The Impact of Removing Coal from Poland’s Energy Mix on Selected Aspects of the Country’s Energy Security

Abstract

The article presents the results of research on the impact of the transformation of Poland’s energy mix on the country’s energy security. Since energy security is a very complex problem, the impact of the transformation has been verified in three aspects, i.e., greenhouse gas emissions; energy availability in terms of its quantity, sufficient to meet the needs of citizens; and energy prices. The MANOVA model was used in the research. The model allowed us to examine the relationship between the share of coal in the energy mix and the above-mentioned factors. The MANOVA model allowed us to determine the influence of one explanatory variable on several response variables. The results obtained enabled the verification of the adequacy of the changes that have been made in the energy mix over the last 10 years. As is shown, the factor that is related to changes in the share of coal in the energy mix is the energy surplus, while a relationship between both prices and emission levels and the changes in the share of coal in the energy mix has not been established. Furthermore, a simulation was carried out, which showed that the correlation between price, emissions, and the share in the mix was obtained only by reducing 2017–2020 emissions by an average of 6% and prices by 17%.

1. Introduction

The concept of energy security was first formulated in the 1920s [1], but became essential in the 1970s when the so-called oil crisis occurred [2]. This term has become an increasingly important issue in recent years in connection with terrorist threats and economic activities. Due to the complexity of the issue, there are many definitions of energy security [3,4,5,6]. One of them is the definition included in the Energy Policy of Poland until 2030, according to which energy security means the condition of the economy, which makes it possible to cover the current and prospective demand of consumers for fuels and energy in an economically and technically justified way, while minimizing the negative impact of the energy sector on the natural environment and living conditions of the society. One of the most consistent, and at the same time simple, is a definition proposed by the International Energy Agency, where energy security means the uninterrupted availability of energy sources at an affordable price [7]. The definition of energy security from the moment of its formulation has undergone numerous transformations, taking into account an increasing number of factors, starting with ensuring the supply of energy carriers [8], then focusing on the energy prices, to the protection of the natural environment [9,10,11,12,13,14]. Energy security was already an important issue [15,16,17,18,19,20] and, furthermore, in 2022, became one of the most pressing issues in Europe and in the world, when it was jeopardized as a result of military operations in Ukraine [21,22]. EU member states are dependent on imports of energy sources [23]. As a result, they found themselves in a new situation, where the supply of raw materials from the current direction, which was mostly the Russian Federation, was under threat [24,25,26]. Therefore, it is necessary to verify and modify the current strategy to meet the energy demand of the EU member states, including Poland [27,28,29]. The prices of raw energy materials are also a growing problem, which translates into limited access of end users to cheap energy [30]. In Polish legislation, the energy sector is subject to the regulations and directives of the applicable law in all member states. The most important legal acts, regulating energy security in Poland since the 1990s, are the Energy Law Act of 10 April 1997; the Principles of the Development Policy Act of 6 December 2006; the Act of 16 February 2007 on stocks of crude oil, petroleum products and natural gas; and the rules of conduct in situations of threat to the state’s fuel security and disruptions in the oil market [31,32,33]. Currently, the documents setting out the guidelines for energy security are the Energy Policy of Poland until 2030 (EPP2030) and the Energy Policy of Poland until 2040, which, since 2019, have been the subject of public consultations [34,35,36,37,38].

National plans determining the shape of the Polish energy sector in terms of energy security and climate protection also include, among others, the National Renewable Energy Action Plan (NREAP), the Strategy for Responsible Development for the period up to 2020—with a perspective up to 2030, the National Energy Efficiency Action Plan for Poland, the Capacity Market Act of 8 December 2017, and the Act of 14 December 2018 on promotion of electricity from high efficiency cogeneration [39,40,41,42,43].

Poland’s energy mix has undergone several changes in recent years. The predominant share of coal was the main factor impacting on the need to implement modifications. As a result of several disadvantages of using fossil fuels, their share has been gradually reduced in the structure of energy production and consumption in Poland and in other EU countries. The most important provisions of PEP2030 shaping present and future of the energy sector in Poland are:

• Diversification of the energy carriers in Poland’s energy mix by increasing the share of renewable and nuclear energy;
• Increasing level of energy security of Poland;
• Increasing the level of energy efficiency;
• Reducing negative impact of the energy sector on the natural environment.

Hence, it should be noted that the actions taken to implement the Energy Policy should have a positive impact on level of energy security of Poland. Therefore, the following thesis was proposed:

Modifications to Poland’s energy mix will increase the level of energy security of the country.

Energy policy is a strategic plan for the development of the Polish energy sector. First, there should be verified adequacy of the already taken steps in order to set the right direction for further transformations. Therefore, the authors decided to analyze whether the actions and modifications of the energy mix undertaken in the last 10 years have brought the expected results. All of them were supposed to lead primarily to increasing the level of energy security and, at the same time, to reducing the negative impact of the energy sector on the natural environment [44].

Taking into account the most important assumptions of the definitions of energy security cited in the article, it can be said that energy security is such a state of the economy when: [45,46]:

• The sources of the energy being consumed do not contribute to an increase in the emission of harmful substances, including, above all, greenhouse gases;
• The energy on the market is available at prices affordable for consumers;
• The energy is delivered in sufficient quantity and on time.

Accordingly, the authors assumed that the transformation of Poland’s energy mix should have a favorable influence on the above factors, which, in the worst scenario, will remain unchanged.

It is believed that the removal of coal from countries’ energy mixes will be beneficial for greenhouse gas emissions, energy availability, and its prices. Therefore, the authors aimed to verify the relationship between the structure of Poland’s energy mix and the amount of greenhouse gas emissions, the price, and surplus of energy.

The purpose of conducted research was to verify the impact of the transformation of Poland’s energy mix on the level of energy security of the country. It was verified whether the abandonment of coal had a positive impact on the level of selected aspects of the energy security.

The research presented started with analysis of the literature related to energy security, which was presented in the introduction. The Materials and Methods section contains a description of the MANOVA method used to perform the research. In the following sections, the course of transformation of Poland’s energy mix, the results obtained, and the discussion are presented. The last section contains the conclusions drawn from the research.

2. Materials and Methods

The stages of the analysis carried out are presented in the diagram below (Figure 1).

The MANOVA method was chosen to carry out the necessary research. Multivariate analysis of variance (MANOVA) provides the possibility of simultaneous analysis of relationships between various dependent variables. MANOVA allows us to verify the hypothesis taking into account group effects for the combination of dependent variables [47,48]. The method uses centroids for the dependent variables to compare the means for individual groups. There are two hypotheses regarding the MANOVA method:

H0—the averages of the analyzed parameters are the same;

H1—at least one parameter has a different average value for the compared populations.

The MANOVA model is used when analysing measurable dependent variables as an interrelated set of data, i.e., a relational structure. This allows us to indicate a subset of variables that have the greatest impact on the set diversity of the analyzed set [49].

During the MANOVA analysis of variance, n_i number of k objects is examined. These objects are analyzed for characteristic p. The observations are placed in the following matrices:

$$\begin{array}{c}Y\\ \left(nxp\right)\end{array}=\left[\begin{array}{c}{Y}_1\\ ⋮\\ Y_k\end{array}\right]$$

$$\begin{array}{c}{Y}_i\\ \left(nxp\right)\end{array}=\left[\begin{array}{ccc}{y}_{i1}^{\left(1\right)}& \cdots & y_{i1}^{\left(p\right)}\\ ⋮& \ddots & ⋮\\ y_{i{n}_i}^{\left(1\right)}& \cdots & y_{i{n}_i}^{\left(p\right)}\end{array}\right]$$

Thus, the data matrix is described by the model:

$$y_{ij}^{\left(r\right)}={\mu }_i^{\left(r\right)}+e_{ij}^{\left(r\right)}$$

where:

$y_{ij}^{\left(r\right)}$—j-th observation of i-th object for r-th feature;

${\mu }_i^{\left(r\right)}$—general average of the r-th feature;

$e_{ij}^{\left(r\right)}$—errors of the experiment for the r-th feature;

$n$—row;

$p$—column;

$y_{in}$—matrix element.

Wilks proposed the multivariate analysis of variance in 1932 [50]. The method became popular only many years later because the level of complexity and sophistication of the calculations required the use of appropriate computer software. The method can also be used when simulating the effect of modifications of independent variables on dependent variables. This gives the answer whether the observed relationship between the variables is the result of the independent variable or whether it is a random phenomenon.

Multivariate analysis of variance (MANOVA) proceeds in the following steps:

• Performing a global multivariate test, an omnibus test for the groups of variables taken into account for linear combinations;
• Verification of linear combinations using discriminant functions;
• Selection of the most significant linear combination;
• Verification of the statistical significance of the selected linear combination.

MANOVA requires the formulation of the null hypothesis about the lack of differentiation of mean values between the groups: the levels of factor x do not differentiate the means, i.e., factor x does not differentiate the results of the experiment.

To verify the null hypothesis, Wilks lambda, Hotelling–Lawley trace, or Roy’s largest root and Pillai’s trace test statistic should be used. Test statistics are based on sums of squares and cross products. Two matrices are created. One of them is related to the hypothesis and contains sums of squares and cross products between groups (matrix H), while the other contains residuals (matrix E).

Wilks’ lambda test [51,52]:

$$\mathsf{\Lambda }=\frac{\left|E\right|}{\left|H+E\right|}$$

$$\mathsf{\Lambda }={\displaystyle \prod }_{i=1}^n{\left(1+{\lambda }_i\right)}^{-1}$$

where:

$H,E$—matrix;

${\lambda }_i$—i-th root of HE-1.

Hotelling–Lawley trace test [53]:

$$T=trace\left(H{E}^{-1}\right)$$

$$T={{\displaystyle \sum }}_{i=1}^s{\lambda }_i$$

$$s=\min \left(g-1,k\right)$$

where:

$k$—objects;

$g$—number of distinguished groups.

Roy’s largest root test [54,55]:

$$T={\displaystyle \sum }_{i=1}^s\frac{{\lambda }_{max}}{1+{\lambda }_{max}}$$

Pillai’s Trace Test Statistic [56]:

$$T={\displaystyle \sum }_{i=1}^s\frac{{\lambda }_i}{1+{\lambda }_i}$$

The situation where the results of the presented tests show significant differences between the average values requires further analysis. In this case, it is necessary to identify the variables that caused the null hypothesis to be rejected. In order to enable this operation the ANOVA method should be used for each of the variables separately.

All the tests used can give analogous results when the degrees of freedom for hypothesis H equal to one. However, in a situation where the degrees of freedom are greater, one of the tests may give different results than the others. This indicates a case where one of the dimensions affects the distribution between the groups. Wilks’ lambda, Lawley’s trace, and Roy’s largest root are often more powerful than Pillai’s trace in this case [57].

3. Transformation of Poland’s Energy Mix

The main result of the implementation of the Energy Policy until 2030 is a decrease in the share of coal in the structure of energy production and demand. Most of Poland’s energy is generated from coal, whose share in primary energy equals 42%, and for electricity generation reaches almost 80%. This is due to natural conditions, i.e., coal deposits, which are estimated at 26 billion tons of documented geological reserves of lignite and 40 billion tons of documented balance resources of hard coal [58]. Figure 2 shows a comparison of the energy mix in 2011 and 2020. During this time, the coal share decreased by 13%. The resulting gap was filled with crude oil and natural gas, whose share increased by approximately 5%. It was assumed that the blue fuel would be the basis for the transition period of the EU energy systems on the way to obtain energy based mainly on RES [59,60,61,62,63].

However, it should be remembered that natural gas is also a fossil fuel and its chemical composition affects the emission of greenhouse gases during the combustion process. After 2004, the share of renewable energy sources in the energy mix increased, which is characteristic of all EU member states. In Poland, the share of RES increased in 2011–2020 by 3%. However, the intensive development of RES in the countries of the old EU, e.g., Germany, began already in the mid-1990s, which means that in the future, also in Poland, it will be possible to support energy security from renewable sources to a greater extent. As a result, the transformation of the German energy mix is a model for other EU countries. Furthermore, the demand for energy in Poland is constantly growing. In the case of electricity, the increase in demand is mainly driven by the service sector and the households. This is caused by the increase in the use of electrically powered appliances and growing standard of living of the EU population.

Taking into account Poland’s energy security, such a share of coal ensures the continuity of supply of raw materials and, thus, energy. Poland does not have domestic gas and oil deposits that would be able to meet 100% of the demand. Domestic resources of natural gas may cover about 20% of the demand, and for oil it is much less, only about 2 to 4%. Additionally, as of today, the degree of diversification of gas and oil sources through imports is insufficient. However, a great hope in this regard are renewable energy sources (RES), whose share in 2020 was about 7% [65,66,67].

Undoubtedly, further transformation of Poland’s energy mix will require significant financial support from the state [68,69,70]. This is one of the strategic spheres of activities of the country, so the nature of such transformation assumes the characteristics of political action. Energy access deprivation will lead to inhibition of economic development and result in loss of energy security, national security, and sovereignty of the country. Therefore, in view of the foregoing, it is necessary to plan the shape of the Polish energy sector rationally. Reducing the negative impact of the energy sector on the natural environment [71] is an essential issue raised by the Energy Policy. It is necessary to implement technologies reducing the level of harmful emissions during coal mining and processing. Emissions are also to be reduced by increasing energy efficiency. The policy also provides for the possibility of building centralized heating systems to improve the efficiency of heat generation to reduce the negative impact on the environment and ensure energy security at the local level. Energy policy should lead to a modification of the country’s energy mix. This will mainly consist of the limiting the role of coal, which will be substituted by RES, whose share will be 21%, and nuclear energy, which will have been introduced by 2033. The goal of PEP2030 is also to reduce greenhouse gas emissions, mainly CO₂. All these activities are ultimately intended to achieve the main goals, which are to ensure Poland’s energy security, reduce greenhouse gas emissions, and increase energy efficiency.

To confirm or exclude the hypothesis, a method had to be used that allowed verification of the influence of an explanatory variable (share of coal in the energy mix) on many dependent variables at the same time (greenhouse gas emissions, price, availability). The tool that enables this type of analysis is the MANOVA method described in the previous chapter.

4. Results

A dynamic analysis for the years 2011–2020 was carried out. The data used in the research came from the Eurostat database and the BP Statistical Review of World Energy [64,72]. The analysis of the impact of energy mix changes on selected aspects of energy security commenced with the determination of the independent variable. As it has been shown in the chapter Transformation of Poland’s energy mix, the most significant changes that have occurred are related to the steady reduction in the share of coal. Therefore, the share of coal in the energy mix was adopted as the explanatory variable. The dependent variables were selected according to the definition of energy security:

• The energy sources used do not contribute to the increase in the emission of harmful substances, including, above all, the greenhouse gases—the dependent variable in this case was the amount of greenhouse gas emissions (Mg);
• The prices of energy available on the market are affordable for the consumers—the dependent variable is the energy price (EUR/KWh);
• Energy is delivered in sufficient quantity and on time; the dependent variable in this case is the excess of gross available energy (toe) over gross domestic consumption (toe).

According to the hypothesis, it was verified whether the change in the share of coal in the energy mix had an impact on above three basic factors, indicating the state of energy security.

Next, it was necessary to transform the independent variable, i.e., the share of coal in the energy mix, into a factor variable. For this purpose, the level of coal share was assigned to three groups:

Group 3—share above the median of 52% (the middle value in an ordered sequence of numbers [73]);

Group 2—share above average (47%);

Group 1—share below average.

The data was entered into the MANOVA model of the Statistica 13.3 program to determine whether there is an impact of a decrease in the share of coal in the mix on the price, emissions, and surplus of energy. The results of Wilks’ lambda, Hotelling–Lawley trace, Roy’s largest root, and Pillai’s trace are presented in

Table 1. Results of the MANOVA analysis, own elaboration.

Test	Value	DF	F	p value	Result
Wilks’ lambda	0.018508	6	10.58	0.00077	Reject
Hotelling–Lawley trace	47.26191	6	31.51	0.000038	Reject
Roy’s largest root	47.13956	3	94.28	0.000019	Reject
Pillai’s trace	1.088238	6	2.39	0.094093	Accept

.

The results of the first three tests indicate that the null hypothesis of means equality should be rejected. In this case, the probability value p is lower than the assumed significance level α = 0.05. Only the Pillai’s trace test indicates that the H0 hypothesis should not be rejected because the p-value is greater than 0.05. As mentioned in the Methods section, this can happen when the model has more than one degree of freedom (df). Therefore, firstly, the results of Wilks’ lambda, Hotelling–Lawley trace, and Roy’s largest root test should be regarded as reliable. Since it is recognized that there is a difference between groups 1, 2, and 3, it means that the change in the share of coal in the energy mix has an impact on price, emissions, and surplus. Therefore, in the next step, it was verified which of the variables was the reason for rejecting the null hypothesis about the equality of multivariate means of all groups. For this purpose, the one-way ANOVA model was used [74]. The results are presented in

Table 2. One-way ANOVA results, own elaboration.

Test	Value	DF	F	p Value	Result
Surplus	11,260.13	2	6.23	0.02789	Reject
Price	0.000022	2	0.8	0.486417	Accept
Emission	2.99 × 108	2	2.3	0.170783	Accept

.

The results obtained indicate that the factor showing a relationship with the change in the share of coal in the energy mix is the energy surplus, as only in this case is the probability value p lower than the alpha significance level. However, prices and emission levels are not related to changes in the share of coal in the energy mix. This is also confirmed by the result of the Pillai’s trace test, since, unlike the other tests, it indicated an adoption of the null hypothesis, and it was expected that only one dimension accounts for most of the separation among groups.

Using the MANOVA model, a simulation was carried out to verify the trend in emissions and prices, so that their changes could be considered as being caused by the withdrawal of coal from the energy mix. The simulation shows that the link between the decrease in the share of coal in the mix and selected factors proving the progress in the implementation of energy policy, prices, and emissions, in order to be considered statistically significant, should be characterised by a dynamic downward trend. The relationship between the variables was achieved only by reducing emissions in 2017–2020 by an average of 6%, while prices decrease by 17% (

Table 3. Results of the MANOVA analysis simulation, own elaboration.

Test	Value	DF	F	p Value	Result
Wilks’ lambda	0.149660	6	2.64	0.084091	Accept
Hotelling–Lawley trace	5.238543	6	3.49	0.053222	Reject
Roy’s largest root	5.152510	3	10.31	0.008800	Reject
Pillai’s trace	0.916683	6	1.69	0.206126	Accept

and

Table 4. One-way ANOVA simulation results, own elaboration.

Test	Value	DF	F	p Value	Result
Surplus	11,260.13	2	6.23	0.02789	Reject
Price	0.000674	2	10.27	0.008278	Reject
Emission	1,546,735,944	2	8.08	0.015187	Reject

).

The actual results, therefore, indicate that Poland’s mix has been converted inadequately. Coal was replaced by crude oil and natural gas. This is resulting in minimal decreases in emissions and energy prices remaining at a constant level, despite the fact that for the research period there were large drops in gas and oil prices on international markets.

5. Discussion

The results of the research indicate that the actions taken to transform Poland’s energy mix have not yet brought the expected results. The main modification, which was the removal of hard coal and lignite from the mix, did not translate sufficiently into reducing the level of greenhouse gas emissions. Environmental protection was the main reason for the modification of the mixes not only in Poland, but also entire European Union. This action was in line with the assumptions of the Polish energy policy. Since the 1990s, the volume of greenhouse gas emissions has been falling, mainly as a result of economic transformation and the reduction in industrial sources of harmful emissions due to the collapse of many industries. However, at the same time, this had negative effects, for example, in the form of an increase in unemployment in Poland. After 2000, the emissions were decreasing mainly as a result of growth of energy efficiency and the share of RES in the mix. However, changes in the level of emissions, mainly of CO2, which accounts for about 80% of emissions, have stabilized at a constant level. Further reduction of the level of harmful substances requires taking additional actions and applying new solutions and technologies that would accelerate this process. Concentrating solely on the abandonment of coal is not the right solution, especially when it has been replaced by other fossil fuels.

Changes in energy prices also do not show a connection with a decrease in the share of coal in the energy mix. In 2011–2020, the price remained practically constant, despite the fact that coal was replaced by more expensive fuels, such as natural gas or crude oil. This is mainly due to the decline in fossil fuel prices on international markets, which falls precisely in the years taken into account in the analysis. It should be remembered that if coal had not been removed from the mix, this price could have been lower. In addition, the coal was also replaced by RESs and the energy obtained from these sources is free. However, the development of RESs in Poland is based mainly on consumers, so all costs related to the construction or maintenance of the infrastructure are borne by persons who have invested in the development of renewable energy sources.

The only explanatory variable that has proved to be associated with the decrease in coal in the energy mix is the amount of surplus energy. This is beneficial in terms of energy security, as it ensures access to energy for citizens in necessary amount. This is a highly beneficial change. However, it should be noted that the analysis took into account the average annual values. This surplus is partially due to the increase in the amount of energy produced from RES. Therefore, because of lack of capacity to store energy, it is available in excess when there is no demand. A large part of renewable energy is wasted and can even a cause of a load on the power grid, which has not been adapted to the new operating conditions and is often the cause of outage.

6. Conclusions

The purpose of the presented research was verifying the adequacy of actions taken in Poland to modify the country’s energy mix in terms of selected aspects of energy security. This is the most important factor to be taken into account when transforming the energy mix of the European Union member states. Energy security was analyzed in terms of access to energy, energy prices, and the impact of the energy sector on the natural environment. Therefore, these three factors should be the goal of the ongoing transformation.

The results of the conducted analysis, in a scope that could be confirmed by the MANOVA, indicate that the steps taken in 2011–2020 have not yet brought the Polish energy sector closer to achieving the set goals. This is also consistent with the previous results of the authors’ research [75], where a synthetic measure of Poland’s energy security was determined, as well as results previously presented in the literature [76]. The literature on research on Poland’s energy security is usually based on indicators such as imports of energy carriers or the energy dependency index [77,78]. It showed that the level of Poland’s energy dependence is about 30%, which places Poland in a privileged position compared to other EU countries [79]. However, it should be remembered that this was only due to the high share of coal in Poland’s mix.

In view of this, it should be considered whether it would not be beneficial to modify the adopted strategy. Poland is a country whose geographical location guarantees access to hard coal and lignite for at least the next few decades [80,81]. This is of great importance for the security of the country, especially in light of recent events, when Poland was cut off from natural gas, oil, and coal from the Russian Federation in a short time. In addition, it should be noted that there are technologies that enable elimination of the negative impact of coal combustion on the environment, and combustion waste can be a valuable secondary source of many raw materials. These include gaseous products, e.g., CO₂ or fly ash, which are, for example, a source of rare earth elements, as well as accompanying minerals, e.g., natural gas. The research results focused exclusively on selected aspects of energy security. The future direction of the research will be to extend the analysis to sustainable development goals, such as the impact of eliminating coal on the poverty level or building a sustainable energy infrastructure.