Abstract
The energy security is a subject often picked by government representatives of current times, who take actions influencing geopolitical relationship of Europe and globe. It is an important aspect because of its economical, ecological and environmental nature. Tensions between countries of Eastern Europe, legislative changes made by European Union and rapidly increasing demand in the energy sector lead players to securing their resources and its supplies, along with infrastructure. Energy Security Index (WBE) proposed by A. Sokołowski (2010) and Kościuszko Institute is an effective tool for measurement, impartial assessment and classification of analyzed economies, checking their flexibility and possibilities in the international energy arena. The index is built as multidimensional comparison analysis, which gives the prospect of creating rankings. This article presents the essence of energy security in the context of an economic potentiality in the gas sector, with the chosen elements counting into WBE and its applications. The vast aggregate is created by calculations, using worked data, to summarize assessment of energy security status of examined country. The authors tried to compare chosen elements of WBE of neighboring Polish and Ukrainian economies. As an addition, based on data availability, information is enriched by appropriate commentary. Graphics shows the essence and summary of gas transportation infrastructure in both countries and gives the idea of possibilities of cooperation between them.