International Journal of Engineering & Technology Sciences (IJETS) 1(4): 206-217, 2013 ISSN 2289-4152 © Academic Research Online Publisher Research Article Energy Analysis of Omotosho Phase 1 Gas Thermal Power Plant Egware H.O a and Obanor A.I b* a,b , Department of Mechanical Engineering, University of Benin, P.M.B 1154, Benin City, Nigeria *Corresponding author E-mail: henryegware@yahoo.com,aiobanor@yahoo.com. A b s t r a c t Keywords: Energy analysis, Efficiency, Power output, Gas Turbine, Ambient temperature, Performance. Many managers of electrical generating utilities are striving to improve the efficiency, heat rate and performance of their existing thermal power stations. The thermal performance of the plant has to be investigated to achieve this aim. This paper describes the use of energy analysis in evaluating the performance of Omotosho Phase I Gas Thermal Power Plant. The data used were obtained from data record book and discussions with personnel during visit to the plant. The efficiency of plant was calculated at various load levels and ambient temperature. The average overall efficiency of the units was found to be 30.28% at ambient temperature range of 21 - 33 0 C and power output of 30.11 – 39.80 MW. This shows that power output and overall efficiency decreases as ambient temperature increases and 66.98% of fuel input is heat lost through the flue gases to the environment was the largest source of energy loss in the turbine units. Based on the results obtained compressor air intake cooling and combined cycle systems are recommend to optimize thermal performance of the plant. Accepted:15 July2013 © Academic Research Online Publisher. All rights reserved. 1. Introduction Gas turbines can be started and stopped easily which make them every useful at peak period in energy demand. Gas turbines are widely used for electricity generation in Nigeria because of the availability and low prices of natural gas compared to distillate fuels in the country [1]. For these reasons they are used are based load units. Energy analysis need to be carried out to know sources of losses during conversion of energy process in the plant and factors affecting the performance of the plant for efficient used of gas turbine power plant[2]. Energy analysis is the traditional method of assessing the way energy is used in an operation involving the physical or chemical processing of materials and the transfer and/or conversion of energy [3, 4]. This usually entails performing energy balances, which are based on the First Law of