As the role that the society plays in energy and use of resources is of importance, what is vital is early education, as it is one of the pillars significantly influencing the planning of a "cleaner future" energy wise, especially through utilizing energy-specific education techniques. Up to this point, it has been suggested that younger students tend to describe Renewable Energy Sources (RES) as 'Clean' rather than 'Green', while their selection in the color that best describes them is Yellow or White rather than Green. On the subject of redefining RES, a total of 2217 face-to-face interviews are conducted in schools in three countries in the Baltics and Eastern Europe countries, i.e. Latvia, Lithuania, and Romania, in order to further contribute to the discussion of which term-'Clean Energy' or 'Green Energy'- is the term of choice for students of younger age with no or less formal education and experience on the subject of best naming RES. As far as the color to best represent RES is concerned, younger students tend to choose Yellow or White instead of Green, a choice that shifts to Green in higher grades. The results, with the exception of Lithuania where older students chose the term 'Clean Energy' as well, confirm those of previous studies in Greece and Bulgaria, enhancing the importance of the elicitation of such preferences in order for energy issues to become part of the educational system of all levels. As Clean and Yellow or White are the terms of choice for naming and describing RES according to young students, it is imperative that the scientific community reconsiders and adjusts said preferences in education and research, for the better -future- implementation of renewable energy practices and use of resources. (C) 2018 Elsevier Ltd. All rights reserved.