With or Without Blockchain? Towards a Decentralized, SSI-based eRoaming Architecture

Fragmentation and limited accessibility of charging infrastructure impede the adoption of electric vehicles. To improve the availability of charging infrastructure independent of providers, eRoaming offers a promising solution. Yet, current eRoaming systems are typically centralized, which raises concerns of market power concentration. While the use of blockchain technology can obviate such concerns, it comes with significant privacy challenges. To address these challenges, we explore a combination of blockchain with self-sovereign identity. Specifically, we apply a design science research approach, which helps us to identify requirements, derive a conceptual architecture, and deduce design principles for decentralized eRoaming and beyond. We find that blockchain may best leverage its benefits when it takes a backseat as a public registry for legal entities. Moreover, we find that the use of self-sovereign identities could improve compliance with privacy regulations, but they should not be overused.