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Recent studies conclude that the global coronavirus (COVID-19) pandemic decreased power sector CO$_2$ emissions globally and in the United States. In this paper, we analyze the statistical significance of CO2 emissions reductions in the U.S. power sector from March through December 2020. We use Gaussian process (GP) regression to assess whether CO2 emissions reductions would have occurred with reasonable probability in the absence of COVID-19 considering uncertainty due to factors unrelated to the pandemic and adjusting for weather, seasonality, and recent emissions trends. We find that monthly CO2 emissions reductions are only statistically significant in April and May 2020 considering hypothesis tests at 5% significance levels. Separately, we consider the potential impact of COVID-19 on coal-fired power plant retirements through 2022. We find that only a small percentage of U.S. coal power plants are at risk of retirement due to a possible COVID-19-related sustained reduction in electricity demand and prices. We observe and anticipate a return to pre-COVID-19 CO2 emissions in the U.S. power sector., Comment: 13 pages, 6 figures, preprint

Jesse D. Jenkins is a postdoctoral Environmental Fellow at the Harvard Kennedy School and the Harvard University Center for the Environment. His research harnesses methods from operations research, power systems engineering, and applied economics to improve regulation, policy, and practice in the rapidly evolving electricity sector. He earned a PhD in Engineering Systems (2018) and an SM in Technology & Policy (2014) at the Massachusetts Institute of Technology, where he was also a researcher at the MIT Energy Initiative and a lead author of the Utility of the Future study. Max Luke is a consultant in the energy practice at NERA Economic Consulting where he specializes in economic, regulatory, and legal implications of emerging trends in the electric power sector. He has worked on projects related to network regulation, electricity tariff design, electricity market design, and the impact of emerging technologies on utility business models. He earned an SM in Technology & Policy (2016) at the Massachusetts Institute of Technology, where he was also a researcher at the MIT Energy Initiative and a contributor to the Utility of the Future study. Samuel Thernstrom is Executive Director of the Energy Innovation Reform Project, a nonprofit organization that promotes the development of advanced energy technologies and practices that will improve the affordability, reliability, safety, and security of American energy supplies and our energy economy. He is also a senior fellow at the Center for the National Interest.

This paper presents a novel, empirical analysis of the most common business models for the deployment of demand response and energy management systems, electricity and thermal storage, and solar PV distributed energy resources. We classify the revenue streams, customer segments, electricity services provided, and resources for 144 business models. We use this assessment to identify a set of business model “archetypes” in each resource category. Our analysis leads us to five observations that have important implications for policymakers and regulators. First, our analysis highlights that business models are deeply embedded in myriad policy and regulatory frameworks. Second, current DER business models are driven more by regulatory and policy factors than by technological factors. Third, the relatively small set of well-defined DER business model archetypes suggests that the determinants of success within a given archetype may include executional capabilities, culture, and other activities that are not captured in our framework. Fourth, continued cost declines, technological innovation, and changing policy and regulatory landscapes mean the business models of tomorrow will likely look very different than the business models of today. Finally, DER business models compete within archetypes for market share in providing a limited set of electricity services.

Aquatic hypoxia can affect predator-prey interactions by altering the success rate of the predator and/or the vulnerability of prey. For example, in the Lake Victoria basin of East Africa, native prey exploit hypoxic wetlands as refugia from predation by introduced Nile perch (Lates niloticus). Here, it is predicted that species exploitation of wetlands depends on their hypoxia tolerance relative to the heterogeneity of wetland hypoxia. In this study, we compared the hypoxia tolerance of four fish taxa that differ in their use of hypoxic wetlands in Lake Nabugabo, Uganda: the cichlid Pseudocrenilabrus multicolor victoriae that inhabits the dense swamp interior; and three taxa that inhabit wetland ecotones including Nile tilapia (Oreochromis niloticus), L. niloticus and juvenile endemic haplochromine cichlids. We characterised hypoxia tolerance by exposing fish to progressive hypoxia and quantifying variation in aquatic surface respiration (ASR). The effect of body size on tolerance was explored in L. niloticus by quantifying ASR behaviour across a range of size classes. ASR behaviour was also compared between O. niloticus groups from wetland versus open-water habitats to detect habitat-associated intraspecific variation. The most tolerant taxon was the swamp specialist P. multicolor, indicated by its low ASR thresholds and small percentage of fish using ASR during the final sample interval. The other three taxa did not differ in ASR behaviour, and no differences were detected between O. niloticus groups. Body size effects were present for L. niloticus suggesting a lower tolerance to hypoxia in larger-bodied individuals, thus limiting their ability to penetrate wetlands.