I am interested in reducing the environmental impacts of energy systems. More specifically, I focus on understanding, measuring, and reducing greenhouse gas (GHG) emissions from fossil energy sources. Reducing GHG emissions from fossil fuels is important because fossil energy sources will continue to be key components of our energy system for decades to come.

My research in this area uses the tools of life cycle assessment (LCA) and process optimization to measure and estimate impacts from technologies at broad scales (LCA) and to help reduce these impacts (optimization). Applications include reducing GHG emissions from transportation energy supply and from power systems through CCS.

Through my teaching, I aim to help train the next generation of energy professionals to: optimize energy systems so as to improve their efficiency; rigorously account for the environmental impacts of energy sources; and think critically about systems-scale phenomena in energy production and consumption

Academic Appointments

Administrative Appointments

  • Acting Assistant Professor, Department of Energy Resources Engineering, Stanford University (2009 - 2012)
  • Assistant Professor, Department of Energy Resources Engineering, Stanford University (2012 - Present)

Honors & Awards

  • Student paper award, United States Association for Energy Economics (2006)

Boards, Advisory Committees, Professional Organizations

  • Science Advisory Panel, Methane Reconciliation Project, National Renewable Energy Laboratory (2015 - Present)
  • Technical steering committee, Independent Review of Well Stimulation, California Council on Science and Technology. (2013 - Present)
  • Organizing committee, Connecting the Dots: The Energy, Water, Food, Climate Nexus (2013 - 2014)
  • Selection committee, Stanford Interdisciplinary Graduate Fellowship (2012 - 2014)
  • Team leader, Technical review of natural gas leakage, NOVIM (2012 - 2013)
  • Invited speaker:, CERA Week 2012, Houston TX, March 6th, 2012 (2012 - 2012)
  • Invited speaker: EES seminar. November 28th, 2012, University of Calgary, Institute for sustainable energy, environment and economy (ISEEE) (2012 - 2012)
  • Technical advisor, California Environmental Protection Agency, Air Resources Board (CARB) - Low Carbon Fuel Standard regulatory proceedings (2011 - Present)
  • Expert testimony, European Commission, Directorate General - Climate. May 27, 2011. (2011 - 2011)
  • Invited speaker, Workshop on Low Carbon Fuel Standards, Victoria, BC, October 12th-13th 2011 (2011 - 2011)
  • Invited speaker, CRC Workshop on life cycle analysis of biofuels. Argonne National Laboratory, October 17th, 2011 (2011 - 2011)
  • Invited speaker, Center for European Policy Studies, Brussels, Belgium. March 21st, 2011 (2011 - 2011)
  • Technical advisor, European Union, DG Climate - Fuel Quality Directive regulatory proceedings (2010 - 2011)
  • Invited Speaker, SLAC National Accelerator Laboratory, February 1st, 2010 (2010 - 2010)
  • Search committee, GCEP post-doctoral scholars (2010 - 2010)
  • Invited Speaker, Energy, Environment and Society Speaker Series, Humboldt State University, CA, April 2009 (2009 - 2009)
  • Invited Speaker, Stanford University, Stanford Energy Seminar, September 23rd, 2009 (2009 - 2009)
  • Invited Speaker, Department of Energy Resources Engineering, Stanford University, CA, December 2007 (2007 - 2007)

Professional Education

  • Ph.D., University of California, Berkeley, Energy and Resources (2008)
  • M.S., University of California, Berkeley, Energy and Resources (2005)
  • B.S., University of California, Santa Barbara, Environmental Studies, emphasis Physics (2003)

Current Research and Scholarly Interests

I am interested in reducing the environmental impacts of energy systems. More specifically, I focus on understanding, measuring, and reducing greenhouse gas (GHG) emissions from fossil energy sources. Reducing GHG emissions from fossil fuels is important because fossil energy sources will continue to be key components of our energy system for decades to come.

My research in this area uses the tools of life cycle assessment (LCA) and process optimization to measure and estimate impacts from technologies at broad scales (LCA) and to help reduce these impacts (optimization). Applications include reducing GHG emissions from transportation energy supply and from power systems through CCS.

Through my teaching, I aim to help train the next generation of energy professionals to: optimize energy systems so as to improve their efficiency; rigorously account for the environmental impacts of energy sources; and think critically about systems-scale phenomena in energy production and consumption

2017-18 Courses

Stanford Advisees

All Publications

  • Methane, Black Carbon, and Ethane Emissions from Natural Gas Flares in the Bakken Shale, North Dakota ENVIRONMENTAL SCIENCE & TECHNOLOGY Gvakharia, A., Kort, E. A., Brandt, A., Peischl, J., Ryerson, T. B., Schwarz, J. P., Smith, M. L., Sweeney, C. 2017; 51 (9): 5317-5325


    Incomplete combustion during flaring can lead to production of black carbon (BC) and loss of methane and other pollutants to the atmosphere, impacting climate and air quality. However, few studies have measured flare efficiency in a real-world setting. We use airborne data of plume samples from 37 unique flares in the Bakken region of North Dakota in May 2014 to calculate emission factors for BC, methane, ethane, and combustion efficiency for methane and ethane. We find no clear relationship between emission factors and aircraft-level wind speed or between methane and BC emission factors. Observed median combustion efficiencies for methane and ethane are close to expected values for typical flares according to the US EPA (98%). However, we find that the efficiency distribution is skewed, exhibiting log-normal behavior. This suggests incomplete combustion from flares contributes almost 1/5 of the total field emissions of methane and ethane measured in the Bakken shale, more than double the expected value if 98% efficiency was representative. BC emission factors also have a skewed distribution, but we find lower emission values than previous studies. The direct observation for the first time of a heavy-tail emissions distribution from flares suggests the need to consider skewed distributions when assessing flare impacts globally.

    View details for DOI 10.1021/acs.est.6b05183

    View details for Web of Science ID 000400723200063

    View details for PubMedID 28401762

  • When Comparing Alternative Fuel-Vehicle Systems, Life Cycle Assessment Studies Should Consider Trends in Oil Production JOURNAL OF INDUSTRIAL ECOLOGY Wallington, T. J., Anderson, J. E., De Kleine, R. D., Kim, H. C., Maas, H., Brandt, A. R., Keoleian, G. A. 2017; 21 (2): 244-248

    View details for DOI 10.1111/jiec.12418

    View details for Web of Science ID 000399664800002

  • Designing better methane mitigation policies: the challenge of distributed small sources in the natural gas sector ENVIRONMENTAL RESEARCH LETTERS Ravikumar, A. P., Brandt, A. R. 2017; 12 (4)
  • Energy Intensity and Greenhouse Gas Emissions from Oil Production in the Eagle Ford Shale ENERGY & FUELS Yeh, S., Ghandi, A., Scanlon, B. R., Brandt, A. R., Cai, H., Wang, M. Q., Vafi, K., Reedy, R. C. 2017; 31 (2): 1440-1449
  • Updating the US Life Cycle GHG Petroleum Baseline to 2014 with Projections to 2040 Using Open-Source Engineering-Based Models ENVIRONMENTAL SCIENCE & TECHNOLOGY Cooney, G., Jamieson, M., Marriott, J., Bergerson, J., Brandt, A., Skone, T. J. 2017; 51 (2): 977-987


    The National Energy Technology Laboratory produced a well-to-wheels (WTW) life cycle greenhouse gas analysis of petroleum-based fuels consumed in the U.S. in 2005, known as the NETL 2005 Petroleum Baseline. This study uses a set of engineering-based, open-source models combined with publicly available data to calculate baseline results for 2014. An increase between the 2005 baseline and the 2014 results presented here (e.g., 92.4 vs 96.2 g CO2e/MJ gasoline, + 4.1%) are due to changes both in modeling platform and in the U.S. petroleum sector. An updated result for 2005 was calculated to minimize the effect of the change in modeling platform, and emissions for gasoline in 2014 were about 2% lower than in 2005 (98.1 vs 96.2 g CO2e/MJ gasoline). The same methods were utilized to forecast emissions from fuels out to 2040, indicating maximum changes from the 2014 gasoline result between +2.1% and -1.4%. The changing baseline values lead to potential compliance challenges with frameworks such as the Energy Independence and Security Act (EISA) Section 526, which states that Federal agencies should not purchase alternative fuels unless their life cycle GHG emissions are less than those of conventionally produced, petroleum-derived fuels.

    View details for DOI 10.1021/acs.est.6b02819

    View details for Web of Science ID 000392457700029

    View details for PubMedID 28092937

  • Are Optical Gas Imaging Technologies Effective For Methane Leak Detection? ENVIRONMENTAL SCIENCE & TECHNOLOGY Ravikumar, A. P., Wang, J., Brandt, A. R. 2017; 51 (1): 718-724


    Concerns over mitigating methane leakage from the natural gas system have become ever more prominent in recent years. Recently, the U.S. Environmental Protection Agency proposed regulations requiring use of optical gas imaging (OGI) technologies to identify and repair leaks. In this work, we develop an open-source predictive model to accurately simulate the most common OGI technology, passive infrared (IR) imaging. The model accurately reproduces IR images of controlled methane release field experiments as well as reported minimum detection limits. We show that imaging distance is the most important parameter affecting IR detection effectiveness. In a simulated well-site, over 80% of emissions can be detected from an imaging distance of 10 m. Also, the presence of "superemitters" greatly enhance the effectiveness of IR leak detection. The minimum detectable limits of this technology can be used to selectively target "superemitters", thereby providing a method for approximate leak-rate quantification. In addition, model results show that imaging backdrop controls IR imaging effectiveness: land-based detection against sky or low-emissivity backgrounds have higher detection efficiency compared to aerial measurements. Finally, we show that minimum IR detection thresholds can be significantly lower for gas compositions that include a significant fraction nonmethane hydrocarbons.

    View details for DOI 10.1021/acs.est.6b03906

    View details for Web of Science ID 000391346900079

    View details for PubMedID 27936621

  • Estimating decades-long trends in petroleum field energy return on investment (EROI) with an engineering-based model. PloS one Tripathi, V. S., Brandt, A. R. 2017; 12 (2)


    This paper estimates changes in the energy return on investment (EROI) for five large petroleum fields over time using the Oil Production Greenhouse Gas Emissions Estimator (OPGEE). The modeled fields include Cantarell (Mexico), Forties (U.K.), Midway-Sunset (U.S.), Prudhoe Bay (U.S.), and Wilmington (U.S.). Data on field properties and production/processing parameters were obtained from a combination of government and technical literature sources. Key areas of uncertainty include details of the oil and gas surface processing schemes. We aim to explore how long-term trends in depletion at major petroleum fields change the effective energetic productivity of petroleum extraction. Four EROI ratios are estimated for each field as follows: The net energy ratio (NER) and external energy ratio (EER) are calculated, each using two measures of energy outputs, (1) oil-only and (2) all energy outputs. In all cases, engineering estimates of inputs are used rather than expenditure-based estimates (including off-site indirect energy use and embodied energy). All fields display significant declines in NER over the modeling period driven by a combination of (1) reduced petroleum production and (2) increased energy expenditures on recovery methods such as the injection of water, steam, or gas. The fields studied had NER reductions ranging from 46% to 88% over the modeling periods (accounting for all energy outputs). The reasons for declines in EROI differ by field. Midway-Sunset experienced a 5-fold increase in steam injected per barrel of oil produced. In contrast, Prudhoe Bay has experienced nearly a 30-fold increase in amount of gas processed and reinjected per unit of oil produced. In contrast, EER estimates are subject to greater variability and uncertainty due to the relatively small magnitude of external energy investments in most cases.

    View details for DOI 10.1371/journal.pone.0171083

    View details for PubMedID 28178318

    View details for PubMedCentralID PMC5298284

  • Potential solar energy use in the global petroleum sector ENERGY Wang, J., O'Donnell, J., Brandt, A. R. 2017; 118: 884-892
  • Methane Leaks from Natural Gas Systems Follow Extreme Distributions ENVIRONMENTAL SCIENCE & TECHNOLOGY Brandt, A. R., Heath, G. A., Cooley, D. 2016; 50 (22): 12512-12520


    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ∼15 000 measurements from 18 prior studies, we show that all available natural gas leakage data sets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the total leakage volume. While prior studies used log-normal model distributions, we show that log-normal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of data sets to increase sample size is not recommended due to apparent deviation between sampled populations. Understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.

    View details for DOI 10.1021/acs.est.6b04303

    View details for Web of Science ID 000388155000051

    View details for PubMedID 27740745

  • Energy Intensity and Greenhouse Gas Emissions from Tight Oil Production in the Bakken Formation ENERGY & FUELS Brandt, A. R., Yeskoo, T., McNally, M. S., Vafi, K., Yeh, S., Cai, H., Wang, M. Q. 2016; 30 (11): 9613-9621
  • Assessment of advanced solvent-based post-combustion CO2 capture processes using a bi-objective optimization technique APPLIED ENERGY Kang, C. A., Brandt, A. R., Durlofsky, L. J., Jayaweera, I. 2016; 179: 1209-1219
  • Improved exergetic life cycle assessment through matrix reduction technique INTERNATIONAL JOURNAL OF LIFE CYCLE ASSESSMENT Smith, S. S., Calbry-Muzyka, A., Brandt, A. R. 2016; 21 (10): 1379-1390
  • GHGfrack: An Open-Source Model for Estimating Greenhouse Gas Emissions from Combustion of Fuel during Drilling and Hydraulic Fracturing. Environmental science & technology Vafi, K., Brandt, A. 2016; 50 (14): 7913-7920


    This paper introduces GHGfrack, an open-source engineering-based model that estimates energy consumption and associated GHG emissions from drilling and hydraulic fracturing operations. We describe verification and calibration of GHGfrack against field data for energy and fuel consumption. We run GHGfrack using data from 6927 wells in Eagle Ford and 4431 wells in Bakken oil fields. The average estimated energy consumption in Eagle Ford wells using lateral hole diameters of 8 (3)/4 and 6 (1)/8 in. are 2.25 and 2.73 TJ/well, respectively. The average estimated energy consumption in Bakken wells using hole diameters of 6 in. for horizontal section is 2.16 TJ/well. We estimate average greenhouse gas (GHG) emissions of 419 and 510 tonne of equivalent CO2 per well (tonne of CO2 eq/well) for the two aforementioned assumed geometries in Eagle Ford, respectively, and 417 tonne of CO2 eq/well for the case of Bakken. These estimates are limited only to GHG emissions from combustion of diesel fuel to supply energy only for rotation of drill string, drilling mud circulation, and fracturing pumps. Sensitivity analysis of the model shows that the top three key variables in driving energy intensity in drilling are the lateral hole diameter, drill pipe internal diameter, and mud flow rate. In hydraulic fracturing, the top three are lateral casing diameter, fracturing fluid volume, and length of the lateral.

    View details for DOI 10.1021/acs.est.6b01940

    View details for PubMedID 27341087

  • Aerial Surveys of Elevated Hydrocarbon Emissions from Oil and Gas Production Sites ENVIRONMENTAL SCIENCE & TECHNOLOGY Lyon, D. R., Alvarez, R. A., Zavala-Araiza, D., Brandt, A. R., Jackson, R. B., Hamburg, S. P. 2016; 50 (9): 4877-4886


    Oil and gas (O&G) well pads with high hydrocarbon emission rates may disproportionally contribute to total methane and volatile organic compound (VOC) emissions from the production sector. In turn, these emissions may be missing from most bottom-up emission inventories. We performed helicopter-based infrared camera surveys of more than 8000 O&G well pads in seven U.S. basins to assess the prevalence and distribution of high-emitting hydrocarbon sources (detection threshold ∼ 1-3 g s(-1)). The proportion of sites with such high-emitting sources was 4% nationally but ranged from 1% in the Powder River (Wyoming) to 14% in the Bakken (North Dakota). Emissions were observed three times more frequently at sites in the oil-producing Bakken and oil-producing regions of mixed basins (p < 0.0001, χ(2) test). However, statistical models using basin and well pad characteristics explained 14% or less of the variance in observed emission patterns, indicating that stochastic processes dominate the occurrence of high emissions at individual sites. Over 90% of almost 500 detected sources were from tank vents and hatches. Although tank emissions may be partially attributable to flash gas, observed frequencies in most basins exceed those expected if emissions were effectively captured and controlled, demonstrating that tank emission control systems commonly underperform. Tanks represent a key mitigation opportunity for reducing methane and VOC emissions.

    View details for DOI 10.1021/acs.est.6b00705

    View details for Web of Science ID 000375521400033

    View details for PubMedID 27045743

  • A new carbon capture proxy model for optimizing the design and time-varying operation of a coal-natural gas power station INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Kang, C. A., Brandt, A. R., Durlofsky, L. J. 2016; 48: 234-252
  • Comparing Natural Gas Leakage Detection Technologies Using an Open-Source "Virtual Gas Field" Simulator ENVIRONMENTAL SCIENCE & TECHNOLOGY Kemp, C. E., Ravikumar, A. P., Brandt, A. R. 2016; 50 (8): 4546-4553


    We present a tool for modeling the performance of methane leak detection and repair programs that can be used to evaluate the effectiveness of detection technologies and proposed mitigation policies. The tool uses a two-state Markov model to simulate the evolution of methane leakage from an artificial natural gas field. Leaks are created stochastically, drawing from the current understanding of the frequency and size distributions at production facilities. Various leak detection and repair programs can be simulated to determine the rate at which each would identify and repair leaks. Integrating the methane leakage over time enables a meaningful comparison between technologies, using both economic and environmental metrics. We simulate four existing or proposed detection technologies: flame ionization detection, manual infrared camera, automated infrared drone, and distributed detectors. Comparing these four technologies, we found that over 80% of simulated leakage could be mitigated with a positive net present value, although the maximum benefit is realized by selectively targeting larger leaks. Our results show that low-cost leak detection programs can rely on high-cost technology, as long as it is applied in a way that allows for rapid detection of large leaks. Any strategy to reduce leakage should require a careful consideration of the differences between low-cost technologies and low-cost programs.

    View details for DOI 10.1021/acs.est.5b06068

    View details for Web of Science ID 000374707100045

    View details for PubMedID 27007771

  • Energy Return on Investment (EROI) for Forty Global Oilfields Using a Detailed Engineering-Based Model of Oil Production PLOS ONE Brandt, A. R., Sun, Y., Bharadwaj, S., Livingston, D., Tan, E., Gordon, D. 2015; 10 (12)

    View details for DOI 10.1371/journal.pone.0144141

    View details for Web of Science ID 000367092500002

    View details for PubMedID 26695068

  • Net energy analysis of Bakken crude oil production using a well-level engineering-based model ENERGY Brandt, A. R., Yeskoo, T., Vafi, K. 2015; 93: 2191-2198
  • Embodied Energy and GHG Emissions from Material Use in Conventional and Unconventional Oil and Gas Operations ENVIRONMENTAL SCIENCE & TECHNOLOGY Brandt, A. R. 2015; 49 (21): 13059-13066

    View details for DOI 10.1021/acs.est.5b03540

    View details for Web of Science ID 000364355300052

    View details for PubMedID 26421352

  • Oil Sands Energy Intensity Assessment Using Facility-Level Data ENERGY & FUELS Englander, J. G., Brandt, A. R., Elgowainy, A., Cai, H., Han, J., Yeh, S., Wang, M. Q. 2015; 29 (8): 5204-5212
  • Well-to-Wheels Greenhouse Gas Emissions of Canadian Oil Sands Products: Implications for US Petroleum Fuels ENVIRONMENTAL SCIENCE & TECHNOLOGY Cai, H., Brandt, A. R., Yeh, S., Englander, J. G., Han, J., Elgowainy, A., Wang, M. Q. 2015; 49 (13): 8219-8227


    Greenhouse gas (GHG) regulations affecting U.S. transportation fuels require holistic examination of the life-cycle emissions of U.S. petroleum feedstocks. With an expanded system boundary that included land disturbance-induced GHG emissions, we estimated well-to-wheels (WTW) GHG emissions of U.S. production of gasoline and diesel sourced from Canadian oil sands. Our analysis was based on detailed characterization of the energy intensities of 27 oil sands projects, representing industrial practices and technological advances since 2008. Four major oil sands production pathways were examined, including bitumen and synthetic crude oil (SCO) from both surface mining and in situ projects. Pathway-average GHG emissions from oil sands extraction, separation, and upgrading ranged from ∼6.1 to ∼27.3 g CO2 equivalents per megajoule (in lower heating value, CO2e/MJ). This range can be compared to ∼4.4 g CO2e/MJ for U.S. conventional crude oil recovery. Depending on the extraction technology and product type output of oil sands projects, the WTW GHG emissions for gasoline and diesel produced from bitumen and SCO in U.S. refineries were in the range of 100-115 and 99-117 g CO2e/MJ, respectively, representing, on average, about 18% and 21% higher emissions than those derived from U.S. conventional crudes. WTW GHG emissions of gasoline and diesel derived from diluted bitumen ranged from 97 to 103 and 96 to 104 g CO2e/MJ, respectively, showing the effect of diluent use on fuel emissions.

    View details for DOI 10.1021/acs.est.5b01255

    View details for Web of Science ID 000357840300086

  • Uncertainty in Regional-Average Petroleum GHG Intensities: Countering Information Gaps with Targeted Data Gathering. Environmental science & technology Brandt, A. R., Sun, Y., Vafi, K. 2015; 49 (1): 679-686


    Recent efforts to model crude oil production GHG emissions are challenged by a lack of data. Missing data can affect the accuracy of oil field carbon intensity (CI) estimates as well as the production-weighted CI of groups ("baskets") of crude oils. Here we use the OPGEE model to study the effect of incomplete information on the CI of crude baskets. We create two different 20 oil field baskets, one of which has typical emissions and one of which has elevated emissions. Dispersion of CI estimates is greatly reduced in baskets compared to single crudes (coefficient of variation = 0.2 for a typical basket when 50% of data is learned at random), and field-level inaccuracy (bias) is removed through compensating errors (bias of ∼5% in above case). If a basket has underlying characteristics significantly different than OPGEE defaults, systematic bias is introduced through use of defaults in place of missing data. Optimal data gathering strategies were found to focus on the largest 50% of fields, and on certain important parameters for each field. Users can avoid bias (reduced to <1 gCO2/MJ in our elevated emissions basket) through strategies that only require gathering ∼10-20% of input data.

    View details for DOI 10.1021/es505376t

    View details for PubMedID 25517046

  • Optimization of carbon-capture-enabled coal-gas-solar power generation ENERGY Brodrick, P. G., Kang, C. A., Brandt, A. R., Durlofsky, L. J. 2015; 79: 149-162
  • Know your oil Gordon, D., Brandt, A. R., Bergerson, J., Koomey, J. Carnegie Endowment for International Peace. 2015
  • Optimization of carbon-capture-enabled coal-gas-solar power generation Energy Brodrick, P. G., Kang, C. A., Brandt, A. R., Durlofsky, L. J. 2015; 79: 149-162
  • Optimizing heat integration in a flexible coal-natural gas power station with CO2 capture INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Kang, C. A., Brandt, A. R., Durlofsky, L. J. 2014; 31: 138-152
  • Reproducibility of LCA Models of Crude Oil Production ENVIRONMENTAL SCIENCE & TECHNOLOGY Vafi, K., Brandt, A. R. 2014; 48 (21): 12978-12985

    View details for DOI 10.1021/es501847p

    View details for Web of Science ID 000344449100060

  • Uncertainty of Oil Field GHG Emissions Resulting from Information Gaps: A Monte Carlo Approach. Environmental science & technology Vafi, K., Brandt, A. R. 2014; 48 (17): 10511-10518


    Regulations on greenhouse gas (GHG) emissions from liquid fuel production generally work with incomplete data about oil production operations. We study the effect of incomplete information on estimates of GHG emissions from oil production operations. Data from California oil fields are used to generate probability distributions for eight oil field parameters previously found to affect GHG emissions. We use Monte Carlo (MC) analysis on three example oil fields to assess the change in uncertainty associated with learning of information. Single factor uncertainties are most sensitive to ignorance about water-oil ratio (WOR) and steam-oil ratio (SOR), resulting in distributions with coefficients of variation (CV) of 0.1-0.9 and 0.5, respectively. Using a combinatorial uncertainty analysis, we find that only a small number of variables need to be learned to greatly improve on the accuracy of MC mean. At most, three pieces of data are required to reduce bias in MC mean to less than 5% (absolute). However, the parameters of key importance in reducing uncertainty depend on oil field characteristics and on the metric of uncertainty applied. Bias in MC mean can remain after multiple pieces of information are learned, if key pieces of information are left unknown.

    View details for DOI 10.1021/es502107s

    View details for PubMedID 25110115

  • Energy and environment. Methane leaks from North American natural gas systems. Science Brandt, A. R., Heath, G. A., Kort, E. A., O'Sullivan, F., Pétron, G., Jordaan, S. M., Tans, P., Wilcox, J., Gopstein, A. M., Arent, D., Wofsy, S., Brown, N. J., Bradley, R., Stucky, G. D., EARDLEY, D., Harriss, R. 2014; 343 (6172): 733-735

    View details for DOI 10.1126/science.1247045

    View details for PubMedID 24531957

  • A better currency for investing in a sustainable future Nature Climate Change Carbajales-Dale, M., Barnhart, C. J., Brandt, A. R., Benson, S. M. 2014; 4 (7): 524-527

    View details for DOI 10.1038/nclimate2285

  • Ensuring benefits from North American shale gas development: Towards a research agenda Journal of Unconventional Oil and Gas Resources Bazilian, M., Brandt, A. R., Billman, L., Heath, G., Logan, J., Mann, M., Melaina, M., Statwick, P., Arent, D., Benson, S. M. 2014; 7: 71–74
  • Oil Sands Energy Intensity Analysis for GREET Model Update Technical Report, Argonne National Laboratory Englander, J. G., Brandt, A. R. 2014
  • Calculating systems-scale energy efficiency and net energy returns: A bottom-up matrix-based approach ENERGY Brandt, A. R., Dale, M., Barnhart, C. J. 2013; 62: 235-247
  • The energetic implications of curtailing versus storing solar- and wind-generated electricity ENERGY & ENVIRONMENTAL SCIENCE Barnhart, C. J., Dale, M., Brandt, A. R., Benson, S. M. 2013; 6 (10): 2804-2810

    View details for DOI 10.1039/c3ee41973h

    View details for Web of Science ID 000325765100002

  • Historical trends in greenhouse gas emissions of the Alberta oil sands (1970-2010) ENVIRONMENTAL RESEARCH LETTERS Englander, J. G., Bharadwaj, S., Brandt, A. R. 2013; 8 (4)
  • Peak oil demand: the role of fuel efficiency and alternative fuels in a global oil production decline. Environmental science & technology Brandt, A. R., Millard-Ball, A., Ganser, M., Gorelick, S. M. 2013; 47 (14): 8031-8041


    Some argue that peak conventional oil production is imminent due to physical resource scarcity. We examine the alternative possibility of reduced oil use due to improved efficiency and oil substitution. Our model uses historical relationships to project future demand for (a) transport services, (b) all liquid fuels, and (c) substitution with alternative energy carriers, including electricity. Results show great increases in passenger and freight transport activity, but less reliance on oil. Demand for liquids inputs to refineries declines significantly after 2070. By 2100 transport energy demand rises >1000% in Asia, while flattening in North America (+23%) and Europe (-20%). Conventional oil demand declines after 2035, and cumulative oil production is 1900 Gbbl from 2010 to 2100 (close to the U.S. Geological Survey median estimate of remaining oil, which only includes projected discoveries through 2025). These results suggest that effort is better spent to determine and influence the trajectory of oil substitution and efficiency improvement rather than to focus on oil resource scarcity. The results also imply that policy makers should not rely on liquid fossil fuel scarcity to constrain damage from climate change. However, there is an unpredictable range of emissions impacts depending on which mix of substitutes for conventional oil gains dominance-oil sands, electricity, coal-to-liquids, or others.

    View details for DOI 10.1021/es401419t

    View details for PubMedID 23697883

  • CO2 Mitigation Potential of Mineral Carbonation with Industrial Alkalinity Sources in the United States. Environmental science & technology Kirchofer, A., Becker, A., Brandt, A., Wilcox, J. 2013; 47 (13): 7548-7554


    The availability of industrial alkalinity sources is investigated to determine their potential for the simultaneous capture and sequestration of CO2 from point-source emissions in the United States. Industrial alkalinity sources investigated include fly ash, cement kiln dust, and iron and steel slag. Their feasibility for mineral carbonation is determined by their relative abundance for CO2 reactivity and their proximity to point-source CO2 emissions. In addition, the available aggregate markets are investigated as possible sinks for mineral carbonation products. We show that in the U.S., industrial alkaline byproducts have the potential to mitigate approximately 7.6 Mt CO2/yr, of which 7.0 Mt CO2/yr are CO2 captured through mineral carbonation and 0.6 Mt CO2/yr are CO2 emissions avoided through reuse as synthetic aggregate (replacing sand and gravel). The emission reductions represent a small share (i.e., 0.1%) of total U.S. CO2 emissions; however, industrial byproducts may represent comparatively low-cost methods for the advancement of mineral carbonation technologies, which may be extended to more abundant yet expensive natural alkalinity sources.

    View details for DOI 10.1021/es4003982

    View details for PubMedID 23738892

  • The energy efficiency of oil sands extraction: Energy return ratios from 1970 to 2010 ENERGY Brandt, A. R., Englander, J., Bharadwaj, S. 2013; 55: 693-702
  • Open-Source LCA Tool for Estimating Greenhouse Gas Emissions from Crude Oil Production Using Field Characteristics. Environmental science & technology El-Houjeiri, H. M., Brandt, A. R., Duffy, J. E. 2013; 47 (11): 5998-6006


    Existing transportation fuel cycle emissions models are either general and calculate nonspecific values of greenhouse gas (GHG) emissions from crude oil production, or are not available for public review and auditing. We have developed the Oil Production Greenhouse Gas Emissions Estimator (OPGEE) to provide open-source, transparent, rigorous GHG assessments for use in scientific assessment, regulatory processes, and analysis of GHG mitigation options by producers. OPGEE uses petroleum engineering fundamentals to model emissions from oil and gas production operations. We introduce OPGEE and explain the methods and assumptions used in its construction. We run OPGEE on a small set of fictional oil fields and explore model sensitivity to selected input parameters. Results show that upstream emissions from petroleum production operations can vary from 3 gCO2/MJ to over 30 gCO2/MJ using realistic ranges of input parameters. Significant drivers of emissions variation are steam injection rates, water handling requirements, and rates of flaring of associated gas.

    View details for DOI 10.1021/es304570m

    View details for PubMedID 23634761

  • Using Infrastructure Optimization to Reduce Greenhouse Gas Emissions from Oil Sands Extraction and Processing ENVIRONMENTAL SCIENCE & TECHNOLOGY Middleton, R. S., Brandt, A. R. 2013; 47 (3): 1735-1744


    The Alberta oil sands are a significant source of oil production and greenhouse gas emissions, and their importance will grow as the region is poised for decades of growth. We present an integrated framework that simultaneously considers economic and engineering decisions for the capture, transport, and storage of oil sands CO(2) emissions. The model optimizes CO(2) management infrastructure at a variety of carbon prices for the oil sands industry. Our study reveals several key findings. We find that the oil sands industry lends itself well to development of CO(2) trunk lines due to geographic coincidence of sources and sinks. This reduces the relative importance of transport costs compared to nonintegrated transport systems. Also, the amount of managed oil sands CO(2) emissions, and therefore the CCS infrastructure, is very sensitive to the carbon price; significant capture and storage occurs only above 110$/tonne CO(2) in our simulations. Deployment of infrastructure is also sensitive to CO(2) capture decisions and technology, particularly the fraction of capturable CO(2) from oil sands upgrading and steam generation facilities. The framework will help stakeholders and policy makers understand how CCS infrastructure, including an extensive pipeline system, can be safely and cost-effectively deployed.

    View details for DOI 10.1021/es3035895

    View details for Web of Science ID 000314675500071

    View details for PubMedID 23276202

  • Historical trends in life-cycle greenhouse gas emissions of Alberta oil sands extraction from 1970 to 2010: Causes and implications for future emissions Environmental Research Letters Englander, J., Brandt, A. R., Bharadwaj, S. 2013; 8 (4): 44036
  • Assessing the Potential of Mineral Carbonation with Industrial Alkalinity Sources in the US International Conference on Greenhouse Gas Technologies (GHGT) Kirchofer, A., Brandt, A., Krevor, S., Prigiobbe, V., Becker, A., Wilcox, J. ELSEVIER SCIENCE BV. 2013: 5858–5869
  • Estimating greenhouse gas (GHG) emissions from oil production operations using detailed field characteristics Environmental Science & Technology El-Houjeiri, H. M., Brandt, A. R. 2013

    View details for DOI 10.1021/es304570m

  • Impact of alkalinity sources on the life-cycle energy efficiency of mineral carbonation technologies ENERGY & ENVIRONMENTAL SCIENCE Kirchofer, A., Brandt, A., Krevor, S., Prigiobbe, V., Wilcox, J. 2012; 5 (9): 8631-8641

    View details for DOI 10.1039/c2ee22180b

    View details for Web of Science ID 000307595000022

  • Variability and Uncertainty in Life Cycle Assessment Models for Greenhouse Gas Emissions from Canadian Oil Sands Production ENVIRONMENTAL SCIENCE & TECHNOLOGY Brandt, A. R. 2012; 46 (2): 1253-1261


    Because of interest in greenhouse gas (GHG) emissions from transportation fuels production, a number of recent life cycle assessment (LCA) studies have calculated GHG emissions from oil sands extraction, upgrading, and refining pathways. The results from these studies vary considerably. This paper reviews factors affecting energy consumption and GHG emissions from oil sands extraction. It then uses publicly available data to analyze the assumptions made in the LCA models to better understand the causes of variability in emissions estimates. It is found that the variation in oil sands GHG estimates is due to a variety of causes. In approximate order of importance, these are scope of modeling and choice of projects analyzed (e.g., specific projects vs industry averages); differences in assumed energy intensities of extraction and upgrading; differences in the fuel mix assumptions; treatment of secondary noncombustion emissions sources, such as venting, flaring, and fugitive emissions; and treatment of ecological emissions sources, such as land-use change-associated emissions. The GHGenius model is recommended as the LCA model that is most congruent with reported industry average data. GHGenius also has the most comprehensive system boundaries. Last, remaining uncertainties and future research needs are discussed.

    View details for DOI 10.1021/es202312p

    View details for Web of Science ID 000299136200087

    View details for PubMedID 22191713

  • Impact of CO2 Emissions Policy and System Configuration on Optimal Operation of an Integrated Fossil-Renewable Energy Park Carbon Management Technologies Conference Kang, C. A., Brandt, A. R., Durlofsky, L. J. 2012
  • Exploring the variation of GHG emissions from conventional oil production using an engineering-based LCA model American Center for Life Cycle Assessment (ACLCA) LCA XII Conference El-Houjeiri, H. M., Brandt, A. R. 2012
  • Optimal heat integration in a coal-natural gas energy park with CO2 capture GHGT-11, the 11th International Conference on Greenhouse Gas Control Technologies Kang, C. A., Brandt, A. R., Durlofsky, L. J. 2012
  • Willingness to Pay for a Climate Backstop: Liquid Fuel Producers and Direct CO2 Air Capture ENERGY JOURNAL Nemet, G. F., Brandt, A. R. 2012; 33 (1): 53-81
  • Optimal operation of an integrated energy system including fossil fuel power generation, CO2 capture and wind ENERGY Kang, C. A., Brandt, A. R., Durlofsky, L. J. 2011; 36 (12): 6806-6820
  • Oil Depletion and the Energy Efficiency of Oil Production: The Case of California SUSTAINABILITY Brandt, A. R. 2011; 3 (10): 1833-1854

    View details for DOI 10.3390/su3101833

    View details for Web of Science ID 000208763700011

  • A General Mathematical Framework for Calculating Systems-Scale Efficiency of Energy Extraction and Conversion: Energy Return on Investment (EROI) and Other Energy Return Ratios ENERGIES Brandt, A. R., Dale, M. 2011; 4 (8): 1211-1245

    View details for DOI 10.3390/en4081211

    View details for Web of Science ID 000294246300008

  • Oil Shale as an Energy Resource in a CO2 Constrained World: The Concept of Electricity Production with in Situ Carbon Capture ENERGY & FUELS Mulchandani, H., Brandt, A. R. 2011; 25 (4): 1633-1641

    View details for DOI 10.1021/ef101714x

    View details for Web of Science ID 000289697700034

  • CO2 Interim Storage: Technical Characteristics and Potential Role in CO2 Market Development 10th International Conference on Greenhouse Gas Control Technologies Farhat, K., Brandt, A., Benson, S. M. ELSEVIER SCIENCE BV. 2011: 2628–2636
  • Land Use Greenhouse Gas Emissions from Conventional Oil Production and Oil Sands ENVIRONMENTAL SCIENCE & TECHNOLOGY Yeh, S., Jordaan, S. M., Brandt, A. R., Turetsky, M. R., Spatari, S., Keith, D. W. 2010; 44 (22): 8766-8772


    Debates surrounding the greenhouse gas (GHG) emissions from land use of biofuels production have created a need to quantify the relative land use GHG intensity of fossil fuels. When contrasting land use GHG intensity of fossil fuel and biofuel production, it is the energy yield that greatly distinguishes the two. Although emissions released from land disturbed by fossil fuels can be comparable or higher than biofuels, the energy yield of oil production is typically 2-3 orders of magnitude higher, (0.33-2.6, 0.61-1.2, and 2.2 5.1 PJ/ha) for conventional oil production, oil sands surface mining, and in situ production, respectively). We found that land use contributes small portions of GHGs to life cycle emissions of California crude and in situ oil sands production ( <0.4% or < 0.4 gCO₂e/MJ crude refinery feedstock) and small to modest portions for Alberta conventional oil (0.1-4% or 0.1-3.4 gCO₂e/MJ) and surface mining of oil sands (0.9-11% or 0.8-10.2 gCO₂e/MJ).Our estimates are based on assumptions aggregated over large spatial and temporal scales and assuming 100% reclamation. Values on finer spatial and temporal scales that are relevant to policy targets need to account for site-specific information, the baseline natural and anthropogenic disturbance.

    View details for DOI 10.1021/es1013278

    View details for Web of Science ID 000284248300064

    View details for PubMedID 20949948

  • The Climate Impacts of Bioenergy Systems Depend on Market and Regulatory Policy Contexts ENVIRONMENTAL SCIENCE & TECHNOLOGY Lemoine, D. M., Plevin, R. J., Cohn, A. S., Jones, A. D., Brandt, A. R., Vergara, S. E., Kammen, D. M. 2010; 44 (19): 7347-7350


    Biomass can help reduce greenhouse gas (GHG) emissions by displacing petroleum in the transportation sector, by displacing fossil-based electricity, and by sequestering atmospheric carbon. Which use mitigates the most emissions depends on market and regulatory contexts outside the scope of attributional life cycle assessments. We show that bioelectricity's advantage over liquid biofuels depends on the GHG intensity of the electricity displaced. Bioelectricity that displaces coal-fired electricity could reduce GHG emissions, but bioelectricity that displaces wind electricity could increase GHG emissions. The electricity displaced depends upon existing infrastructure and policies affecting the electric grid. These findings demonstrate how model assumptions about whether the vehicle fleet and bioenergy use are fixed or free parameters constrain the policy questions an analysis can inform. Our bioenergy life cycle assessment can inform questions about a bioenergy mandate's optimal allocation between liquid fuels and electricity generation, but questions about the optimal level of bioenergy use require analyses with different assumptions about fixed and free parameters.

    View details for DOI 10.1021/es100418p

    View details for Web of Science ID 000282209700029

    View details for PubMedID 20873876

  • Global oil depletion: A review of the evidence ENERGY POLICY Sorrell, S., Speirs, J., Bentley, R., Brandt, A., Miller, R. 2010; 38 (9): 5290-5295
  • Review of mathematical models of future oil supply: Historical overview and synthesizing critique ENERGY Brandt, A. R. 2010; 35 (9): 3958-3974
  • Energy Intensity and Greenhouse Gas Emissions from Thermal Enhanced Oil Recovery ENERGY & FUELS Brandt, A. R., Unnasch, S. 2010; 24: 4581-4589

    View details for DOI 10.1021/ef100410f

    View details for Web of Science ID 000281029700059

  • Dynamics of the oil transition: Modeling capacity, depletion, and emissions ENERGY Brandt, A. R., Plevin, R. J., Farrell, A. E. 2010; 35 (7): 2852-2860
  • Converting Oil Shale to Liquid Fuels with the Alberta Taciuk Processor: Energy Inputs and Greenhouse Gas Emissions ENERGY & FUELS Brandt, A. R. 2009; 23: 6253-6258

    View details for DOI 10.1021/ef900678d

    View details for Web of Science ID 000272700300063

  • An assessment of the evidence for a near-term peak in global oil production UK Energy Research Centre Sorrell, S., Speirs, J., Bentley, R., Brandt, A., Miller, R. 2009
  • Carbon Dioxide Emissions from Oil Shale Derived Liquid Fuels 236th National Meeting of the American-Chemical-Society Brandt, A. R., Boak, J., Burnham, A. K. AMER CHEMICAL SOC. 2009: 219–248
  • Converting oil shale to liquid fuels: Energy inputs and greenhouse gas emissions of the Shell in situ conversion process Environmental Science & Technology Brandt, A. R. 2008; 42: 7489-7495
  • Dynamics of the oil transition: Modeling capacity, costs, and emissions University of California Energy Institute, Energy Policy and Economics Working Paper 021 Brandt, A. R., Farrell, A. E. 2008
  • The Race for 21 Century Auto Fuels AIP Conference Proceedings Farrell, A., Brandt, A., Arons, S., Levi, B., Levine, M., Schwartz, P. edited by Hafemeister, D. 2008: 235–50
  • A low carbon fuel standard for California, part 1: Technical analysis California Energy Commission Farrell, A. E., Sperling, D., et al 2007
  • Testing Hubbert Energy Policy Brandt, A. R. 2007; 35: 3074-3088
  • Scraping the bottom of the barrel: CO2 emissions consequences of a transition to low-quality and synthetic petroleum resources Climatic Change Brandt, A. R., Farrell, A. E. 2007; 84: 241-263
  • A low carbon fuel standard for California, part 2: Policy analysis California Energy Commission Farrell, A. E., Sperling, D. 2007
  • Risks of the oil transition Environmental Research Letters Farrell, A. E., Brandt, A. R. 2006; 1 (1)
  • Research roadmap for greenhouse gas inventory methods California Energy Commission Report Farrell, A. E., Kerr, A., Brandt, A. R., Torn, M. 2005; CEC-500-2005-097