Q651. Would a monitoring plan that results in 10% of stations being monitored in each of years 1 and 2, 40% in year 3, 20% in year 4 and 20% in year five, be consistent with the rule language of “approximately equal across all years in the cycle.”
A651. As noted in the preamble, the purpose of this provision was to reduce burden for reporters, including the option to better align survey frequencies between the Greenhouse Gas Reporting Program and Department of Transportation regulations. The statement in the preamble regarding a “minimum of 20 percent of their total number of stations being leak surveyed annually” was considered for cases where a facility chose a period of less than 5 years. We also recognize that there is a related comment and response in, “Mandatory Greenhouse Gas Reporting Rule: EPA's Response to Public Comments: “2011 Technical Revisions to the Petroleum and Natural Gas Systems Category of the Greenhouse Gas Reporting Rule” (see DCN: EPA-HQ-OAR-2011-0512-0030) where EPA may also appear to reject the 10%-10%-40%-20%-20% approach outlined above. However, EPA understood the commenter’s recommendation as to be suggesting measurement of 10% of stations per year, over a ten year period. EPA’s objection to the comment to monitor 10% of stations per year would have been inconsistent with a five-year cycle. Yes. According to 98.233(q)(8)(i), “Natural gas distribution facilities may choose to conduct leak detection at T-D transfer stations over multiple years, not exceeding a five year period to cover all T-D transfer stations. If the facility chooses to use the multiple year option, then the number of T-D transfer stations monitored in each year should be approximately equal across all years in the cycle without monitoring the same station twice during the multiple year survey.” EPA confirms that an approach of conducting monitoring at 10% of the facilities in each of the first two years, followed by 40%, 20% and 20% in years three, four and five would be consistent with the rule language that the number of stations monitored be “approximately equal” over the number of years surveyed.
In summary, the rule does not include any minimum threshold and the 10%-10%-40%-20%-20% is consistent with the rule requirements and there is no need to request use of BAMM to follow this monitoring approach.
Please note that consistent with the preamble to the final rule (76 FR 80570), you must describe in your monitoring plan how the annual leak detection surveys represent cross sections of the total number of stations.