In this paper, we presented a literature review on clean energy between 1993 and 2012. We organized these studies into six main categories: (i) production of clean energy, (ii) energy policy, (iii) energy efficient management, (iv) energy technology R&D policy, (v) managing the energy use, and (vi) the relationship between clean energy and economy. All of the papers in the review distributed to the main and sub-categories were based on their main contents. A comprehensive list of references is also presented at the end of this paper. It is hoped that the review will be a good resource for anyone who is interested in clean energy research, and will help to stimulate further interest in this area.