In this week’s blog, we focus on natural gas and greenhouse gas emissions.
Gaining a better understanding of greenhouse emissions released from natural gas production and delivery systems helps clarify how the proper deployment of natural gas can deliver significant environmental benefits. Join us in taking a closer look at the numbers.
Industry-wide Natural Gas Emissions are Low and Declining
The U.S. Environmental Protection Agency (EPA) made further updates to its estimates of methane emissions in its Inventory of U.S. Greenhouse Gas (GHG) Emissions and Sinks: 1990–2018 (“Inventory”), released in April 2020. The Inventory incorporates new data available from studies on emissions as well as the EPA’s own Greenhouse Gas Reporting Program (GHGRP).
The Inventory found that industry-wide methane emissions¹ as a rate of natural gas production were 1 percent. The ratio of methane emissions per unit of natural gas produced has declined continuously during the past several decades, dropping 48 percent since 1990.
U.S. Methane Emissions per Mcf of Gas Produced ²
The inventory also confirmed that natural gas distribution systems have a small emissions footprint that continues to decline. Distribution systems emit less than 0.1 percent of produced natural gas annually, a decline of 73 percent from 1990 to 2017 even as U.S. natural gas utility companies added more than 730,000 miles of pipeline to serve 19 million more customers,
increases of 50 and 36 percent respectively, and natural gas production increased by 50 percent.
The bottom line: New control technologies, replacement of old cast iron and bare steel pipes, and better industry practices have contributed to significant emissions reductions, even as annual natural gas production and consumption have hit record highs.
U.S. Methane Emissions from Natural Gas Distribution Systems
Regionally, Emissions are Already Lower and Expected to Decline Even Faster
In the basins from which the Pacific Northwest sources most of its natural gas, policymakers and regulators have taken action to further decrease methane emissions from upstream operations. Effective January 2020 in BC, the source of about two-thirds of our region’s natural gas, the BC Oil and Gas Commission (BC OGC) has committed to reduce methane emissions from upstream oil and gas operations by 45 percent by 2025 relative to 2014 levels, targeting everything from compressor seals to storage tanks. The BC approach is expected to reduce methane emissions by 10.9 megatonnes (10.9 million metric tons) of CO2 equivalent over a 10-year period, the equivalent of taking 390,000 cars off the road each year.³ In addition, BC’s natural gas transmission sector is expected to reduce its emissions by 40 to 45 percent below 2012 levels by 2050 under the Canadian federal Methane Regulation, which also came into force in January 2020. Like the BC OGC, the federal Methane Regulation is focused on reducing emissions from fugitives and venting.
In 2014, Colorado (which provides much of our region’s Rockies’ gas, about one-third of our supply overall) approved the first methane regulations in the U.S. requiring energy companies to reduce methane emissions from oil and natural gas operations by routinely checking their oil and natural gas wells—both new and existing—statewide, and immediately addressing any leaks. The regulations go beyond those of the EPA, which apply only to new or modified operations, according to the Environmental Defense Fund, which helped craft Colorado’s regulations.
Where does the PNW get it’s natural gas?
By 2016, field surveys of oil and gas equipment by the Colorado Department of Public Health and Environment (CDPHE) found a 75 percent drop in the number of sites where methane leaks were detected compared to similar surveys conducted prior to the regulations taking effect, said Will Allison, former director of the department’s Air Pollution Control Division. By 2018, Garry Kaufman, the division’s new director, said, “Colorado’s program has reduced emissions of methane and volatile organic compounds from the oil and gas sector by hundreds of thousands of tons per year, while still allowing for growth in this important economic resource for Colorado.”
As a result, gas pipelines serving the Northwest have the lowest methane emissions on the continent and will continue to improve.
Regional Natural Gas Emissions are Small Relative to Other Sectors
Overall, direct use of natural gas for space and water heating in homes and commercial buildings in the Pacific Northwest accounts for just eight percent of total regional GHG emissions (see pie chart). The transportation sector (trucking, fleets, personal vehicles, public transit, etc.) produces the largest share of regional emissions (42 percent). The “other” category in the chart includes agriculture, forest practices, waste streams (landfills, wastewater treatment), building heat from fuels other than natural gas, oil and gas extraction (BC only), and industrial emissions not related to natural gas combustion.
¹Industry-wide, or “lifecycle” emissions, as defined by the EPA, include natural gas field production, processing, transmission and storage, and distribution.
²Includes methane emissions from petroleum production based on the natural gas fraction of total energy content produced from oil wells.
³For details from the BC Oil and Gas Commission, see https://www.bcogc.ca/public-zone/reducing-methane-emissions