FAQs > Rule Subparts > Subpart NN. Suppliers of Natural Gas and Natural Gas Liquids > Q289. How should a Local Distribution Company (LDC) determine if it "delivers" more than 460,000 Mscf per year? Does this include quantities delivered to other LDCs and or large end-users? What about natural gas placed into or removed from storage?
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Q289. How should a Local Distribution Company (LDC) determine if it "delivers" more than 460,000 thousand standard cubic feet (Mscf) per year? Does this include quantities delivered to other LDCs and or large end-users? What about natural gas placed into or removed from storage?

A289. According to Table A-5 of Part 98 (Subpart A), LDCs that deliver 460,000 thousand standard cubic feet (Mscf) or more of natural gas per year are subject to 40 CFR part 98, subpart NN. This threshold includes deliveries to all end-users, including deliveries of gas not owned by the LDC and deliveries of gas to end-users that receive greater than 460,000 Mscf per year. Gas deliveries to other LDCs or downstream gas transmission pipelines are excluded as they are not deemed "end-users". We recommend you use one of the following two approaches to determine whether your LDC exceeds the 460,000 Mscf threshold.

Option 1:  Sum the following parameters:

  1. Annual volume of natural gas received by the LDC that passed through the city gate(s);
  2. Annual volume of natural gas received by the LDC that did not pass through a city gate (e.g., gas delivered directly to LDCs from producers or gas processing plants);
  3. Annual volume of natural gas withdrawn from on-system storage, including vaporized LNG produced at on-system vaporization facilities for delivery, that is not included in items 1 or 2 above.

From the total, subtract the following:

  • Annual volume of natural gas placed into storage,
  • Annual volume of natural gas re-delivered to downstream gas transmission pipelines and other LDCs.

Option 2: Use the equations in 40 CFR 98.403(a) and (b) to calculate the CO2 emissions that would result from the combustion of gas supplied using Equations NN-4 and NN-6. Next, sum the values calculated using Equations NN-4 and NN-6. Divide the resulting total by the CO2 emission factor for natural gas to convert from metric tons of CO2 to volume of natural gas in Mscf. Use the default CO2 emissions factor from Table NN-2 (0.0544 metric tons CO2e per Mscf as of January 2018) or a reporter-specific CO2 emissions factor, if you developed your own CO2 emission factor and used it to calculate the CO2 emissions.


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