This thesis examines the role of sovereign wealth funds (SWFs) in financing the clean energy transition within the broader context of contemporary state capitalism. It examines the extent to which sovereign wealth funds mobilize capital toward renewable energy investments, and how this engagement varies across fund types and mandates. Through an empirical analysis of six sovereign wealth funds between 2017 and 2024, the research maps their allocation to renewable energy, grid infrastructure, and other low-carbon assets using an original asset-level classification. The findings reveal significant heterogeneity across stabilization, strategic, and savings funds, with strategic funds displaying the most direct engagement in renewable energy investment, while stabilization funds remain structurally constrained by liquidity requirements. The thesis argues that although SWFs possess distinctive advantages as long-term public investors, their current level of engagement remains insufficient to position them as systemic leaders of the cleanenergy transition. It concludes that the emergence of a greenform of state capitalism through sovereign wealth funds is contingent on stronger mandates, governance frameworks, and political commitment to climate-aligned investment strategies.