Design and analysis of grid-connected energy systems for commercial buildings

This paper presents the design of energy generation based on the national grid, solar photovoltaic (PV), and diesel-based supply systems for a commercial building in Obanikoro, Lagos with a total demand and peak load of ~56,000 kWh/yr and 13.5 kW, respectively. The grid is simulated based on the average daily supply of 6 hours being experienced in the study location, indicating that the building is not served for an average of 18 hours/day. The paper considers three design configurations: grid, grid + PV, and grid + PV + generator systems in HOMER Microgrid tool and their performances are compared in terms of the annual generation, load not served, and the emissions. A load demand of ~14,000 kWh/yr meaning that 75 % of total demand is not met. A 35.2 kW PV was added to the grid, with both supplying 49,687 and 13,826 kWh/yr, respectively. However, a 6.98% of the load is not served. A 15 kW generator is then added to form the grid + PV+ diesel generator configuration, and the participating energy sources supply 15,818, 49,723 and 4,834 kWh/yr, respectively. This configuration is able to meet the demand without any deficit. The CO2, CO, unburned hydrocarbons, particulate matter and SO2 and nitrogen oxides emissions for the three configurations are 8.824, 0, 0, 0, 0.0383 and 0.0187 tonnes/yr; 8.192, 0, 0, 0, 0.0355 and 0.0174 tonnes/yr, and 11.833, 0.0259, 0.00113, 0.000157, 0.0435 and 0.0407 tonnes/yr, respectively. The study can help to mitigate the energy shortage in commercial buildings.