Aim of the paper is to outline a research methodology, which would ultimately allow predicting and enhancing competitiveness of less developed economies, which encounter energy security issues. The following theoretical questions are to be discussed. The first, what we mean by sustainable development in countries, which are in different economic development phases, i.e. if emphasis on different facets of sustainability (particularly economic environmental, related to energy consumption patterns) changes as country develops. The second research question raised in the paper deals with energy security issues. Authors tackle the following questions of methodological character: if/what natural consistent patterns of economies development exist; and how to indicate efficient ways of economic restructuring. Answer to the indicated questions would allow formulating policy implications directed towards energetically secure and sustainable development.