Nowadays, as most of the countries in the world pledged to the low-carbon future, global energy problems become more acute. One of the most promising ways to address the growing problems of energy supply widely considered by the international community is use of alternative energy source such as the renewable or "clean" energy. Renewable energy is highly praised for its wide availability and environmental friendliness and its decisive advantage over traditional energy is that it is not subjected to depletion like the fossil fuel resources and that it does not lead to the increasing pollution. Th e paper examines how renewable energy sources can be made useful in the case of Ukraine. Our analysis run along two dimensions: the EU and world's global tendencies as well as the internal current situation. Our main focus is on whether the investing in renewable energy sources can be regarded as a country's "smart" power policy and what the outcomes of turning to the renewable resources might be like over some time period in the future. On the base of statistical approach we came to the conclusions for Ukraine: 1) renewable energy sources (RES) production has a potential to replace oil, gas and coal sources, however the same could not be said about nuclear power; 2) the "green tariff " indeed makes renewable energy projects more attractive for investments; 3) RES production opens new projects in industry thus the employment rate in industry can grow, but not such could be said about agriculture; 4) in analyzed years RES production had very low level of impact on the economic performance; 5) RES have positive eff ect on the environment in Ukraine in analyzed period; 5) RES consumption has a potential to boost positive eff ects of alternative energy resources,

The paper analyzes the impact of energy consumption on the three pillars of sustainable development in 74 countries. The main methodological challenge in this research is the choice of a single integral indicator for assessing the social component of sustainable development. Disability-adjusted life year (DALY), ecological footprint, and GDP (Gross domestic product) are used to characterize the social, ecological, and economical pillars. The concept of physics, namely the concept of density (specific gravity), is used. It characterizes the ratio of the mass of a substance to its volume, i.e., reflects the saturation of a certain volume with this substance. Thus, to assess the relationship between energy consumption and the three foundations of sustainable development, it is proposed to determine the energy density of the indicators DALY, the ecological footprint, and GDP. The reaction to changes in energy consumption is described by the elasticity of energy density functions, calculated for each of the abovementioned indicators. The state of the social pillar is mostly dependent on energy consumption. As for the changes in the ecological pillar, a 1% reduction in energy consumption per capita gives only a 0.6% ecological footprint reduction, which indicates a low efficiency of reducing energy consumption policy and its danger for the social pillar. The innovative aspect of the research is to apply a cross-disciplinary approach and a calculative technique to identify the impact that each of the pillars of sustainable development imposes on energy policy design. The policy of renewable energy expansion is preferable for all sustainable development pillars.

The term “energy security” is used almost everywhere in economic and political discussions related to energy supply. However, different authors use different meanings to express the concept of energy security. Quite often, this term is used to give more importance or relevance to issues that are often not inherently related to energy security. Attempts to define the essence of the concept of “energy security” have hitherto not been systematic and are characterized by a variety of approaches, and some insufficient justification especially in the aspect of state national security is notable. Our contribution to the discourse development is the consideration of energy security as part of internationally recognized indices that are developed to assess the temperature of world security. A regression modeling approach to test the crucial factors of social-economic development that impact the energy security indicators is presented. The literature analysis and review of the world’s existing national security indices show that the link between energy security and national security is in fact hardly considered. Mostly, energy security is considered in the dichotomy concerning economic security at the international, as well as national levels. The calculative regression modeling revealed that the significant correlation of economic and energy security is just for the U.S.A., the rest of the analyzed countires display the weak or non-significant correlations of the indices of economic/energy/security threats. That pushes the discussion on whether energy security is indeed so impactful a factor for geo-policy and geo-economy, or whether it is mostly the well-rolled media-supported megatrend. However, the present study notes a great shortage of long-term cross-state indices to reflect energy, economic, and national security to allow for valuable modeling.

The green energy transition is associated with the use of a wide range of metals and minerals that are exhaustible. Most of these minerals are limited in access due to small resource fields, their concentration in several locations and a broader scale of industry usage which is not limited exclusively to energy and environmental sectors. This article classifies 17 minerals that are critical in the green energy transition concerning the 10 main technologies. The following classification signs of metal resources were used: (1) the absolute amount of metals used in the current period for energy;(2) projected annual demand in 2050 from energy technologies as a percentage of the current rate;(3) the number of technologies where there is a need for an individual metal;(4) cumulative emissions of CO₂, which are associated with metal production;(5) period of reserves availability;(6) the number of countries that produced more than 1% of global production;(7) countries with the maximum annual metal productivity. The ranking of metals according to these characteristics was carried out using two scenarios, and the index of the availability of each mineral was determined. The lowest availability index values (up to 0.15) were calculated for cobalt, graphite and lithium, which are key battery minerals for energy storage. Low indices (up to 0.20) were also obtained for iron, nickel and chromium. The calculation of the availability index for each mineral was enhanced with linear trend modelling and the fuzzy logic technique. There are two scenarios of demand–supply commodity systems with a pre-developed forecast up to 2050: basic independent parameter probability and balanced fuzzy sum. Both scenarios showed comparable results, but the second one highlighted supply chain importance. Generally, the lowest availability index values (up to 0.15) were calculated for cobalt, graphite and lithium, which are key battery minerals for energy storage. Low indices (up to 0.20) were also obtained for iron, nickel and chromium. The fuzzy logic model helped to reveal two scenarios up to 2050. The two scenarios presented in the current research expose a high level of uncertainty of the projected 2050 forecast.

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