Charging infrastructure access and operation to reduce the grid impacts of deep electric vehicle adoption

Nature Energy · 2022 · 306 citations

• Environmental economics
• Automotive engineering
• Environmental science

Abstract Electric vehicles will contribute to emissions reductions in the United States, but their charging may challenge electricity grid operations. We present a data-driven, realistic model of charging demand that captures the diverse charging behaviours of future adopters in the US Western Interconnection. We study charging control and infrastructure build-out as critical factors shaping charging load and evaluate grid impact under rapid electric vehicle adoption with a detailed economic dispatch model of 2035 generation. We find that peak net electricity demand increases by up to 25% with forecast adoption and by 50% in a stress test with full electrification. Locally optimized controls and high home charging can strain the grid. Shifting instead to uncontrolled, daytime charging can reduce storage requirements, excess non-fossil fuel generation, ramping and emissions. Our results urge policymakers to reflect generation-level impacts in utility rates and deploy charging infrastructure that promotes a shift from home to daytime charging.

The food we eat, the air we breathe: a review of the fine particulate matter-induced air quality health impacts of the global food system

Environmental Research Letters · 2021 · 56 citations

• Environmental science
• Environmental health
• Environmental protection

The global food system is essential for the health and wellbeing of society, but is also a major cause of environmental damage. Some impacts, such as on climate change, have been the subject of intense recent inquiry, but others, such as on air quality, are not as well understood. Here, we systematically synthesize the literature to identify the impacts on ambient PM _2.5 (particulate matter with diameter ⩽2.5 μ m), which is the strongest contributor to premature mortality from exposure to air pollution. Our analysis indicates that the life-cycle of the global food system (pre-production, production, post-production, consumption and waste management) accounts for 58% of anthropogenic, global emissions of primary PM _2.5 , 72% of ammonia (NH _3 ), 13% of nitrogen oxides (NO _x ), 9% of sulfur dioxide (SO _2 ), and 19% of non-methane volatile organic compounds (NMVOC). These emissions result in at least 890 000 ambient PM _2.5 -related deaths, which is equivalent to 23% of ambient PM _2.5 -related deaths reported in the Global Burden of Disease Study 2015. Predominant contributors include livestock and crop production, which contribute >50% of food-related NH _3 emissions, and land-use change and waste burning, which contribute up to 95% of food-related primary PM _2.5 emissions. These findings are largely underestimated given the paucity of data from the post-production and consumption stages, total underestimates in NH _3 emissions, lack of sector-scale analysis of PM _2.5 -related deaths in South America and Africa, and uncertainties in integrated exposure-response functions. In addition, we identify mitigation opportunities—including shifts in food demand, changes in agricultural practices, the adoption of clean and low-energy technologies, and policy actions—that can facilitate meeting food demand with minimal PM _2.5 impacts. Further research is required to resolve sectoral-scale, region-specific contributions to PM _2.5 -related deaths, and assess the efficiency of mitigation strategies. Our review is positioned to inform stakeholders, including scientists, engineers, policymakers, farmers and the public, of the health impacts of reduced air quality resulting from the global food system.

The impact of Uber and Lyft on vehicle ownership, fuel economy, and transit across U.S. cities

iScience · 2021 · 62 citations

• Business
• Demographic economics
• Economics

We estimate the effects of transportation network companies (TNCs) Uber and Lyft on vehicle ownership, fleet average fuel economy, and transit use in U.S. urban areas using a set of difference-in-difference propensity score-weighted regression models that exploit staggered market entry across the U.S. from 2011 to 2017. We find evidence that TNC entry into urban areas causes an average 0.7% increase in vehicle registrations with significant heterogeneity in these effects across urban areas: TNC entry produces larger vehicle ownership increases in urban areas with higher initial ownership (car-dependent cities) and in urban areas with lower population growth (where TNC-induced vehicle adoption outpaces population growth). We also find no statistically significant average effect of TNC entry on fuel economy or transit use but find evidence of heterogeneity in these effects across urban areas, including larger transit ridership reductions after TNC entry in areas with higher income and more childless households.

Global food system emissions could preclude achieving the 1.5° and 2°C climate change targets

Science · 2020 · 1037 citations

• Environmental science
• Business
• Biology

The Paris Agreement's goal of limiting the increase in global temperature to 1.5° or 2°C above preindustrial levels requires rapid reductions in greenhouse gas emissions. Although reducing emissions from fossil fuels is essential for meeting this goal, other sources of emissions may also preclude its attainment. We show that even if fossil fuel emissions were immediately halted, current trends in global food systems would prevent the achievement of the 1.5°C target and, by the end of the century, threaten the achievement of the 2°C target. Meeting the 1.5°C target requires rapid and ambitious changes to food systems as well as to all nonfood sectors. The 2°C target could be achieved with less-ambitious changes to food systems, but only if fossil fuel and other nonfood emissions are eliminated soon.

The COVID-19 lockdowns: a window into the Earth System

Nature Reviews Earth & Environment · 2020 · 218 citations

• Natural resource economics
• Environmental resource management
• Environmental planning

Reducing Mortality from Air Pollution in the United States by Targeting Specific Emission Sources

Environmental Science & Technology Letters · 2020 · 157 citations

• Environmental science
• Natural resource economics
• Environmental protection

Air quality in the United States has dramatically improved, yet exposure to air pollution is still associated with 100000–200000 deaths annually. Reducing the number of deaths effectively, efficiently, and equitably relies on attributing them to specific emission sources, but so far, this has been done for only highly aggregated groups of sources, or a select few sources of interest. Here, we estimate mortality in the United States attributable to all domestic, human-caused emissions of primary PM2.5 and secondary PM2.5 precursors. We present detailed source-specific attributions in four alternate groupings relevant for identifying promising ways to reduce mortality. We find that nearly half of the deaths can be attributed to just five activities, all in different sectors. Around half of the deaths can be attributed to fossil fuel combustion, with the remainder attributable to combustion of nonfossil fuels, agricultural processes, and other noncombustion processes. Both primary and secondary PM2.5 are important, including PM2.5 from currently unregulated precursor pollutants such as ammonia. We suggest improvements in air quality can be realized by continued reductions of emissions from traditionally important sources and by novel strategies for reducing emissions from sources of emerging relative importance and research focus. Such changes can contribute to improved health outcomes and other environmental goals.