This article is devoted to the financing of innovation activities targeting low-carbon technologies. Its aim is to guide European energy policy makers in the design and implementation of public support policies given the inevitable constraints on funding. We focus on pre-deployment innovation, namely research, development and demonstration activities that belong to the early, highly risky stages of the innovation chain and, thus, need direct public support. This article is devoted to the financing of innovation activities targeting low-carbon technologies. Its aim is to guide European energy policy makers in the design and implementation of public support policies given the inevitable constraints on funding. We focus on pre-deployment innovation, namely research, development and demonstration activities that belong to the early, highly risky stages of the innovation chain and, thus, need direct public support.