The Use of the Local and Regional Potential in Building Energy Independence—Polish and Ukraine Case Study

Abstract

Biogas production in Poland and Ukraine seems to be a good way to both reduce greenhouse gas emissions and increase energy self-sufficiency by supplementing conventional energy sources. The aim of the research was to assess the potential of biogas production and the possibility of increasing it at the regional level of both studied countries and was conducted in 2018. The study included an analysis of seasonal heat demand, and the results showed biogas heat surpluses and shortages in each region. The financial side of the investment discussed using the example of the selected administrative unit showed that the construction costs of the biogas plant would be paid back after 7~9 years. The presented results also showed that Polish regions have much higher variation of biogas production potential (0.14~1.09 billion m³) than Ukrainian regions (0.09~0.3 billion m³). The analysis of the possibilities of increasing the potential based on the cultivation of maize in wastelands showed that in this respect, the Ukrainian regions have better opportunities compared to Polish regions. In the case of 20 regions, the maximum use of the potential of biogas should result in an increase in the share of renewable sources in the energy mix to above the level of 25%. Poland and Ukraine have comparable biogas production potentials of ~10 billion m³ annually, which results in a comparable number of biogas plants needed to consume that potential as well as the number of new jobs. The above analyses were also carried out at the LAU level (powiats and raions) where the potential of regional cooperation for four border regions is discussed.

1. Introduction

Energy is a necessary factor driving the economy both at a global and local scale, and given the progressive urbanization and growing population, the demand for electricity and heat is growing year by year. Unfortunately, the vast majority of energy is produced with the use of non-renewable sources, which include crude oil, natural gas, coal, etc. This directly contributes to the greenhouse effect, threats related to the over-exploitation of natural resources, growing social inequalities, and the degradation of natural ecosystems [1]. A smart action to avoid the situation is to increase the share of renewable energy sources in the energy mix, which would reduce the negative effects associated with the production of electricity and heat from fossil fuels while having a positive impact on the natural environment.

The aim of this article is to characterize the potential of biogas production as a renewable energy production alternative in Poland and Ukraine, with particular emphasis on the border regions of Podkarpacie, Lublin, Lviv, and Volyn, which are characterized by different production potentials that can complement each other. Against the background, an assessment of the possibilities of cooperation in joint biogas projects carried out at the local level would be a valuable addition to the knowledge of trans-border areas (usually referred to as peripheral). The following research questions were addressed in the paper:

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To what extent can biogas production cover local electricity and heat demand?

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To what extent will increasing the biogas production potential improve the share of renewable energy sources in the region at the regional level?

When characterizing our country’s involvement in the development of renewable energy, it should be emphasized that Poland, which adjusted its economy to the assumptions of the EU energy policy, has reduced the involvement of coal in energy production to over 73% in 2019 [2]. However, the key factor in increasing energy security and minimizing greenhouse gas emissions to the atmosphere is the concept of an energy mix, in which special attention is paid to the increase in the share of renewable energy sources. In this direction, Ukraine is also implementing a program for the development of renewable energy sources, where obtaining energy from biomass and the directions for the development of biogas production are an important element in this process [3,4]. As it turns out, Ukraine has one of the largest biomass potentials in Europe, and it is estimated that only France has a greater one [5]. This broadly understood potential of biomass, built mainly by the resources of wood, hay, straw, and also energy crops, should also translate into biogas production possibilities. Large hay resources are a sign of intensive livestock farming, which is a source of natural fertilizers used in the production of biogas. However, it should be remembered that the process of producing energy from biogas should take place in the context of understanding the system of links between technological, economic, social, and environmental conditions [6].

As shown in the literature, the share of renewable energy sources in gross final energy consumption in 2019 in Poland reached the level of approximately 12%. According to the National Plan for Energy and Climate, in 2030, Poland is to reach a 23% share of RES in the gross final energy consumption. This goal is to be achieved through an increase in the use of advanced biofuels, the development of offshore wind energy, and an increase in the dynamics of the development of renewable energy micro-installations (currently, most of the electricity from renewable sources in Poland in 2019 was produced in wind farms, i.e., approx. 10%). The share of electricity generated in biofuel installations and in photovoltaic installations in Poland amounted to 5.8%, and 1.5%, respectively. Liquid biofuels had a significant share in the structure of energy production from RES—approximately 10%. However, as it turns out, conventional sources have a higher capacity factor within a year than unstable renewable sources, which should change in the near future [7]. Among the renewable sources, apart from the use of solid biomass, biogas is characterized by the greatest stability; moreover, it can be produced in each territorial unit based on biodegradable waste generated in its area. In technical and financial terms, the development of biogas plants does not seem to exceed the possibilities of each of the countries discussed [8,9]. Therefore, the potential of biogas in Poland and Ukraine is not being sufficiently exploited. One of the leaders of the European Union—Germany—produces 33 times more of this type of fuel than Poland. A favorable system of financial support in the form of subsidies to biogas energy has contributed to the development of the biogas market in many European countries [7]. In addition to the system of subsidies for biogas production (Feed-in-Tariff, FIT, dominant in the EU-15 countries or Feed-in-Premium, FIP), more funds are needed for the capital costs of building biogas plants, which should also be extended to the production of bio-methane [10]. Taking into account the studies of the literature and the collected research material, the following research hypotheses were formulated:

• Biogas plants have a positive impact on the local labor market;
• There is a significant impact of biogas plants on reducing CO₂ and methane emissions;
• Poland and Ukraine have a significant potential for biogas production and show further possibilities of increasing it; and
• The differences in economic development can be used to strengthen the biogas production potential.

2. Methodology

The spatial scope of the research covered regions (NUTS 2) [11] in Poland and Ukraine, and calculations at the level of Polish powiats and Ukraine raions were performed only for the following regions: Podkarpacie, Lublin, Lviv, and Volyn. Due to the fact that biogas combustion in cogeneration units ensures higher efficiency of the entire system and allows for energy production in a more economical way, for the purposes of the calculations, it was assumed that from 1 m³ of biogas with a calorific value of ~23 MJ/m³ in cogeneration units, 2.2 kWh and 8 MJ of heat can be produced [12].

The above assumption infers the operation of cogeneration units with an efficiency of 67% (usually it is close to 85% [13]). On the other hand, considering only the production of electricity, a conventional generator would work with 36% efficiency [13], so 1 m³ of biogas could produce 2.3 kWh. The values of electricity and heat production obtained in this way were compared with the consumption described in the reports of Statistics Poland [2] and the State Statistics Service of Ukraine [14] for 2018. From the point of view of energy security, the focus on consumption results from the fact that not every region is able to meet its own electricity or heat demand on its own. Thus, the analysis of the impact of biogas production on energy consumption results in a better assessment of the share of this energy fuel in the regional energy mix. Moreover, taking into account the fact that some regions, due to the location of large professional power plants, may show electricity consumption resulting from the so-called parasite power, further calculations considered only electricity consumption excluding the energy industry and lignite mining (lignite-fired power plants and lignite mines are in fact the same complexes). The above assumption made it possible to calculate the coverage of energy demand by the potential of biogas, disregarding the influence of utility power plants.

Please note that both Statistics Poland and the State Statistics Service of Ukraine collect data on an annual basis. Therefore, estimating the impact of biogas on the coverage of heat consumption for individual months required disaggregation based on the demand for heat for individual months of the year [15,16]. In this way, the energy consumption (EC) was obtained, the value of which was corrected using the equation [17]:

$$FEC=\frac{EC}{1-0.9\alpha \left(1-\frac{Actual Sd}{term average Sd}\right)}$$

(1)

where FEC is the final energy consumption; Sd is the number of degree days; and α is the share of energy consumption for heating purposes in the total energy consumption in the housing sector (in this case, α = 1 was assumed).

Subsequently, it was assumed that for the two hottest months of the year, June and July, heat consumption is negligibly low [15]. On the other hand, in the case of biogas potential, a disaggregation was also made taking into account changes in the livestock population occurring during the studied year. Due to the fact that the State Statistics Service of Ukraine examines the livestock population on an annual basis while Statistics Poland provides data on a semi-annual basis, the model of disaggregation of the herd from Poland was transferred to Ukraine. It is worth noting that, in the case of Poland, there are significant biyearly changes in cattle population (e.g., in the Warmińsko–Mazurskie region, there was a decrease in the cattle population by 4.9% (June 2018 = 100) [2]). In the case of the other two sources, organic waste in landfills and sewage sludge in sewage treatment plants, it was assumed that their share in biogas production is evenly distributed over the year. The above disaggregation allowed for a more detailed assessment of the coverage of heat demand by biogas combusted in cogeneration units.

2.1. Calculation of the Biogas Production Potential

Biogas is produced in the process of anaerobic digestion of organic waste, in which organic substances are broken down by bacteria into simple compounds. In the process of anaerobic digestion, up to 60% of organic matter is converted into biogas. For energy purposes, it is produced as a result of the fermentation of:

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organic waste in landfills;

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animal and vegetable waste on farms; and

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sewage sludge in sewage treatment plants.

Under optimal conditions, about 400~500 m³ of biogas can be produced from one ton of municipal waste. However, in reality, not all organic waste is fully decomposed, and the fermentation process depends on many factors. Therefore, it is assumed that up to 200 m³ of biogas can be obtained from one ton of waste [18].

Livestock farms generate significant amounts of waste that can be used for biogas production. In the calculations, it was assumed that from 1 m³ of liquid manure, it is possible to obtain an average of 20 m³ of biogas, and from 1 m³ of manure, 30 m³ of biogas [18]. The analyzed data included the stock of livestock broken down into species and use groups as well as the average annual production volumes, natural fertilizers depending on the species of animal, its age, and the maintenance system. A study prepared by the National Research Institute of Animal Production [19] was used to calculate biogas emissions from fertilizers from individual animal species such as cattle, pigs, sheep, and poultry. The sludge from the wastewater treatment plant was also been used to produce biogas. In order to calculate the biogas emissions from the treatment plant, 100 m³ of biogas can be obtained from 1000 m³ flowing into the sewage treatment plant [20].

Another source that presents a significant potential for biogas production is agricultural crops, where the calculations only took into account the losses and losses in agricultural crops such as basic cereals with mixtures, potatoes, vegetables, fruit, corn, legumes, and oilseeds. The amount of biogas that can be obtained from plant biomass was calculated according to the studies in [21,22].

The above described methodology allowed us to calculate the so-called “basic” potential of biogas production built on the basis of natural fertilizers, losses in polonies, landfills, and sewage treatment plants. On the other hand, discussing the role of biogas in building energy security also requires examining the possibilities of increasing its potential. When calculating the increase in the biogas production potential, the focus was on the possibility of using the wasteland for maize cultivation. For the purposes of this “scenario”, an assumption was made that maize is cultivated on the entire wasteland and the yield is typical for a given region (NUTS 2). In order to calculate the emissions, it was assumed that 200 m³ of biogas can be obtained from one ton of wet mass [22].

2.2. Calculating the Impact on CO₂ Emissions and the Labor Market

When assessing the impact of the development of biogas plants on the labor market in Poland and Ukraine, the calculations used the model of a so-called “medium” agricultural biogas plant operating in Poland in 2017 [23]. According to the literature, for the needs of the calculations, it was assumed that the model biogas plant consumed an average of 39.55 thousand tons of substrate annually producing 3.04 million m³ of biogas, while substrate supplies were carried out with the use of trucks with a loading of 15 tons delivering the substrate from a distance not exceeding 50 km (distance measured along the actual road network). When calculating the number of trucks, it was assumed that, on average, each of them worked 8 h a day seven days a week, while the execution of one course took an average of 3 h. In order to assess the impact on employment and the local cooperation network, assumptions were made, according to the study in [23], that the model biogas plant employs an average of five people and cooperates with 112 farms. At this stage of the calculations, only the construction of a biogas plant is considered, but without the installation enabling the conversion of biogas to the biomethane standard.

Estimation of the possibility of reducing CO₂ emissions resulting from the consumption of biogas for energy purposes was made at the national level using the emission indicators typical for each of the analyzed countries. In 2018, 1 MWh of electricity was generated in Poland at the cost of 790 kg of CO₂ emissions [24]. Due to the large share of nuclear power plants in the energy mix, the emission factor for the Ukrainian energy sector was clearly lower, only 326 kg CO₂ from 1 MWh [25]. Then, using the share of biogas potential in the energy mix, the reduction in CO₂ emissions was calculated.

The basic assumptions of the methodology along with a graphical representation of the calculation path are presented in the diagram below (Figure 1).

3. Results

3.1. Potential and Sources of Biogas

The importance of biogas is easier to understand when comparing the production potential of this fuel with the consumption of natural gas. This type of statement is presented graphically in Figure 2. The potential of biogas production as well as the share of individual “sources” in its building was calculated for each of the regions (NUTS 2). The analysis of the results showed that only in the case of two Polish regions, Podlaskie and Warmińsko–Mazurskie, the potential of biogas could fully cover the local demand for natural gas of over 261% and 105%, respectively. The potential of biogas would also play a very important role in satisfying the consumption of natural gas in the following regions: Wielkopolskie (51% of the demand), Łódzkie (44%), and Transcarpathia (26%). Moreover, in as many as 12 regions in Poland and 15 regions in Ukraine, the share of biogas in covering the demand for natural gas would exceed 10%.

The calculation results presented in Figure 2 also showed a large variation in terms of the share of individual “sources” in building the biogas potential. In both analyzed countries, the greatest contribution to building biogas potential was made by natural fertilizers, where their share in Poland reached 55%, while in Ukraine, it was over 63%. In Ukraine, only in the case of three regions—Donetsk, Luhansk, and the city of Kiev—did the share of natural fertilizers not exceed 50%. In this respect, Polish regions showed much greater differentiation. In Poland, manure is the dominant source of biogas for as many as eight regions, located mainly in the central and northeastern part of the country.

It is worth noting that for the Podlasie region, due to intensive cattle breeding, the share of natural fertilizers exceeded 84% (Figure 3). The dominant share of natural fertilizers (>50%) in the potential of biogas production also occurred in the following regions: Wielkopolskie, Warmińsko–Mazurskie, Świętokrzyskie, Mazowieckie, Łódzkie, Lubelskie, and Kujawsko–Pomorskie. The clear differentiation in the share of natural fertilizers in the biogas potential is the result of changes in the structure of Polish agriculture that occurred mainly in 2002–2015, where there was a significant increase in regional differences in terms of the intensity of cattle breeding in Poland, a phenomenon partly due to the introduction of milk quotas upon accession to the EU. Compared to other regions, Podlaskie has become a real “dairy land”, with 93.9 head of cattle per 1 ha of agricultural land in 2018 [2]. On the other hand, a retreat from this direction of production took place in the following regions: Podkarpackie, Małopolskie, and Lubelskie [26]. It is worth noting that the abolition of milk quotas in 2015 did not significantly change the disproportion in the cattle population in Poland. The aforementioned specificity of Polish agriculture translated into a clear disproportion in the basic potential of biogas, ranging from ~140 million m³ (Lubuskie region) to ~1.09 billion m³ (Mazowieckie region). On the other hand, in the case of Ukraine, which is beyond the scope of EU regulations, a much more equal biogas production potential was observed: from ~85 million m³ (Kyiv city) to ~304 million m³ (Vinnytsya region). An in-depth analysis showed the potential of this source, both in Poland and Ukraine of over 70%, was through fertilizer of cattle origin, while for the Podlasie region, its share exceeded 95%.

Sewage treatment plants and landfills show a very large variation in terms of the share in biogas production depending on region. In the case of as many as six Polish regions (Zachodniopomorskie, Śląskie, Podkarpackie, Małopolskie, Lubuskie, and Dolnośląskie), the share of biogas from landfills and sewage treatment plants exceeded 50%. It is worth noting that for the Silesia region, this share exceeded 74%, while for the Podlasie region, it was slightly more than 9%; this difference results, among others, from the amount of waste and sewage discharged in individual regions. The Silesia region is a much more urbanized and industrialized area with a population density of more than six times higher; moreover, it annually discharges over 4.5 times more sewage and 5.6 times more municipal waste than the Podlaskie region [2]. In Ukraine, the share of landfills and sewage treatment plants in biogas production exceeded 50% only for three regions: Donetsk, Luhansk, and the city of Kiev (100%). On the other hand, for the remaining Ukrainian regions, the share of sewage treatment plants and landfills varied between 12% (Chernihiv region) and 35% (Dnipropetrovsk region).

Crop losses were the sources that contributed the least to building biogas potential. In the case of Poland, the share of this source varied from 3.6% (Silesia region) to over 15% (Lubelskie region). On the other hand, in Ukraine, the share of yield losses was clearly higher: from 6.1% (Zakarpattia region) to over 21.8% (Kherson region), which should be associated with the fact that agricultural production in Ukraine is less developed.

3.2. Using the Potential of Biogas for Energy Production

While discussing the importance of biogas for energy security, two scenarios for the use of this raw material have been discussed. The second “scenario” assumes the use of biogas to partially cover the consumption of natural gas, an issue widely discussed in numerous publications [3,6,7]. In the first “scenario”, it is assumed that the entire biogas production could be allocated to the production of electricity and heat (Figure 1). The results of the heat demand obtained with the use of disaggregation on a monthly basis are presented in

Table 1. Thermal energy balance (in TJ units) for individual months obtained with the use of the basic potential of biogas (red colors mean excess, green color means shortage). Source: Own study.

	I	II	III	IV	V	VI	VII	VIII	IX	X	XI	XII
Dolnośląskie	2102.21	1824.29	1441.40	725.72	350.29	−185.14	−209.88	339.73	547.36	1184.94	1725.06	2063.38
Kujawsko-Pomorskie	1238.64	1051.16	792.88	310.10	56.85	−304.32	−321.01	49.73	189.79	619.88	984.23	1212.44
Lubelskie	972.03	828.28	630.23	260.05	65.87	−211.08	−223.88	60.40	167.80	497.58	776.96	951.95
Lubuskie	516.80	443.40	342.29	153.29	54.15	−87.24	−93.78	51.36	106.19	274.56	417.20	506.54
Łódzkie	2086.22	1797.28	1399.23	655.19	264.89	−291.76	−317.48	253.91	469.76	1132.60	1694.13	2045.85
Małopolskie	2173.25	1883.55	1484.45	738.46	347.13	−210.97	−236.76	336.12	552.54	1217.13	1780.13	2132.77
Mazowieckie	5343.50	4613.47	3607.75	1727.88	741.75	−664.65	−729.63	714.01	1259.38	2934.10	4352.84	5241.49
Opolskie	525.10	448.16	342.17	144.06	40.14	−108.08	−114.93	37.21	94.69	271.18	420.70	514.35
Podkarpackie	708.29	609.73	473.95	220.15	87.02	−102.86	−111.63	83.27	156.90	383.01	574.55	694.52
Podlaskie	485.32	376.29	226.08	−54.70	−201.98	−412.04	−421.74	−206.12	−124.67	125.46	337.36	470.09
Pomorskie	2007.84	1741.97	1375.69	691.04	331.90	−180.31	−203.97	321.80	520.42	1130.35	1647.05	1970.69
Śląskie	4680.05	4090.34	3277.94	1759.41	962.83	−173.24	−225.73	940.42	1380.96	2733.78	3879.81	4597.64
Świętokrzyskie	444.66	378.42	287.16	116.58	27.10	−100.52	−106.42	24.58	74.07	226.03	354.77	435.40
Warmińsko-Mazurskie	795.42	669.37	495.72	171.14	0.87	−241.97	−253.19	−3.92	90.24	379.41	624.37	777.81
Wielkopolskie	1291.70	1054.48	727.68	116.82	−203.62	−660.62	−681.74	−212.63	−35.42	508.78	969.79	1258.55
Zachodniopomorskie	1331.30	1152.41	905.97	445.34	203.70	−140.92	−156.85	196.90	330.54	740.90	1088.55	1306.30
Vinnytsya	2088.31	1812.84	1433.35	724.02	351.92	−178.75	−203.27	341.46	547.24	1179.17	1714.50	2049.81
Volyn	984.06	851.55	669.00	327.78	148.78	−106.50	−118.29	143.75	242.74	546.72	804.24	965.55
Dnipropetrovsk	8338.38	7315.34	5905.97	3271.58	1889.66	−81.21	−172.28	1850.78	2615.05	4961.94	6950.11	8195.42
Donetsk	5171.42	4533.22	3654.01	2010.61	1148.53	−80.95	−137.76	1124.28	1601.05	3065.11	4305.38	5082.24
Zhytomyr	1289.24	1115.66	876.54	429.56	195.09	−139.31	−154.76	188.49	318.17	716.36	1053.70	1264.99
Zakarpattya	850.51	733.62	572.60	271.62	113.74	−111.44	−121.84	109.30	196.61	464.75	691.90	834.17
Zaporizhzhya	3734.98	3273.85	2638.57	1451.12	828.21	−60.16	−101.21	810.69	1155.19	2213.05	3109.22	3670.55
Ivano-Frankivsk	1872.96	1631.81	1299.59	678.60	352.85	−111.73	−133.20	343.69	523.84	1077.06	1545.72	1839.27
Kyiv	2372.29	2069.00	1651.16	870.15	460.46	−123.84	−150.84	448.93	675.51	1371.29	1960.72	2329.91
Kirovohrad	1128.53	981.86	779.81	402.13	204.01	−78.55	−91.60	198.43	308.00	644.46	929.50	1108.03
Luhansk	1745.15	1526.13	1224.38	660.37	364.51	−57.45	−76.94	356.19	519.81	1022.27	1447.93	1714.55
Lviv	2612.83	2275.61	1811.04	942.68	487.16	−162.50	−192.52	474.34	726.26	1499.87	2155.22	2565.71
Mikolayiv	2983.26	2612.30	2101.27	1146.04	644.95	−69.68	−102.71	630.86	907.98	1758.96	2479.87	2931.42
Odesa	2363.80	2060.69	1643.11	862.57	453.12	−130.82	−157.80	441.61	668.05	1363.41	1952.47	2321.45
Poltava	2134.14	1854.89	1470.19	751.10	373.88	−164.09	−188.95	363.27	571.89	1212.50	1755.20	2095.12
Rivne	2209.37	1929.15	1543.12	821.54	443.02	−96.82	−121.76	432.37	641.71	1284.54	1829.11	2170.21
Sumy	1134.63	984.65	778.04	391.84	189.25	−99.68	−113.03	183.55	295.59	639.65	931.11	1113.67
Ternopil	997.36	862.48	676.68	329.37	147.18	−112.65	−124.66	142.06	242.81	552.22	814.33	978.51
Kharkiv	2965.27	2587.67	2067.48	1095.13	585.07	−142.38	−175.99	570.72	852.81	1719.04	2452.86	2912.51
Kherson	894.90	774.49	608.60	298.53	135.88	−96.09	−106.81	131.31	221.26	497.49	731.50	878.07
Khmelnytskiy	1354.89	1170.24	915.86	440.38	190.95	−164.77	−181.21	183.94	321.88	745.47	1104.32	1329.09
Cherkasy	2108.87	1837.71	1464.16	765.92	399.64	−122.74	−146.88	389.33	591.90	1213.94	1740.91	2070.98
Chernivtsi	620.13	536.30	420.80	204.91	91.66	−69.85	−77.31	88.48	151.11	343.44	506.37	608.42
Chernihiv	830.71	712.50	549.64	245.23	85.55	−142.19	−152.71	81.06	169.37	440.56	670.29	814.19
Kyiv city	3397.41	2982.18	2410.14	1340.90	780.00	−19.94	−56.90	764.22	1074.42	2026.98	2833.94	3339.39

, where heat produced from biogas combustion in a cogeneration unit was subtracted from the heat consumption in a given month. Therefore, in the months when biogas production predominates, negative values are obtained (excess heat—red color).

The results presented in Table 1 indicate that for each region in the summer months of June and July, the cogeneration unit will produce excess heat that cannot be used. In the case of the Podlasie region, due to its great potential, this period should be extended from April to September, while for the Wielkopolskie region, it will extend from May to September. The first solution to this problem seems to be the construction of biogas purification installations to the biomethane standard, which would allow for its subsequent distribution using the existing transmission network [27]. The second option is only the production of electricity, which, however, is associated with a decrease in efficiency [13]. This “scenario” on an annual basis is presented in Figure 4. It is worth noting that the use of wasteland for maize cultivation would not be a problem as the harvested crops could be stored until there is an increased demand for biogas.

Most of the existing commercial power plants are located within the administrative boundaries of cities, which translates into low transmission losses due to proximity to the customer. On the other hand, most biogas plants, due to their use of natural fertilizers, will be located in rural areas (i.e., at a greater distance from the main recipients (cities)), which unfortunately translates into higher transmission losses. It is worth mentioning that in the case of new networks, average annual losses are at the level of 6~7%. In the case of older grids, the share of heat losses exceeds 10% and in extreme cases, it can reach 20% during the heating season and 50% in summer [28]. Therefore, the effect of further distance of the biogas plant can be partially compensated for by a better quality of the transmission network, the cost of which reaches 2 million PLN per 1 km [29].

In order to discuss the economic aspects in more detail, the powiat of Hrubieszow (Lublin region) was chosen, which has a “basic” biogas production potential estimated at ~16.2 million m³ per year (average value for all surveyed powiats and raions). According to the adopted model [23], the use of this potential would involve the construction of five biogas plants with a capacity of 1 MW each per year, thus possibly producing a total of ~130 TJ of heat and over 34 GWh of electricity. Taking into account the 2018 heat and electricity prices [30,31], in PLN, this would be respectively 5.02 million PLN and 6.61 million PLN. The total cost of five biogas plants would reach 70 million PLN, of which 19 million could be covered by a grant from the National Fund for Environmental Protection and Water Management [32]. Assuming that each biogas plant is located at a distance of up to 5 km from the recipient, the cost of a modern district heating network would be approximately 50 million PLN. Therefore, assuming the energy prices of 2018, the total investment amount estimated at about 101 million PLN would pay for itself after nearly nine years, whereas for the energy prices of 2020 [30,31], such payback would occur after only seven years. The above case shows that the economic attractiveness of biogas is largely determined by energy prices and the amount of funding, which in the case of EU projects can reach 85% [33].

The results shown in Figure 4 present that in terms of covering the demand for electricity and heat, Polish regions showed greater differentiation than the Ukrainian ones. While in Ukraine, the share of biogas, both in terms of covering the consumption of electricity and heat, did not exceed 22%. On the other hand, in the case of Polish regions, there was clearly greater differentiation in the impact of biogas, especially in terms of covering the heat demand. In this respect, the Podlaskie region remains the leader, for which the share of heat produced from biogas exceeded 57%, while in the case of electricity, it was over 53%. Biogas would also be the dominant source of heat for the Wielkopolske region (over 53% of demand). It is worth noting that for only one region in Poland, the share of biogas in covering heat consumption would not exceed 10% (the Silesia region around 7.7%), and in the case of Ukraine, the “threshold” of 10% would not be exceeded by 11 regions. For the Silesian region, biogas could cover only 3% of electricity demand, which results from the fact that it is a region with a high concentration of energy-intensive industries. A similar situation was observed in the industrial areas of Ukraine, particularly for the regions of Dnietropetrovsk (2.2%), Donetsk (3%), and Zaporizhia (3.3%).

3.3. Opportunities to Increase Potential of Biogas Production

Discussing the importance of biogas potential for energy security also requires analyzing the possibilities of increasing its potential. One of the easiest ways to increase biogas production seems to be the use of wasteland for the cultivation of maize, the crops of which could supply local biogas plants. The calculation results for this scenario are presented in Figure 5.

The results in Figure 5 show that the regions Mazowieckie and Wielkopolskie, which have the largest “basic” biogas production potential, respectively, 1.09 billion m³ and 1.02 billion m³ per year, had the lowest possibilities of increasing it. Based on the use of maize crops on wasteland, the Mazowieckie region could increase its potential by only 23.4%, while the Wielkopolskie region would increase by 26.1%. Such low values result from the developed agricultural economy in these regions and thus from the small area of available wasteland. A different situation was observed in the Zachodniopomorskie region, whose “basic” potential, estimated at over 235 million m³, may increase by over 200%. The Ukrainian regions showed much less differentiation in terms of the “basic” biogas production potential compared to the Polish regions, but due to the larger area of wasteland, they showed better opportunities to increase the potential based on the use of wasteland. In this respect, the clear leaders in Ukraine are the Chernihiv and Sumy regions, for which the increases in potential would amount to 294% and 272%, respectively. However, it should be remembered that Ukraine is not making proper use of its agricultural potential. This is due to the very difficult socio-economic and military-political situation. In the case of maize cultivation, the average yield per ha in Ukraine in 2018 was 257 dt/ha, while for Poland, it was over 446 dt/ha [2,14].

In order to better visualize the potential of wastelands, a similar estimation of the possibility of increasing biogas production was made for each of the 380 Polish powiats and Ukraine raions from two selected regions (NUTS 3). The distribution of the potential for powiats, presented in Figure 6, resembles the distribution shown in Figure 5. A more detailed analysis showed that the powiats for which the annual potential of biogas production ranges from about 5 million m³ to over 15 million m³ had the greatest potential to increase their potential. The identification of powiats belonging to border regions (Podkarpacie, Lubelskie) showed that the “growth potential” was similar for each of them, and resembled a “quasi-Maxwellian” distribution (Figure 6). A similar phenomenon was also observed at the regional level (Figure 5), where the “quasi-Maxwell” distribution not only determines the possibilities of increasing the potential based on maize cultivation, but also, mainly for Ukrainian regions, defines the limits of growth based on the expansion of the so-called “basic” potential. The grouping of Ukrainian regions due to their similar values of the “basic” potential also shows that Ukrainian agriculture is less developed than Polish agriculture.

As in the case of the regions (NUTS 2), the same regularity could be observed in the powiats and raions consisting of the inability to significantly increase the biogas production by territorial units with the “basic” potential exceeding the average values. A good example visible on the right side of Figure 6 is the city of Warsaw, with the “basic” potential reaching 130 million m³ and the city of Kiev with a potential of over 85 million m³ (shown in Figure 5 as point number 25), which is because territorial division and functions usually do not have wasteland resources. This situation also appeared for all powiats, whose borders mainly enclose urban areas.

The results collected in

Table 2. Basic potential of biogas. Source: Own study.

Country	Natural Fertilizers Billion m3	Plant Production Waste (Yield Losses) Billion m3	Landfills and Sewage Treatment Plants Billion m3	Biogas Production Potential Billion m3	Share: Natural Fertilizers %	Share: Plant Production Waste (Yield Losses) %	Share: Landfills and Sewage Treatment Plants
Ukraine	3.19	0.63	1.22	5.04	63.29	12.50	24.21
Poland	3.63	0.59	2.40	6.61	54.92	8.93	36.31

indicate that Ukraine, which has a much larger territory (603.7 thousand km²) compared to Poland (312.7 thousand km²) as well as a larger area of arable land, has a clearly lower potential for biogas production. The reasons for this should be sought not only in the lack of a proper agricultural culture destroyed by years of domination of state-owned farms, but also in the technological delay of Ukrainian agriculture [34]. These phenomena translate not only into lower average yields per hectare (e.g., maize), but also into higher crop losses [35]. It is worth noting that in both countries, the share of natural fertilizers in building the biogas production potential exceeds 50%, with the second highest source in terms of share are landfills and sewage treatment plants. The clearly greater share of this source on the Polish side (36.31%) proves it to be the much better management of solid and liquid waste.

Summing up the results of the calculations, it is worth emphasizing that in the case of the Polish economy, the use of wasteland would increase the potential of biogas production from 6.61 billion m³ to over 10.01 billion m³ of biogas, which is the equivalent of more than 6.58 billion m³ of biomethane. Therefore, taking into account the consumption of natural gas in 2018 (17.2 billion m³ [2]), biogas production in Poland could cover up to 38.25% of the domestic demand. In Ukraine, the use of wastelands would increase the potential from 5.04 billion m³ to 9.33 billion m³ (6.13 billion m³ of biomethane). Therefore, even the use of numerous wastelands would not allow Ukraine to surpass Poland in terms of the size of its potential, which is mainly a result of the lower average maize yield per ha in Ukraine.

However, bearing in mind that the extraction of natural gas in Ukraine amounts to 21 billion m³ annually while the consumption in 2018 exceeded 33.46 billion m³, it can be seen that the potential of biogas (converted into biomethane) would cover about 50% of this raw material import to Ukraine.

3.4. Impact on the Labor Market

The analysis of the impact of biogas plant development on the labor market, both in Poland and in Ukraine, was carried out with the help of the “average” rural biogas plant model presented in the work of M. Nikiciuk [23]. The results obtained for the “basic” potential of biogas production and with the use of wastelands are summarized in

Table 3. The impact of biogas plants on the labor market, transport fleet, and cooperation network. Source: Own study.

Country	Number of Biogas Plants		Number of Vehicles Require to Delivering the Substrate (Equal to Numbers of Drivers)		Number of Cooperating Entities		Workplaces Directly in Biogas Plants
	Basic Potential	Basic Potential and the Use of Wastelands	Basic Potential	Basic Potential and the Use of Wastelands	Basic Potential	Basic Potential and the Use of Wastelands	Basic Potential	Basic Potential and the Use of Wastelands
PL	2178	3299	11,699	17,863	232,341	354,769	10,040	15,331
UA	1661	3073	9950	18,068	197,612	358,843	8540	15,507

.

The results collected in Table 3 indicate that the use of only the so-called basic biogas potential in Poland would require the construction of 2178 biogas plants, which would employ over 21,700 people (including drivers responsible for the supply of substrates). On the other hand, the use of wasteland would increase the number of employees to nearly 33,200. Due to the similar potential, a similar scale of investments will be needed in Ukraine, where the use of the basic potential would require the construction of 1661 biogas plants and employment of over 18,500 employees to operate these installations. The use of wasteland would result in an increase in the number of biogas plants to 3073 and an increase in employment to over 33,500 employees. The given figures are a small value in the agricultural sector of both countries, however, when discussing the above results, it should be remembered that they only take into account the number of people directly employed in biogas plants. In fact, the impact of the development of biogas plants on the generation of new jobs would translate into entire branches of industry responsible for the design, modernization of these installations and, in the case of agriculture, in additional jobs in connection with the cultivation of wastelands.

Taking into account the number of cooperating entities, it can be seen that in the case of Poland, the number of subcontractors would constitute over 10% of all farms, and only in the “scenario” of using the basic potential based mainly on waste from agricultural production. On the other hand, activation of the wasteland potential would increase the percentage of Polish farms actively cooperating with local biogas plants to over 15.5%. When analyzing the data in Table 3 in terms of cooperation with local entities, it should be remembered that Ukrainian agriculture, unlike Polish agriculture, is characterized by a strong dualism. In Ukraine, an important role is played by agroholdings [36], while the total number of Ukrainian farms still remains small, ~50 thousand, of which around 46,000 are family farms [35]. This is a very small value compared to Poland, where in 2018, there were over 2.3 million individual farms [2]. Thus, in the case of Ukraine, the result suggests that establishing cooperation with a group of up to 35,800 entities should be understood rather as the number of employees in the agricultural sector that may be involved in work for the benefit of biogas plants.

3.5. Reduction in CO₂ and Methane Emissions

A very important aspect related to the combustion of biogas for energy purposes is the possibility of reducing CO₂ emissions. In 2018, the generation of 1 MWh of electricity in Poland took place at the cost of the emissions of 790 kg of CO₂ [24], therefore, the production of over 170 TWh of electricity [2] resulted in the emissions of over 134.31 million tons of CO₂ into the atmosphere. On the other hand, the use of the basic potential of biogas, 6.61 billion m³, could cover about 8.2% of electricity production (13.9 TWh), therefore, taking into account the biogas emissivity maintained at 81.5 kg CO₂ from 1 GJ [37], it is easy to calculate that the use of biogas in Poland for the production of electricity would result in a reduction in CO₂ emissions by over 5.1% nationwide. Activation of the wasteland potential could increase the share of biogas in electricity production to over 12.4% (21 TWh) and contribute to a further reduction in CO₂ emissions by over 2.7%.

In the case of the Polish energy sector, a stable downward trend in CO₂ emissions has been observed for 20 years. In 2000, the production of 1 MWh was associated with the emission of 950 kg of CO₂, while in 2019, it was 751 kg of CO₂ [24], therefore, limiting the linear prediction in 2025, emissions of ~700 kg of CO₂ can be expected. Assuming slight fluctuations in the “basic” potential of biogas and taking into account the end of electricity production in some Polish power plants by 2025 [38],

Table 4. The impact of biogas on the reduction in CO₂ emissions in Poland. Source: Own study.

	2015	2018	2019	2025
kg CO2/MWh	803	790	740	700
Energy production—TWh	164.9	170	163.9	187.9 [34]
Biogas—energy production—TWh	12.9	13.9	12.9	13.9
Reduction in CO2 emissions resulting from biogas consumption—%	4.9	5.1	4.7	4.3

presents the results describing the possibilities of reducing CO₂ emissions in the selected years.

The results in Table 4 indicate that the reduction in CO₂ emissions per MWh does not significantly affect the share of biogas. On the other hand, the decrease in the importance of biogas in reducing CO₂ emissions can be observed with the increase in electricity production envisaged in the PEP2040 report [38].

Due to the large share of nuclear power plants in the energy mix, the emission factor for the Ukrainian energy sector is clearly lower, with only 326 kg CO₂ from 1 MWh [25]. In Ukraine, the use of the basic potential of biogas of 5.04 billion m³ for electricity production could provide 10.6 TWh per year, which would cover over 7.1% of energy production and result in a reduction in CO₂ emissions by over 0.71% at the country scale. The use of wastelands could increase the share of biogas in electricity production to over 13.2% (19.59 TWh) and reduce CO₂ emissions by over 1.32%.

The results shown in

Table 5. The impact of biogas on the reduction in CO₂ emissions in Ukraine. Source: Own study.

	2015	2018	2019	2025
kg CO2/MWh	355	326	316	300 [39]
Energy production—TWh	145	148.3	141.2	165.3 [39]
Biogas—energy production—TWh	9.6	10.6	10.6	9.6
Reduction in CO2 emissions resulting from biogas consumption—%	1.14	0.71	0.54	0.13

were also obtained by assuming changes in biogas potential. In the case of Ukraine, the report prepared by IRENA [39] predicted an increase in electricity production, which should reduce the role of biogas in reducing CO₂ emissions. Such a low decrease in emissions compared to the Polish economy speaks in favor of using Ukrainian biogas to meet the demand for natural gas than to produce electricity.

It is worth emphasizing that the use of natural fertilizers, yield losses as well as landfills and sewage treatment plants for the production of biogas would also significantly reduce the uncontrolled emissions of methane into the atmosphere.

In 2016, methane emissions in Poland amounted to 46.8 million tons, of which agriculture accounted for 13.98 million tons and waste management 9.48 million tons [40]. As can be noted, the use of these sources for the production of biogas would result in the reduction in methane emissions by nearly 50%. In the case of Ukraine, the annual methane emissions reach 64.46 million tons [41], where agriculture accounts for 10.07 million tons and waste management for 13.22 million tons. Therefore, in the case of Ukraine, the use of these sources would reduce methane emissions by nearly 37%.

4. Possibilities of Regional Cooperation

Establishing cooperation as part of building energy security has always been the domain of government institutions, but when looking at the potential of border areas, it is worth asking what the local authorities can do to improve this area of life. In terms of biogas production potential, the Podkarpacie region ranks fourteenth in Poland, with a potential estimated at over 167 million m³ of biogas. The Lublin region, with a potential of 335 million m³, ranks eighth. On the other hand, in Ukraine, the Lviv region with a potential of 288 million m³ takes second place, while the Volyn region was seventeenth (177 million m³). At this point, it is worth asking whether establishing cross-border cooperation between the above-mentioned Ukrainian and Polish regions would be justified and what such possible cooperation would involve.

The length of the Polish–Ukrainian border is over 535 km and runs through the Podkarpackie (236 km) and Lubelskie (296 km) voivodships. An important advantage in favor of establishing cooperation is the fact that there are 10 border crossings that ensure high capacity for both people and goods. It should be remembered that in addition to access to substrates, efficient transport and a developed network of roads are very important for the efficient operation of any biogas plant. For this reason, the Transcarpathia region, due to the lack of a border crossing with the Podkarpacie region, was not taken into account. There are significant “developmental” differences between the Polish and Ukrainian regions under consideration, which can be transformed into attributes of a fruitful energy policy conducted, for example, within the framework of cross-border cooperation of functional areas. The greatest advantages of Polish regions include access to European funds related to the EU energy transformation and a well-developed agri-food economy, while the low cattle population remains a downside, mainly due to the structural changes that took place in agriculture after Poland joined the EU [26]. The undoubted advantage of the Ukrainian regions that there is a much greater (compared to Polish partners) potential for biogas production and the lack of strict regulations on agricultural production in contrast to UE members [42]. At this point, it is worth emphasizing that in the case of the Ukrainian agricultural economy, there is a noticeable increase in monoculturalism [43], a generally unfavorable trend for the development of agriculture, but allows for a significant increase in the biogas production potential in relation to Polish partners (Figure 6).

The problem on the Ukrainian side is the lack of sufficient funds for the development of the renewable energy sector, therefore, Ukrainian regions with their lack of funds and great potential would be a “natural” partner for Polish regions with better financial resources and a more developed agri-food industry. Figure 6 shows the potential of biogas production for individual powiats and raions as well as the possibilities of increasing it based on the cultivation of maize in wastelands.

In the Podkarpackie region, the entire use of wasteland for maize cultivation could result in an increase in the biogas production potential by over 85 million m³ (approximately 51% in relation to the “basic” potential), while for the Lublin region, it would be an increase of over 198 million m³ (increase about 60%). On the other hand, on the Ukrainian side, which has a greater resource of wastelands, maize cultivation could increase the biogas production potential in the Lviv region by a further 386 million m³ (an increase by over 133%), while for the Volyn region, it would increase by over 184 million m³ (an increase of over 104%). It is worth noting that intensive cross-border cooperation could also result in the flow of broadly understood agricultural knowledge, which could further translate into an increase in the number of crops on the Ukrainian side and thus an increase in the potential of biogas production.

The more developed agricultural economy on the Polish side (using a larger percentage of land for cultivation) caused Polish powiats to show much fewer opportunities to increase the potential of biogas compared to Ukrainian raions with larger resources of wasteland. In addition, it is worth noting that the possibilities of increasing the potential based on the use of wasteland clearly decrease with the increase in the so-called “basic” potential built mainly on the basis of natural fertilizers, polonium losses as well as landfills and sewage treatment plants. Among the powiats shown in Figure 6, medium and large urban centers have the smallest potential to increase their potential, or the lack of such opportunities. Cities, due to the large number of people and thus considerable resources of municipal waste, sometimes have a large so-called “basic” potential on the regional scale, however, due to the small area and the lack of wasteland, they do not show any possibility of increasing it. The potential of cities is sometimes 100% built by municipal waste and biogas obtainable from sewage treatment plants (Figure 7). In the case of other powiats, natural fertilizers play a dominant role in building the “basic” potential of biogas, which is particularly clear in the Lviv, Volyn, and Lubelskie regions. In terms of spatial distribution, it is worth emphasizing that Polish powiats with a greater potential for biogas production in relation to the consumption of natural gas tended to group close to the border (Figure 7). On the other hand, the opposite tendency was visible for the Lviv region.

Analyzing the data in

Table 6. The impact of biogas plants at a regional scale. Source: Own study.

Region	Number of Biogas Plants		Number of Vehicles Require to Delivering the Substrate (Equal to Numbers of Drivers)		Number of Cooperating Entities		Workplaces Directly in Biogas Plants
	Basic Potential	Basic Potential and the Use of Wastelands	Basic Potential	Basic Potential and the Use of Wastelands	Basic Potential	Basic Potential and the Use of Wastelands	Basic Potential	Basic Potential and the Use of Wastelands
Podkarpackie	55	84	312	471	6180	9344	267	404
Lviv	96	223	540	1258	10,715	24,978	463	1080
Lubelskie	110	176	624	992	12,388	19,695	535	851
Volyn	58	119	330	672	6546	13,354	283	577

, it can be seen that the increase in employment in the agricultural sector on both sides of the border would be minor, around 1~2%. In the Podkarpackie region, the number of people employed directly in the biogas sector, taking into account the activation of wastelands, would amount to 875 people, and in the Lubelskie region, it would amount to 1843 people. These numbers could increase in the event of the commencement of cooperation and, consequently, the import of substrates from Ukraine to Poland. It is worth emphasizing at this point that the Polish side also has much more experience in this field: in 2018, there were 308 biogas plants in operation in Poland, of which 20 were in the Lubelskie region and 17 in the Podkarpackie region. On the other hand, in the same year, a total of 33 biogas plants operated in Ukraine [44]. On a European scale, Poland is not a biogas power, but the development of significant operational knowledge on the functioning of agricultural biogas plants as well as the development of competitive technologies in terms of investment costs, constitute a significant premise for establishing such cooperation. Thus, referring to the fourth hypothesis, it is worth noting that not only would economic differences be one of the factors driving effective cooperation, it would also be an intensive flow of knowledge.

5. Discussion

One of the solutions that can ensure the coverage of the growing energy needs, while taking into account the activities supporting the environment (as a long-term strategy for the development of natural energy), seems to be the development of biogas plants [45]. In contrast to coal-based power generation, which is generally located in the vicinity of coal deposits and water reservoirs, biogas plants can primarily support the local economy, but also build the ecological, economic, and energy potential of the entire country [46]. This is due to the fact that each region, regardless of the dominant form of economic activity, is primarily a generator of biodegradable resources for the production of clean energy [47] and may act as a catalyst for the development of infrastructure for biogas production, of which a biogas plant is an integral part.

This type of spatial distribution of biogas plants dependent on the production of biomass [48] can be observed, for example, in Germany, where in 2018, over 10,900 centers producing about 9.8 billion m³ of this fuel were spread relatively evenly across all regions, although their greatest accumulation occurred in the northwest and south of Germany [49]. A similar distribution can also be observed in the Czech Republic, where 574 installations produced over 1.2 billion m³ of biogas [50]. On the other hand, in France, which has a similar biomass potential as Ukraine [5], in 2018, only 742 biogas plants were in operation, which gave it third place in Europe, just behind Italy, with a significantly lower biomass potential, but using 1655 biogas plants [51]. Against this background, Poland, with 308 biogas plants and an annual production of 350 million m³ of biogas, ranks eighth in Europe [52]. However, taking into account the calculated potential (Table 2), it is easy to see that the Polish biogas sector, using only 5.3% of its basic potential, is still in the development phase.

In terms of using the potential, the biogas sector in Ukraine [53] is at an even earlier stage of development, where 33 biogas plants used approximately 1% of the basic potential in 2018 [44]. As can be seen, biogas, especially in Ukraine, but also in Poland, is an unused, multi-faceted resource [54]. Biogas plants can produce electricity, heat, and biofuel. Thus, contributing to the development of decentralized energy solutions based on local resources [55,56,57] and unlike wind and solar energy that do not require specific terrain conditions. The development of the biogas market is advisable and beneficial both in Poland and Ukraine [58,59,60]. In Poland, the use of the “basic” biogas potential would be associated with the creation of over 21,700 jobs only to operate 2178 biogas plants that would establish cooperation with over 232 thousand farms scattered throughout the country. Additionally, in Ukraine, the development of a network of 1661 biogas plants would allow for the creation of nearly 18,500 new jobs. Therefore, answering the first hypothesis, it can be concluded that the development of this energy sector definitely has a positive impact on the labor market, especially in rural areas. It is worth adding that in Germany, which produces nearly 9.8 billion m³ of biogas annually, this energy sector creates about 345,000 jobs [61]. In the context of broadly understood ecology, and thus the reduction in greenhouse gas emissions, the use of the basic potential could reduce methane emissions in Poland by nearly 50% and by 37% in Ukraine. On the other hand, the combustion of biogas in cogeneration units would allow for the reduction in CO₂ emissions by 5% in Poland. Thus, in the case of the second research hypothesis, a positive answer can be confirmed. The share of RES in energy production is still small, but at the same time, in most regions, there are large possibilities of obtaining additional energy from biogas. In this respect, there is a large spatial differentiation both in terms of the size of biogas potential and the share of renewable energy in the energy balance of individual regions [62]. The impact of the basic potential of biogas (taking into account only electricity production in the summer months) and its increase based on the use of wastelands on the share of renewable energy sources in electricity consumption is shown in Figure 8.

When analyzing the results shown in Figure 8, it is worth paying attention to the points located near the origin of the coordinate system because they indicate regions that would gain the most by activating the biogas potential. A very good example is the Chernihiv region, which could increase its share of renewable sources in energy consumption from the current 4.3% to over 88.8%, thus becoming a leader in Ukraine. A better result was obtained for the Podlasie region in Poland, where the share of renewable energy sources in energy consumption would increase from the current 22% to about 104% (Figure 8b). In terms of covering the demand for electricity, only one of the regions would achieve complete self-sufficiency (Podlasie region), but activating the potential of biogas would have a very positive impact on the energy security of many regions. In the case of eight of them, the share of renewable energy sources would cover over 50% of electricity consumption, while for another 14 regions, this share would range from 25% to 50% (Figure 8b). The results presented above confirm the validity of the third hypothesis.

The presented results indicate that the problem presented deserves a more thorough analysis, which would need to be done at the powiat and raion level. Moreover, future analyses should also take into account the role of solid biomass in the energy balance.

6. Conclusions

In recent years, in Western Europe, mainly in Germany, an extremely rapid development of biogas plants has been observed. This is partly due to the consistently conducted energy transformation and the need to diversify gas supplies. Poland and Ukraine, with potentials of 9~10 billion m³ of biogas, are at the beginning of this road. The presented research results showed that the use of biomass as a renewable energy source offers excellent prospects for Ukraine, but the possibilities of its use in the energy sector are very diverse. The maximum use of the potential of biogas in Ukraine would allow for the replacement of about 50% of this raw material import, while in the case of combustion in cogeneration units, biogas could cover up to 13.2% of the demand for electricity and up to 18.2% of heat consumption.

It is worth noting that in the case of Poland, the coverage of electricity consumption would be similar (12.3%), while the potential of biogas would be clearly more important in covering the demand for heat (41.2%). Moreover, at the regional level, two Polish regions, Podlaskie and Warmińsko–Mazurskie would not only be self-sufficient in terms of the demand for natural gas, but could also become local biogas exporters. On the national scale, however, biogas would cover over 38.25% of Poland’s demand for natural gas. In Poland, the use of biogas for energy production would reduce CO₂ emissions by more than 7.7%, while for Ukraine, due to the large share of nuclear energy in the energy mix, it would be only 1.3%. However, even a slight decrease in emissions could bring significant savings related to the purchase of CO₂ emission quotas and should in turn stimulate economic growth [63].

The development of biogas plants would also have a positive impact on the labor market, generating 33,200 new jobs in Poland and over 33,500 in Ukraine directly in this industry sector. Moreover, more than 15.5% of farms in Poland could count on greater economic stability resulting from cooperation with local rural biogas plants. Therefore, it would be a very important support for the economy of both countries in the era of energy transformation [64]. The production of biogas on such a large scale would also solve the problem of managing waste generated during agricultural production, and due to the use of post-fermentation mass for fertilization, it would also have a beneficial effect on the ecological balance of arable land.

Both Poland and Ukraine have large so-called “basic” potentials of biogas production, which could be enhanced not only by the use of wastelands, but also on the developmental differences in the border areas. In these regions, the construction of a biogas network could not only improve local energy security, but ultimately reduce energy costs for nearby recipients, improve the use of the endogenous potential of the regions (mainly wastelands on the Ukrainian side), and above all, economically stimulate areas in both countries considered peripheral and actively counteract their marginalization.