Public developmental institutions are pivotal in shaping the contours of the electricity sector of the developing world and its associated greenhouse gas emissions pathways. However, we have a fragmented and incomplete picture of the evolution of their investments over time and space. This is particularly the case for the recent rise of various Chinese Developmental Institutions (CDIs) for which infrastructure investment estimates range in the trillions under China’s Belt and Road Initiative (BRI) and for which data is mostly not publicly disclosed. We address this gap in two ways: first, we compile and analyze a novel dataset that draws on commercial data tracking, publicly available datasets, and more than 1,000 supporting documents to match financial transactions by the main CDIs and traditional Multilateral Development Banks (MDBs) to power plant projects worldwide. This allows us to conduct a quantitative, comparative analysis of the role of CDIs and MDBs to understand the relative size, technology, and country focus of such investments in the period 1999–2020. Second, we complement the quantitative dataset with 39 expert interviews to shed light on the drivers behind the Chinese investments, with a particular focus on coal projects. The analysis shows that CDIs have rapidly emerged as the largest public finance provider for the electricity sector in the developing world. We also find that, in contrast with the increasingly green BRI rhetoric, the technology portfolio of CDI investments in power plants is still heavily dominated by coal plants. Over time, however, CDIs have increasingly supported more efficient coal plants and increased the share of their portfolio supporting non-hydro renewables and supported a growing number of projects jointly with MDBs. Steering China’s bilateral coal finance flows through international efforts into a more sustainable direction to meet climate goals will require careful consideration of a set of drivers and enablers of the involvement of CDIs and recipient countries in coal projects, which we discuss, as well as of the role of other finance providers, including traditional MDBs.