As part of the annual process to develop the U.S. Inventory of Greenhouse Gas Emissions and Sinks (GHG Inventory), EPA assessed new data for updates to its estimates for natural gas and petroleum systems. EPA updated its estimates for natural gas systems in the exploration, production, processing, and transmission and storage segments. EPA updated its estimates for petroleum systems in the exploration, production, crude oil transportation, and refining segments.

Please see the memos below for information on these updates. The natural gas and petroleum systems methodology annexes for the 1990-2017 GHG Inventory are available below as well.

For previously posted information from the stakeholder process, view the archives of memos and presentation slides regarding updates considered for the 1990-2017 GHG Inventory.

View information about revisions to estimates for natural gas and petroleum systems in the GHG Inventory for earlier Inventory release years.

Methodology Annexes

• Annex 3.5: Methodology for Estimating CH4, CO2, and N2O Emissions from Petroleum Systems(210 K)
• Annex 3.6: Methodology for Estimating CH4, CO2, and N2O Emissions from Natural Gas Systems(360 K)

Memos on updates to estimates for natural gas and petroleum systems

• Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2017: Updates to Natural Gas Gathering & Boosting Pipeline Emissions (PDF)(8 pp, 365 K)
• Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2017: Updates to Liquefied Natural Gas Segment (PDF)(19 pp, 641 K)
• Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2017: Other Updates Considered for 2019 and Future GHGIs (PDF)(17 pp, 653 K)