Abstract This paper describes the results of expert assessments about the range of likely energy penalties (EP), the energy required to capture and compress CO2, for coal power plants in 2025 for six capture technologies under three different policy scenarios. Expert opinions about the EP of each technology varied substantially. Measuring EP in terms of the fractional decrease in output per unit input, we found that a scenario of worldwide carbon pricing leads to a decrease in the mean energy penalty of 1–10% across the technologies, and a scenario of increased US government research and development (R&D) funding leads to a decrease in the mean energy penalty of 6–14%. EP for pre-combustion capture showed the smallest improvement from R&D and carbon pricing, while EP for post-combustion capture with membranes or “other” approaches showed the largest improvement. Although other factors will also affect costs, EP is a large component and these results suggest that capture costs are likely to fall both through investments in research and through the process of commercializing the technology in response to carbon prices. We summarize the challenges for each technology that were described by the experts, as well as the quantitative results.