Bio


Professor Azevedo is passionate about solving problems that include environmental, technical, economic, and policy issues, where traditional engineering approaches play an important role but cannot provide a complete answer. In particular, she is interested in assessing how energy systems are likely to evolve, which requires comprehensive knowledge of the technologies that can address future energy needs and the decision-making process followed by various agents in the economy.

Academic Appointments


Administrative Appointments


  • Professor, Carnegie Mellon University (2013 - 2019)
  • Co-Director, Climate and Energy Decision Making (CEDM) Center (2013 - Present)
  • Associate Professor, Energy Resources Engineering (2019 - Present)

Honors & Awards


  • C3E Women in Clean Energy, Research Award, C3E (2017)
  • Philip L. Dowd Fellowship Award, Carnegie Mellon University (2017)
  • Emerging Female Scientist Award (Honorable Mention), Carnegie Science (2016)
  • "Young Scientists Under 40, World Economic Forum (WEF) (2014)
  • CIT Dean’s Early Career Fellowship, Carnegie Mellon University (2013)

Boards, Advisory Committees, Professional Organizations


  • Council Member, United States Association for Energy Economics (2016 - Present)
  • Board member, Pecan Street Research Data Board (2013 - Present)

Professional Education


  • Ph.D., Carnegie Mellon University, Engineering and Public Policy (2009)
  • M.Sc., IST Technical University of Lisbon, Innovation and Management of Technology (2009)
  • B.Sc., IST Technical University of Lisbon, Environmental Engineering (2004)

Current Research and Scholarly Interests


Professor Azevedo is passionate about solving problems that include environmental, technical, economic, and policy issues, where traditional engineering approaches play an important role but cannot provide a complete answer. In particular, she is interested in assessing how energy systems are likely to evolve, which requires comprehensive knowledge of the technologies that can address future energy needs and the decision-making process followed by various agents in the economy.

Stanford Advisees


All Publications


  • Fine particulate matter damages and value added in the US economy. Proceedings of the National Academy of Sciences of the United States of America Tschofen, P., Azevedo, I. L., Muller, N. Z. 2019

    Abstract

    Emissions of most pollutants that result in fine particulate matter (PM2.5) formation have been decreasing in the United States. However, this trend has not been uniform across all sectors or regions of the economy. We use integrated assessment models (IAMs) to compute marginal damages for PM2.5-related emissions for each county in the contiguous United States and match location-specific emissions with these marginal damages to compute economy-wide gross external damage (GED) due to premature mortality. We note 4 key findings: First, economy-wide, GED has decreased by more than 20% from 2008 to 2014. Second, while much of the air pollution policies have focused to date on the electricity sector, damages from farms are now larger than those from utilities. Indeed, farms have become the largest contributor to air pollution damages from PM2.5-related emissions. Third, 4 sectors, comprising less than 20% of the national gross domestic product (GDP), are responsible for 75% of GED attributable to economic activities. Fourth, uncertainty in GED estimates tends to be high for sectors with predominantly ground-level emissions because these emissions are usually estimated and not measured. These findings suggest that policymakers should target further emissions reductions from such sectors, particularly in transportation and agriculture.

    View details for DOI 10.1073/pnas.1905030116

    View details for PubMedID 31501345

  • How Much Are We Saving after All? Characterizing the Effects of Commonly Varying Assumptions on Emissions and Damage Estimates in PJM. Environmental science & technology Donti, P. L., Kolter, J. Z., Azevedo, I. L. 2019

    Abstract

    In recent years, several methods have emerged to estimate the emissions and health, environmental, and climate change damages avoided by interventions such as energy efficiency, demand response, and the integration of renewables. However, differing assumptions employed in these analyses could yield contradicting recommendations regarding intervention implementation. We test the magnitude of the effect of using different key assumptions-average vs marginal emissions, year of calculation, temporal and regional scope, and inclusion of nonemitting generation-to estimate Mid-Atlantic region power pool (PJM) emissions and damage factors. We further highlight the importance of factor selection by evaluating three illustrative 2017 power system examples in PJM. We find that for a simple building lighting intervention, using average emissions factors incorporating nonemitting generation underestimates avoided damages by 45% compared to marginal factors. For PJM demand response, outdated marginal emissions factors from 2016 overestimate avoided damages by 25% compared to 2017 factors. Our assessment of PJM summer load further suggests that fossil-only average emissions factors overestimate damages by 63% compared to average factors incorporating nonemitting generation. We recommend that energy modelers carefully select appropriate emissions metrics when performing their analyses. Furthermore, since the U.S. electric grid is rapidly changing, we urge decision-makers to frequently update (and consider forecasting) grid emissions factors.

    View details for DOI 10.1021/acs.est.8b06586

    View details for PubMedID 31380628

  • Choice at the pump: measuring preferences for lower-carbon combustion fuels ENVIRONMENTAL RESEARCH LETTERS Helveston, J. P., Seki, S. M., Min, J., Fairman, E., Boni, A. A., Michalek, J. J., Azevedo, I. L. 2019; 14 (8)
  • Alternative-fuel-vehicle policy interactions increase US greenhouse gas emissions TRANSPORTATION RESEARCH PART A-POLICY AND PRACTICE Jenn, A., Azevedo, I. L., Michalek, J. J. 2019; 124: 396–407
  • Trace Element Mass Flow Rates from US Coal Fired Power Plants ENVIRONMENTAL SCIENCE & TECHNOLOGY Sun, X., Gingerich, D. B., Azevedo, I. L., Mauter, M. S. 2019; 53 (10): 5585–95

    Abstract

    Trace elements (TEs) exit coal-fired power plants (CFPPs) via solid, liquid, and gaseous waste streams. Estimating the TE concentrations of these waste streams is essential to selecting pollution controls and estimating emission reduction benefits. This work introduces a generalizable mass balance model for estimating TE mass flow rates in CFPP waste streams and evaluates model accuracy for the U.S. coal fleet given current data constraints. We stochastically estimate, using a bootstrapping approach, the 2015 plant-level mass flow rates of Hg, Se, As, and Cl to solid, liquid, and gas phase waste streams by combining publicly available data for combusted coal TE concentrations with estimates of TE partitioning within installed air pollution control processes. When compared with measured and reported data on TE mass flow rates, this model generally overestimates masses by 30-50%, with larger errors for Hg. The partitioning estimates are consistent for Se, As, and Cl removal from flue gas, but tend to underestimate Hg removal. While our model is suitable for first-order estimates of TE mass flows, future work to improve model performance should focus on collecting and using new data on TE concentrations in the coal blend, where data quality is the weakest.

    View details for DOI 10.1021/acs.est.9b01039

    View details for Web of Science ID 000469288100008

    View details for PubMedID 31074623

  • Support for Emissions Reductions Based on Immediate and Long-term Pollution Exposure in China ECOLOGICAL ECONOMICS Sergi, B., Azevedo, I., Xia, T., Davis, A., Xu, J. 2019; 158: 26–33
  • Solar PV as a mitigation strategy for the US education sector ENVIRONMENTAL RESEARCH LETTERS Hanus, N. L., Wong-Parodi, G., Vaishnav, P. T., Darghouth, N. R., Azevedo, I. L. 2019; 14 (4)
  • Expert assessments of the cost and expected future performance of proton exchange membrane fuel cells for vehicles PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Whiston, M. M., Azevedo, I. L., Litster, S., Whitefoot, K. S., Samaras, C., Whitacre, J. F. 2019; 116 (11): 4899–4904

    Abstract

    Despite decades of development, proton exchange membrane fuel cells (PEMFCs) still lack wide market acceptance in vehicles. To understand the expected trajectories of PEMFC attributes that influence adoption, we conducted an expert elicitation assessment of the current and expected future cost and performance of automotive PEMFCs. We elicited 39 experts' assessments of PEMFC system cost, stack durability, and stack power density under a hypothetical, large-scale production scenario. Experts assessed the median 2017 automotive cost to be $75/kW, stack durability to be 4,000 hours, and stack power density to be 2.5 kW/L. However, experts ranged widely in their assessments. Experts' 2017 best cost assessments ranged from $40 to $500/kW, durability assessments ranged from 1,200 to 12,000 hours, and power density assessments ranged from 0.5 to 4 kW/L. Most respondents expected the 2020 cost to fall short of the 2020 target of the US Department of Energy (DOE). However, most respondents anticipated that the DOE's ultimate target of $30/kW would be met by 2050 and a power density of 3 kW/L would be achieved by 2035. Fifteen experts thought that the DOE's ultimate durability target of 8,000 hours would be met by 2050. In general, experts identified high Pt group metal loading as the most significant barrier to reducing cost. Recommended research and development (R&D) funding was allocated to "catalysts and electrodes," followed in decreasing amount by "fuel cell performance and durability," "membranes and electrolytes," and "testing and technical assessment." Our results could be used to inform public and private R&D decisions and technology roadmaps.

    View details for DOI 10.1073/pnas.1804221116

    View details for Web of Science ID 000460911500030

    View details for PubMedID 30804192

    View details for PubMedCentralID PMC6421432

  • Economic Viability of a Natural Gas Refueling Infrastructure for Long-Haul Trucks JOURNAL OF INFRASTRUCTURE SYSTEMS Tong, F., Azevedo, I., Jaramillo, P. 2019; 25 (1)
  • Understanding Cumulative Risk Perception from Judgments and Choices: An Application to Flood Risks RISK ANALYSIS De La Maza, C., Davis, A., Gonzalez, C., Azevedo, I. 2019; 39 (2): 488–504

    Abstract

    Catastrophic events, such as floods, earthquakes, hurricanes, and tsunamis, are rare, yet the cumulative risk of each event occurring at least once over an extended time period can be substantial. In this work, we assess the perception of cumulative flood risks, how those perceptions affect the choice of insurance, and whether perceptions and choices are influenced by cumulative risk information. We find that participants' cumulative risk judgments are well represented by a bimodal distribution, with a group that severely underestimates the risk and a group that moderately overestimates it. Individuals who underestimate cumulative risks make more risk-seeking choices compared to those who overestimate cumulative risks. Providing explicit cumulative risk information for relevant time periods, as opposed to annual probabilities, is an inexpensive and effective way to improve both the perception of cumulative risk and the choices people make to protect against that risk.

    View details for DOI 10.1111/risa.13206

    View details for Web of Science ID 000458171100016

    View details for PubMedID 30368850

  • Reduced-Order Dispatch Model for Simulating Marginal Emissions Factors for the United States Power Sector. Environmental science & technology Deetjen, T. A., Azevedo, I. L. 2019

    Abstract

    This study develops a reduced-order power plant dispatch model and uses it to simulate marginal emissions factors (MEFs) for the 2014-2017 United States (U.S.) electric grid at the North American Electric Reliability Corporation (NERC) regional level. MEFs help quantify the health, environmental, and climate change impacts caused by changes in marginal net electricity consumption, which could result, for example, from new technologies or policies. This study develops the model, validates it against historical data, and compares its simulated MEFs against historically derived regression-based MEFs. Our method accurately reproduces CO2, SO2, and NO x emissions for multiple U.S. NERC regions and years and enables us to analyze future scenarios that are absent from the historical data. Though historically derived regression-based MEFs are generally more accurate, our simulated MEFs provide a more nuanced picture of how clusters of low- or high-emitting power plants of similar production cost create large swings in MEFs throughout the day. Policymakers could use these dynamic MEFs to target demand-reduction strategies at high-emissions portions of the power plant merit order.

    View details for DOI 10.1021/acs.est.9b02500

    View details for PubMedID 31436968

  • Meeting U.S. Solid Oxide Fuel Cell Targets Joule Whiston, M. M. 2019
  • The implications of scope and boundary choice on the establishment and success of metropolitan greenhouse gas reduction targets in the United States ENVIRONMENTAL RESEARCH LETTERS Markolf, S. A., Matthews, H., Azevedo, I. L., Hendrickson, C. 2018; 13 (12)
  • Global carbon intensity of crude oil production. Science (New York, N.Y.) Masnadi, M. S., El-Houjeiri, H. M., Schunack, D., Li, Y., Englander, J. G., Badahdah, A., Monfort, J., Anderson, J. E., Wallington, T. J., Bergerson, J. A., Gordon, D., Koomey, J., Przesmitzki, S., Azevedo, I. L., Bi, X. T., Duffy, J. E., Heath, G. A., Keoleian, G. A., McGlade, C., Meehan, D. N., Yeh, S., You, F., Wang, M., Brandt, A. R. 2018; 361 (6405): 851–53

    View details for DOI 10.1126/science.aar6859

    View details for PubMedID 30166477

  • Decarbonizing intraregional freight systems with a focus on modal shift ENVIRONMENTAL RESEARCH LETTERS Kaack, L. H., Vaishnav, P., Morgan, M., Azevedo, I. L., Rai, S. 2018; 13 (8)
  • Expert assessments on the future of direct current in buildings ENVIRONMENTAL RESEARCH LETTERS Glasgo, B., Azevedo, I., Hendrickson, C. 2018; 13 (7)
  • Net-zero emissions energy systems SCIENCE Davis, S. J., Lewis, N. S., Shaner, M., Aggarwal, S., Arent, D., Azevedo, I. L., Benson, S. M., Bradley, T., Brouwer, J., Chiang, Y., Clack, C. M., Cohen, A., Doig, S., Edmonds, J., Fennell, P., Field, C. B., Hannegan, B., Hodge, B., Hoffert, M. I., Ingersoll, E., Jaramillo, P., Lackner, K. S., Mach, K. J., Mastrandrea, M., Ogden, J., Peterson, P. F., Sanchez, D. L., Sperling, D., Stagner, J., Trancik, J. E., Yang, C., Caldeira, K. 2018; 360 (6396): 1419-+

    Abstract

    Some energy services and industrial processes-such as long-distance freight transport, air travel, highly reliable electricity, and steel and cement manufacturing-are particularly difficult to provide without adding carbon dioxide (CO2) to the atmosphere. Rapidly growing demand for these services, combined with long lead times for technology development and long lifetimes of energy infrastructure, make decarbonization of these services both essential and urgent. We examine barriers and opportunities associated with these difficult-to-decarbonize services and processes, including possible technological solutions and research and development priorities. A range of existing technologies could meet future demands for these services and processes without net addition of CO2 to the atmosphere, but their use may depend on a combination of cost reductions via research and innovation, as well as coordinated deployment and integration of operations across currently discrete energy industries.

    View details for PubMedID 29954954

  • Assessing the evolution of power sector carbon intensity in the United States ENVIRONMENTAL RESEARCH LETTERS Schivley, G., Azevedo, I., Samaras, C. 2018; 13 (6)
  • Estimation of the year-on-year volatility and the unpredictability of the United States energy system NATURE ENERGY Sherwin, E. D., Henrion, M., Azevedo, I. L. 2018; 3 (4): 341–46
  • Towards demand-side solutions for mitigating climate change NATURE CLIMATE CHANGE Creutzig, F., Roy, J., Lamb, W. F., Azevedo, I. L., de Bruin, W., Dalkmann, H., Edelenbosch, O. Y., Geels, F. W., Grubler, A., Hepburn, C., Hertwich, E. G., Khosla, R., Mattauch, L., Minx, J. C., Ramakrishnan, A., Rao, N. D., Steinberger, J. K., Tavoni, M., Uerge-Vorsatz, D., Weber, E. U. 2018; 8 (4): 268–71
  • A sunny future: expert elicitation of China's solar photovoltaic technologies ENVIRONMENTAL RESEARCH LETTERS Lam, L. T., Branstetter, L., Azevedo, I. L. 2018; 13 (3)
  • Induced seismicity hazard and risk by enhanced geothermal systems: an expert elicitation approach ENVIRONMENTAL RESEARCH LETTERS Trutnevyte, E., Azevedo, I. L. 2018; 13 (3)
  • Consumers' perceptions of energy use and energy savings: A literature review ENVIRONMENTAL RESEARCH LETTERS Lesic, V., de Bruin, W., Davis, M. C., Krishnamurti, T., Azevedo, I. L. 2018; 13 (3)
  • Quantifying the capacity value of natural gas efficiency in New England UTILITIES POLICY Gilbraith, N., Jaramillo, P., Azevedo, I. 2018; 50: 101–10
  • Distributional costs of wind energy production in Portugal under the liberalized Iberian market regime ENERGY POLICY Prata, R., Carvalho, P. S., Azevedo, I. L. 2018; 113: 500–512
  • Do tidal stream energy projects offer more value than offshore wind farms? A case study in the United Kingdom ENERGY POLICY Lamy, J. V., Azevedo, I. L. 2018; 113: 28–40
  • The effect of providing climate and health information on support for alternative electricity portfolios ENVIRONMENTAL RESEARCH LETTERS Sergi, B., Davis, A., Azevedo, I. 2018; 13 (2)
  • Marginal Emissions Factors for Electricity Generation in the Midcontinent ISO ENVIRONMENTAL SCIENCE & TECHNOLOGY Thind, M. S., Wilson, E. J., Azevedo, I. L., Marshall, J. D. 2017; 51 (24): 14445–52

    Abstract

    Environmental consequences of electricity generation are often determined using average emission factors. However, as different interventions are incrementally pursued in electricity systems, the resulting marginal change in emissions may differ from what one would predict based on system-average conditions. Here, we estimate average emission factors and marginal emission factors for CO2, SO2, and NOx from fossil and nonfossil generators in the Midcontinent Independent System Operator (MISO) region during years 2007-2016. We analyze multiple spatial scales (all MISO; each of the 11 MISO states; each utility; each generator) and use MISO data to characterize differences between the two emission factors (average; marginal). We also explore temporal trends in emissions factors by hour, day, month, and year, as well as the differences that arise from including only fossil generators versus total generation. We find, for example, that marginal emission factors are generally higher during late-night and early morning compared to afternoons. Overall, in MISO, average emission factors are generally higher than marginal estimates (typical difference: ∼20%). This means that the true environmental benefit of an energy efficiency program may be ∼20% smaller than anticipated if one were to use average emissions factors. Our analysis can usefully be extended to other regions to support effective near-term technical, policy and investment decisions based on marginal rather than only average emission factors.

    View details for DOI 10.1021/acs.est.7b03047

    View details for Web of Science ID 000418625900048

    View details for PubMedID 29152978

  • Estimating the Quantity of Wind and Solar Required To Displace Storage-Induced Emissions ENVIRONMENTAL SCIENCE & TECHNOLOGY Hittinger, E., Azevedo, I. L. 2017; 51 (21): 12988–97

    Abstract

    The variable and nondispatchable nature of wind and solar generation has been driving interest in energy storage as an enabling low-carbon technology that can help spur large-scale adoption of renewables. However, prior work has shown that adding energy storage alone for energy arbitrage in electricity systems across the U.S. routinely increases system emissions. While adding wind or solar reduces electricity system emissions, the emissions effect of both renewable generation and energy storage varies by location. In this work, we apply a marginal emissions approach to determine the net system CO2 emissions of colocated or electrically proximate wind/storage and solar/storage facilities across the U.S. and determine the amount of renewable energy required to offset the CO2 emissions resulting from operation of new energy storage. We find that it takes between 0.03 MW (Montana) and 4 MW (Michigan) of wind and between 0.25 MW (Alabama) and 17 MW (Michigan) of solar to offset the emissions from a 25 MW/100 MWh storage device, depending on location and operational mode. Systems with a realistic combination of renewables and storage will result in net emissions reductions compared with a grid without those systems, but the anticipated reductions are lower than a renewable-only addition.

    View details for DOI 10.1021/acs.est.7b03286

    View details for Web of Science ID 000414887200104

    View details for PubMedID 29016129

  • Assessing the value of information in residential building simulation: Comparing simulated and actual building loads at the circuit level APPLIED ENERGY Glasgo, B., Hendrickson, C., Azevedo, I. 2017; 203: 348–63
  • Was it worthwhile? Where have the benefits of rooftop solar photovoltaic generation exceeded the cost? ENVIRONMENTAL RESEARCH LETTERS Vaishnav, P., Horner, N., Azevedo, I. L. 2017; 12 (9)
  • China's wind industry: Leading in deployment, lagging in innovation ENERGY POLICY Lam, L. T., Branstetter, L., Azevedo, I. L. 2017; 106: 588–99
  • Consistency and robustness of forecasting for emerging technologies: The case of Li-ion batteries for electric vehicles ENERGY POLICY Sakti, A., Azevedo, I. L., Fuchs, E. H., Michalek, J. J., Gallagher, K. G., Whitacre, J. F. 2017; 106: 415–26
  • Rethinking the Social Cost of Carbon Dioxide ISSUES IN SCIENCE AND TECHNOLOGY Morgan, M., Vaishnav, P., Dowlatabadi, H., Azevedo, I. L. 2017; 33 (4): 43–50
  • Estimating the effect of multiple environmental stressors on coral bleaching and mortality PLOS ONE Welle, P. D., Small, M. J., Doney, S. C., Azevedo, I. L. 2017; 12 (5): e0175018

    Abstract

    Coral cover has been declining in recent decades due to increased temperatures and environmental stressors. However, the extent to which different stressors contribute both individually and in concert to bleaching and mortality is still very uncertain. We develop and use a novel regression approach, using non-linear parametric models that control for unobserved time invariant effects to estimate the effects on coral bleaching and mortality due to temperature, solar radiation, depth, hurricanes and anthropogenic stressors using historical data from a large bleaching event in 2005 across the Caribbean. Two separate models are created, one to predict coral bleaching, and the other to predict near-term mortality. A large ensemble of supporting data is assembled to control for omitted variable bias and improve fit, and a significant improvement in fit is observed from univariate linear regression based on temperature alone. The results suggest that climate stressors (temperature and radiation) far outweighed direct anthropogenic stressors (using distance from shore and nearby human population density as a proxy for such stressors) in driving coral health outcomes during the 2005 event. Indeed, temperature was found to play a role ~4 times greater in both the bleaching and mortality response than population density across their observed ranges. The empirical models tested in this study have large advantages over ordinary-least squares-they offer unbiased estimates for censored data, correct for spatial correlation, and are capable of handling more complex relationships between dependent and independent variables. The models offer a framework for preparing for future warming events and climate change; guiding monitoring and attribution of other bleaching and mortality events regionally and around the globe; and informing adaptive management and conservation efforts.

    View details for DOI 10.1371/journal.pone.0175018

    View details for Web of Science ID 000400648500007

    View details for PubMedID 28472031

    View details for PubMedCentralID PMC5417430

  • Lessons from wind policy in Portugal ENERGY POLICY Pena, I., Azevedo, I. L., Fialho Marcelino Ferreira, L. 2017; 103: 193–202
  • Spatially resolved air-water emissions tradeoffs improve regulatory impact analyses for electricity generation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Gingerich, D. B., Sun, X., Behrer, A., Azevedo, I. L., Mauter, M. S. 2017; 114 (8): 1862–67

    Abstract

    Coal-fired power plants (CFPPs) generate air, water, and solids emissions that impose substantial human health, environmental, and climate change (HEC) damages. This work demonstrates the importance of accounting for cross-media emissions tradeoffs, plant and regional emissions factors, and spatially variation in the marginal damages of air emissions when performing regulatory impact analyses for electric power generation. As a case study, we assess the benefits and costs of treating wet flue gas desulfurization (FGD) wastewater at US CFPPs using the two best available treatment technology options specified in the 2015 Effluent Limitation Guidelines (ELGs). We perform a life-cycle inventory of electricity and chemical inputs to FGD wastewater treatment processes and quantify the marginal HEC damages of associated air emissions. We combine these spatially resolved damage estimates with Environmental Protection Agency estimates of water quality benefits, fuel-switching benefits, and regulatory compliance costs. We estimate that the ELGs will impose average net costs of $3.01 per cubic meter for chemical precipitation and biological wastewater treatment and $11.26 per cubic meter for zero-liquid discharge wastewater treatment (expected cost-benefit ratios of 1.8 and 1.7, respectively), with damages concentrated in regions containing a high fraction of coal generation or a large chemical manufacturing industry. Findings of net cost for FGD wastewater treatment are robust to uncertainty in auxiliary power source, location of chemical manufacturing, and binding air emissions limits in noncompliant regions, among other variables. Future regulatory design will minimize compliance costs and HEC tradeoffs by regulating air, water, and solids emissions simultaneously and performing regulatory assessments that account for spatial variation in emissions impacts.

    View details for DOI 10.1073/pnas.1524396114

    View details for Web of Science ID 000395099500058

    View details for PubMedID 28167772

    View details for PubMedCentralID PMC5338367

  • An integrated approach for estimating greenhouse gas emissions from 100 US metropolitan areas ENVIRONMENTAL RESEARCH LETTERS Markolf, S. A., Matthews, H., Azevedo, I. L., Hendrickson, C. 2017; 12 (2)
  • How much electricity can we save by using direct current circuits in homes? Understanding the potential for electricity savings and assessing feasibility of a transition towards DC powered buildings APPLIED ENERGY Glasgo, B., Azevedo, I., Hendrickson, C. 2016; 180: 66–75
  • Known unknowns: indirect energy effects of information and communication technology ENVIRONMENTAL RESEARCH LETTERS Horner, N. C., Shehabi, A., Azevedo, I. L. 2016; 11 (10)
  • Should we build wind farms close to load or invest in transmission to access better wind resources in remote areas? A case study in the MISO region ENERGY POLICY Lamy, J. V., Jaramillo, P., Azevedo, I. L., Wiser, R. 2016; 96: 341–50
  • Air emission implications of expanded wastewater treatment at coal-fired generators Gingerich, D., Sun, X., Behrer, A., Azevedo, I., Mauter, M. AMER CHEMICAL SOC. 2016
  • Trace element allocation across air pollution control devices in coal fired power plants Sun, X., Gingerich, D., Azevedo, I., Mauter, M. AMER CHEMICAL SOC. 2016
  • China's wind electricity and cost of carbon mitigation are more expensive than anticipated ENVIRONMENTAL RESEARCH LETTERS Lam, L. T., Branstetter, L., Azevedo, I. L. 2016; 11 (8)
  • Effect of regional grid mix, driving patterns and climate on the comparative carbon footprint of gasoline and plug-in electric vehicles in the United States ENVIRONMENTAL RESEARCH LETTERS Yuksel, T., Tamayao, M. M., Hendrickson, C., Azevedo, I. L., Michalek, J. J. 2016; 11 (4)
  • Alternative Fuel Vehicle Adoption Increases Fleet Gasoline Consumption and Greenhouse Gas Emissions under United States Corporate Average Fuel Economy Policy and Greenhouse Gas Emissions Standards ENVIRONMENTAL SCIENCE & TECHNOLOGY Jenn, A., Azevedo, I. L., Michalek, J. J. 2016; 50 (5): 2165–74

    Abstract

    The United States Corporate Average Fuel Economy (CAFE) standards and Greenhouse Gas (GHG) Emission standards are designed to reduce petroleum consumption and GHG emissions from light-duty passenger vehicles. They do so by requiring automakers to meet aggregate criteria for fleet fuel efficiency and carbon dioxide (CO2) emission rates. Several incentives for manufacturers to sell alternative fuel vehicles (AFVs) have been introduced in recent updates of CAFE/GHG policy for vehicles sold from 2012 through 2025 to help encourage a fleet technology transition. These incentives allow automakers that sell AFVs to meet less-stringent fleet efficiency targets, resulting in increased fleet-wide gasoline consumption and emissions. We derive a closed-form expression to quantify these effects. We find that each time an AFV is sold in place of a conventional vehicle, fleet emissions increase by 0 to 60 t of CO2 and gasoline consumption increases by 0 to 7000 gallons (26,000 L), depending on the AFV and year of sale. Using projections for vehicles sold from 2012 to 2025 from the Energy Information Administration, we estimate that the CAFE/GHG AFV incentives lead to a cumulative increase of 30 to 70 million metric tons of CO2 and 3 to 8 billion gallons (11 to 30 billion liters) of gasoline consumed over the vehicles' lifetimes - the largest share of which is due to legacy GHG flex-fuel vehicle credits that expire in 2016. These effects may be 30-40% larger in practice than we estimate here due to optimistic laboratory vehicle efficiency tests used in policy compliance calculations.

    View details for DOI 10.1021/acs.est.5b02842

    View details for Web of Science ID 000371371700006

    View details for PubMedID 26867100

  • Forecasting light-duty vehicle demand using alternative-specific constants for endogeneity correction versus calibration TRANSPORTATION RESEARCH PART B-METHODOLOGICAL Haaf, C., Morrow, W., Azevedo, I. L., Feit, E., Michalek, J. J. 2016; 84: 182–210
  • Dynamic Data Center Load Response to Variability in Private and Public Electricity Costs Horner, N., Azevedo, I., Sicker, D., Agarwal, Y., IEEE IEEE. 2016
  • Heterogeneity in the response to gasoline prices: Evidence from Pennsylvania and implications for the rebound effect ENERGY ECONOMICS Gillingham, K., Jenn, A., Azevedo, I. L. 2015; 52: S41–S52
  • A review of learning rates for electricity supply technologies ENERGY POLICY Rubin, E. S., Azevedo, I. L., Jaramillo, P., Yeh, S. 2015; 86: 198–218
  • Comparison of Life Cycle Greenhouse Gases from Natural Gas Pathways for Light-Duty Vehicles ENERGY & FUELS Tong, F., Jaramillo, P., Azevedo, I. L. 2015; 29 (9): 6008–18
  • Regional Variability and Uncertainty of Electric Vehicle Life Cycle CO2 Emissions across the United States ENVIRONMENTAL SCIENCE & TECHNOLOGY Tamayao, M. M., Michalek, J. J., Hendrickson, C., Azevedo, I. L. 2015; 49 (14): 8844–55

    Abstract

    We characterize regionally specific life cycle CO2 emissions per mile traveled for plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs) across the United States under alternative assumptions for regional electricity emission factors, regional boundaries, and charging schemes. We find that estimates based on marginal vs average grid emission factors differ by as much as 50% (using National Electricity Reliability Commission (NERC) regional boundaries). Use of state boundaries versus NERC region boundaries results in estimates that differ by as much as 120% for the same location (using average emission factors). We argue that consumption-based marginal emission factors are conceptually appropriate for evaluating the emissions implications of policies that increase electric vehicle sales or use in a region. We also examine generation-based marginal emission factors to assess robustness. Using these two estimates of NERC region marginal emission factors, we find the following: (1) delayed charging (i.e., starting at midnight) leads to higher emissions in most cases due largely to increased coal in the marginal generation mix at night; (2) the Chevrolet Volt has higher expected life cycle emissions than the Toyota Prius hybrid electric vehicle (the most efficient U.S. gasoline vehicle) across the U.S. in nearly all scenarios; (3) the Nissan Leaf BEV has lower life cycle emissions than the Prius in the western U.S. and in Texas, but the Prius has lower emissions in the northern Midwest regardless of assumed charging scheme and marginal emissions estimation method; (4) in other regions the lowest emitting vehicle depends on charge timing and emission factor estimation assumptions.

    View details for DOI 10.1021/acs.est.5b00815

    View details for Web of Science ID 000358557900066

    View details for PubMedID 26125323

  • Comparison of Life Cycle Greenhouse Gases from Natural Gas Pathways for Medium and Heavy-Duty Vehicles ENVIRONMENTAL SCIENCE & TECHNOLOGY Tong, F., Jaramillo, P., Azevedo, I. L. 2015; 49 (12): 7123–33

    Abstract

    The low-cost and abundant supply of shale gas in the United States has increased the interest in using natural gas for transportation. We compare the life cycle greenhouse gas (GHG) emissions from different natural gas pathways for medium and heavy-duty vehicles (MHDVs). For Class 8 tractor-trailers and refuse trucks, none of the natural gas pathways provide emissions reductions per unit of freight-distance moved compared to diesel trucks. When compared to the petroleum-based fuels currently used in these vehicles, CNG and centrally produced LNG increase emissions by 0-3% and 2-13%, respectively, for Class 8 trucks. Battery electric vehicles (BEVs) powered with natural gas-produced electricity are the only fuel-technology combination that achieves emission reductions for Class 8 transit buses (31% reduction compared to the petroleum-fueled vehicles). For non-Class 8 trucks (pick-up trucks, parcel delivery trucks, and box trucks), BEVs reduce emissions significantly (31-40%) compared to their diesel or gasoline counterparts. CNG and propane achieve relatively smaller emissions reductions (0-6% and 19%, respectively, compared to the petroleum-based fuels), while other natural gas pathways increase emissions for non-Class 8 MHDVs. While using natural gas to fuel electric vehicles could achieve large emission reductions for medium-duty trucks, the results suggest there are no great opportunities to achieve large emission reductions for Class 8 trucks through natural gas pathways with current technologies. There are strategies to reduce the carbon footprint of using natural gas for MHDVs, ranging from increasing vehicle fuel efficiency, reducing life cycle methane leakage rate, to achieving the same payloads and cargo volumes as conventional diesel trucks.

    View details for DOI 10.1021/es5052759

    View details for Web of Science ID 000356755200005

    View details for PubMedID 25938939

  • How will we fund our roads? A case of decreasing revenue from electric vehicles TRANSPORTATION RESEARCH PART A-POLICY AND PRACTICE Jenn, A., Azevedo, I., Fischbeck, P. 2015; 74: 136–47
  • Nonproliferation improvements and challenges presented by small modular reactors PROGRESS IN NUCLEAR ENERGY Prasad, S., Abdulla, A., Morgan, M., Azevedo, I. 2015; 80: 102–9
  • Bulk Energy Storage Increases United States Electricity System Emissions ENVIRONMENTAL SCIENCE & TECHNOLOGY Hittinger, E. S., Azevedo, I. L. 2015; 49 (5): 3203–10

    Abstract

    Bulk energy storage is generally considered an important contributor for the transition toward a more flexible and sustainable electricity system. Although economically valuable, storage is not fundamentally a "green" technology, leading to reductions in emissions. We model the economic and emissions effects of bulk energy storage providing an energy arbitrage service. We calculate the profits under two scenarios (perfect and imperfect information about future electricity prices), and estimate the effect of bulk storage on net emissions of CO2, SO2, and NOx for 20 eGRID subregions in the United States. We find that net system CO2 emissions resulting from storage operation are nontrivial when compared to the emissions from electricity generation, ranging from 104 to 407 kg/MWh of delivered energy depending on location, storage operation mode, and assumptions regarding carbon intensity. Net NOx emissions range from -0.16 (i.e., producing net savings) to 0.49 kg/MWh, and are generally small when compared to average generation-related emissions. Net SO2 emissions from storage operation range from -0.01 to 1.7 kg/MWh, depending on location and storage operation mode.

    View details for DOI 10.1021/es505027p

    View details for Web of Science ID 000350611100077

    View details for PubMedID 25629631

  • Assessing regional differences in lighting heat replacement effects in residential buildings across the United States APPLIED ENERGY Min, J., Azevedo, I., Hakkarainen, P. 2015; 141: 12–18
  • Changing the Renewable Fuel Standard to a Renewable Material Standard: Bioethylene Case Study ENVIRONMENTAL SCIENCE & TECHNOLOGY Posen, I., Griffin, W., Matthews, H., Azevedo, I. L. 2015; 49 (1): 93–102

    Abstract

    The narrow scope of the U.S. renewable fuel standard (RFS2) is a missed opportunity to spur a wider range of biomass use. This is especially relevant as RFS2 targets are being missed due to demand-side limitations for ethanol consumption. This paper examines the greenhouse gas (GHG) implications of a more flexible policy based on RFS2, which includes credits for chemical use of bioethanol (to produce bioethylene). A Monte Carlo simulation is employed to estimate the life-cycle GHG emissions of conventional low-density polyethylene (LDPE), made from natural gas derived ethane (mean: 1.8 kg CO2e/kg LDPE). The life-cycle GHG emissions from bioethanol and bio-LDPE are examined for three biomass feedstocks: U.S. corn (mean: 97g CO2e/MJ and 2.6 kg CO2e/kg LDPE), U.S. switchgrass (mean: -18g CO2e/MJ and -2.9 kg CO2e/kg LDPE), and Brazilian sugar cane (mean: 33g CO2e/MJ and -1.3 kg CO2e/kg LDPE); bioproduct and fossil-product emissions are compared. Results suggest that neither corn product (bioethanol or bio-LDPE) can meet regulatory GHG targets, while switchgrass and sugar cane ethanol and bio-LDPE likely do. For U.S. production, bioethanol achieves slightly greater GHG reductions than bio-LDPE. For imported Brazilian products, bio-LDPE achieves greater GHG reductions than bioethanol. An expanded policy that includes bio-LDPE provides added flexibility without compromising GHG targets.

    View details for DOI 10.1021/es503521

    View details for Web of Science ID 000347589300011

    View details for PubMedID 25478782

  • Evaluating the Benefits of Commercial Building Energy Codes and Improving Federal Incentives for Code Adoption ENVIRONMENTAL SCIENCE & TECHNOLOGY Gilbraith, N., Azevedo, I. L., Jaramillo, P. 2014; 48 (24): 14121–30

    Abstract

    The federal government has the goal of decreasing commercial building energy consumption and pollutant emissions by incentivizing the adoption of commercial building energy codes. Quantitative estimates of code benefits at the state level that can inform the size and allocation of these incentives are not available. We estimate the state-level climate, environmental, and health benefits (i.e., social benefits) and reductions in energy bills (private benefits) of a more stringent code (ASHRAE 90.1-2010) relative to a baseline code (ASHRAE 90.1-2007). We find that reductions in site energy use intensity range from 93 MJ/m(2) of new construction per year (California) to 270 MJ/m(2) of new construction per year (North Dakota). Total annual benefits from more stringent codes total $506 million for all states, where $372 million are from reductions in energy bills, and $134 million are from social benefits. These total benefits range from $0.6 million in Wyoming to $49 million in Texas. Private benefits range from $0.38 per square meter in Washington State to $1.06 per square meter in New Hampshire. Social benefits range from $0.2 per square meter annually in California to $2.5 per square meter in Ohio. Reductions in human/environmental damages and future climate damages account for nearly equal shares of social benefits.

    View details for DOI 10.1021/es502894m

    View details for Web of Science ID 000346686100010

    View details for PubMedID 25383692

  • Economic analysis of the profitability of existing wind parks in Portugal ENERGY ECONOMICS Pena, I., Azevedo, I., Fialho Marcelino Ferreira, L. 2014; 45: 353–63
  • Comparing the magnitude of simulated residential rebound effects from electric end-use efficiency across the US ENVIRONMENTAL RESEARCH LETTERS Thomas, B. A., Hausfather, Z., Azevedo, I. L. 2014; 9 (7)
  • The role of energy storage in accessing remote wind resources in the Midwest ENERGY POLICY Lamy, J., Azevedo, I. L., Jaramillo, P. 2014; 68: 123–31
  • Should policy-makers allocate funding to vehicle electrification or end-use energy efficiency as a strategy for climate change mitigation and energy reductions? Rethinking electric utilities efficiency programs ENERGY POLICY Thomas, B. A., Azevedo, I. L. 2014; 67: 28–36
  • Consumer End-Use Energy Efficiency and Rebound Effects ANNUAL REVIEW OF ENVIRONMENT AND RESOURCES, VOL 39 Azevedo, I. L., Gadgil, A., Liverman, D. M. 2014; 39: 393–418
  • Labeling energy cost on light bulbs lowers implicit discount rates ECOLOGICAL ECONOMICS Min, J., Azevedo, I. L., Michalek, J., de Bruin, W. 2014; 97: 42–50
  • The impact of federal incentives on the adoption of hybrid electric vehicles in the United States ENERGY ECONOMICS Jenn, A., Azevedo, I. L., Ferreira, P. 2013; 40: 936–42
  • Effects of government incentives on wind innovation in the United States ENVIRONMENTAL RESEARCH LETTERS Horner, N., Azevedo, I., Hounshell, D. 2013; 8 (4)
  • Regional variations in the health, environmental, and climate benefits of wind and solar generation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Siler-Evans, K., Azevedo, I., Morgan, M., Apt, J. 2013; 110 (29): 11768–73

    Abstract

    When wind or solar energy displace conventional generation, the reduction in emissions varies dramatically across the United States. Although the Southwest has the greatest solar resource, a solar panel in New Jersey displaces significantly more sulfur dioxide, nitrogen oxides, and particulate matter than a panel in Arizona, resulting in 15 times more health and environmental benefits. A wind turbine in West Virginia displaces twice as much carbon dioxide as the same turbine in California. Depending on location, we estimate that the combined health, environmental, and climate benefits from wind or solar range from $10/MWh to $100/MWh, and the sites with the highest energy output do not yield the greatest social benefits in many cases. We estimate that the social benefits from existing wind farms are roughly 60% higher than the cost of the Production Tax Credit, an important federal subsidy for wind energy. However, that same investment could achieve greater health, environmental, and climate benefits if it were differentiated by region.

    View details for DOI 10.1073/pnas.1221978110

    View details for Web of Science ID 000322086100036

    View details for PubMedID 23798431

    View details for PubMedCentralID PMC3718187

  • Expert assessments of the cost of light water small modular reactors PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Abdulla, A., Azevedo, I., Morgan, M. 2013; 110 (24): 9686–91

    Abstract

    Analysts and decision makers frequently want estimates of the cost of technologies that have yet to be developed or deployed. Small modular reactors (SMRs), which could become part of a portfolio of carbon-free energy sources, are one such technology. Existing estimates of likely SMR costs rely on problematic top-down approaches or bottom-up assessments that are proprietary. When done properly, expert elicitations can complement these approaches. We developed detailed technical descriptions of two SMR designs and then conduced elicitation interviews in which we obtained probabilistic judgments from 16 experts who are involved in, or have access to, engineering-economic assessments of SMR projects. Here, we report estimates of the overnight cost and construction duration for five reactor-deployment scenarios that involve a large reactor and two light water SMRs. Consistent with the uncertainty introduced by past cost overruns and construction delays, median estimates of the cost of new large plants vary by more than a factor of 2.5. Expert judgments about likely SMR costs display an even wider range. Median estimates for a 45 megawatts-electric (MWe) SMR range from $4,000 to $16,300/kWe and from $3,200 to $7,100/kWe for a 225-MWe SMR. Sources of disagreement are highlighted, exposing the thought processes of experts involved with SMR design. There was consensus that SMRs could be built and brought online about 2 y faster than large reactors. Experts identify more affordable unit cost, factory fabrication, and shorter construction schedules as factors that may make light water SMRs economically viable.

    View details for DOI 10.1073/pnas.1300195110

    View details for Web of Science ID 000320930100033

    View details for PubMedID 23716682

    View details for PubMedCentralID PMC3683777

  • Reducing US Residential Energy Use and CO2 Emissions: How Much, How Soon, and at What Cost? ENVIRONMENTAL SCIENCE & TECHNOLOGY Azevedo, I., Morgan, M., Palmer, K., Lave, L. B. 2013; 47 (6): 2502–11

    Abstract

    There is growing interest in reducing energy use and emissions of carbon dioxide from the residential sector by deploying cost-effectiveness energy efficiency measures. However, there is still large uncertainty about the magnitude of the reductions that could be achieved by pursuing different energy efficiency measures across the nation. Using detailed estimates of the current inventory and performance of major appliances in U.S. homes, we model the cost, energy, and CO2 emissions reduction if they were replaced with alternatives that consume less energy or emit less CO2. We explore trade-offs between reducing CO2, reducing primary or final energy, or electricity consumption. We explore switching between electricity and direct fuel use, and among fuels. The trade-offs between different energy efficiency policy goals, as well as the environmental metrics used, are important but have been largely unexplored by previous energy modelers and policy-makers. We find that overnight replacement of the full stock of major residential appliances sets an upper bound of just over 710 × 10(6) tonnes/year of CO2 or a 56% reduction from baseline residential emissions. However, a policy designed instead to minimize primary energy consumption instead of CO2 emissions will achieve a 48% reduction in annual carbon dioxide emissions from the nine largest energy consuming residential end-uses. Thus, we explore the uncertainty regarding the main assumptions and different policy goals in a detailed sensitivity analysis.

    View details for DOI 10.1021/es303688k

    View details for Web of Science ID 000316594000010

    View details for PubMedID 23398047

  • Estimating direct and indirect rebound effects for US households with input-output analysis Part 1: Theoretical framework ECOLOGICAL ECONOMICS Thomas, B. A., Azevedo, I. L. 2013; 86: 199–210
  • Estimating direct and indirect rebound effects for US households with input-output analysis. Part 2: Simulation ECOLOGICAL ECONOMICS Thomas, B. A., Azevedo, I. L. 2013; 86: 188–98
  • Electricity consumption and energy savings potential of video game consoles in the United States ENERGY EFFICIENCY Hittinger, E., Mullins, K. A., Azevedo, I. L. 2012; 5 (4): 531–45
  • Edison Revisited: Should we use DC circuits for lighting in commercial buildings? ENERGY POLICY Thomas, B. A., Azevedo, I. L., Morgan, G. 2012; 45: 399–411
  • Marginal Emissions Factors for the U.S. Electricity System ENVIRONMENTAL SCIENCE & TECHNOLOGY Siler-Evans, K., Azevedo, I., Morgan, M. 2012; 46 (9): 4742–48

    Abstract

    There is growing interest in reducing emissions from electricity generation in the United States (U.S.). Renewable energy, energy efficiency, and energy conservation are all commonly suggested solutions. Both supply- and demand-side interventions will displace energy-and emissions-from conventional generators. Marginal emissions factors (MEFs) give a consistent metric for assessing the avoided emissions resulting from such interventions. This paper presents the first systematic calculation of MEFs for the U.S. electricity system. Using regressions of hourly generation and emissions data from 2006 through 2011, we estimate regional MEFs for CO(2), NO(x), and SO(2), as well as the share of marginal generation from coal-, gas-, and oil-fired generators. Trends in MEFs with respect to system load, time of day, and month are explored. We compare marginal and average emissions factors (AEFs), finding that AEFs may grossly misestimate the avoided emissions resulting from an intervention. We find significant regional differences in the emissions benefits of avoiding one megawatt-hour of electricity: compared to the West, an equivalent energy efficiency measure in the Midwest is expected to avoid roughly 70% more CO(2), 12 times more SO(2), and 3 times more NO(x) emissions.

    View details for DOI 10.1021/es300145v

    View details for Web of Science ID 000303348800014

    View details for PubMedID 22486733

  • Distributed cogeneration for commercial buildings: Can we make the economics work? ENERGY POLICY Siler-Evans, K., Morgan, M., Azevedo, I. 2012; 42: 580–90
  • ICT solutions in transportation systems: estimating the benefits and environmental impacts in the Lisbon Baptista, P. C., Azevedo, I. L., Farias, T. L., Aguilera, Bhouri, N., Farhi, N., Leurent, F., Seidowsky, R. ELSEVIER SCIENCE BV. 2012: 716–25
  • Designing building energy efficiency programs for greenhouse gas reductions ENERGY POLICY Blackhurst, M., Azevedo, I., Matthews, H., Hendrickson, C. T. 2011; 39 (9): 5269–79
  • Preparing US community greenhouse gas inventories for climate action plans ENVIRONMENTAL RESEARCH LETTERS Blackhurst, M., Matthews, H., Sharrard, A. L., Hendrickson, C. T., Azevedo, I. 2011; 6 (3)
  • Residential electricity consumption in Portugal: Findings from top-down and bottom-up models ENERGY POLICY Wiesmann, D., Azevedo, I., Ferrao, P., Fernandez, J. E. 2011; 39 (5): 2772–79
  • The Transition to Solid-State Lighting PROCEEDINGS OF THE IEEE Azevedo, I., Morgan, M., Morgan, F. 2009; 97 (3): 481–510