This book addresses how a country with Europe’s best solar irradiation potential yet very low installed solar capacity of less than 0.5 gigawatt (GW) in 2017, went on to become the darling of Europe’s solar scene. By 2023, installed capacity has exceeded 2.5 GW, a five-fold increase within six years, but even more striking is the latest target of 20.4 GW by 2030 in Portugal’s National Energy and Climate Plan, up from the earlier target of 9 GW by 2027. These are large ambitions, and policymakers, practitioners, and scholars alike wonder: will these targets bear out in practice? Drawing on long-term, multi-sited and multi-scalar ethnographic fieldwork, this book aims to address this concern. There is no comparable existing work that tells this story of Portugal, a case that has global significance as a laggard rather than a frontrunner and that is rapidly in the ascendancy.Available open access digitally under CC-BY licence. Portugal is among the best-placed European countries to take advantage of solar power, having achieved a five-fold increase in installed capacity during 2017-2023 despite financial constraints. In 2023, its National Energy and Climate Plan set an ambitious target for a further eight-fold increase from 2.5 GW to 20.4 GW by 2030. How can such fast-paced deployment secure sociospatial justice? What insights do political economic dynamics hold for future transitions? Drawing on long-term, multi-sited ethnographic fieldwork, this book is a one-stop resource for policymakers, practitioners, scholars, and anyone interested in just solar energy transitions. Siddharth Sareen won the 2024 Nils Klim Prize, recognising his exemplary work in the search for renewable and sustainable sources of energy.