Trinidad and Tobago has a distinctive greenhouse gas emissions profile, shaped by its hydrocarbon-based economy and energy-intensive industries. Strengthening the accuracy of its national greenhouse gas inventory is therefore essential to credible reporting and progress under its Nationally Determined Contributions. The inventory currently relies on default emission factors published by the Intergovernmental Panel on Climate Change; however, their suitability for the country's mature natural gas infrastructure has not previously been systematically evaluated.

This research evaluated the applicability of these default factors and developed study-derived, balance-based methane and carbon dioxide emission factors for key segments of the national natural gas network. The mass-balance framework integrated gas-network mapping, nodal analysis, validated operator information, national statistics, and statistical, uncertainty, and sensitivity analyses. Optical gas imaging provided an additional line of evidence for interpreting the results.

The findings reveal important differences between locally derived estimates and international defaults, particularly within the transmission segment, where the principal unresolved system-level discrepancy was identified. They also demonstrate that measurement quality, especially the reliability of flow data, strongly influences the precision of calculated emission factors. This underscores the need for targeted improvements in measurement, monitoring, and verification across the natural gas value chain.

By providing the first balance-based emission factors developed specifically for Trinidad and Tobago's natural gas network, this study establishes a foundation for advancing toward a country-specific inventory approach. Its outcomes can strengthen national greenhouse gas reporting, support evidence-based mitigation, and improve the management of natural gas resources.