Life Cycle Analysis

Natural Gas

Natural gas is a fossil fuel that is used in residential, industrial, and transportation applications in addition to an expanding role in power production. Domestic sources of natural gas include onshore and offshore conventional wells with a wide range of production rates. Other domestic sources of natural gas include unconventional wells that use technologies that stimulate the reservoir to enhance natural gas recovery.


Life cycle GHG Footprint of a U.S. Energy Export Market for Coal and Natural Gas
This presentation was given at the LCA XIV Conference and shows that the majority of life cycle GHG emissions come from power plants; even the LNG export scenarios, which lose approximately 10% of transported natural gas to parasitic loads, have lower life cycle GHG emissions than the coal scenarios.
Authors: Timothy J. Skone, PE, James Littlefield, Joe Marriott, Greg Cooney, Greg Schivley
Date: December, 2014

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Understanding the Importance of Leakage Rates to the GHG Footprint of Natural Gas Production
This presentation was given at the LCA XIV Conference. It further examines the boundary assumptions behind recent methane leakage studies, and then provides details behind a life cycle model that can be used to reconcile inconsistent boundary choices and inform critical policy questions regarding future use of fossil fuels.
Authors: Timothy J. Skone, PE, James Littlefield, Joe Marriott, Greg Cooney, Greg Schivley
Date: December, 2014

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Value of LCA and its Applicability to Natural Gas Analysis
This presentation discusses the value of an LCA perspective on natural gas with a focus on upstream natural gas. It also discusses the current natural gas research.
Authors: James Littlefield, Joe Marriott, Timothy J. Skone
Date: June, 2014

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LCA GHG Report (LNG Report)
This analysis calculates the life cycle greenhouse gas (GHG) emissions from imported natural gas and regional coal used by power plants in Europe and Asia. Liquefied natural gas (LNG) exported from the U.S. and combusted by power plants in Europe or Asia was compared to regional coal combusted by power plants in Europe and Asia. This analysis also calculates the GHG emissions from natural gas that is extracted in Russia and delivered by pipeline to European and Asian power plants. This analysis is based on data that were originally developed to represent U.S. energy systems. Foreign natural gas and coal production were modeled as representative of U.S. natural gas production and average U.S. coal production. The results show that the use of U.S. LNG exports for power production in European and Asian markets will not increase GHG emissions, on a life cycle perspective, when compared to regional coal extraction and consumption for power production. This analysis is based on data that were originally developed to represent U.S. energy systems. 
Authors: Tim Skone
Date: May, 2014

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Natural Gas and Power LCA Model Documentation (NG Report)
Natural gas is considered a cleaner burning and more flexible alternative to other fossil fuels today. It is used in residential, commercial, industrial, and transportation applications in addition to having an expanding role in power production. However, the primary component of natural gas is methane, which is also a powerful greenhouse gas (GHG). Methane losses from natural gas extraction vary geographically and by extraction technology. This analysis expands upon previous life cycle analyses (LCA) of natural gas power generation technologies performed by the National Energy Technology Laboratory (NETL). It inventories the GHG emissions from extraction, processing, and transmission of natural gas to large end users, and the combustion of that natural gas to produce electricity. It includes scenarios for the 2010 average natural gas production mix as well as for natural gas produced from the next highly productive well for each source of natural gas. This context allows an analysis of what the emissions are currently and what they could be in the future. In addition to GHG emissions, this analysis inventories other air emissions, water quality, water use, land use, and resource energy metrics.

Authors: Tim Skone
Date: May, 2014

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Life Cycle Analysis at the National Energy Technology Laboratory
This is a summary of the Life Cycle Analysis capabilities at NETL. It compares two technology options and evaluating the impact of a policy on an entire system. Boundaries and functions considered are coal and natural gas. It discusses how LCA is beneficial for energy analysis because it draws a more complete picture, allows direct comparison of different options, includes methods for evaluating emissions and impacts, and brings clarity to results.
Authors: Tim Skone
Date: April, 2014

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Understanding the Life Cycle Environmental Footprint of the Natural Gas Value Chain
This is a presentation given to the North Association of Regulatory Utility Commissioners (NARUC), Gas Subcommittee meeting on February 9, 2014. The agenda includes the importance of understanding methane emissions from the natural gas sector, the Department of Energy Office's role in reducing methane emissions from the natural gas value chain, a primer on life cycle analysis, and understanding the life cycle environmental footprint of the natural gas value chain.
Authors: Tim Skone, Joe Marriott, James Littlefield
Date: February, 2014

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LCA and the U.S. Natural Gas Resource
From a life cycle perspective, baseload power is NETL's preferred basis for comparing energy sources. For fossil energy systems, the emissions from power plants account for the majority of greenhouse gas (GHG) emissions. However, focusing on the activities that precede the power plant is still necessary in order to identify near-term opportunities for GHG emission reductions. NETL's upstream natural gas model allows detailed modeling of the extraction, processing, and pipeline transmission of natural gas. This model can identify key contributors to the GHG emissions from the natural gas supply chain, and has parameters that can be used to assess opportunities for reducing GHG emissions. The model shows that current domestic natural gas extraction, processing, and pipeline technologies leak 1.2% of the methane that is extracted at the wellhead. Improved practices, such as those in the latest New Source Performance Standards (NSPS), can reduce this upstream methane leakage rate. From a life cycle perspective (1 MWh of delivered electricity), power production from natural gas has lower GHG emissions than power produced from coal. There are several methods and technology combinations that can be used for determining how high the upstream natural gas methane leakage rate has to be in order for the life cycle GHG emissions from natural gas power to equal those from coal power. Ongoing research is developing data that will improve the accuracy of NETL's upstream natural gas model.
Authors: Tim Skone, Joe Marriott, James Littlefield
Date: December, 2013

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Improved Natural Gas Extraction as a Strategy for Reducing Climate Impacts of Transportation
This presentation discusses a gas-to-liquids (GTL) system that nominally produces 50,000 bbl/day of fuels fungible in the refined product infrastructure without further refining steps. The system produces 15,500 bbl/day of finished motor gasoline, and 34,500 bbl/day of low-density diesel fuel. The life cycle greenhouse gas (GHG) emissions for GTL diesel and gasoline, when based on current practices in the natural gas industry, are 90.6 g CO2e/MJ and 89.4 g CO2e/MJ, respectively. If the natural gas extraction and processing sector complies with New Source Performance Standards (NSPS), the upstream GHG emissions from natural gas are reduced by 23 percent.
Authors: Tim Skone, James Littlefield
Date: October, 2013

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Analysis of Natural Gas-to-Liquid Transportation Fuels via Fischer-Tropsch
This study models a gas-to-liquids (GTL) system that nominally produces 50,000 bbl/day of fuels fungible in the refined product infrastructure without further refining steps. Specifically, the system produces 15,500 bbl/day of finished motor gasoline, and 34,500 bbl/day of low-density diesel fuel. The study provides an updated evaluation of cost, technical, and environmental performance. With an estimated total as-spent capital cost of 4.3 billion dollars (3.7 – 5.6 billion dollars) or $86,188 ($73,260 - $112,045) per bbl of daily production of Fischer-Tropsch liquids, such a facility would be commercially viable should the market conditions (liquid fuel and natural gas prices) remain as favorable or better throughout the life of the project than during the middle of May 2013. The life cycle greenhouse gas (GHG) emissions for GTL diesel and gasoline when based on current practices in the natural gas industry are 90.6 g CO2e/MJ and 89.4 g CO2e/MJ, respectively. If the natural gas extraction and processing sector complies with New Source Performance Standards (NSPS), the upstream GHG emissions from natural gas are reduced by 23 percent. The key challenges of GTL are the risk associated with varying gas and product prices, the lack of sustained effort in its development, and its high capital costs. A robust research and development program, besides driving capital cost reductions, can serve the role of sustaining the deep knowledge base in GTL.
Authors: , Jesse Goellner
Date: September, 2013

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Life Cycle Analysis: Natural Gas Combined Cycle (NGCC) Power Plant
Life cycle analysis of a natural gas combined cycle (NGCC) plant. Develops an inventory of emissions results, and calculates life cycle costs for the plant with and without CCS.
Authors: Tim Skone, Robert James
Date: June, 2013

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Unconventional Natural Gas: An LCA with a Conventional Answer
LCA of a Natural Gas Combined Cycle plant. Develops an Inventory of emissions results, and calculates Life Cycle costs for the plant with and without CCS.
Authors: Tim Skone, James Littlefield, Joe Marriott, PhD
Date: October, 2012

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Life Cycle Greenhouse Gas Inventory Sensitivity to Changes in Natural Gas System Parameters
This presentation focuses on the greenhouse gases from the extraction, processing, and delivery of natural gas and the key variables that affect the results. It includes eight distinct sources of natural gas and performs a number of sensitivity studies. The production rate of natural gas wells, episodic emission factors and the flaring rate have the most impact on the cradle-to-gate emissions profile, while power plant heat rate or efficiency most affects the cradle-to-grave emissions. New Source Performance Standards have recently focused on the oil and gas sector and could be effective at reducing the upstream emissions from natural gas systems.
Authors: Tim Skone
Date: September, 2012

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Role of Alternative Energy Sources: Natural Gas Technology Assessment
Natural gas is seen as a cleaner burning and flexible alternative to other fossil fuels, and is used in residential, industrial, and transportation applications in addition to an expanding role in power production. New technologies have allowed increased domestic production of natural gas. The projected supply contributions afforded by new natural gas plays may keep the price of natural gas relatively low for the foreseeable future. Since natural gas is comprised mostly of methane, the control of fugitive emissions is imperative to reduce the greenhouse gas footprint of natural gas.
Authors: Tim Skone, James Littlefield, Robert Eckard, Greg Cooney, Joe Marriott, PhD
Date: June, 2012

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LCA of Natural Gas Extraction, Delivery and Electricity Production
This is a life cycle inventory of greenhouse gases from natural gas power systems. The average greenhouse gas (GHG) emissions from natural gas power are 527 kg of carbon dioxide equivalents per MWh of delivered electricity.  Data uncertainty include emission factors for natural gas extraction, natural gas pipeline parameters, and well production rates. Opportunities for reducing GHG emissions from natural gas extraction and delivery include better practices for unconventional gas well completions, improved compressor efficiency, and reduced pipeline fugitive emissions.
Authors: Tim Skone, Joe Marriott, PhD, James Littlefield
Date: January, 2012

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Life Cycle Greenhouse Gas Inventory of Natural Gas Extraction, Delivery, and Electricity Production
This greenhouse gas (GHG) analysis inventories six different sources of natural gas, including three types of unconventional gas, combines them into a domestic mix, and then compares the inventory on both a delivered feedstock and delivered electricity basis to a similar domestic mix of coal. On a delivered power basis, natural gas has lower GHG emissions that coal. With methane comprising 75-to-95 percent of the composition of natural gas, there are many opportunities for reducing the climate change impact associated with direct venting of natural gas.
Authors: Tim Skone, James Littlefield and Joe Marriott, PhD
Date: October, 2011

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Life Cycle Greenhouse Gas Analysis of Natural Gas Extraction and Delivery in the United States
On May 12, 2011, NETL provided the following presentation at the Cornell University lecture series on unconventional natural gas development. The presentation summarizes the life cycle analysis (LCA) greenhouse gas (GHG) research on natural gas extraction and delivery in the United States (on a lb CO2e/MMBtu basis) and a comparison of the life cycle GHG profiles of average natural gas and coal-fired power production and delivery to an end-user (lb CO2e/MWh basis). Specifically, the presentation details seven natural gas profiles: onshore conventional gas, associated gas, offshore gas, tight sands (gas), shale gas (based on Barnett Shale), coal bed methane gas, and the year 2009 domestic average mix. Each natural gas source is upgraded in a gas processing plant, compressed, and delivered to a large end-user (e.g., power plant).
Authors: Tim Skone, Joe Marriott, PhD, James Littlefield
Date: May, 2011

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LCA of Greenhouse Gas Emissions for Hydrogen Fuel Production in the USA from LNG and Coal
This is a LCA (LCA) that accounts for the greenhouse gas (GHG) emissions from the production of hydrogen from liquefied natural gas (LNG) via steam methane reforming (SMR) or from coal gasification. Carbon capture and sequestration (CCS) is one option for managing carbon dioxide emissions from hydrogen production.  By employing a CCS system with a 92 percent capture rate at an SMR plant, the life cycle GHG emissions from hydrogen production from LNG are reduced by 64 percent. Gasification of coal is another pathway to hydrogen production, but the GHG emissions are highly variable due to coal mine methane (CMM) emissions. Mitigation of CMM is a key opportunity for improving GHG emissions from the the coal-to-hydrogen pathway.
Authors: Eric Grol, Massood Ramezan, John Ruether
Date: November, 2005

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