Suppliers of Natural Gas and Natural Gas
Liquids	

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Environmental Prgtwton

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Subpart NN, Greenhouse Gas Reporting Program	*flencv

Under the Greenhouse Gas Reporting Program (GHGRP'), suppliers of natural gas and natural gas
liquids (NGLs) must report the emissions that would result from the complete combustion or oxidation of
the products that they place in commerce. Suppliers of natural gas and NGLs are required to collect data
on their products: calculate the GHG emissions associated with these products; and follow the specified
procedures for ensuring data quality, amending missing data, and meeting recordkeeping and reporting
requirements specified in 40 CFR Part 98 Subpart NN - Suppliers of Natural Gas and Natural Gas

Many natural gas and NGL suppliers are also required to report GHGs emitted by their facilities. For
more information, see the subpart W (Petroleum and Natural Gas Systems) information sheets.

How Is This Source Category Defined?

Natural gas and NGL suppliers are local natural gas distribution companies (LDCs) and NGL
fractionators. These suppliers are defined as follows:

•	Local distribution companies are companies that own or operate distribution pipelines that
physically deliver natural gas to end users and that are within a single state that are regulated as
separate operating companies by State public utility commissions or that operate as independent
municipally-owned distribution systems. LDCs do not include pipelines (both interstate and
intrastate) delivering natural gas directly to major industrial users and farm taps upstream of the
local distribution company inlet.

•	Natural gas liquids fractionators are installations that fractionate NGLs into their constituent
liquid products (ethane, propane, normal butane, isobutane, or pentanes plus) for supply to
downstream facilities.

This supply category does not include the following facilities:

•	Field gathering and boosting stations.

•	Natural gas processing plants that separate NGLs from natural gas and produce bulk or y-grade
NGLs but do not fractionate these NGLs into their constituent products.

•	Facilities that meet the definition of refineries and report under subpart MM (Suppliers of
Petroleum Products).

•	Facilities that meet the definition of petrochemical plants and report under subpart X
(Petrochemical Production).

•	All NGL fractionators are subject to subpart NN regardless of the quantity of NGL products
supplied.

•	All LDCs that supply 460,000 thousand standard cubic feet of natural gas during a calendar year
are subject to subpart NN.

Liquids.

Who Must Report?

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What Greenhouse Gases Must Be Reported?

•	NGL fractionators must report carbon dioxide (CO2) emissions that would result from the
complete combustion or oxidation of the annual quantity of ethane, propane, normal butane,
isobutane, and pentanes plus that is sold or delivered to others.

•	LDCs must report CO2 emissions that would result from the complete combustion or oxidation of
the annual volumes of natural gas provided to end users on their distribution systems.

How Must Greenhouse Gas Emissions Be Calculated?

Two different methods can be used to calculate CO2 emissions that would result from the complete
oxidation or combustion of the product supplied:

•	Calculation Methodology 1: Calculate CO2 mass emissions from a natural gas or NGL product
by multiplying the volume of product by its higher heating value (HHV) and its CO2 emission
factor (EF). Use either measured or default fuel HHVs and CO2 EFs.

•	Calculation Methodology 2: Calculate CO2 mass emissions from a natural gas or NGL product
by multiplying the volume of product by its CO2 EF. Use either measured or default CO2 EFs.

To avoid double counting of CO2 emissions associated with the supply of natural gas and NGLs,

•	NGL fractionators account for any NGL products received from other fractionators by subtracting
the quantity of CO2 associated with any NGL they receive from the CO2 associated with quantity
of NGL supplied.

•	LDCs account for CO2 emissions from natural gas consumption reported by other GHGRP
reporters by subtracting the quantity of CO2 associated with natural gas supplied to customers
receiving equal to or greater than 460,000 thousand standard cubic feet per year from the total
quantity of CO2 associated with the quantity of natural gas supplied.

A checklist for data that must be monitored is available at: https://www.epa.gov/ghgreporting/subpart-nn-
checklist.

What Information Must Be Reported?

In addition to the information required by the General Provisions at 40 CFR 98.3(c) each NGL
fractionator must report the following information:

•	Annual CO2 emissions in metric tons associated with all NGLs supplied, excluding emissions
from quantities of NGL received from other fractionators.

•	Annual CO2 emissions in metric tons associated with the total quantities of NGL that are supplied
to facilities, reported in the following product categories:

o Ethane
o Propane
o Normal butane
o Isobutane
o Pentanes plus

•	Annual quantities in barrels (bbl) of ethane, propane, normal butane, isobutane, and pentanes plus
supplied and the specific industry standard used to measure these quantities.

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•	Annual quantities in bbl of ethane, propane, normal butane, isobutane, and pentanes plus received
from other NGL fractionators.

•	Annual volume in thousand standard cubic feet of natural gas received for processing.

•	Annual quantity in bbl of y-grade, o-grade and other bulk NGLs received.

•	Annual quantity in bbl of y-grade, o-grade and other bulk NGL supplied to downstream users that
are not fractionated by the reporter.

•	Annual quantity in bbl of propane that the NGL fractionator odorizes at the facility and delivers
to others.

•	Developed EFs and HHVs and the industry standard(s) used to develop them, if developed site-
specific EFs or HHVs are used to calculate CO2.

•	Number of days in the reporting year for which substitute data procedures were used to measure
quantity, develop HHVs, and develop EFs.

In addition to the information required by the General Provisions at 40 CFR 98.3(c), each LDC must
report the following information:

•	Annual CO2 mass emissions in metric tons associated with gas delivered to each large-end user or
meter that receives 460,000 thousand standard cubic feet or more per year.

•	Annual CO2 mass emissions in metric tons associated with gas delivered to all customers that
receive less than 460,000 thousand standard cubic feet per year.

•	Annual volume of natural gas (in thousand standard cubic feet) and the annual CO2 mass
emissions (in metric tons) that would result from the complete combustion or oxidation of the
following:

o Annual volume of natural gas received at the LDC's city gate stations for redelivery on its

distribution system, including natural gas used by the LDC.
o Annual volume of natural gas that bypassed the city gate(s) and was supplied through the
LDC distribution system. This includes natural gas from producers and natural gas processing
plants from local production, or natural gas that was vaporized upon receipt and delivered,
and any other source that bypassed the city gate,
o Annual volume of natural gas withdrawn from on-system storage and annual volume of
vaporized liquefied natural gas (LNG) withdrawn from storage for delivery on the
distribution system.

o Annual volume of natural gas placed into storage, including gas liquefied and placed into
storage.

o Annual volume of natural gas delivered to downstream gas transmission pipelines and other
LDCs.

o Annual volume of natural gas delivered to each large-end user's facility or large-end user's
meter registering supply equal to or greater than 460,000 thousand standard cubic feet during
the calendar year and the large-end user's customer name, address, meter number, and EIA
identification number (if known).

•	Specific industry standard used to measure the volumes of natural gas reported.

•	Developed EFs and HHVs and the industry standard(s) used to develop them, if developed site-
specific EFs or HHVs are used to calculate CO2.

•	Annual volume of natural gas delivered to each of the following end-user categories (in thousand
standard cubic feet):

o Residential consumers,
o Commercial consumers,
o Industrial consumers,
o Electricity-generating facilities.

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•	Number of days in the reporting year for which substitute data procedures were used to measure
quantity, develop HHVs and develop EFs.

•	Name of the state or U.S. territory in which the LDC operates.

When and How Must Reports Be Submitted?

Annual reports must be submitted by March 31 of each year, unless the 31st is a Saturday, Sunday, or
federal holiday, in which case the reports are due on the next business day. Annual reports must be
submitted electronically using the electronic Greenhouse Gas Reporting Tool (c-GGRT). the GHGRP's
online reporting system. Additional information on setting up user accounts, registering a facility and
submitting annual reports is available at https://ccdsupport.com/confluence/.

When Can a Facility Stop Reporting?

There are several scenarios under which a facility may discontinue reporting. These scenarios are
summarized in the Subpart A Information Sheet as well as in an FAQ.

For More Information

For additional information on Subpart NN, visit the Subpart NN Resources webpage. For additional
information on the Greenhouse Gas Reporting Program, visit the Greenhouse Gas Reporting Program
Website, which includes information sheets on other rule subparts, data previously reported to the
Greenhouse Gas Reporting Program, training materials, and links to frequently asked questions.

This document is provided solely for informational purposes. It does not provide legal advice, have
legally binding effect, or expressly or implicitly create, expand, or limit any legal rights, obligations,
responsibilities, expectations, or benefits in regard to any person. The series of information sheets is
intended to assist reporting facilities/owners in understanding key provisions of the Greenhouse Gas
Reporting Program.

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