This study evaluates the integration of renewable energy solutions in sustainable building projects across three major Nigerian urban centers: Lagos, Abuja, and Port Harcourt. The research investigates the viability and impact of solar photovoltaic (PV) systems, wind energy, and biomass waste-to-energy solutions in reducing energy consumption and greenhouse gas (GHG) emissions. A comprehensive methodology was employed, including data collection through semi-structured interviews, site visits, and simulations using energy performance modeling software. Advanced analyses, such as cost–benefit analysis (CBA), sensitivity analysis, and life cycle assessment (LCA), were conducted to assess the financial feasibility and environmental impact of these renewable energy systems. The findings highlight that solar PV systems are the most effective renewable energy technology for urban buildings, achieving energy savings of 25% to 35% with a payback period of 6 to 8 years. Biomass waste-to-energy systems demonstrated significant potential in industrial settings, providing energy savings of 20% and substantial reductions in GHG emissions. In contrast, wind energy adoption remains limited due to high upfront costs and longer payback periods, making it less viable without substantial government support. The study identifies key barriers to renewable energy adoption, including high initial capital costs, a lack of local technical expertise, and inconsistent policy enforcement, all of which hinder widespread implementation. To overcome these challenges, the study proposes policy recommendations aimed at accelerating renewable energy adoption in Nigeria’s urban centers. These include increasing financial incentives such as subsidies and low-interest loans, strengthening the enforcement of renewable energy policies, investing in education and training to develop local technical capacity, and fostering public–private partnerships (PPPs) to mobilize funding for large-scale renewable energy projects. With these interventions, renewable energy solutions can play a transformative role in advancing the sustainable development of Nigeria’s cities.