Energy Audit and Efficiency Improvement in a Biscuit Manufacturing Plant in Lagos

Rising energy costs represent a significant operational burden for food manufacturing enterprises in Nigeria, where electricity instability has increased reliance on diesel generators. This study conducts a detailed energy audit of a biscuit manufacturing plant in Lagos, South West Nigeria, with an installed production capacity of 5 tonnes per day. The energy audit followed the American Society of Heating, Refrigerating and Air-Conditioning Engineers Level II protocol, covering electrical distribution, baking ovens, cooling tunnels, mixers, refrigeration units, and compressed air systems. Energy consumption was measured and disaggregated by process unit, and an energy intensity index of megajoules per kilogram of finished product was calculated and compared against industry benchmarks. Results showed total energy intensity of 3.2 MJ per kg, which was 28 percent above the benchmark for equivalent biscuit plants. The baking tunnel oven accounted for 54 percent of total energy consumption. Specific inefficiencies identified included inadequate oven insulation, excessive reject conveyor idle running, and compressed air system leakages estimated at 18 percent of system flow. An energy efficiency investment plan was developed, estimating a 22 percent reduction in energy intensity through oven seal replacement, variable speed drives for conveyors, and a compressed air leak repair programme, with a simple payback period of 18 months. The study draws on food manufacturing energy management literature. Findings are applicable to the wider Nigerian biscuit and bakery industry. Keywords: energy audit, biscuit manufacturing, energy efficiency, process optimisation, Lagos