This study challenges the implicit assumption of homogeneity in national institutional contexts made in past studies of (renewable) energy policy. We propose that institutional differences matter by focusing on several technology-specific and generic policy factors that can foster technology diffusion through private sector activity. More specifically, we explore perceptions of early adopters in emerging economy contexts using wind park project developers as an example. By applying a parsimonious method for our questionnaire as well as qualitative data we make several contributions: Methodologically, we introduce Maximum Difference Scaling to the energy policy domain. Empirically, we identify several public influences on private investment, and assess their relative importance. This leads to new insights challenging findings from industrialized economies; we identified additional institutional barriers to diffusion, hence, the requirement of a combination of technology-specific and generic policy measures. (C) 2014 Elsevier Ltd. All rights reserved.