摘要：The present paper is approaching the energy efficiency topic from the viewpoint of its trends and influence factors, in the context of requirements, criteria and principles of sustainable development. Energy efficiency is measured as ratio of GDP and energy use and its multiple factors of influence are considered. With a view to deducing some conclusions of theoretical-methodological but also of practical-applicative character, we are researching the variation in energy efficiency in European Union, but also in the case of new candidates and other countries, by means of multifactor econometric modeling
关键词：energy efficiency; piecewise linear regression; energy consumption
