"This PhD research focuses on the innovation of community energy projects in two European countries, Finland and the United Kingdom (UK). The European Union has a target to increase renewable energy generation to 20% by 2020 and reduce carbon dioxide (CO2) emissions by 20% below 1990 levels in the same timeline. This PhD aims to find out what has made the UK a place for community energy to flourish in the last five years. In order to do that, the development of community energy in the UK is reflected on another EU country, Finland, which has similar energy generation sources to the UK, but much less actual citizen-owned and/or led community energy projects. Both Finland and the UK use a mix of renewable and conventional energy sources, though focus on either medium or large-scale energy developments (megawatts rather than kilowatts, medium-sized district heating, large centralised power plants). Using concepts from socio-technological transitions theory, qualitative case study analysis and views of intermediary organisations, this research answers the question why and how do community energy innovations develop in Finland and the UK? The research is interested in how community energy projects are developed, how they establish themselves and potentially diffuse. Outcomes of the research are expected to be useful for citizens, organisations involved in community energy projects and academics researching the field.