Utilizing Rooftops Space of Large Government Buildings for Sustainable Electricity Distributed Generation Economy

This study proposes a solar Distributed Generation (DG) system for Awka, Anambra State, utilizing rooftops of major government buildings—Awka City Stadium, Alex Ekwueme Square, and the International Conference Center—to deploy 1,000 pieces of 450W solar panels, generating 270kW of electricity. The system serves small-scale (200–1,000W), medium-scale (1.1–5kW), and large-scale (5.1–10kW) consumers at daily tariffs of N2,000, N5,000, and N15,000, respectively, powering 250, 50, or 25 consumers per category. It also supports 200 pieces of 100W floodlights for 12-hour nightly operation, enhancing urban infrastructure. Project costs are estimated at N430.3 million over 5 years, N891.5 million over 15 years, and N1.48 billion over 25 years. Economic analysis projects 5-year outcomes of N409.7 million profit (small-scale), N10.3 million loss (medium-scale), and N199.7 million profit (large-scale); 15-year profits of N1.63 billion, N368.5 million, and N998.5 million; and 25-year profits of N2.72 billion, N618.2 million, and N1.67 billion, respectively. This scalable, cost-effective DG model enhances energy access, reduces grid dependency, and fosters economic growth in Awka, providing a replicable framework for sustainable urban energy solutions across Nigeria and informing regional renewable energy policies.