This chapter focuses on legal approaches in the intersection between hydrogen storage and the electricity sector. With the increase of intermittent renewable energy sources in the electricity markets, new solutions are needed to ensure a reliable supply of electricity when renewable sources are not available. While technologies such as batteries are able to store electricity for short periods of time, medium- to long-term storage of electricity continues to be a challenge. Hydrogen storage has been presented as a potential solution to address this need. This chapter analyses the legal questions that emerge in using hydrogen as a storage medium to balance the intermittency of renewable energy sources in the low-carbon energy transition. It reviews the legal challenges and opportunities of using hydrogen as an energy storage medium and the definition of end use in this context. The discussion draws on the European Union (EU) legal frameworks for electricity and hydrogen as an illustrative case study to demonstrate how these legal questions can be governed through a transnational legal framework. The chapter concludes with an assessment of the principal gaps in the EU legal framework and evaluates the likely future directions of regulating hydrogen as an energy storage medium in the Union’s low-carbon energy transition.