The development of new energy technologies is widely viewed as an essential element in addressing climate change. However, identifying and prioritizing which energy technologies should receive research, development and demonstration (RD&D) funding is a key challenge for policymakers. Particular difficulties arise in estimating the future performance and costs of these technologies. To address these uncertainties, researchers have reached out to technology experts in order to develop probability distributions that can provide an indication of future performance and costs of technologies, and allow for an assessment of how government RD&D spending might affect the future prospects for technological change. This GGKP Working Paper provides a comprehensive and systematic overview and analysis of expert elicitation studies that have focused on climate mitigation technologies. The report also reviews the literature on modelling and decision-making that has utilized the data produced through expert elicitations.