Today energy is directly related with progress or growth of any country and every event requires a huge amount of energy. In today’s global competitiveness, demand for energy is very high and India is facing a problem of very poor energy supply. So, researchers and planners are worried about very poor productivity of thermal power plant and the most critical cause for this problem is high capacity waste at these plants. This paper focuses on causes of capacity waste and for this, DMAIC approach is adopted. The study also clears some myths of Six Sigma compatibility at process industries (thermal power plant) for performance improvement. After implementation of the first phase i.e. “Define”, the study confirms the competence of Six Sigma in defining the issue of capacity waste.

The long term operation and planning of power plant depend upon an effective availability analysis and assessment of various systems in the plant concerned. The plant is expected to remain operational in a continual manner to achieve the desired production targets. Hence, the availability analysis of the boiler air circulation system plays an important role in this direction. For this purpose, the concerned system mathematical model based on Markov Birth-Death process has been developed. The system consists of four subsystems. The transition diagram represents reduced capacity, full working and failed state of the system. The differential equations associated with the transition diagram based on probabilistic approach have been solved recursively in order to develop the system steady state availability. Availability matrices represented measures the performance of the system concerned. In addition, different combinations of failures and repair rates provide various availability levels of the system. Maintenance decisions are taken based upon these values for improving availability of the power plant as well as the power supply. The result shows that the failure of the primary air fan affects the system availability at most, while failure of air heater affect it at least for different failures and repair rate combination of subsystems under study.