Sustainable Techno-Economic Assessment of a Grid-Connected Wind–Solar Street-Lighting Microgrid for Land-Constrained Urban Regions: A Case Study of the Tokyo Bay Area

Urban energy infrastructure in dense metropolitan regions must decarbonize essential public services while avoiding additional land take and excessive costs. This study presents a techno-economic and sustainability assessment of a grid-connected hybrid wind–solar street-lighting microgrid, created by retrofitting an existing nine-node off-grid installation at Odaiba Beach, Tokyo Bay, into an embedded distributed generation asset. The design departs from complementary sizing by independently scaling PV and wind so that each source can satisfy worst-case winter lighting demand, enabling both a reduction in battery autonomy from five to two days and the deliberate use of seasonal surpluses for grid export. Steady-state load-flow analysis in ETAP indicates annual generation of 1803.73 kWh from PV and 1192.54 kWh from wind, corresponding to approximately 1.84 MWh/year of net clean energy export after supplying 1009.15 kWh/year of lighting demand and incurring 149.09 kWh/year of distribution losses, with voltages compliant with industry standards. Sensitivity analysis under conservative solar and wind scenarios shows that the system remains export-positive in all cases, thereby supporting sustainable urban development by decarbonizing street-lighting, improving land-use efficiency through infrastructure co-location, and providing a replicable framework for similar coastal cities.