Tora developed a data collection protocol and managed field testing for an engineering evaluation of methane emissions from centrifugal compressors used at midstream natural gas transmission stations. The study focused on comparing emissions from two compressor types:

• Dry-seal compressors, which use gas pressure to create a seal
• Wet-seal compressors, which use oil and are often assumed to emit more methane

Using a statistically valid dataset from multiple sites, Tora’s analysis challenged a key EPA assumption: in some cases, wet-seal compressor emissions were found to be lower than dry-seal emissions, contrary to longstanding regulatory guidance.

This project demonstrates the importance of empirical testing and site-specific data in informing emissions control strategies—and opens the door to more nuanced permitting approaches in compressor station regulation.