NGA ISSUE BRIEF: Natural Gas & the Environment |
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January 2012
SUMMARY
Natural gas is a low carbon fuel, and is seen as a key part—or "bridge fuel" - in U.S. efforts to transform its energy system to be more efficient and environmentally positive. Natural gas has been the “fuel of choice” for power generation in the Northeast for the last decade in large part because of its positive impacts on air quality and the environment; and it is also seen as a positive environmental fuel for transportation and other sectors. A review of some environmental trends regarding natural gas is provided in this summary. Environmental Advantages of Natural Gas
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." As noted in the table below, natural gas has far fewer emissions of sulfur, nitrogen and carbon than other fossil fuels such as coal and oil. For instance, compared to coal, natural gas produces half as much carbon dioxide, less than a third as much nitrogen oxides, and one percent as much sulfur oxides at the power plant. Natural Gas and Power Generation
Natural gas has been the dominant fuel for new power generation in the Northeast and nationally for over a decade, and one of the leading reasons has been its beneficial impact on air emissions. The U.S. EPA has noted that, "because of their relatively high efficiency and reliance on natural gas as the primary fuel, gas turbines emit substantially less carbon dioxide (CO2) per kilowatt-hour (kWh) generated than any other fossil technology in general commercial use." The electric utility sector in the Northeast has achieved major reductions in several air emission areas over the last 20 years—in great part thanks to new, more efficient power sources, from natural gas to renewables. And the progress continues. In January 2011, Environment Northeast released a status report on air emissions from power plants in the Regional Greenhouse Gas Initiative (RGGI) region – corresponding to the New England and Mid-Atlantic area. It found that emissions, through September 2011, had declined 11% from the same time period in 2010. Based on data through the third quarter of 2011, ENE projects that total 2011 emissions are likely to have fallen slightly below the historic low in 2009. The group reported that "Low emissions are a consequence of fuel-switching to natural gas, increased generation from non-emitting sources, stable electricity consumption, and - to a lesser extent - mild weather and weak economic conditions in the region." Natural gas helps improve air quality. The charts below show changes in utility emissions for SO2, NOX and CO2, for MA and NY, for the years 1990, 2000 and 2010.
The MIT natural gas study of June 2011 stated that using very efficient natural gas powerplants to replace coal-fired plants is "the most cost-effective way of reducing CO2 emissions in the power sector" over the next 25 to 30 years. Natural gas will also play "a central role in integrating more intermittent renewable sources — wind and solar — into the electricity system because they can easily be brought in and out of service as needed." Continued investments in gas power generation will yield greater efficiencies and help the region meet its Clean Air—and energy—requirements. Natural Gas Vehicles (NGVs)
The natural gas vehicle (NGV), also known as CNG vehicles (for compressed natural gas), has many environmental advantages. NGVs remain a very competitive alternative to gasoline or diesel fuels, particularly for certain key markets such as fleets and urban bus systems. The U.S. Department of Energy's alternative fuel vehicle website notes: "Commercially available medium- and heavy-duty natural gas engines have demonstrated over 90% reductions of carbon monoxide (CO) and particulate matter, and more than 50% reduction in nitrogen oxides (NOx) relative to commercial diesel engines." According to NGV America, typical dedicated NGVs can reduce exhaust emissions of:
In February 2011, ACEEE rated the compressed natural gas (CNG) vehicle the "greenest vehicle" on the road in the U.S. In October 2009, the National Research Council, affiliated with the National Academies of Science, released a report which noted that: "compressed natural gas had lower damages than other options, as the technology’s operation and fuel produce very few emissions." Reducing Methane Emissions from Gas System Operations
Shale Gas Production and the Environment
Finally, an environmental issue of growing regional interest concerns the development of gas resources in the Marcellus Shale. The industry performance has been positive but there remains public concern in some quarters about system oversight and transparency. The MIT study on natural gas from June 2011 notes that "the environmental impacts of shale development are challenging but manageable." Industry and government regulatory agencies are working to address development in an environmentally safe manner. The natural gas production industry is moving to address the issue of disclosure regarding the additives used in the hydraulic fracturing process. One major step was announced on April 11, 2011, when the Ground Water Protection Council (GWPC) and the Interstate Oil and Gas Compact Commission (IOGCC), with funding support from the United States Department of Energy (DOE), unveiled a landmark web-based national registry disclosing the chemical additives used in the hydraulic fracturing process on a well-by-well basis. The information on the website covers wells drilled starting in 2011. The initiative provides energy companies involved in oil and gas exploration and production a single-source means to publically disclose the chemical additives used in the hydraulic fracturing process. The web site address is: www.fracfocus.org/ Government is also undertaking its own reviews. In August 2011, an advisory group to the U.S. Energy Secretary released a series of consensus-based recommendations calling for increased measurement, public disclosure and a commitment to continuous improvement in the development and environmental management of shale gas. The group’s report noted that shale gas has rapidly grown to nearly 30 percent of natural gas production in the United States. Increased transparency and a focus on best practices "benefits all parties in shale gas production: regulators will have more complete and accurate information, industry will achieve more efficient operations and the public will see continuous, measurable, improvement in shale gas activities," the report says. The report calls for industry leadership in improving environmental performance, underpinned by strong regulations and rigorous enforcement, evolving to meet the identified challenges. The press release and August 2011 report can be found here: http://energy.gov/articles/secretary-energy-advisory-board-subcommittee-releases-shale-gas-recommendations The U.S. Environmental Protection Agency (EPA), under the Obama administration and at the direction of Congress, is undertaking a study of the practice to better understand any potential impacts of hydraulic fracturing on drinking water and groundwater. EPA consulted with experts in the field through peer review and technical workshops, and engaged stakeholders in a dialogue about the study through facilitated public meetings. In February 2011, EPA submitted its draft study plan on hydraulic fracturing for review to the agency's Science Advisory Board (SAB). The overall purpose of the study is to understand the relationship between hydraulic fracturing and drinking water resources. The scope of the proposed research includes the full lifespan of water in hydraulic fracturing, from acquisition of the water, through the mixing of chemicals and actual fracturing, to the post-fracturing stage, including the management of flowback and produced water and its ultimate treatment and disposal. Initial research results are expected by the end of 2012 with a goal for a report in 2014. The Pennsylvania Department of Environmental Protection (DEP) has a very good web site on its regulatory role regarding shale gas production in that state; it can be found here: http://www.dep.state.pa.us/dep/deputate/minres/oilgas/new_forms/marcellus/marcellus.htm On July 1, 2011, the New York Department of Environmental Conservation (DEC) released its revised recommendations on mitigating the environmental impacts of high-volume hydraulic fracturing (high-volume fracturing) for natural gas production in New York State. The DEC subsequently released a revised draft Supplemental Generic Environmental Impact Statement (SGEIS) on September 7, 2011. The DEC said: "These recommendations, if adopted in final form, would protect the state's environmentally sensitive areas while realizing the economic development and energy benefits of the state's natural gas resources. Approximately 85 percent of the Marcellus Shale would be accessible to natural gas extraction under these recommendations." DEC Commissioner Joseph Martens noted, "This report strikes the right balance between protecting our environment, watersheds, and drinking water and promoting economic development." The recommendations contain these major revisions:
Look for more information on the DEC’s web site: http://www.dec.ny.gov/energy/46288.html NGA notes that Marcellus Shale development, managed with the greatest care for the environment, will contribute to a "clean energy" path for New York and other producing states, and will create jobs, provide local and state tax benefits, air quality improvements, and diversity and security of supply. For Further Information U.S. EPA Natural Gas STAR Program U.S. Alt Fuels Vehicle Center, Natural Gas Vehicle Emissions U.S. EPA, Greenhouse Gas Emissions FracFocus U.S. Dept. of Energy, Shale Gas Report, August 2011 Pennsylvania Dept. of Environmental Protection, Marcellus Shale page New York Dept. of Environmental Conservation, Marcellus Shale page National Research Council / National Academy of Science, "Hidden Costs" of Energy U.S. EPA Update on NGA Companies and Natural Gas STAR Program Accomplishments [pdf] |
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