Selected Publications
Planning reliable wind- and solar-based electricity systems
Advances in Applied Energy | August 10, 2024
We investigated how the number of years of weather data used in designing least-cost systems relying on wind, solar, and energy storage affects resource adequacy. Nearly 40 years of weather data are required to plan systems that experience zero lost load over a decade, but only 15 years of weather data are needed when there is dispatchable generation to supply 5% of electricity demand.
Opportunities and constraints of hydrogen energy storage systems
Environmental Research: Energy | July 22, 2024
We modeled the sensitivity of wind-solar-battery electricity system costs to characteristics of hydrogen-based energy storage. Even at current costs, hydrogen energy storage is included in least-cost systems, but we found that the capital costs of such storage represent a key opportunity to minimize curtailment of renewable generation and reduce overall system costs.
Climate change impacts on the reliability of wind-solar resources
Nature Communications | June 18, 2024
We use hourly reanalysis data to examine the trends in periods of low wind and solar resources over the past 40 years, and find that such periods are becoming more frequent, extreme, and longer. Our findings suggest that wind-solar systems may become less reliable in a warmer future.
Drivers of natural gas use in U.S. residential buildings
Science Advances | April 3, 2024
We use daily, county-level gas consumption data and interpretable machine learning models to assess spatial patterns in natural gas consumption of households as a function of outdoor air temperature, as well as factors such as household income, employment rates, the size, age and type of homes, employment rates, and a range of other characteristics.
Rebound effects could offset more than half of avoided food loss and waste
Nature Food | July 20, 2023
We model reductions in food loss and waste to show that there could be substantial rebound effects--price decreases and consumption increases—-that would offset some of the benefits of avoided loss and waste.
Food without agriculture
Nature Sustainability | November 6, 2023
Edible molecules can be directly synthesized without agricultural feedstocks, saving land, water and GHG emissions. Dietary fats made from natural gas feedstock and average U.S. electricity would emit ~0.8 gCO2-eq/kcal (and 0 if using atmospheric carbon and renewable electricity) compared to 1-3 gCO2-eq/kcal from agricultural fat production.
Climate warming increases extreme daily wildfire growth risk in California
Nature | August 30, 2023
We use machine learning to quantify the relationship of temperature and wildfires that grow by >10,000 acres/day in California, finding that human-caused warming has increased the frequency of such wildfire growth by ~25% relative to the preindustrial era, which will further increase to ~59% by 2100 even if warming is kept low (i.e. <2°C).
Pathways to net-zero emissions aviation
Nature Sustainability | January 30, 2023
We assess nine possible pathways to achieve net-zero emissions from aviation, including changes and trade-offs in demand, energy efficiency, propulsion systems, and alternative fuels for both passenger and freight transport, as well as atmospheric carbon removal to offset non-CO2 radiative forcing.
Materials for electricity in mitigation scenarios
Joule | January 27, 2023
We estimate how many tons of steel, copper, silver, rare earth metals, and other materials will be needed to build power generation facilities across a wide range of scenarios. Although wind and solar energy require lots of such materials and current production will need to increase, availability of metals and materials will not constrain the projected expansion.
Economic and biophysical limits to seaweed farming for climate change mitigation
Nature Plants | December 23, 2022
Global modeling shows that potential climate benefits of farming seaweed are large but sensitive to uncertain yields and competition with phytoplankton. We also find that carbon removal by sinking seaweed is much costlier than avoiding emissions by substituting seaweed for land-based crops.
Large and inequitable flood risks in Los Angeles
Nature Sustainability | October 31, 2022
Ultra-high-resolution modeling of Los Angeles flood risks reveals risks that are vastly larger than suggested by federally-defined floodplains and with both racial and socio-economic inequalities in exposure. Our approach points to opportunities for assessing and equitably reducing flood risks in densely-populated urban areas.
Land-use emissions embodied in trade
Science | May 6, 2022
Annually, 27% of land-use emissions are related to agricultural products consumed in a different region from where they were produced. The largest transfers are land-use change emissions from Brazil, Indonesia, and Argentina embodied in products consumed in Europe, the US, and China. Our results highlght the importance of trade in stopping deforestation and making food systems more sustainable.
Cement and steel - nine steps to net-zero
Nature | March 24, 2022
It is possible — and crucial — to green the building blocks of the modern world. We highlight nine priorities for research and action. Steel manufacturing processes need a rethink; cement’s biggest gains will require carbon capture and storage (CCS). Together, these steps could take steel close to being carbon neutral and cement to becoming a carbon sink.
Geophysical constraints on the reliability of solar and wind power worldwide
Nature Communications | October 22, 2021
Analyzing 39 years of hourly weather data across 42 countries, we show that, to a first approximation, the variability of solar and wind resources in a country largely determine how much "overbuilding," long-duration storage, long-distance transmission, and/or firm generation back-up will be necessary.
Global and regional drivers of land-use emissions
Nature | January 27, 2021
We estimate country-, process-, GHG- and product-specific land-use emissions 1961-2017. Total emissions have increased to 14.6 GtCO2-eq in 2017 (~25% of anthropogenic GHG emissions). Our results may help prioritize mitigation efforts, but suggest drastic reductions in emissions will require similarly drastic changes in agricultural production and/or practices.