This dissertation examines the nexus of three trends in electricity systems transformations underway worldwide—the scale-up of renewable energy, regionalization, and liberalization. Interdependent electricity systems are being envisioned that require partnership and integration across power disparities. This research explores how actors in the Mediterranean region envisioned a massive scale-up of renewable energy within a single electricity system and market across Europe, North Africa, and the Middle East. It asks: How are regional sociotechnical systems envisioned? What are the anticipated consequences of a system for a region with broad disparities and deep sociopolitical differences? What can be learned about energy justice by examining this vision at multiple scales? A sociotechnical systems framework is used to analyze energy transformations, interweaving the technical aspects with politics, societal effects, and political development issues. This research utilized mixed qualitative methods to analyze Mediterranean electricity transformations at multiple scales, including fieldwork in Morocco and Germany, document analysis, and event ethnography. Each scale—from a global history of concentrating solar power technologies to a small village in Morocco—provides a different lens on the sociotechnical system and its implications for justice. This study updates Thomas Hughes’ Networks of Power, the canonical history of the sociotechnical development of electricity systems, by adding new aspects to sociotechnical electricity systems theory. First, a visioning process now plays a crucial role in guiding innovation and has a lasting influence on the justice outcomes. Second, rather than simply providing people with heat and light, electrical power systems in the 21st century are called upon to address complex integrated solutions. Furthermore, building a sustainable energy system is now a retrofitting agenda, as system builders must graft new infrastructure on top of old systems. Third, the spatial and temporal aspects of sociotechnical energy systems should be amended to account for constructed geography and temporal complexity. Fourth, transnational electricity systems pose new challenges for politics and political development. Finally, this dissertation presents a normative framework for conceptualizing and evaluating energy justice. Multi-scalar, systems-level justice requires collating diverse ideas about energy justice, expanding upon them based on the empirical material, and evaluating them with this framework.