The Urban Sustainability Directors Network in collaboration with the cities of Boulder, Helsinki, Minneapolis, and Stockholm engaged the Ithaka Institute to develop a high-level overview on the topic of converting urban waste streams into both bioenergy and biochar. This assessment included a survey of the organic materials generated within each city, existing and potential uses for excess heat generated during the carbonization process, urban uses for biochar, existing pyrolysis or gasification technologies capable of converting urban waste streams into both energy and biochar, a preliminary assessment of the potential climate impacts from carbonization of urban waste streams, a brief discussion of the variability of biochar’s qualities and where biochar can be analyzed, and finally a discussion of the potential costs and revenue streams that are associated with carbonizing biomass.