From Watermills to Smart Grids - How Digital Technologies and Collaborative Action Enable Decentralized Energy Systems

The transition toward renewable energy is often framed as a technological challenge centred on photovoltaics, digitalization, artificial intelligence, and smart grids. This article argues that such a perspective remains incomplete unless it is complemented by a socio-technical understanding of how technologies become embedded in local practices, institutions, and forms of collective action. Drawing on the historical example of water mills as decentralized energy infrastructures, the article develops a comparative perspective on contemporary renewable energy communities (RECs). Combining insights from the history of technology, socio-technical transition research, and a qualitative case study of a citizen-led Austrian energy community, it examines how decentralized energy systems emerge through the interplay of digital technologies, local knowledge, organizational innovation, and civic engagement. A biographical account of the author's grandfather, who worked in a hydropower-driven mill in the 1930s, illustrates the historical role of mills as regional socio-technical hubs and serves as a point of comparison for present-day energy communities. The analysis shows that digital technologies such as smart meters and data-driven coordination expand opportunities for decentralized energy production but also raise questions of governance, participation, and recentralization through platform-based infrastructures. The article concludes that resilient and sustainable energy transitions depend not only on technological innovation but equally on strengthening local capacities for cooperation, experimentation, and democratic co-design within evolving digital energy ecosystems.