As the polycentric nature of climate governance becomes ever more apparent, understanding the role played by individual initiatives becomes an increasingly urgent research priority. In recent years, community initiatives have blossomed in relation to clean energy, both in their overall number and diversity. Polycentric governance thinking offers a powerful but incomplete account of how and why such initiatives emerge, grow, and replicate in different contexts, that is, how they “scale.” This article investigates the conditions under which different clean energy communities scale. Based on a systematic literature review, it identifies 23 separate conditions, which are subsequently categorized into what happens within, between and in the context of individual initiatives. As well as enriching polycentric governance thinking, this article identifies practical ways to inform and facilitate the emergence of new community initiatives.