The merits of renewable energy, of targeted renewable energy policies, and appropriate evaluation methods, are each contested at various levels including national politics and in energy policy literature. Here, first a range of renewable energy goals across countries and the policies directed at achieving those objectives are reviewed. Second, the arguments advanced to support use of renewable energy policies in many nations are critiqued. Third, some principles are proposed for design of renewable energy policies. Context always matters, and it is essential to consider energy, economic, and geography opportunities and constraints before developing renewable energy policies. Fourth, to ensure renewable energy policies contribute towards attainment of high-level national goals, a decision support approach is outlined that considers the energy context, and asks a series of evaluation questions to aid identification of first best policy measures. Fifth, barriers to and benefits from implementation of appropriate renewable energy policies are briefly reviewed.