The emerging field of structural supercapacitors (SSCs), (also known as power composites), integrate energy storage capabilities into structural components. Conventionally, SSC material selection has focused solely on technical functionalities such as energy density and mechanical strength. To achieve sustainable power composites, Safe and Sustainable by Design (SSbD) principles must be considered at an early stage of innovation and development. In this study, a comprehensive dataset of existing SSCs was compiled, and their environmental footprints were quantified using credible data sources. Ashby material selection diagrams were then constructed, considering both technical performance and environmental impact. Remarkably, only one reported SSC was found to meet the requirements of both high multifunctionality and low environmental impact. The findings underscore the imperative for adopting more sustainable material production methods in the development of future SSCs. In this way, the identified pathways will help to develop environmentally responsible energy storage solutions.