In particular, they do not link to the extensive field of the Energy Technology Innovation System (ETIS), and do not fully touch upon how innovation is financed, adopted and diffused. Technology push and market pull policies need to be properly modelled because it is the proper combination at both ends of the innovation chain which offers the best prospect of accelerating the pace of innovation. This is equivalent to a technology supply-push and contrasts with the accumulating evidence around market-based technology learning.