Preventive Maintenance Programme consists of actions that improve the condition of system elements for performance optimization and aversion of unintended system failure or collapse. It involves inspection, servicing, repairing or replacing physical components of machineries, plant and equipment by following the prescribed schedule. It is commonly agreed nowadays that preventive maintenance programme can be very successful in improving equipment reliability while minimizing maintenance related costs. The availability of a complex system, such as steam turbine power plant is strongly associated with its parts reliability and maintenance policy. That policy not only has influence on the parts' repair time but also on the parts' reliability affecting the system integrity, degradation and availability. The objective of this paper is to study the effects of Preventive Maintenance Programme (PMP) implementation on the performance of the Egbin 1320 MW thermal power plant in Nigeria. This paper considers the reliability and availability of the 6 × 220 MW steam turbine units installed in the power station. The reliability and availability of the turbines are computed based on a five-year failure database. The availability analysis of available data from 2005 to 2009 shows different results for each unit and variation in availability for different year: availability of unit1 varies between 59.11% to 91.76%; unit 2, 64.02% to 94.53%; unit 3, 28.79% to 91.57%; unit 4, 80.31% to 92.76% and unit 5, 73.38% to 87.76%. Unit 6 was out of service for the past 2 to 3 years. This indicates differences in their systems installation maintenance and operation.

The aim of this paper is to review previous works on the performance appraisal of Nigerian government-owned refineries. The review has been done in a general sense, covering appraisal works by engineers, scientists, management experts, economists, sociologists and even historians. The outcome indicates that while there seems to be several works directly and/or indirectly assessing the performance of the refineries in a general sense, there is a dearth of such in the specific area of energy consumption. There also appears to be no single one appraising energy utilisation of all the refineries at the same time in the open literature. This is in spite of the fact that refining processes are energy intensive. Despite popularisation of exergy analysis as a veritable tool, the only energy utilisation appraisal within our reach which was carried out on just one of the refineries has not been done exergetically. However, the work still reveals, within the limitations of 1st Law energy analysis that the energy consumption patterns are below international benchmarks in the oil and gas industry. Some suggestions have also been offered to take care of the energy efficiency challenges in these refineries. These include plant to plant analyses of energy utilisation patterns in the four refineries, periodical determination of GHG emission levels in the refineries using current international best practices as benchmarks, use of exergy analysis to check avoidable energy wastage in the refining processes, shifting refinery fuelling pattern in favour of low carbon content fuels like natural gas and ensuring regular turnaround maintenance of the system