{
  "id": "R44090",
  "type": "CRS Report",
  "typeId": "REPORTS",
  "number": "R44090",
  "active": true,
  "source": "EveryCRSReport.com",
  "versions": [
    {
      "source": "EveryCRSReport.com",
      "id": 442604,
      "date": "2015-06-26",
      "retrieved": "2016-04-06T18:52:15.564350",
      "title": "Life-Cycle Greenhouse Gas Assessment of Coal and Natural Gas in the Power Sector",
      "summary": "Recent expansion in natural gas production has made the resource an increasingly significant component in the U.S. energy market. Further, a number of policies recently proposed and/or promulgated at the federal, state, and local levels may serve to accelerate this development. Examples of federal policies include U.S. Environmental Protection Agency air standards for power plants and vehicles, as well as bills introduced in the 114th Congress to promote increased natural gas production on federal lands, amend provisions in the tax code to incentivize natural gas production and use, and streamline the approval, permitting, and/or construction of natural gas infrastructure. Many of these proposals promote technology and infrastructure investments that could be significant and long lasting. For this reason, some stakeholders recommend a thorough analysis of the costs and benefits of these proposals as well as a full assessment of the economic and environmental impacts of increased natural gas development. \nFuel-switching strategies from other fossil fuels to natural gas have the potential to impact many segments of the general economy, including jobs, investments, infrastructure, national security, human health, safety, and the environment. A full assessment of the costs and benefits of these strategies would demand an integrated analysis across all issues. Some contend that an important component of this assessment would be a comparative analysis of the various fuels\u2019 greenhouse gas (GHG) emissions. However, reports in the scientific literature and popular press have created some confusion about the climate implications of natural gas. On the one hand, a shift to natural gas is promoted as climate change mitigation because natural gas combustion has a lower carbon dioxide (CO2) emissions intensity than either oil or coal. On the other hand, methane, the primary constituent of natural gas, is itself a more potent GHG than CO2, and some contend that methane leakage from the production, transport, and use of natural gas has the potential to offset the GHG emissions benefits of switching. \nThe net climate impact of replacing other fossil fuels with natural gas depends upon a number of analytic assumptions, including the choice of fuel, end-use sector, equipment, and processes modeled. This report presents a comparative analysis of the potential climate implications of switching from coal to natural gas in the domestic electric power generating sector. The findings include the following:\nNatural gas, when combusted at different types of existing U.S. power plants, produces anywhere from 42% to 63% of the CO2 emissions of coal, depending upon the power plant technology.\nHowever, in order to more fully assess the climate impacts of a fuel employed in the power sector, analyses aim to aggregate emissions across the entire supply and utilization chain (i.e., from extraction to end use). Such analyses are referred to as life-cycle assessments (LCAs).\nDue to its potency as a GHG, methane lost to the atmosphere during the production and transport of fossil fuels (i.e., fugitive emissions) can greatly impact the life-cycle GHG emissions estimates for power generation. The Department of Energy currently estimates a fugitive emissions rate (FER) of around 1% in natural gas systems; a number of academic studies estimate rates in the range of 2%-4%.\nFurther, due to its chemical composition, methane\u2019s climate impacts are significantly more pronounced in the short term as compared to the long term. \nThus, when considering existing power plants, the average natural-gas-fired combined cycle technology produces approximately 50% of the life-cycle GHG emissions of coal-fired steam generation, both in the short and the long terms, given a FER of around 1%.\nHowever, when considering other existing natural-gas-fired technologies (e.g. single cycle) or advanced technologies, the comparative life-cycle emissions benefits of natural gas are reduced.\nFurther, when considering the possibility of higher FERs (e.g., 2%-4%), the life-cycle GHG emissions of both existing and advanced natural-gas-fired technology may be comparable to coal-fired technology in the short term and could remain within range of coal-fired technology for several decades after emissions.",
      "type": "CRS Report",
      "typeId": "REPORTS",
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      "topics": [
        {
          "source": "IBCList",
          "id": 2913,
          "name": "Electric Power Sector"
        },
        {
          "source": "IBCList",
          "id": 3878,
          "name": "Climate Change Science, Technology, and Policy"
        }
      ]
    }
  ],
  "topics": []
}