The increasing demand for reliable, affordable, and environmentally sustainable energy infrastructure has intensified the need for innovative financing mechanisms, particularly at subnational and municipal levels where public resources are often constrained. This study examines the role of public–private partnerships (PPPs) as a strategic tool for financing sustainable energy infrastructure projects and improving energy diversification within municipal public infrastructure systems. The study explores the effectiveness of selected PPP models, including Design–Build–Finance–Operate–Transfer (DBFOT), Operate–Maintain–Transfer (OMT), Build–Lease–Operate–Transfer (BLOT), and Build–Operate–Transfer (BOT), in supporting sustainable energy delivery. A mixed-method research approach using a concurrent triangulation design (CTD) was adopted, integrating quantitative and qualitative data collection and analysis to enhance reliability and validity. The study evaluates the suitability of PPP models based on stakeholder responses and performance indicators. Findings indicate that the DBFOT model provides the strongest framework for sustainable energy infrastructure development due to its capacity to integrate private sector investment, technical expertise, operational efficiency, and long-term asset management. The DBFOT model achieved the highest preference among respondents, demonstrating its potential as an effective financing structure for municipal renewable energy and waste-to-energy infrastructure projects. The study concludes that PPP arrangements can serve as a veritable mechanism for achieving sustainable energy transition by reducing public-sector financial pressure, encouraging private investment, and promoting efficient infrastructure delivery. The research recommends the adoption of well-designed PPP frameworks supported by strong governance, transparent contractual arrangements, and effective regulatory systems.
Keywords: Public–Private Partnership, sustainable energy transition, municipal infrastructure, renewable energy financing, DBFOT, BOT, BLOT, OMT, energy mix.