Due to climate change, there is an urgent need to decarbonize high-emission industries. As coal-based operations predominate in primary steelmaking, the steel industry offers an exceptionally high potential for reducing greenhouse gas emissions. Alternative processes for almost fully decarbonized primary steelmaking exist but require substantial investments by steelmakers for their implementation while maintaining desired production levels during the transformation periods. In this context, the energy carriers required change such that the transformation of the steelmaking processes is deeply intertwined with the transformation of the background system. For the first time, we evaluate potential transformation pathways from the steelmakers’ perspective using a prospective life cycle assessment approach. We find that hydrogen may facilitate a reduction of direct emissions by around 96 % compared to conventional steelmaking in 2050. However, indirect emissions remain at a high level throughout the transformation period unless the upstream stages of the value chain are transformed accordingly.