**3. Global Energy Situation Review**

Human beings have always used energy to fulfill needs and to transform the world around them. When considering energy consumption from 1800 to 2019, its growth is exponential and could be described with a function. e = 2.71828 is Euler's number. The "*x*" occurs as an exponent (1). The R<sup>2</sup> indicator—0.9671 is very high in that case and shows that the curve equation almost perfectly fits the analyzed data (2).

$$y = 0.1449e^{0.1329x} \tag{6}$$

$$\text{R}^2 = 0.9671\tag{7}$$

When considering the energy sources' mix, traditional biomass gave 5653 TWh in 1800, and 11,111 TWh in 2020. That means over 100% growth, but it was the slowest growing energy source (Figure 1).

**Figure 1.** Global primary energy consumption by source: (**a**) In Twh; (**b**) relative (%) [17].

Coal was the second traditional primary energy source. It delivered about 97 TWh in 1800, and 44,109 TWh in 2019. In the 19th century, coal was the primary energy source to enable the "1st Industrial Revolution" and was 55.23% of the global energy mix in 1910. Since then, no primary energy source achieved such a significant share in the world energy mix. The percentage of coal in the global energy mix has been declining and now is about 25.7%.

Oil was the third primary energy source that has appeared in the 19th century and has become the essential energy source. The history of oil began in occupied Poland. The Polish pharmacist, engineer, businessman, inventor, and philanthropist Ignacy Łukasiewicz was the pioneer who designed the world's first modern oil refinery in 1856. "His achievements included discovering the methods of distilling kerosene from seep oil, the invention of the modern kerosene lamp, the introduction of the first modern street lamp in Europe, and the construction of the world's first modern oil well" [18,19]. Oil has provided 53,620 TWh in 2019, and was the first most crucial energy source, but its share was about 31% at that time. It obtained its highest share—43.3% in the global energy mix in 1973.

Natural gas was the fourth most crucial energy source in 2019. The history of gas also began in the 19th century. The popularity of natural gas is still growing. In 2019, gas provided 39,292 TWh, which constituted 22.5% of the global energy mix.

Hydropower was the fifth most crucial energy source in 2019. It has provided 10,455 TWh, making 6.05% of the global primary energy mix—the most significant share of the renewables.

Nuclear fusion was the sixth most important primary energy source in 2019. It provided 6923 TWh and about 3.99%.

Recently, the most popular renewables: wind, solar, and modern biofuels, and other sources provided 4.64%, merely 1.64% more is considered a statistical error in the analysis. It has to be mentioned that all of the four primary energy sources used in 2019 were fossil fuels that have provided around 147,876 TWh, making 85.31% of the global energy mix.

This is the perfect time to ask about the possibility of the total reconstruction of the global energy mix by 2050. However, please wait a little bit for the answer and scenarios for the future related to Poland.

Other statistics are even more interesting, such as the energy consumption per capita. Qatar was the first place according to primary energy consumption in 2020—200.00 MWh per capita. The rest included: Iceland—181.38; Singapore—171.23; Trinidad and Tobago—143.26; United Arab Emirates—138.42; Kuwait—108.99; Canada—106.38; Norway—91.97; Saudi Arabia—90.17; and Oman—85.21. The average energy consumption was 21.19, and the median value—28.71 MWh per capita. That means that the average use of primary power sources is about 9.4× lower than the consumption in Qatar. Poland with 31.61 was between median and average. Almost all countries in that ranking acquire their energy primarily from fossil fuels they possess and excavate. That means that the countries' governments could not be particularly interested in energy transformation. According to the UN, there is one exception—Iceland, which could be the model energy transformation for the world because over 85% of the energy consumed there was acquired from renewable energy sources [20,21].

The factor that encourages the investment in renewable energy sources is the combination of the cost of energy generation and the market price of the electricity. According to the authors, this relationship is essential in encouraging potential investors to invest in distributed power plants. Figure 2 presents the average wholesale baseload electricity prices for the first quarter of 2021 [21].

Compared to the previous year, the average electricity prices in the EU have grown 57% compared to the preceding 12 months. The highest growth has been observed in (a) Norway (about 190%), (b) Sweden (about 160%), (c) Denmark (about 130%), and (d) Finland (about 100%).

Although that situation means higher prices and enabling inflation, it will still boost investment in the eco-distributed power plants.

Will the growing trend continue? It depends. EU citizens might remember when in 2009, the EU called for withdrawing traditional halogen light bulbs [22]. The only developed lightning technology at that time was compact fluorescent lamps (CFL). Unfortunately, that technology was much more expensive than traditional halogen lightbulbs. Light emitting diode (LED) technology was marginal at that time. Nowadays, consumers prefer LED instead of CFL [22–24]. The same case could be with energy generation, and that is why relying only on statistical data referring to changes in the technology, including energy technology, is useless. Statistical information has nothing to do with "destructive technologies" that appear on the market and are changing it dramatically. The exact mechanism could be seen in other sectors, too [25,26]. This is why the authors treat the statistical analysis as background for further additional analysis like expert panels with the Delphi method and CAWI surveys.

**Figure 2.** Average wholesale electricity prices, for the first quarter of 2021.

For those who think that the status quo in which fossil fuels burned traditionally will still be the leading source of energy, the words of Don Huberts should be recalled. He was "convinced that fuel cells, which generate clean energy from hydrogen, would soon replace power stations and cars that mostly burn coal, oil, or natural gas" [26]. The Royal Dutch/Shell manager said: "The stone age did not end because the world ran out of stones, and the oil age will not end because we run out of oil".

### **4. Characteristics of the Different Energy Sources That Could Be Used in Ecological Distributed Energy Generation Systems**

The following energy generation systems are characterized in that section: • Photovoltaic systems; • Concentrating Solar Power (CSP) system; • Wind systems; • Natural Gas; • Geothermal systems; • Hydropower systems; • Coal systems; • Nuclear systems; and • Biomass and biogas systems.

Photovoltaic systems are designed to provide usable solar energy through photovoltaic cells. The system consists of various modules, including • solar panels that absorb sunlight and convert it into electricity; • solar inverter to convert direct current to alternating current; • plumbing; • cables; and • other equipment. PV systems range from an integrated roof or building systems with several kilowatts to large power plants of several hundred megawatts. Nowadays, most photovoltaic systems are on-grid, while off-grid systems make up a small market [27–37]. In the publication year, PV systems are mostly made from crystalline silicon (c-Si), and the most popular on the market are:


It has been estimated that the silicon-based PV systems efficiency is limited to about 30%, which outputs about 330 (Pmax) W/m2. According to respondents who took part in the survey, PV systems have become "disruptive technologies" and could be most suitable for distributed power plants [38,39]. According to the respondents or literature sources, the popularity of PV systems will grow because the systems are becoming cheaper and cheaper over time [40,41].

The photovoltaic systems are very elastic in terms of their application, for example, (a) rooftop and building integrated systems; (b) photovoltaic thermal hybrid solar collector; (c) power stations; (d) agrivoltaics; (e) rural electrification; (f) spacecraft applications; (g) indoor photovoltaics (IPV); and (h) spacecraft applications [41]. In the future, this technology will be even cheaper and more accessible due to research on Perovskite solar cells (PSC). "PSC is a type of solar cell that includes a perovskite-structured compound, most commonly a hybrid organic–inorganic lead or tin halide-based material, as the light-harvesting active layer. The researchers have estimated that solar systems based on PSC could gain efficiency about 66%" [42–49]. That means the potential output is about 1200 (Pmax) W/m2. It is even more important that perovskite PV systems, according to Saule Technologies, can be placed on almost every surface that makes them perfect for building distributed powerplants [44,45]. The advantages of PV systems include: (a) high reliability; (b) strong persistence; (c) low maintenance costs; (d) zero fuel consumption; and (e) strong independence. The most important disadvantages of photovoltaic systems are (a) high start-up cost, (b) available solar radiation instability, and (c) have energy storage requirements. According to the IRENA photovoltaic system, even based on silicone, in 2019, it had the lowest LCOE—618.00 USD/kW (Table 2). That makes it one of the most economic-efficient energy systems. The cost per unit in 2019 was about 0.25 USD/kWh and competed with hydropower systems and biofuels. The experts predict that with upcoming perovskite and mix silicon-perovskite in no more than five years, photovoltaic systems will be the most economically effective from the others discussed in the paper.

Concentrating Solar Power (CSP) systems—sunlight is focused by mirrors or lenses on the receiver generating a large amount of energy. When sunlight is converted into heat (solar heat), electricity is generated, connecting a heat engine (usually a steam turbine) with an electricity generator, or carrying out a thermochemical reaction. "The CSP had a total installed capacity of 5500 MW worldwide in 2018, compared to 354 MW in 2005" [34–36]; in 2020, 133 powerplants in 22 countries [45]. According to the experts' system, concentrating solar power (CSP) is also a "disruptive technology", but technical aspects are not accessible for individuals or small businesses. This is why the potential of using solar power (CSP) as distributed powerplants is more limited than photovoltaic systems. It is not very popular technology.

Wind systems—onshore wind is the type that blows straight from the sea. On the other hand, an offshore wind is composed of waves that blow from the ground. In 2019, wind power provided 1430 TWh of electricity, equivalent to 5.3% of global electricity production, with a worldwide installed wind capacity of over 651 GW, an increase of 10% compared to 2018. According to the experts, the onshore and offshore wind systems are also "disruptive technologies." Offshore wind systems, due to technical aspects, are not so accessible for individuals or small businesses. Onshore wind systems are very scalable and more accessible for smaller investors. The experts predict that due to ongoing research on wind turbines, they will be more effective. Figure 3 presents different wind turbines that could have been in various industrial, commercial, or residential installations. The LCOE of the onshore wind turbine systems is second-lowest from analyzed energy generation systems—Table 2.

**Figure 3.** Different types of small wind turbines.

Natural Gas systems—Natural gas belongs to fossils but burns more cleanly than others. The systems that transform energy are mainly gas turbines and steam turbines. Natural gas burns. Natural gas could support future renewable energy sources. Natural gas is used in nearly every country and is traded on every continent. The LCOE of the natural gas made it the most attractive energy—Table 2. Technologies like micro-combined heat and power (CHP), which produce power and heat from natural gas, could be the disruptive technology that keeps natural gas as one of the most important energy sources, and makes the technology very important in ecological-distributed powerplants [50,51].

Geothermal systems—is the thermal energy from Earth's crust. In 2019, 13,900 MW (MW) of geothermal energy were retrieved worldwide. Since 2010, 28 gigawatts of direct geothermal heating systems have been installed. Geothermal power generators have been used in 26 countries and heating facilities in 70 countries [52–55]. Although the LCOE of the geothermal systems was above the average for renewables (Table 2), they are promising alternatives for fossil fuels depending on the individual counties' physical conditions. According to the experts, small-scale geothermal energy systems could build ecological distributed powerplants in countries that are rich in geothermal sources. This point of view has also be seen in recent publications [56,57].

Hydropower systems—Hydropower systems installed capacity was 1308 GW in 2020, making over 71% of all RES in 2020. Hydropower generated [2] and was expected to increase by about 3.1% each year for the next 25 years. As can be seen by LCOE analysis, the cost of hydroelectricity was low. When natural conditions are available, hydropower systems are the most compatible of RES. Traditionally, hydropower systems are related to rivers or water reservoirs [58–60]. According to the experts, small-scale hydropower energy systems could even be used as power accumulation for PV or wind turbines to store energy when more energy from renewables is produced than used and retrieved when it is needed.


**Table 2.** The cost of different RES (USD/kW, 2019 price).

n.a.—not available because the study does not include the particular technology, n.u.—not used as the values are outliers. Data from the sources were transformed to 2019 prices using US GDP deflators.

> Coal systems—traditional coal transformation is conducted by burning coal to generate heat or electricity. Coal-fired power plants are responsible for one-third of the world's electricity, "but cause hundreds of thousands of early deaths each year, mainly from air pollution" [60,61]. According to the experts and current literature, there are technologies to burn coal cleanly [62,63]. There are also technologies to transform coal into gas underground [64,65]. Coal in the future may be treated as a clean energy source because of the proper transformation process that coal will undergo. The possibility of using coal as ecological distributed powerplants strongly would depend on the technology applied to transform coal into energy.

> Nuclear systems—atomic energy can now be produced by nuclear fusion and decay. At present, the grea<sup>t</sup> majority of electricity is generated through nuclear fission of uranium and plutonium. In 2019, civilian atomic power generated 2586 TWh, or in other words, nearly 10% of worldwide energy output. That made nuclear systems the second-largest low-carbon power source. At the beginning of 2021, there were 442 civilian facilities, with 392 GW.

Moreover, there were 53 facilities under construction and 98 planned. There is a popular hypothesis regarding cold fusion [66–68]. That it is only a matter of time that clean fusion generators would be in nearly every home [68]. Temporary in many countries, there is a fear of implementing this type of technology because of spectacular nuclear catastrophes such as the Chernobyl Nuclear Power Plant—1986, and the Fukushima Daini Nuclear Power Plant—2011.

Biomass and biogas systems—The facilities use green or animal wastes to produce heat or electricity. Although biomass technically can be used directly as a fuel, some people use biomass and biofuel interchangeably [69,70]. According to the experts, biomass systems are excellent solutions for the ecological distributed powerplants, especially in rural areas.

### **5. The Current State of Production and Prognosis of Energy in Poland**

*5.1. Polish Energy Sector—Overview and Limitations*

Every analysis should start with the demand side, followed by the supply analysis. It is good to put the study in context to understand the upcoming trends better. This idea highlighted the following analysis. The data from Poland were presented in the context of Germany and the EU or the world average. The previous research performed by the authors on different economic branches ensured that analyzing trends in Germany was helpful to predict changes in Poland.

The primary energy consumption in MWh per capita changed from 1965 to 2019. While the consumption of primary energy per capita in the world was growing over the analyzed period, the energy consumption per capita in Germany and Europe (average) was maximum in the early 1990 of the XX century and then started to fall. In 2019, the consumption in Germany was 78.3% of its maximum and 85.1% in Europe. The consumption in Poland dropped rapidly from 1990 to 2001 due to the fall of communism (Figure 4). From 2002, energy consumption had started to grow again. The period from that year should be taken into consideration to predict the consumption for the future. In 2019, the consumption in Poland was 71.7% of the consumption of Germany. The authors have estimated that the consumption in Poland and Germany would be equal in the statistical scenario in about 2040.

**Figure 4.** Energy consumption per capita in 2019 in Poland (in MWh), based on [17].

The change in primary consumption in Poland can be described by the equation below. The R-Squared (R2) indicator over 0.5 is acceptable.

$$y = 0.2827 \text{x} + 26.904\tag{8}$$

$$\text{R}^2 = 0.6217 \tag{9}$$

The costs of fuel and energy in Poland constitute a significant share of household expenditure. According to Jurdziak and others [71–73], this share may be over 20%. That means that an increase in energy prices contributes to the impoverishment of society.

When analyzing the energy balance of Poland (Figure 5) from 2014 (except 2015), it turns outthatelectricityproductioninPolanddidnotcoverthedemand.Unfortunately,theexperts between security.

**Figure 5.** Balance of domestic electricity production and consumption [73].

The supply of the Polish energy system in 2019 was one of the largest in Europe [71,72] was covered mainly by coal-fired power plants—about 70% of the installed capacity [71,72]. Unfortunately, many outdated power plants and combined heat and power plants operate in Poland.

Agencja Rynku Energii S.A. (ARE) has reported in 2019 that hard coal systems with 23.9 GW had 50.4% of Poland's total installed capacity, which output 78.9 TWh of energy production and was 48.1% of total energy production in Poland. The second biggest share in the installed capacity was lignite—9.3 GW; 19.6% made 41.7 TWh; 25.5% of energy production. The other were natural gas systems—2.7 GW (5.7%) installed capacity and 14.5 TWh (8.8%) production; other industrial systems 0.6 GW (1.2%) installed capacity and 3.0 TWh (1.8%) production; pumped-storage systems 1.4 GW (3.0%) installed capacity and 0.7 TWh (0.4%) production. The total renewable energy systems had 9.5 GW (20.1%) installed capacity and 25.2 TWh (15.4%) production (hydropower systems 1.0 GW (2.0%) installed capacity and 2.0 TWh (1.2%) in production; onshore wind systems 5.9 GW (12.5%) installed capacity and 15.1 TWh (9.2%) production; biogas systems 0.2 GW (0.5%) installed capacity and 1.2 TWh (0.7%) production; biomass systems 0.9 GW (1.9%) installed capacity and 6.3 TWh (3.9%) production (including co-firing); and photovoltaics systems 1.5 GW (3.2%) installed capacity and 0.7 TWh (0.4%) production [73–76].

The structure of the energy facilities in Poland correlated to the structure of primary energy consumption by source (Figure 6).

Based on the opinion of the experts and the previous studies, the weighted SWOT analysis of the Polish energy sector has been made (Table 3). It has to be said in terms of the world energy transformation that the Polish energy sector does not fit those trends. A lot has to be done to build a future Polish energy sector that fulfills the EU policy regulations and demand requirements.




**Table 3.** *Cont.*

The conclusion from the weighted SWOT matrix for the Polish energy sector (Table 3) was not very optimistic. The internal factors ratio (IFR) was below 1, meaning the weaknesses were more critical than strengths. Opportunities and threats were balanced, which means that development perspectives of the Polish energy sector are not favorable. The ratio between internal factors ratio (IFR) and external factors ratio EFR) was 0.96:1.00. The strategy of the Polish policymakers should be focused on building or better allowing private investors to build distributed energy generation systems, especially photovoltaic systems, wind systems, hydropower systems, biogas, and biomass systems [27,77–79]. The Polish policymakers' strategic activity should also modernize and keep good quality energy distribution grids.

In Poland, the sources of distributed energy generation systems are classified as follows according to the "installed capacity:

