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

Abstract

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.