljeno s https://re.jrc.ec.europa.eu/pvg_tools/en/#MR [21] Efektivno sončno obsevanje za mesto Hyderabad. (n.d.). V Photovoltaic geographical information system. Pridobljeno s https://re.jrc.ec.europa.eu/pvg_tools/en/#MR Nomenclature (Symbols) (Symbol meaning) t time h hour CO2 carbon dioxide SO2 sulphur dioxide € euros mio million GEN generator MWh megawatt hour Analysis of revitalisation model behaviour for thermal power plants in different geographical areas 66 JET 16 Martin Bricl, Jurij Avsec JET Vol. 16 (2023) Issue 1 ---------- [13] S. C. Ksushik, V. Reddy Siva, S.K. Tyagi: Energy and exergy analyses of thermal power plants – a review, Renewable and sustainable energy reviews, December 2010 [14] H.R. Kulkarni, P.P. Revankar, S.G. Hadagal: Energy and exergy analysis of coal-fired power plant, International Journal of Innovative Science and Research Technology, Vol.1, No.3 [15] Babcock & Wilcox Company: Steam its generation and use, Edition 41; Ohio, U.S.A., 1992 [16] L. Chao, Z. Rongrong: Thermal performance of different integration schemes for a solar tower aided coal-fired power system, Energy Conversion and Management, Vol.171, 2018, Pages 1237–1245 [17] E. Spayde, P. Mango: Evaluation of a solar-powered organic Rankine cycle using dry organic working fluids, Cogent Engineering, Vol.2, 2015 – Issue 1 [18] Povprečno trajanje sončnega obsevanja. (n.d.). V Meteo. Pridobljeno s www.meteo.si [19] Efektivno sončno obsevanje za mesto Wuwei. (n.d.). V Photovoltaic geographical information system. Pridobljeno s https://re.jrc.ec.europa.eu/pvg_tools/en/#MR [20] Efektivno sončno obsevanje za mesto Berlin. (n.d.). V Photovoltaic geographical information system. Pridobljeno s https://re.jrc.ec.europa.eu/pvg_tools/en/#MR [21] Efektivno sončno obsevanje za mesto Hyderabad. (n.d.). V Photovoltaic geographical information system. Pridobljeno s https://re.jrc.ec.europa.eu/pvg_tools/en/#MR Nomenclature (Symbols) (Symbol meaning) t time h hour CO2 carbon dioxide SO2 sulphur dioxide € euros mio million GEN generator MWh megawatt hour Martin Bricl, Jurij Avsec JET Volume 16 (2023) Issue 1, 2023