NGA ISSUE BRIEF: Natural Gas & Climate Change

Natural gas is a key part of the U.S. energy system, representing one-third of total energy consumed in 2020. It is a lower-carbon fuel than other fossil fuels, such as oil or coal, and has helped the U.S. achieve environmental progress in recent decades. In the future, it can continue to play an important sustaining role in the U.S. energy system and economy by supporting the integration of "clean energy" resources, and providing a reliable and cost-effective energy source.

As a fossil fuel, natural gas does contribute to carbon emissions, including methane. The natural gas sector is working to lower its carbon output and be part of the needed solution to environmental challenges facing the U.S. and the globe.

A review of natural gas's potential to address the nation's climate change challenge is provided in this summary.

Natural Gas: Less Carbon Intensive than other Fossil Fuels

Natural gas is composed primarily of methane. As described by U.S. EPA: "Natural gas is a fossil fuel formed when layers of buried plants and animals are exposed to intense heat and pressure over thousands of years. The energy that the plants and animals originally obtained from the sun is stored in the form of carbon in natural gas."

Natural gas has lower emissions of carbon dioxide than other fossil fuels such as coal and oil. Compared to coal, natural gas produces half as much carbon dioxide, and about 30% less than oil.

Advantages for Transportation Sector

Natural gas represents an efficient alternative transportation fuel for the U.S. and the Northeast region. Natural gas vehicles employ a technology that is available now and applicable to taxis, passenger vehicles, heavy-duty trucks and buses. Natural gas vehicles provide lower emissions of carbon dioxide, carbon monoxide and nitrogen oxide compared to gasoline and diesel vehicles. (For more information, click here.)

Advantages for Power Generation

For power generation, natural gas has been the leading fuel option in the U.S. and the Northeast over recent years, reflecting the technological advances of natural gas combined cycle power plants, with higher efficiency, lower heat rates, and lower emissions than other fuel options. Natural gas is the least carbon-intensive fossil fuel, and is helping to drive down overall CO2 emissions in the electric power sector.

Natural gas is positioned to remain a reliable and sustaining fuel for electric generation for years to come. Gas also can readily and reliably provide the back-up power generation for intermittent renewable resources like wind and solar power.


In New York State over the last 20 years (from 2000-2020), NY ISO reports that emissions rates from the power sector dropped by 52% for CO2, 93% for NOx, and 99% for SO2. ISO-NE reports that since 2001, total emissions from power plants in New England have dropped by 99% for sulfur dioxide (SO2), 78% for nitrogen oxides (NOx), and 42% for CO2. PJM reports that over the last 15 years, between 2005 and 2020, CO2 emission rates fell 39% across its footprint, while nitrogen oxides declined by 86% and sulfur dioxide by 95%.

Natural gas has been a key factor in all three power systems in helping achieve these environmental gains.



Advantages for Homes and Businesses


For homes and businesses, natural gas also offers opportunities for increased efficiency, reduced emissions, and lower costs. The American Gas Association (AGA) notes: "Natural gas usage per household has decreased even as overall demand for energy has risen. This trend is due in part to the installation of tighter-fitting windows and doors, better insulation, utility-sponsored energy efficiency programs, and the development of increasingly more efficient natural gas appliances."

Efficiency remains a supply resource of immense opportunity to the nation and climate change legislation should encourage cost-effective programs that yield positive results. The Northeast states are national leaders in per capita energy efficiency, and the natural gas and electric utilities in the region have been active for years in efficiency programs. These natural gas efficiency program investments will be expanded even further in coming years. (For more information, click here.)

In a 2017 paper, the National Regulatory Research Institute (NRRI) observed: "For most of the country, natural gas is the most economical energy source for homes and businesses."


Reducing Methane Emissions within Gas System Operations


Natural gas companies are committed to reducing their own carbon footprint and are actively involved in such initiatives as the U.S. EPA's "Natural Gas STAR" Program to reduce methane emissions from natural gas system operations. Progress continues on this front, and new technologies are helping in that regard.

NGA encourages increased funding for innovative research and development programs that support improved technologies in all stages of the natural gas supply and delivery chain to achieve environmental improvements.

More information on Natural Gas STAR can be found here: https://www.epa.gov/natural-gas-star-program/natural-gas-star-program#tab-4

Natural gas systems are a leading contributor to CH4 or methane emissions in the U.S., along with agriculture, landfills and coal mining. But methane emissions from natural gas have come down compared to prior decades. CH4 emissions from natural gas systems declined by 15.7% from 1990 to 2019, according to the U.S. EPA's 2019 Greenhouse Gas Inventory released in April 2021. (This decline occurred in a timeframe when total U.S. natural gas consumption grew from 19 Tcf in 1990 to 31 Tcf in 2019 - a growth of 63%.)

EPA notes in its 2021 report: "Natural gas systems were the second largest anthropogenic source category of CH4 emissions in the United States in 2019 with 157.6 MMT CO2 Eq. of CH4 emitted into the atmosphere. Those emissions have decreased by 29.3MMT CO2 Eq. (15.7 percent) since 1990. The decrease in CH4 emissions is largely due to decreases in emissions from distribution, transmission, and storage... Distribution system emissions, which accounted for 9 percent of CH4 emissions from natural gas systems and less than 1 percent of CO2 emissions, result mainly from leak emissions from pipelines and stations. An increased use of plastic piping, which has lower emissions than other pipe materials, has reduced both CH4 and CO2 emissions from this stage, as have station upgrades at metering and regulating (M&R) stations. Distribution system CH4 emissions in 2019 were 69 percent lower than 1990 levels and 1 percent lower than 2018 emissions. Distribution system CO2 emissions in 2019 were 69 percent lower than 1990 levels and 1 percent lower than 2018 emissions." [[EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2019, pages ES-16 and 3-91]

Massachusetts has seen a considerable decline in methane emissions over the several decades. The MA DEP's greenhouse gas emissions inventory shows that methane (CH4) emissions from natural gas systems declined by 67% from 1990 to 2018. New York State reports that methane emissions related to "natural gas leakage" in-state declined by 20% from 2005 to 2016. The leading sources of methane emissions in New York State are landfills (54%) and agricultural animals (18%), followed by natural gas (14%), according to NYSERDA's July 2019 GHG state inventory (2016 data). Also, "natural gas systems" overall represent 1% of total statewide GHG emissions in NY. Connecticut reports that the contribution of methane emissions from leakage from natural gas distribution and transmission systems within Connecticut is less than one percent (0.6%) of all statewide GHG emissions (source: Connecticut 2017 GHG Inventory, released Jan. 2020). Natural gas system leakage has declined by two-thirds since 1990 in Connecticut.

Accelerated pipeline replacement of "leak-prone" system components, such as cast iron and bare steel, is an industry and U.S. DOT priority - see the separate issue brief at: https://www.northeastgas.org/accelerated_infrastructure.html

New Technology Innovations

Another element of focus for the natural gas industry is utilizing new technology innovations to reduce or offset carbon intensity in supply. These include renewable natural gas (RNG), hydrogen, and carbon capture sequestration.

RNG, also known as bio-methane or biogas, is pipeline quality gas derived from biomass that is fully interchangeable with natural gas. The future natural gas network could include renewable gas from dairy farms, waste water treatment plants, landfills, wood waste and food waste plants. In the Northeast, there is growing interest and initiatives toward incorporating RNG, with several pilot programs underway. Look for further information on NGA's RNG page here:

https://www.northeastgas.org/renewable_natural_gas.php

Among the energy sources seen as potentially significant for helping establish a low-carbon energy future is hydrogen. For natural gas systems, hydrogen has the potential to reduce carbon intensity through blending into existing gas pipeline systems. Look for further information on hydrogen's potential here:

https://www.northeastgas.org/hydrogen.php

For Further Information:

EPRI & GTI: Low-Carbon Resources Initiative (LCRI)

IEA: Carbon Capture, Utilization & Storage

U.S. EPA's Greenhouse Gas Emissions Inventory

GTI's Hydrogen Technology Center

Renewable Natural Gas Coalition

ACEEE Energy Efficiency State Scorecard