Innovative financing for sustainable transport infrastructure in Africa: The role of green bonds and public-private partnerships

Africa’s transport infrastructure financing gap, projected to exceed USD 400 billion annually by 2030 amid rising public debt and intensifying climate risks, created an urgent need to reassess the effectiveness of emerging financing mechanisms. The study aimed to evaluate how green bonds and public-private partnerships (PPPs) performed in mobilising and delivering sustainable transport infrastructure finance across South Africa, Nigeria, and Kenya, with particular attention to the role of institutional capacity and policy coherence. The study employed a mixed-methods design, combining quantitative data from the African Development Bank, World Bank, and national sources covering green bond issuances (2013-2024) and PPP investments (2008-2024), with comparative case analysis and semistructured stakeholder interviews. South Africa recorded USD 545 million in green bond issuance and an 82% project completion rate, reflecting stronger regulatory alignment and capital market depth. Nigeria and Kenya recorded lower completion rates of 65% and 61%, respectively, with weaker integration between financing instruments and transportsector priorities. PPPs mobilised over USD 4 billion across major projects, including the Lagos-Ibadan Railway, Gautrain Rapid Rail, and Nairobi Expressway. Nigeria exhibited high capital mobilisation with execution delays and cost overruns, Kenya demonstrated relatively efficient delivery supported by emerging risk-sharing mechanisms, while South Africa showed stronger institutional coordination but higher long-term operational costs. The study found that institutional capacity, regulatory coherence, and project preparation quality were more decisive in shaping project outcomes than the scale of financing mobilised. It concluded that fragmented regulatory frameworks and weak inter-agency coordination systematically undermined both green bond effectiveness and PPP performance. The findings indicated that strengthening institutional frameworks, standardising project preparation processes, and aligning financing instruments with sectoral policies are critical to scaling sustainable transport infrastructure finance in Africa