To achieve sustainable development goals (SDGs), it is necessary to solve the problem of assessing and measuring energy sustainability performance. A popular indicator used for this purpose is the World Energy Council (WEC) energy sustainability index, or the Energy Trilemma Index, which is based on such key metrics as energy security, energy equity, environmental sustainability, and country context. Each of the four metrics, or dimensions, includes many indicators that depend on both internal and external factors. By combining a variety of indicators into integral ones, WEC ranks countries in terms of energy sustainability. However, what is not taken into account is how countries differ in terms of economic development, income, energy mix, renewables use, ownership in the energy sector, and other factors, and neither is the methodology itself disclosed by the developers. As a provider for all other sectors of the economy, the energy sector plays an important role in developing countries. Ecuador, Colombia, Peru, and Bolivia, being members of the Andean Community, are neighbors and have similar economic conditions but lack transnational power grid interconnections, which hinders the development of a common energy market. In terms of energy sustainability, these countries’ ranks range from 45 to 101, according to the Energy Trilemma Index. The aim of the study is to develop a new methodology for assessing energy sustainability performance that will factor in the specific features of developing countries with a high share of hydroelectricity generation, and to calculate energy sustainability index indicators taking into account contemporary requirements for sustainable development, which include developing green and renewable energy and fostering decarbonization. This research reveals whether the countries’ energy sustainability indices correspond to their actual performance in energy development and identifies the factors influencing the values of the metrics in the Energy Trilemma Index. The methodology can be used to integrate the energy sectors of countries, as it allows for evaluating the state of the energy sector of several countries (for example, those of the Andean Community) as a whole.

The relevance of the technical and economic evaluation of options for the optimization of electrification projects of hydrocarbon production facilities is due to the growing need for the development of new fields in undeveloped and hard-to-reach territories. Development of new fields requires the construction of large amounts of infrastructure energy facilities, new solutions to improve energy efficiency, reducing capital intensity of projects, solutions to improve the efficiency of resource use in the circular economy, and the use of renewable energy sources (RES). Analysis of the technological directions of electrification of hydrocarbon production facilities proves that the low level of application of RES for energy supply purposes is due to the lack of experimental data on the implementation of this kind of project. This study considers features of technological solutions, practical recommendations, and the main limitations of the application of a hybrid automated system based on RES for the electrification of gas production facilities located in poorly-developed territories. A comparative technical and economic analysis of electrification options using autonomous RES and construction of a power transmission line (PTL) to a remote section of an oil and gas condensate field located in the Arctic zone was carried out. In order to justify the implementation of the electrification project with the use of RES sources, the climatic potential of the region was assessed, and the calculation of energy supply needs and a comparison of alternatives on the basis of specific total capital and operating costs were provided. Assessment of the specific indicator of costs for the proposed variant of the autonomous energy complex based on wind generation indicated savings of RUB 2.24 per kilowatt-hour of energy used. The results of the study can be used in project planning and evaluation of proposed technological solutions based on the rational choice of energy sources and optimization of cost indicators for the construction and operation of energy supply systems.

The energy sector is an essential element in an economy’s infrastructure, so a deficit of national mineral resources makes the energy sector dependent on imports of raw materials, which in turn can negatively affect a country’s energy security. The sustainable development of the energy sector for countries with transitioning economies should be based on the energy trilemma. Four principles are proposed: diversification of energy resources and energy generation sources, ensuring energy efficiency, ensuring energy affordability, and green energy production. Based on a comparative analysis of the economic and energy indicators (for the years 2014 to 2019) of European countries that are not members of the European Union, the situation in the energy sector of the Republic of Moldova is classified as critical and its fundamental issues are identified (107th place in the World Energy Trilemma Index). The main objectives of the study are: (1) To analyze energy and economic efficiency as well as the conditions for and problems of the functioning of the energy sector in countries with transition economies (using non-European Union countries as an example); (2) To present a substantiation of the directions for development of the energy sector in countries with transition economies that lack energy resources (using the Republic of Moldova as an example), taking into account the identified factors and principles of sustainable development; (3) To develop an economic and mathematical model for assessing the directions for the development of the energy sector in countries with transition economies using multiple-criteria decision analysis (MCDA). Decision-making methods can be used to select strategic development alternatives, particularly in the energy sector. MCDA has several advantages and uses in the following situations: comparing several alternatives; identifying the most preferable and unacceptable alternatives; comparing alternatives based on several (sometimes conflicting) criteria; looking for a compromise in a situation where different stakeholders have conflicting goals or values. A methodology including a system of 7 indicators and an economic and mathematical model for assessing development paths for the energy sector in countries with transition economies were developed that are based on multiple-criteria decision analysis. An algorithm and a computer program were developed to carry out MCDA and select the best development path for the energy sector of the Republic of Moldova. The article presents a rationale for choosing the best option regarding the development of the energy sector of the Republic of Moldova, which is a country with a deficit of its own energy resources.