The article presents a synthetic analysis of the crude oil market in Poland. As of today, this safety is provided mainly on the basis of native lignite and hard coal resources. However, the analysis of the hard coal market conducted by the authors indicates that the carried out mining restructuring (among others) led to an excessive reduction of mining volume and employment level in the hard coal mining sector. This led to a precedent situation when Poland became an importer of this energy carrier. In addition, the European Union’s requirements for greenhouse gas emissions must be taken into account. In connection with the above, it is necessary to search for new energy sources or technologies that enable hard coal to meet the requirements. It is possible to apply the so-called clean coal technologies that allow the greenhouse gas emissions generated during coal combustion to be reduced. As of today, they are not used on a mass scale, because the use of this type of technology involves additional financial expenses. However, taking into account that technologies have been growing faster and faster, are modernized in a shorter time, making a breakthrough discovery took hundreds of years, now it is often a few months, clean coal technologies can become the optimal solution in the near future. It is also necessary to diversify the sources of obtaining imported energy carriers.

The article describes coal and crude oil in terms of their mutual substitution. The article is a continuation of research conducted by the authors. Previous publications presented considerations on analogous topics related to natural gas and renewable energy sources. The crude oil market in Poland was analyzed and forecasts for oil extraction and the demand in the world and Poland by 2023 were presented. The SARIMA model was also created. The model made it possible to obtain oil an prices forecast.

Polycyclic aromatic hydrocarbons can affect all stages of plant growth from germination to reproduction. A sensitive response to PAHs loading can be assumed above all in the first stages of ontogenesis, the germination of seeds and the root elongation. The germination of the seed is the existential condition of the further development of the plant. In this relatively short period the plant has not yet sufficient detoxicative ability. The affection of germination due to the contamination of soils with polyaromatic compounds can be one of the factors of natural selection and even also of the plant evolution. It can be assumed that in plants there exists and is further developed the adaptation of germination to those selected conditions. In this study the phytotoxic effects of crude oil were studied. The effect of increasing concentration of the used oil in the soil (1, 10, 25, 50, 75, 100, 125, 150 g/kg) on: the root elongation, biomass of roots, the stalk elongation, biomass of stalk and synthesis of chlorophyll of rye Seca/e cerea/e L., red clover Trifolium repens L., charlock Sinapis alba L., were studied. The results demonstrated that the increasing concentration of used oil inhibited on: the root elongation, biomass of roots, the stalk elongation, biomass of stalk and synthesis of chlorophyll by all tested plant. The species studied showed different sensitivity to the concentration of used oil.

A device with a frequency-modulated output signal has been developed to increase the sensitivity and accuracy of measuring moisture content in crude oil and petroleum products in the range of 0~20%. The main element of the device is a self-oscillator transducer based on a transistor structure with negative differential resistance. A capacitive sensor in the form of a capacitive cylindrical structure with cylindrical electrodes was used to determine moisture content in crude oil and petroleum products. Electric permittivity of a two-component mixture of oil and water was estimated and the capacitance of the humidity-sensitive capacitive cylindrical structure with cylindrical electrodes was calculated. An electrical diagram of the device for measuring and controlling the humidity of crude oil and petroleum products has been developed. The relative error of converting the humidity of oil and petroleum products into capacitance which was caused by the change in oil temperature, was determined to be 0.225%. Values of relative errors of the device for measuring the humidity of oil and petroleum products are as follows: 1.355 · 10 ^-5% is caused by instability of the oscillator frequency, 0.01% is caused by fluctuations in the supply voltage of the self-oscillator transducer, 0.05% is caused by a change in ambient temperature by 1°C. For the developed device, which used errors of the first and second type, the reliability of humidity control of oil and petroleum products has been determined to be 0.9591.

The aim of the paper is to identify which factors influence the production of crude oil in Africa and what it means for the investments in oil production on this continent in the future. In order to identify these factors it is necessary to create a function of production. A number of variables have been chosen, which are likely to have an influence on the level of exploitation, such as the price of oil, oil consumption in Africa, oil import by the US, etc. The estimation of the function was based on the statistical analysis of empirical data. For the years 1980–2015 the linear regression model was estimated using the method of ordinary least squares (OLS) and econometric software – GRETL. In order to find the best model the academic research on the global oil market has been taken into account and a variety of statistical and econometric tests have been made. According to the literature on the subject, the production of crude oil in Africa is mostly affected by two players – Europe and the US. The first includes the member states of the OPEC. There are also countries of West Africa which in the past exported most of their production to the US. The model shows that the situation has changed after the “shale revolution”, which reduced the level of imported oil and consequently the level of African production. Moreover, an interesting trend has been noticed, namely that when oil prices go up, the oil production in Africa decreases. The reason for this phenomenon is that high oil prices make American shale plays more profitable than West African petroleum basins. The model aggregating macroeconomic indicators and statistics is a very useful management tool and it reveals the problems of the efficiency of investments in oil production in Africa.

The aim of the study is to discuss the relationship of the crude oil price, speculative activity and fundamental factors. An empirical study was conducted with a VEC model. Two cointegrating vectors were identified. The first vector represents the speculative activity. We argue that the number of short non-commercial positions increases with the crude oil stock and price, decreases with the higher number of long non-commercial positions. A positive trend of crude oil prices may be a signal for traders outside the industry to invest in the oil market, especially as access to information could be limited for them. The second vector represents the crude oil price under the fundamental approach. The results support the hypothesis that the crude oil price is dependent on futures trading. The higher is a number of commercial long positions, the greater is the pressure on crude oil price to increase.

New oil and natural gas deposits can be recognized using X-ray computed tomography (CT) technology, and their potential value can be evaluated using increasingly advanced computational methods.

Accidental oil spills at open sea is a common environmental problem. They lead to degradation of sea and shoreline life. In the last ten years there has been an increased interest in bioremediation using the enzymatic activity of the naturally occurring microorganisms. In this work the potential of mixed microbial cultures for biodegradation of crude oil in seawater and sand has been examined. Artificial seawater supplemented with nitrogen and phosphorus was inoculated with cultures isolated from refinery sludge. The same cultures were used for experiments in sand polluted by 5% (v/w) of crude oil. These experiments were performed in sterile and semi-natural (not sterile) conditions to see the degradation potential of isolated cultures, their growth characteristics and possible antagonisms between supplemented microorganisms and natural microflora. During the experiments the oxygen demand, number of bacteria (cfu) and optical density (OD660 ) were monitored. After 14 days of cultivation, the concentration of total petroleum hydrocarbons (TPH) in all samples was measured. All tested cultures had a potential for degradation of hydrocarbons in seawater and sand. After two weeks of experiment, loss of hydrocarbons in seawater polluted with crude oil was between 56.8% (A2 culture) and 64.4% (Al culture). The most effective culture for bioaugmentation of seawater does not have to be the best solution for bioaugmcntation of sand. In sand the best degraders in sterile and semi-natural conditions were found in the mixed cultures isolated from Corinth refinery sludge. For this culture concentration of hydrocarbons in sterile sand was 73.2% lower than in control sample and in non-sterile sand 70.5% lower than in control (sterile sand) without bioaugmentation. Finally, the addition of seawater and fertilizers to sand had also a positive influence on contaminants degradation by naturally occurring microorganisms (48%). Experiments performed with different environments (seawater and sand) and under different conditions (sterilized material and semi-natural conditions) confirmed that cultures should be tested in semi-natural conditions especially when indigenous microflora cans posse's high degradation potential. Allochtonie cultures, very active in sterile conditions, after inoculation to natural environment can even slow down the degradation.

The article compares the management of energy resources in Poland and Ukraine over the period 2000–2017. The analysis took changes in the volume of coal, oil and natural gas resources into consideration. The indicators of supplies of these fuels for Poland and Ukraine have additionally been compared with selected EU countries. In order to assess energy security of Poland and Ukraine, the changes in the primary energy consumption have been analyzed in general in first order, then the possibilities of meeting the demand for natural gas, coal and oil have been determined based on the domestic extraction of individual energy resources. Such a comparison indicates the dominant role of coal in Poland while the extraction of oil and natural gas meets the domestic demand to a greater extent in Ukraine. Over the period 2000-2017, trends in primary energy consumption were different; a 17% increase was noted in Poland, while a nearly 40% decline was noted in Ukraine. The main factors responsible for radical changes in fuel and energy management in Ukraine have been identified: military operations in the east of the country and the annexation of Crimea, demographic changes. These events had a negative impact especially on the volume of hard coal mining in Ukraine; the significant increase in imports from 5.36 to 19.14 million tons in 2011-2017 was necessary for balancing. The balance of foreign exchange for electricity was also compared. Over the past years, this comparison has been favorable for Ukraine, where the dominance of electricity exports over imports is noticeable, which generated revenues of over USD 200 million in 2017.