Grand sustainability challenges span multiple sectors and fields of policymaking. Novel technologies that respond to these challenges may trigger the emergence of new policy subsystems at the intersection of established sectors. We develop a framework that addresses the complexities of ‘multi-system settings.’ Empirically, we explore belief and coalition formation in the nascent policy subsystem around hydrogen technologies in Germany, which emerges at the intersection of electricity, transport, heating, and industry and is characterised by a broad range of actors from different sectoral backgrounds. We find two coalitions: a rather unusual coalition of actors from industry, NGOs, and research institutes as well as an expectable coalition of gas and heat sector actors. Actors disagree over production, application, and import standards for hydrogen. However, there is widespread support for hydrogen and for a strong role of the state across almost all actors. We explain our findings by combining insights from the advocacy coalition framework and politics of transitions: Belief and coalition formation in a nascent subsystem are influenced by sectoral backgrounds of actors, technology characteristics, as well as trust and former contacts. Our study contributes to a better understanding of early stages of coalition formation in a multi-system setting.

可持续发展的巨大挑战涉及决策的多个部门和领域。应对这些挑战的新技术可能会在现有部门的交叉点引发新政策子系统的出现。我们开发了一个框架来解决“多系统设置”的复杂性。根据经验，我们探讨了德国围绕氢技术的新兴政策子系统的信念和联盟的形成，该子系统出现在电力、运输、供热和工业的交叉点，其特点是由来自不同部门背景的广泛参与者组成。我们发现了两个联盟：一个由工业界、非政府组织和研究机构的参与者组成的相当不寻常的联盟，以及一个由天然气和热力行业参与者组成的预期联盟。各方对氢气的生产、应用和进口标准存在分歧。然而，几乎所有参与者都广泛支持氢能以及国家发挥强有力的作用。我们通过结合倡导联盟框架和转型政治的见解来解释我们的发现：新生子系统中的信念和联盟形成受到参与者的部门背景、技术特征以及信任和以前的联系的影响。我们的研究有助于更好地理解多系统环境中联盟形成的早期阶段。