Solar photovoltaics (PV) deployment is not easy in dense urban areas because there is little space for the installation. Furthermore, tenants have few incentives to install PV panels because they frequently relocate, and most PV facilities are nonremovable. To address these factors, this study reports on an innovative model that collectively installed 260 W of mini-PV on the balconies of almost all the households in two high-rise apartment complexes in Seoul, South Korea. This project was unique in that it established energy commons in a community using private space. This study found that economic and social factors significantly influenced community-internal or micro factors, which in turn affected the success of the community energy project. Economic factors such as the expected economic benefit and residents paying no direct installation costs shaped the initial conditions for the commencement of the project. Leadership played a key role by speeding up the process, relieving residents’ concerns and distrust. This study introduced an innovative community energy model that can be referenced by megacities and communities. It provides opportunities for enhancing awareness of energy transition via on-site energy production using renewable energy and allows even communities that have insufficient common space to build energy commons.

The integrated regional energy policy and planning (IREPP) framework was devised to evaluate the feasibility of energy policies in meeting declared national targets. While the framework advances the comprehensiveness of the feasibility assessment by bringing in concepts like environment economic equity, the muted way in which institutional factors and capacity are addressed remains weak and ineffective. Here, we corrected this weakness by presenting an IREPP framework that is enhanced by integrating principles of the institutional assessment and design (IAD) framework. The IAD framework emphasizes the careful consideration of contextual factors, it draws attention to the full range of transaction costs, and does not presume a priori that one type of institutional arrangement. This IREPP-IAD framework was used to evaluate the feasibility of energy policies in three different island jurisdictions—Taiwan, Mauritius, and Trinidad and Tobago. With ambitious national targets, these islands are good testing grounds for this updated approach. Through qualitative comparative case study analysis, several institutional factors were found to play an influence if national energy policies are likely to meet set targets. These factors included: government/policy decision makers and the decision/policymaking environment; governance structure and commitment for energy policy; existing policy instruments and tools that are in play and those planned; polycentricity; stakeholder participation and community building; market dynamics; information transparency; pilot programs and technology innovations/research; compliance or responsibilities under the Paris Accord; grid connectivity and monitoring of the policy implementation progress. This study contributes in two ways. First, by providing a more robust framework for assessing institutional arrangements that moderate how energy policies are implemented and second, providing insightful assessments of the energy policies in three island jurisdictions, thereby increasing our understanding of island energy policymaking and implementation in these understudied geographies.