Economic Conditions for Developing Hydrogen Production Based on Coal Gasification with Carbon Capture and Storage in Poland

This study documents the results of economic assessment concerning four variants of coal gasification to hydrogen in a shell reactor. That assessment has been made using discounting methods (NPV: net present value, IRR: internal rate of return), as well as indicators based on a free cash flow to firm (FCFF) approach. Additionally, sensitivity analysis has been carried out, along with scenario analysis in current market conditions concerning prices of hard coal, lignite, hydrogen and CO2 allowances, as well as capital expenditures and costs related to carbon capture and storage (CCS) systems. Based on NPV results, a negative economic assessment has been obtained for all the analyzed variants varying within the range of EUR −903 to −142 million, although the variants based on hard coal achieved a positive IRR (5.1–5.7%) but lower than the assumed discount rates. In Polish conditions, the gasification of lignite seems to be unprofitable, in the assumed scale of total investment outlays and the current price of coal feedstock. The sensitivity analyses indicate that at least a 20% increase of hydrogen price would be required, or a similar reduction of capital expenditures (CAPEX) and costs of operation, for the best variant to make NPV positive. Analyses have also indicated that on the economic basis, only the prices of CO2 allowances exceeding EUR 40/Mg (EUR 52/Mg for lignite) would generate savings due to the availability of CCS systems.


Introduction
Hydrogen has been used in various forms of human activity for over 200 years. Originally, it was used in steam engines and also for lifting balloons and airships in the 18th and 19th centuries. It is often said that hydrogen is the "fuel of the future". This sentence seems to be justified. The physical properties of hydrogen make it interesting and attractive in comparison to other fuels and energy sources. For example, hydrogen density is one tenth (1:10) of natural gas, its energy per unit of mass (Lower Heating Value-LHV) is three times higher than that of gasoline, flame velocity is eight times higher than that for methane and its autoignition temperature is 585 • C (ignition energy is 1/10 of methane). This makes hydrogen light, storable and reactive, with high energy content per unit mass; it can be readily produced at an industrial scale. In recent times, there have been some other reasons enforcing the popularity and development of the hydrogen market, such as: steadily falling cost of hydrogen supply, the observed shift in attention and interest from the automobile industry to other hydrogen applications (aviation, shipping, heating) and, finally, hydrogen is considered a clean, ecological fuel, especially when it is produced from renewables [1]. It should also be added that However, CCS technologies have not been widely implemented. At present, there are only 19 operating installations globally. The International Energy Agency (IEA) estimations, outlined by 2030, assume that CCS will reach a level of 750 MM g CO 2 stored annually (currently only 5% of that amount has been achieved) [22]. That seems to be an optimistic scenario. Currently, two of the operating CCS projects are dedicated to hydrogen production [1]. As mentioned by Rock et al. [23], achieving a capture rate of 80% is still a challenge. It is also crucial to ensure CO 2 retention after injection, which largely depends on the formation type [24]. Currently, there are no CCS installations in Poland. Although there are geological formations where CO 2 could be stored, all efforts in this respect are still at the conceptual stage [25][26][27]. On the other hand, there are technological and economic reasons for the gasification of coal to hydrogen, especially where the costs of feedstock are relatively low. Coal gasification technologies for hydrogen production are among the most advanced and well established in the world. They seem to be the cheapest alternative for hydrogen production. Based on IEA [2], the total production cost (involving capital expenditures; CAPEX) is five times lower than in the case of grid electricity technologies, three times lower than in electricity generation from renewables and 2-2.5 lower than in steam methane reforming processes (hereinafter SMR). In China, the expected hydrogen production cost is about USD 1/kg of H 2 . In relation to those facts, the production of every 1 Mg of H 2 causes the release into the atmosphere of nearly 20 Mg of CO 2 (without CCS systems), two times more than from natural gas, but 1.5 times less than in grid electricity systems. Yet, the amount of CO 2 produced from coal may also raise some concerns.
The technological and economic efficiency of coal gasification was discussed by Gnanapragasam et al. [4], who analyzed the effectiveness of the coal gasification process with the application of a CCS unit in classical integrated gasification combined cycle (IGCC) solutions and in syngas-to-hydrogen systems. According to the authors of that study, syngas-to-hydrogen systems are more effective then IGCC systems. An interesting comparison of technologies focused on hydrogen production, for all primary fuels, has been made by Muritala et al. [28], who pointed out the advantage of SMR over coal gasification (operating at industrial scale),which strongly depends upon the availability of cheap gas. Similar conclusions have been made by Xuet al. [29]. Additionally, Guban et al. [30] have agreed with that conclusion, adding that the development of an effective CCS system shall enhance the development of hydrogen production technologies based on gas and other fossil fuels. Similar aspects have also been discussed by Ren et al. [31], who commented that in the regions with access to cheap coal, efficient CCS systems may reveal the advantage of coal gasification over SMR technologies. This opinion was also supported by Cloete and Hirh [32] and Collodi et al. [33]. The abovementioned studies can be summarized by the statement that the final success of hydrogen production based on fossil fuels depends on the production scale and fuel price, the latter being the most important cost component. Thus, the key problem is to answer the question concerning the level at which these factors should be for fully commercial applications of these technologies. An attempt to answer this question for clean hydrogen technologies in Polish conditions is provided in the work of Ceren [10], which is a multi-criteria analysis of these solutions. In turn, the work of Bartel et al. [34] discusses the economic factors behind the development of CCS technology in combination with combined heat and power (CHP) installations. An interesting work analyzing the gasification of coal to hydrogen and the transit of the Polish economy towards a hydrogen economy is given in the study by Murray et al. [35]. The authors discuss various possible technological solutions, analyzing their impact on the Polish economy. However, none of the mentioned studies answers the question: for which economic conditions is it possible to commercially use the coal gasification technology with CSS for hydrogen production?
A literature review shows that the interest in the topic has not declined over the years, with ever more modern technological solutions emerging which improve the efficiency of both coal gasification [36] as well as CCS systems [4,37]. Some of the advanced, new and ecological energy technologies are very promising indeed, but because of the limited scale, they cannot be developed to a mass production scale very quickly. They need technological advancement but can be applied locally. The research conducted also indicates that the direction of the development of hydrogen generation technologies depends on the criteria assumed. Kwaśniewski et al. [36] point out that meeting the country's energy needs should be, first of all, based on the domestic resource base, assuming that local resources are the cheapest ones. On the other hand, highly developed countries are focused on producing hydrogen based on renewables. At the same time, EU law clearly promotes clean coal technologies, hence the question arises as to whether the economic efficiency of coal gasification to hydrogen in Polish conditions (taking into account environmental aspects and the quality of end products) may favor coal gasification technologies sufficiently enough. The importance of the coal gasification scenario in Poland is also supported by the availability of coal reserves (hard coal and lignite), amounting to 5.77 billion Mg [38]. Additionally, having in mind the current problems encountered by the mining sector (reduced output, loss of profitability, depletion of resources), the analyses provided make a contribution to the ongoing discussion concerning the future of coal in Poland and in the European Union.
Based on a literature review, our research objectives comprise several important issues and problems connected with the assessment of the economic efficiency of hard coal and lignite gasification to hydrogen in Polish conditions. The studies documented in this paper attempt to answer several fundamental questions, namely: • First research objective. What is the economic efficiency of hard coal and lignite gasification with and without CCS units at the current level of hydrogen prices, the cost of its production and investment outlays for specific technologies? • Second research objective. At which levels of hydrogen price and coal feedstock is the economic efficiency of the best systems positive? • Third research objective. At which price of CO 2 emission allowances is the investment in a CCS system for both hard coal and lignite more profitable? • Fourth research objective. In which market conditions is it possible to use CCS systems efficiently when gasifying coal to hydrogen?
The formulation of an opinion concerning the economic efficiency of hard coal and lignite gasification to hydrogen, identification of the key factors influencing the results and discussion concerning the balance between the level of CSS capital expenditures and the price of CO 2 emission allowances are the research goals.

Methodology and Scope of Work
Because coal gasification technologies, operating at a large scale, are complicated investments (cost-intensive processes with high risk related to their implementation, relatively long investment cycle, long time of project operation [39]), the research process was divided into a few steps: • data preparation; • literature research aiming to reduce the number of analyzed coal gasification variants; • for selected coal gasification processes, mass and energy balances were calculated allowing for identification of the amount of final product, wastes and energy flows; • building a professional economic assessment model for selected variants and calculating the value and risk measures; • conducting the sensitivity analyses for selected economic inputs, as well as value and risk measures; • providing scenario analyses for the mutual impact of hydrogen price, the cost of building and operating the CSS units and the price of CO 2 emission allowances.
An economic efficiency assessment supported by preliminary analyses and data collecting played a fundamental role. The descriptive part, which comprised other analyses and comments on the obtained results, following the order of established research objectives, supplemented the basic analyses. Based on preliminary research, we decided to analyze only four variants of coal gasification technologies (hard coal and lignite gasification with and without CCS units), based on a shell reactor and developed on an industrial scale, which is stable and proven. There is also a sufficient amount of reliable data in the literature for these technologies (the main source of data is the project entitled "Development of coal gasification technology for high production of fuels and electricity" funded by the National Center for Research and Development, documented in [40]).

Economic Assessment
In our research, we use the most popular methods of assessing economic efficiency [40]. The values of the analyses carried out are their comprehensiveness and the broad spectrum of the answers provided. According to Murillo-Zamorano, the economic efficiency of an investment project may be understood as the relation between the project's outcomes and inputs (capital, financial and operating costs) related to its execution, expressed in financial terms [41]. Economic efficiency was evaluated by analyzing a set of financial measures and indicators, determined for each technology separately. Economic analyses were prepared in a professional assessment model. In this model, the following methods and indicators were considered to be crucial: Those methods belong to the group of discount techniques [42]. The discounting process anticipates the future cash flows and returns their present values, thus enabling the comparison of capital expenditures to be made at the beginning with the cashflow expected in future. The process of discounting is directly related to the effect of "the time value of money" [43]. In our calculations, FCFF represents the free cash flow to firm corrected for depreciation expenses, taxes, working capital and investment outlays.
The levelized cost of energy/hydrogen production (LCOE/LCOH 2 ) is a widely accepted standard for assessing and comparing energy technologies. LCOH 2 is a sum of total capital expenditures and operational costs divided by an amount of a final product. LCOE/LCOH 2 is in fact the price of the main product which guarantees the return of capital expenditures, costs of operation and cost of debt throughout the technology lifespan. The costs also comprise the required return of capital suppliers, expressed as the percentage of the revenue assigned for that purpose [5,39].
In the calculations, we used only the cash costs (operating costs without amortization and depreciation), including the cost of feedstock (coal) and capital expenditures. The risk premium comprised the discount rate r in Equation (1): where: LCOH 2 : levelized cost of hydrogen production; n: period of cost averaging (economic lifespan of the project); CAPEX t : capital expenditures in year t; OPEX t : operating costs (excluding the cost of coal) in year t; CC t : cost of coal in year t; Energies 2020, 13, 5074 6 of 20 P t : production of hydrogen in year t; r: discount rate; t: year (time).
The assessment of the economic efficiency of the analyzed technologies focused upon the expenditures and costs of key technological processes and income components corresponding to hydrogen sale. Capital expenditures were calculated at the level of total plant cost (TPC), and after taking into account other overheads and provisions (demand for working capital and materials and chemicals in the start-up phase, as well as provisioning, amounting to 15% of TPC as total capital expenditures; TASC).

Description of Coal Gasification Process
As mentioned before, the gasification process in a shell reactor was chosen for analysis ( Figure 1). To the best of our knowledge, the selected technology is among the most popular worldwide; it is characterized by high efficiency and technological maturity. In shell technology, coal is initially dried by tail gas (remaining after hydrogen separation from syngas) to 5% in the case of hard coal or 12% in the case of lignite. Dried coal is fed into the dispersive reactor, with a supply of fuel in dry conditions in which, at a temperature of 1430 • C and pressure of 4.2 MPa, the gasification process takes place. Purified synthesis gas (syngas), from which 99.9% of solid particles, 90% of chlorides and all the alkaline compounds have been removed, goes to a water gas shift (WGS) reactor (in that process, carbon monoxide, in reaction with steam generated in the gas cooling process, is converted to CO 2 ). After conversion, the synthesis gas is cooled to about 35 • C and purified in a Selexol unit from coal oxysulfide, mercury and acid gases, including hydrogen sulfide, with an efficiency of 99.9%, and from carbon dioxide, with an efficiency of 90%. In the case of installations provided with a CCS system, the separated carbon dioxide is compressed and subsequently pumped underground via a pipeline system and ultimately stored. The remaining gas is combusted in a boiler, providing the heat necessary to generate steam. The steam is used for driving the turbine coupled with a generator of electric energy, and it is entirely used for internal consumption, which amounts to 33.1 MW in the case of the gasification of hard coal and 34.6 MW for lignite (higher energy consumption is associated with the coal handling process). In the case of installations equipped with a CCS system, the electricity consumption for both coals amounts to 51.6 MW and 53.4 MW, respectively) [44]. taking into account other overheads and provisions (demand for working capital and materials and chemicals in the start-up phase, as well as provisioning, amounting to 15% of TPC as total capital expenditures; TASC).

Description of Coal Gasification Process
As mentioned before, the gasification process in a shell reactor was chosen for analysis ( Figure  1). To the best of our knowledge, the selected technology is among the most popular worldwide; it is characterized by high efficiency and technological maturity. In shell technology, coal is initially dried by tail gas (remaining after hydrogen separation from syngas) to 5% in the case of hard coal or 12% in the case of lignite. Dried coal is fed into the dispersive reactor, with a supply of fuel in dry conditions in which, at a temperature of 1430 °C and pressure of 4.2 MPa, the gasification process takes place. Purified synthesis gas (syngas), from which 99.9% of solid particles, 90% of chlorides and all the alkaline compounds have been removed, goes to a water gas shift (WGS) reactor (in that process, carbon monoxide, in reaction with steam generated in the gas cooling process, is converted to CO2). After conversion, the synthesis gas is cooled to about 35 °C and purified in a Selexol unit from coal oxysulfide, mercury and acid gases, including hydrogen sulfide, with an efficiency of 99.9%, and from carbon dioxide, with an efficiency of 90%. In the case of installations provided with a CCS system, the separated carbon dioxide is compressed and subsequently pumped underground via a pipeline system and ultimately stored. The remaining gas is combusted in a boiler, providing the heat necessary to generate steam. The steam is used for driving the turbine coupled with a generator of electric energy, and it is entirely used for internal consumption, which amounts to 33.1 MW in the case of the gasification of hard coal and 34.6 MW for lignite (higher energy consumption is associated with the coal handling process). In the case of installations equipped with a CCS system, the electricity consumption for both coals amounts to 51.6 MW and 53.4 MW, respectively) [44]. To compare the effectiveness of the technologies discussed, we assumed the same amount of chemical energy of about 1935 GJ/h in coal feedstock (at the beginning of the gasification process). In the analyses, we used steam coal with a calorific value (HHV) of 21.3 GJ/Mg and lignite with a calorific value of 12.4 GJ/Mg (typical in the Polish mining sector). The availability of the plant was assumed to be 0.9, resulting in on-stream times of 7 884 h/y. Based on that, mass and energy balances  To compare the effectiveness of the technologies discussed, we assumed the same amount of chemical energy of about 1935 GJ/h in coal feedstock (at the beginning of the gasification process). In the analyses, we used steam coal with a calorific value (HHV) of 21.3 GJ/Mg and lignite with a calorific value of 12.4 GJ/Mg (typical in the Polish mining sector). The availability of the plant was assumed to be 0.9, resulting in on-stream times of 7 884 h/y. Based on that, mass and energy balances were calculated for all variants. Because it was assumed that some of the chemical energy will be used for internal consumption, the yearly net production capacity varied between 63-73 thousand Mg of H 2 for lignite consumption of about 1.59 million Mg and was in the range of 74-81 thousand Mg of H 2 for hard coal consumption of about 0.84 million Mg.
It was also assumed that technologies without CCS emit CO 2 to the atmosphere in amounts typical for chemical and thermal reactions, as well as the energy conversion characteristics for a given technology with respect to the analyzed coals. For installations with a CCS system, 90% of CO 2 would be captured and stored geologically. The basic information for the analyzed technologies with values of average yearly emissions of carbon dioxide is presented in Table 1.

Revenues
When calculating the price of hydrogen, data concerning the cost of its production in various technologies, available, among others, in [1, 45,46], were analyzed. Both costs and prices are subject to considerable regional fluctuations. In Europe and in Russia, they are in the range between USD 1.1 and 2.35/kg of H 2 produced from natural gas. In the case of coal gasification, the benchmark is the Chinese market, where the cost varies in the range of USD 1.0-2.45/kg of H 2 for technologies with a CCS unit in use. For economic analyses, the price of hydrogen was assumed at the level of EUR 2.28/kg of H 2 . It should be added that the sales of by-products have not been considered in the calculations.

Capital Expenditures
The total capital expenditures comprise: spending for working capital • reserves for incidentals.
Among capital expenditures, the widely understood outlays on technological infrastructure were identified, along with those on auxiliary infrastructure, construction works, project documentation or reconstruction. Capital expenditures were calculated at the level of TPC, as well as after taking into account other overheads and provisions (demand for working capital and materials and chemicals in the start-up phase, as well as reserves and provisions amounting to 15% of TPC), as well as total as spent costs (TASC).  The total values of CAPEX for specific technological variants are presented in Table 3.

Operating Costs
For each technology, the following operational costs were included in the calculation: consumption of materials and chemicals (  Source: own study based on [39,47].
The calculation of total operating costs also comprised the cost of management and administration support, which accounted for 30% of wage costs. Taxes and fees were calculated as a surcharge of TPC, amounting to 0.7%, and the assumed cost of insurance amounted to 0.5% of TPC. Costs of repairs, servicing and overhauls were calculated on an individual basis.
The costs related to site monitoring, discounted for the last year of analysis, were a part of the total operating costs in the case of variants with CCS units (Table 5). Source: own study based on [39,47].
In the calculations, the following assumptions were made concerning the initial values of costs of feedstock and emission allowances: As a result of the assumptions made, for the analyzed technologies, the following structure of the operating costs was obtained (Table 6).

Risk and Discount Rate Calculation
Risks were assessed separately for each technological variant. Total risk comprised the cost of own and borrowed capital (debt), as well as the premium for specific risks for a given technology. The share of equity and borrowed capital in the evaluation model amounted to 100%. Moreover, for each technological variant, the premium for specific (technological) risks was determined. The share and actual cost of borrowing capital was calculated as a function of actual (in a given accounting period) cost of interest and capital (debt) payments. Thus, the effective cost of debt was in the range of 2.8% to 3.8%. The premium for the specific risks of the analyzed technologies varied between 6% and 14%. Finally, the assessment process allowed for different values of the discount rate influenced by the change in financial structure and technological maturity of the installation. The average effective discount rates for the analyzed technological variants are presented in Table 7. The calculation was prepared for the beginning of 2021 and the expenditures for the construction period for all variants were prepared in a three-year perspective, whereas the entire calculation horizon comprised 33 years. The calculations were made in nominal prices, assuming a yearly inflation rate of 2.25%. Figure 2 present the results for the analyzed variants in the basic scenario.  For the lignite gasification without CCS (L_H2_0), the NPV achieved was EUR −662 million, which was caused by higher capital expenditures (EUR 985 million) and a simultaneous increase in costs, resulting from the unfavorable price relation between lignite and hard coal. For the fourth technology analyzed, lignite gasification with a CCS system (L_H2_1), the NPV amounted to EUR −904 million, which was due to a higher level of capital expenditures (EUR 1133 million), an expensive CCS system and a lower efficiency of lignite conversion to syngas. For both of those technological variants, a negative IRR was determined. It can be noted that for all four variants, the increase in expenditures related to CCS was relatively greater that the influence of the prices of CO2 allowances (the variants with CCS systems demonstrated less economic efficiency in each case).

Discussion
Here, we extend our studies, providing sensitivity and scenario analyses.

NPV Sensitivity to Change of Key Market Factors
In this chapter, we document the results of sensitivity analyses, answering the second research question about the input values affecting the analyzed technologies most significantly. Here, we also identify the levels of key inputs that would make the considered variants profitable.
The DCF (Discounted Cash Flow) analysis assumes that the input (expected) values are constant in time, thus the discount rate is the only parameter reflecting the risk level. Thus, we examined and documented the influence on NPV exerted by the most crucial input variables, such as: • price of hydrogen • coal price • price of CO2 emission allowances • CAPEX • variable costs • discount rate.
A ±40% range of changes affecting the above variables was assumed, with a step in analysis of 10 percentage points. It should be added that the conducted sensitivity analysis examined the influence of only one input variable each time. The results are presented in Tables 9-12 and in Figures  3-6.
All the analyzed technologies are most sensitive to the price of hydrogen, which in turn is followed by discount rate, level of variable costs and capital expenditures (in that order), as well as the price of coal and CO2 allowances. On the basis of Table 9, it can be stated that the most promising On the basis of the table provided, taking into account the NPV criterion, it can be noted that the gasification of hard coal, and subsequently of lignite for the production of hydrogen, is not economically efficient for the basic values of the assumptions.
The best result was achieved in the case of the hard coal gasification without CCS (HC_H2_0), resulting in an NPV value of EUR −142 million and an approximate IRR at the level of 5.7%. Negative NPV and IRR, lower than the discount rate assumed, indicate, however, the existence of economic efficiency for the assumed input variables. The most promising result applies to the variant characterized by the lowest capital expenditures (EUR 818 million) and highest revenues (EUR 193 million yearly). The second best result was achieved in the case of hard coal gasification technology with CCS units (HC_H2_1). That variant has an NPV of EUR −366 million due to the internal consumption of energy in the CCS unit (here we noticed an increase in CAPEX for CCS of EUR 122 million, as well as lower revenues, amounting to EUR 176 million). The approximated IRR for this variant equaled 5.1% and was lower than the discount rate assumed.
For the lignite gasification without CCS (L_H2_0), the NPV achieved was EUR −662 million, which was caused by higher capital expenditures (EUR 985 million) and a simultaneous increase in costs, resulting from the unfavorable price relation between lignite and hard coal. For the fourth technology analyzed, lignite gasification with a CCS system (L_H2_1), the NPV amounted to EUR −904 million, which was due to a higher level of capital expenditures (EUR 1133 million), an expensive CCS system and a lower efficiency of lignite conversion to syngas. For both of those technological variants, a negative IRR was determined. It can be noted that for all four variants, the increase in expenditures related to CCS was relatively greater that the influence of the prices of CO 2 allowances (the variants with CCS systems demonstrated less economic efficiency in each case).

Discussion
Here, we extend our studies, providing sensitivity and scenario analyses.

NPV Sensitivity to Change of Key Market Factors
In this chapter, we document the results of sensitivity analyses, answering the second research question about the input values affecting the analyzed technologies most significantly. Here, we also identify the levels of key inputs that would make the considered variants profitable. The DCF (Discounted Cash Flow) analysis assumes that the input (expected) values are constant in time, thus the discount rate is the only parameter reflecting the risk level. Thus, we examined and documented the influence on NPV exerted by the most crucial input variables, such as: A ±40% range of changes affecting the above variables was assumed, with a step in analysis of 10 percentage points. It should be added that the conducted sensitivity analysis examined the influence of only one input variable each time. The results are presented in Tables 9-12 and in Figures 3-6.
All the analyzed technologies are most sensitive to the price of hydrogen, which in turn is followed by discount rate, level of variable costs and capital expenditures (in that order), as well as the price of coal and CO 2 allowances. On the basis of Table 9, it can be stated that the most promising variant (hard coal gasification without a CCS system) would achieve a positive NPV after assuming a 20% increase in hydrogen prices or a 30% reduction of capital expenditures. The positive NPV value would also occur when the variable costs drop by 20-30% or after a 30% reduction of the discount rate. variant (hard coal gasification without a CCS system) would achieve a positive NPV after assuming a 20% increase in hydrogen prices or a 30% reduction of capital expenditures. The positive NPV value would also occur when the variable costs drop by 20-30% or after a 30% reduction of the discount rate.     (Tables  11 and 12), the NPV is negative in the entire range of input values, which entails that a change of any   10, in turn, presents the sensitivity analysis concerning the variant of hard coal gasification with CCS systems. The discussed technology would achieve a positive NPV only if the prices of hydrogen increase by at least 40%. A change of other input variables in the range of ±40% would not result in the NPV turning positive. In the case of variants concerning the gasification of lignite (Tables 11 and 12), the NPV is negative in the entire range of input values, which entails that a change of any of the parameters analyzed would not improve their negative economic evaluation.

Efficiency of Analyzed Coal Gasification Technologies in the Condition of Assumed Prices of CO2 Allowances and Expenditures Related to CCS
This part of the study provides answers to the question concerning the market conditions which enable efficient use of the CCS systems in coal gasification to hydrogen (here, we do not assume, though, that such conditions necessarily exist). In order to answer that question, a multi-dimensional scenario was carried out for the following input parameters: • price of CO2 allowances • prices of hard coal and lignite

Efficiency of Analyzed Coal Gasification Technologies in the Condition of Assumed Prices of CO 2 Allowances and Expenditures Related to CCS
This part of the study provides answers to the question concerning the market conditions which enable efficient use of the CCS systems in coal gasification to hydrogen (here, we do not assume, Energies 2020, 13, 5074 15 of 20 though, that such conditions necessarily exist). In order to answer that question, a multi-dimensional scenario was carried out for the following input parameters: • price of CO 2 allowances • prices of hard coal and lignite • CAPEX and OPEX of CCS.
In this case, the value of LCOH 2 was assumed to be the main decisive parameter. In the first place, analysis was carried out to assess the influence of the yearly OPEX of CCS and total CAPEX of CCS. The results of this analysis for hard coal are presented in Table 13 and for lignite in Table 14. For example, in the case of CAPEX for CCS amounting to EUR 100 million and the average yearly OPEX of the CCS unit amounting to about EUR 6 million, LCOH 2 for the hard coal variant is EUR 3.05/kg while for lignite it is EUR 4.02/kg of H 2 produced. As can be noted, the levelized cost of hydrogen production for variants based on hard coal is lower in the entire range of analysis than for the lignite gasification. Moreover, for both hard coal and lignite, the LCOH 2 does not drop below the assumed market price of EUR 2.28/kg of H 2 (the lowest cost amounts to EUR 2.96/kg of H 2 , with the CAPEX for CCS amounting to EUR 62 million and yearly OPEX for the installation amounting to EUR 4.6 million). In the case of lignite, the limit value is EUR 3.93/kg of H 2 (for the analyzed scope of fluctuations of CAPEX for CCS and OPEX related to its functioning). The key issue for CCS development is the availability and price of CO 2 allowances. Thus, further in the study, an answer was provided to the question concerning the price level of CO 2 allowances at which the profitability of CCS systems applied for the production of hydrogen from coal can be achieved. The results of analysis for variants based on hard coal are presented in Table 15, whereas  Table 16 contains a similar analysis for lignite.
To provide an example, for the production of hydrogen from hard coal (for the CCS CAPEX of EUR 100 million and the average CCS OPEX of about EUR 6 million), the reference price of CO 2 allowances amounts to EUR 45/Mg. For every higher price of CO 2 allowance, the construction of a CCS system would be justified. In the case of variants based on lignite, for the investment in CCS of about EUR 100 million and an average operating cost of such a system of about EUR 6.3 million, the minimum price of CO 2 allowances which would justify the decision concerning building such an installation is a mere EUR 56/Mg. To generalize, CCS provided to hydrogen production from hard coal would be worthwhile only if the CO 2 allowance price is EUR 40/Mg (or higher), while in the case of lignite gasification, the price of CO 2 allowances would have to exceed EUR 52/Mg. Will that limit be exceeded permanently? There are strong indications that this may be the case, in a definite perspective.

Conclusions
The study provides the results of an economic assessment concerning four variants of coal gasification to hydrogen in a shell reactor (two each for both types of coal). In the widely conceived analyses, we provide the answers to several crucial questions and research objectives.
Based on conducted analyses, we formulate the following conclusion: • concerning prices of hard coal, lignite, hydrogen and CO 2 allowances, as well as capital expenditures and costs related to CCS systems, a negative economic evaluation, based on NPV and IRR, was obtained for all analyzed variants of coal gasification: NPV varied between EUR −903 and −142 million variants based on hard coal gasification generated a positive approximate IRR, although slightly lower than the discount rates assumed for those technologies for hard coal gasification, IRR was in the range of 5.1-5.7% (for lignite variants, IRR was negative).
• Gasification of lignite in Polish conditions appears to be unprofitable, having in mind the scale of total capital expenditures and the current price of coals used as feedstock.
at least a 20% increase in hydrogen price, or a similar reduction of CAPEX of installations and costs would be required to make hydrogen production profitable (a different combination of several factors occurring simultaneously is also possible, yet it was not the subject of the analyses).
• Analyses have also indicated that the prices of CO 2 allowances exceeding EUR 40/Mg would generate savings due to the availability of CCS systems, while in the case of lignite gasification, the price of CO 2 allowances would have to exceed EUR 52/Mg.
The achieved results have practical significance. They may be helpful in formulating an energy strategy for Poland. Unfortunately, at the present level of prices, there seems to be no place for economically effective and clean hydrogen production based on coal gasification without suitable national supporting mechanisms. It is also very important in relation to the policy of the European Union that is strongly focused on providing support for energy production technologies (including hydrogen) from renewables.
The novelty of this paper is mostly expressed in the complexity of the analyses conducted. The research revives the discussion carried out in the literature about the prosperity and future of coal gasification to hydrogen in Poland. The added value is therefore a multidimensional answer to the question both about the efficiency of the coal gasification and the conditions of its occurrence. In the literature on the subject, especially for Poland, there are no current studies and results in this field. Hence, we believe that such a discussion is important, taking into account the zero-emission policy of the European Union. Because of the negative economic effectiveness of all the analyzed variants in the present business conditions, this attempt seems to provide sufficient arguments to end our research efforts in this field.
Author Contributions: Conceptualization-R.K. and M.K., methodology-M.K., software and computation-R.K., model validation-R.K., formal analysis-M.K., writing and original draft preparation-R.K. and M.K., writing-review and editing-M.K., visualization-R.K., supervision-M.K. Both authors have read and agreed to the published version of the manuscript.

Funding:
The publication has been financed using a subsidy for maintenance and development of research potential and received no external funding.