NGSI is a voluntary, industry-wide effort to enable companies to calculate their methane emissions intensity by the segments of the natural gas value chain in which they operate. This initiative is a collaborative effort spearheaded by the American Gas Association (AGA) and Edison Electric Institute (EEI) together with the investor community and experts from upstream, midstream, and downstream natural gas companies.

Methane intensity is a measure of methane emissions relative to natural gas throughput. Investors, customers, environmental groups, and other stakeholders are increasingly requesting information on natural gas company performance based on methane emissions intensity. While intensity is becoming a preferred approach for communicating methane emissions data throughout the industry, currently there is no single, universally accepted standard methodology for calculating it. This is an obstacle to managing, tracking, and more transparently communicating the natural gas industry’s efforts to reduce methane emissions.

To address this, NGSI created the Methane Emissions Intensity Protocol (Protocol)—a consistent, transparent, and comparable method for measuring and reporting methane emissions throughout the natural gas supply chain. Specifically, the NGSI Protocol establishes intensity metrics for specific segments of the supply chain and provides comparable points of reference between companies within each segment. The Protocol seeks to improve the quality of available methane intensity information and helps companies more effectively identify ways to reduce methane emissions and communicate progress.

NGSI Protocol Version 1.0, was publicly announced in February 2021. Version 1.0 includes a Protocol overview (PDF document) and 5 data reporting templates (Excel spreadsheets), one for each of the following segments of the natural gas value chain: production, gathering & boosting, processing, transmission & storage, and distribution. The reporting templates are updated periodically to reflect new information, such as updated U.S. Environmental Protection Agency (EPA) emission factors and distribution segment weather normalization data. The resulting methane emissions intensity metric can be disclosed by AGA and EEI members via the Sustainability Reporting Template as well as on each company’s sustainability webpage. Non-AGA and EEI members are encouraged to use the NGSI Protocol to disclose their methane intensity metric on their own sustainability webpages.

NGSI Protocol Version 2.0 (released in September 2024) updated Version 1.0 to maintain consistency with EPA methodologies and industry standardized methodologies used for other reporting programs. Version 2.0 aligned with the version of EPA’s Greenhouse Gas Reporting Program (GHGRP) Subpart W regulations for Petroleum and Natural Gas Systems that were in effect as of January 1, 2024. NGSI Protocol Version 3.0 (released in January 2026) supersedes Version 2.0 and incorporates the May 2024 revisions to Subpart W that became effective on January 1, 2025 for reporting year 2025 emissions.¹

NGSI Methane Intensity Protocol Version 3.0 (updated March 2026 to incorporate additional option for reporting Distribution dig-in emissions)

NGSI Data Reporting Template for Distribution (updated March 2026 to incorporate additional option for reporting emissions from dig-ins, correct typos, and fix data display error)

NGSI Data Reporting Template for Transmission & Storage (updated March 2026 to correct typos)

NGSI Data Reporting Template for Processing (January 2026)

NGSI Data Reporting Template for Gathering & Boosting (January 2026)

NGSI Data Reporting Template for Production (January 2026)

NGSI Version 3.0 Overview – Slide Deck (updated March 2026 to incorporate additional option for reporting Distribution dig-in emissions)

For further information or questions, please contact the following AGA staff: Jennifer Golinsky Baseman (jbaseman@aga.org), Tim Parr (tparr@aga.org).  You may also contact the following EEI staff: Huiyi Jackson (hjackson@eei.org), Sandra Safro (ssafro@eei.org).

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[1] In September 2025, EPA proposed to eliminate most of the GHGRP, which would include discontinuing reporting obligations for the natural gas distribution segment and delay until reporting year 2034 the reporting obligations of all other Subpart W segments.  As of the release date of NGSI Version 3.0, EPA’s proposed rule has not been finalized and the GHGRP remains in effect.