The reliability of power generation assets is critical to ensuring uninterrupted operations, particularly in offshore environments such as Pertamina Hulu Energi Offshore South East Sumatra (PHE OSES). This study introduces a comprehensive assessment of power generation asset reliability using the Health Index (HI) method, integrated with the Analytical Hierarchy Process (AHP) to determine parameter weights objectively. The HI framework evaluates six key parameters: asset age, running hours, heat rate, maintenance factor, failure history, and environmental factors. Data were collected from operational records, maintenance logs, and performance metrics of 16 generators in the PHE OSES work area. The results reveal HI scores ranging from 48.14 to 87.29, categorizing assets from poor to excellent reliability. Generators with lower HI scores, such as G101-A and G101-B, require intensive diagnostics and immediate maintenance, while high-performing units like GT#14 and GT#15 need routine maintenance to sustain reliability.
The integration of AHP provided a robust weighting mechanism, reflecting the relative importance of each parameter to asset health. The analysis also identified a strong correlation between HI scores and reliability indicators such as MTBF and MTTR, demonstrating the validity of the HI model in representing asset reliability. This study highlights the potential of HI as a decision-support tool for optimizing maintenance strategies, prioritizing resource allocation, and mitigating operational risks. The findings offer a scalable framework for reliability assessment and contribute to advancing condition-based maintenance practices in the offshore oil and gas industry.