Journal Publications
Restructuring the Rate Base.
AEA Papers and Proceedings, 115: May 2025.
Abstract +
While electricity market restructuring appears to have lowered generation costs, it does not seem to have benefitted consumers. Where did the savings go? This paper evaluates whether the downstream transmission and distribution (T&D) utilities who remained rate-regulated capitalized the savings into earnings by increasing their capital stocks. Returns on these additional assets raise delivery charges for customers with restructured utilities. I use a matched-difference-in-differences design based on proximate, similarly sized utilities with an annual panel of U.S. utilities' capital stocks from 1993-2009. Nine years after divestiture the average restructured utility held an additional $0.45B (9.5%) of T&D capital.
Powering Work from Home.
Journal of Urban Economics: Insights, 133: 103474, January 2023.
Abstract +
NBER Digest
This paper documents a shift in energy consumption toward residential usage during the COVID-19 pandemic in the United States. Focusing on electricity, I find a 7.9% increase in residential consumption, and a 6.9% and 8.0% reduction in commercial and industrial usage, respectively, from a monthly panel of electric utilities. Natural gas consumption also shifted toward residential use, so that aggregate electricity and gas expenditure only fell by 1% on net during a period in which GDP fell by 5%. Hourly smart meter data from Texas reveal how daily routines changed during the pandemic, with residential electricity usage during weekdays closely resembling those of weekends. In total, residential energy expenditures were an estimated $13B higher during Q2-Q4 2020, with the largest increases occurring in areas with a greater propensity to work from home. I find that transportation fuel consumption declined about 16%, so that total energy consumption in the U.S. economy fell by 8%.
Imperfect Markets versus Imperfect Regulation in U.S. Electricity Generation.
American Economic Review, 112(2): 409-441, February 2022.
Abstract +
Online Appendix
NBER Digest
Machine Learning Methods (NBER 2017)
This paper evaluates changes in electricity generation costs caused by the introduction of market mechanisms to determine production in the United States. I use the staggered transition to markets from 1999-2012 to estimate the causal impact of liberalization using a differences-in-differences design on a comprehensive hourly panel of electricity demand, generators' costs, capacities, and output. I find that markets reduce production costs by 5% by reallocating production: Gains from trade across service areas increase by 55% based on a 25% increase in traded electricity, and costs from using uneconomical units fall 16%.
The Incidence of Extreme Economic Stress: Evidence from Utility Disconnections.
Journal of Public Economics, 200: 14461, August 2021.
Abstract +
This paper uses monthly zip code-level data on electricity disconnections in Illinois to document the socioeconomic correlates of extreme economic distress among 5 million customers. In 2018-2019, customers in Black and Hispanic zip codes were about 4 times more likely to be disconnected for non-payment, 2-3 times more likely to be on deferred payment plans, and 70% more likely to participate in utility-based low-income assistance programs, controlling for zip code distributions of income and other demographic characteristics. During the COVID-19 pandemic, there has been a nine-fold expansion in low-income assistance to pay utility bills, but disconnections were double and deferred payment plans triple their historical averages in October 2020. Disconnection notices were served to 2.5% of commercial and industrial accounts, and 3.4% of residential accounts each month in late 2020. About 20% of all accounts were charged late fees. The odds for each of these measures were multiples higher in minority zip codes.
Expected Health Effects of Reduced Air Pollution from COVID-19 Social Distancing.
with Stephen P. Holland, Erin T. Mansur, Nicholas Z. Muller, and Andrew J. Yates.
Atmosphere, 12(8): 951, July 2021.
Abstract +
The COVID-19 pandemic resulted in stay-at-home policies and other social distancing behaviors in the United States in spring of 2020. This paper examines the impact that these actions had on emissions and expected health effects through reduced personal vehicle travel and electricity consumption. Using daily cell phone mobility data for each U.S. county, we find that vehicle travel dropped about 40% by mid-April across the nation.
States that imposed stay-at-home policies before March 28 decreased travel slightly more than other states, but travel in all states decreased significantly. Using data on hourly electricity consumption by electricity region (e.g., balancing authority), we find that electricity consumption fell about six percent on average by mid-April with substantial heterogeneity. Given these decreases in travel and electricity use, we estimate the county-level expected improvements in air quality, and therefore expected declines in mortality. Overall, we estimate that, for a month of social distancing, the expected premature deaths due to air pollution from personal vehicle travel and electricity consumption declined by approximately 360 deaths, or about 25% of the baseline 1500 deaths. In addition, we estimate that CO2 emissions from these sources fell by 46 million metric tons (a reduction of approximately 19%) over the same time frame.
When Does Regulation Distort Costs? Lessons from Fuel Procurement in U.S. Electricity Generation: Reply.
American Economic Review, 111(4): 1373-1381, April 2021.
Abstract +
The average effect of deregulatory policies on fuel prices at coal-fired power plants is strongly influenced by plants that were initially paying the highest prices for fuel. Primary sources document that these plants were locked into long-term, high-cost fuel contracts, and only secured market rates post-deregulation. While these plants' fuel costs were unusual, their response to deregulation was not: both coal- and gas-fired plants reduce fuel prices one-for-one with the amount they were initially paying above their neighbors' costs. Our understanding of deregulation is not improved by excluding those who benefit most.
Regulating Markups in U.S. Health Insurance.
with Ethan M.J. Lieber and Victoria Marone.
American Economic Journal: Applied Economics, 11(4): 71-104, October 2019.
Abstract + Online Appendix
A health insurer's Medical Loss Ratio (MLR) is the share of premiums spent on medical claims, or the inverse markup over average claims cost. The Affordable Care Act introduced minimum MLR provisions for all health insurance sold in fully-insured commercial markets, thereby capping insurer profit margins, but not levels. While intended to reduce premiums, we show this rule creates incentives to increase costs. Using variation created by the rule's introduction as a natural experiment, we find medical claims rose nearly one-for-one with distance below the regulatory threshold: 7% in the individual market, and 2% in the group market. Premiums were unaffected.
Self-Selection and Comparative Advantage in Social Interactions.
with Roland G. Fryer and Jörg L. Spenkuch.
Journal of the European Economic Association, 16(4): 983-1020, August 2018.
Abstract + Online Appendix
We propose a model of social interactions based on comparative advantage. When comparative advantage is the guiding principle of social interactions, the effect of moving a student into an environment with higher-achieving peers depends on where in the ability distribution she falls and the shadow prices that clear the social market. We show that the model's key prediction--an individual's ordinal rank predicts her behavior and test scores, ceteris paribus--is borne out in one randomized controlled trial in Kenya as well as two large observational data sets from the U.S. To test whether comparative advantage can explain the effect of rank on outcomes, we conduct an experiment with nearly 600 public school students in Houston. The experimental results suggest that social interactions are, at least in part, governed by comparative advantage.
This paper evaluates changes in fuel procurement practices by coal- and gas-fired power plants in the United States following state-level legislation that ended cost-of-service regulation of electricity generation. I find that deregulated plants substantially reduce the price paid for coal (but not gas) and tend to employ less capital-intensive sulfur abatement techniques relative to matched plants that were not subject to any regulatory change. Deregulation also led to a shift toward more productive coal mines. I show how these results lend support to theories of asymmetric information, capital bias, and regulatory capture as important sources of regulatory distortion.
This paper applies principles of adverse selection to overcome obstacles that prevent the implementation of Pigouvian policies to internalize externalities. Focusing on negative externalities from production (such as pollution), we evaluate settings in which aggregate emissions are known, but individual contributions are unobserved by the government. We propose giving firms the option to pay a tax on their voluntarily and verifiably disclosed emissions, or pay an output tax based on the average rate of emissions among the undisclosed firms. The certification of relatively clean firms raises the output-based tax, setting off a process of unraveling in favor of disclosure. We derive sufficient statistics formulas to calculate the welfare of such a program relative to mandatory output or emissions taxes. We find that our mechanism would deliver significant gains over output-based taxation in two empirical applications: methane emissions from oil and gas fields, and carbon emissions from imported steel.