Fusion energy holds the prospect of an energy source that is clean, safe, affordable and limitless. It will transform the global energy system. Today, around $1.5 billion in private capital has been invested in companies that are working on transformative approaches to fusion. Annually, even more than that is spent on fusion research by governments around the world. However, just achieving a scientific demonstration of fusion power will not be enough on its own to transition the global energy system. It will require innovations in the legal, regulatory, commercial and political spheres to support the massive deployment of fusion power that we know will be necessary to meet the global challenges of climate change and energy scarcity. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 1)’.