Life Cycle Analysis


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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Using Life Cycle Analysis to Inform Energy Policy
NETL uses LCA to understand the environmental burdens of energy systems and to inform policy makers. LCA is well suited for energy analysis, but its answers can change depending on what questions are being asked. NETL approaches all LCAs using a consistent method, which ensures comparability among LCAs. The granularity and flexibility of NETL's models makes it possible to identify key contributors to the environmental burdens of a system, as well as the ability to understand how results can change with changes to a given input parameter. In addition to understanding the attributes of a given energy technology, NETL can also perform consequential modeling that allows an understanding of how a given energy technology can affect the performance of other energy technologies. The effect of enhanced oil recovery (EOR) on conventional crude oil extraction is one example of such consequential analysis. The results of consequential analyses have more uncertainty than those for analyses that focus on the attributes of isolated systems, but the conclusions of consequential analyses provide more context for policy makers.
Authors: Tim Skone, Joe Marriott, James Littlefield
Date: December, 2013

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A Comparative Assessment of CO2 Sequestration through Enhanced Oil Recovery and Saline Aquifer Sequestration
A comparative assessment of CO2 sequestration through enhanced oil recovery and saline aquifer sequestration.
Authors: Tim Skone, Robert Dilmore
Date: July, 2013

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Overview of Energy LCA at NETL
Life Cycle Analysis (LCA) is used to inform and defend NETL's technology programs, provide bases for comparison, and identify opportunities for improvement. NETL uses a 5-stage life cycle approach, beginning with raw material acquistion and ending with product use. Metrics include greenhouse gas emissions, other air emissions, water use, water quality, and resource consumption. Uncertainty is quantified for all results produced by NETL's LCA program. NETL's LCA program has made data and modeling tools available to the public.
Authors: Tim Skone
Date: September, 2012

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Modeling the Uncertainty of Fischer-Tropsch Jet Fuel Life Cycle Inventories with Monte Carlo Situation
NETL used Monte Carlo simulation to model the uncertainty in a life cycle inventory that included 6 pathways for the production of Fischer-Tropsch jet fuel. While the inventory is dominated by carbon dioxide emissions from the combustion of the fuel, small changes to the feedstocks can move results above or below the baseline for the Energy Independence and Security Act of 2007. All scenarios have the potential to have life cycle greenhouse gas emissions less than or equal to the life cycle emissions from conventional jet fuel based on uncertainty analysis of the results.
Authors: Tim Skone, Greg Cooney
Date: September, 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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From Unit Processes to Completed LCAs: NETL LCA Library
NETL's unit process library holds over 300 unit processes that allow cradle-to-grave analyses of energy systems. It includes gate-to-gate unit processes as well as "rolled up" unit processes that provide cradle-to-gate inventory results. In addition to the unit process database, NETL has also developed publicly available tools that allow calculation of life cycle results.
Authors: Tim Skone
Date: September, 2012

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Exploring Economics and Environmental Performance: Power Systems LCA Tool
The Power LCAT tool shows environmental and cost results for NETL's LCA's of power systems, including fossil and wind power. In addition to reporting results for costs and emissions, it allows trade-off analysis between costs and emissions. It also allows the user to evaluate the sensitivity of results to changes in key parameters.
Authors: Tim Skone
Date: September, 2012

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Contribution of Biomass to the LCI of Cofiring Power
Biomass includes agricultural residues, forest thinnings, and dedicated energy crops. Life cycle greenhouse gas (GHG) emission reductions can be accomplished with coal and biomass co-firing only if biomass is produced with high yield rates and there are miniminal changes to land use. Increasing power plant efficiency or using post-combustion carbon dioxide capture and sequestration can lead to larger GHG reductions than co-firing biomass with coal.
Authors: Tim Skone, Joe Marriott, PhD
Date: September, 2012

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Role of Alternative Energy Sources: Technology Assessment Compilation
NETL has applied a single set of methods for calculating the environmental, cost, and other aspects of seven options for baseload power generation. LCA is used to calculate environmental results, and life cycle boundaries are also applied to cost results. A set of other technical and non-technical criteria are used to gain a broad understanding of the roles of alternative energy sources in the U.S. energy portfolio.
Authors: Robert James, Tim Skone
Date: September, 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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Progress Update: Interagency Workgroup on Life Cycle GHG Emissions of Alternative Aviation Fuels
This presentation covers efforts to examine life cycle greenhouse gas (GHG) emissions of alternative aviation fuels, as led by the U.S. Air Force Research Laboratory with the support of a multi-disciplinary group of federal, industrial, academic institutions. The primary objective of the workgroup is to develop a set of standard guidance on how to evaluate the life cycle GHG footprint of various alternative jet fuel production pathways using a wide-range of feedstock sources. Application of the guidelines can be used by fuel suppliers, military, and commercial airlines to assess the environmental preferability of a specific fuel production pathway when compared to conventional jet fuel. Workgroup activity status and plans for testing on specific case studies are also discussed.
Authors: Tim Skone
Date: February, 2010

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