Many canonical integrated assessment models examining the relationship between energy, climate, economics, and public policy represent negative emissions interventions poorly and haphazardly, if these approaches to decarbonization are included at all in such models. This grant supports work by scholars at the Institute for Carbon Removal Law & Policy at American University to improve how negative emissions technologies are represented in two of the most often used integrated assessment models. One of these models, EnROADS, is a highly aggregated economy-climate-energy model. The other, the Global Change Assessment Model (GCAM), is one of the most widely used open source energy and climate models in the field. Grant funds will support two postdoctoral researchers, who will work to develop extensions of these two models to better account for the potential emergence of negative emissions (decarbonization) technologies over the coming decades.

This grant provides partial support to the National Academy of Sciences, Engineering, and Medicine for the production and dissemination of an ambitious consensus study that will examine the technological, policy, and societal dimensions of deep decarbonization efforts in the United States across a range of sectors, including manufacturing, food and agriculture, transportation, electricity generation, and carbon dioxide removal. This consensus study will be conducted under the auspices of the Board on Energy and Environmental Systems (BEES) and led by Director and Scholar John Holmes. The plans for this consensus study were developed following an initial public workshop, and this process will bring together experts from multiple disciplines to assess the best way to scale up decarbonization developments across different sectors and offer a roadmap for how to move forward. The consensus study is also expected to lead to the formation of a longer-running Deep Decarbonization Forum, an ongoing dialogue effort that would involve developing a set of additional dissemination products. The Deep Decarbonization Forum will hold a series of workshops and briefings to continue the discussion of these critical, long-term topic areas for years to come.

Comparisons of the land use estimates of different electricity generation technologies often rely on poorly estimated, rule-of-thumb calculations, with little direct observation of how much land each of these components actually occupies in the real world. This grant supports a project by Sarah Jordaan, Vishal Patel, and Benjamin Hobbs to rigorously estimate the land use requirements for different electricity generation technologies and their associated fuel supplies. The team will conduct satellite imagery analysis that can more accurately account for the individual land footprint of different components of the energy system. The focus of this effort will be on the United States portion of what is known as the Western Interconnection, a region from the Rocky Mountains westward that includes almost every type of power generation facility (including natural gas, coal, nuclear, wind, and, solar), elements of their supply chains (natural gas production facilities, coal mines, uranium mines, and pipelines), and transmission and distribution lines for connecting wind and solar sites to the grid. The team has access to high-resolution satellite data that not only allows them to accurately detect the land use implications of large-scale infrastructure like generation facilities, but also harder-to-determine infrastructure like pipes and transmission lines. This study will also provide the tools to better assess the power density and land use intensity of each generation technology.

Direct air capture (DAC) is one of the most exciting and novel advancements in negative emissions science and technology. DAC systems remove carbon dioxide (CO2) from the atmosphere by flowing ambient air through a filter. Sorbent chemicals embedded in the filter bind to the atmospheric CO2, trapping it. The trapped CO2 is subsequently removed from the filter for capture, disposal, or reuse. Doing so, however, requires heating the filter, and thus typically requires proximity to an appropriate heat source. This requirement substantially limits where DAC systems can be sited and increases their carbon footprint, since energy must be expended to produce the needed heat. This grant funds exciting new work by a team led by University of California, Irving chemist Jenny Yang to address this core challenge by exploring new electrochemical processes that would facilitate the capture and concentration of CO2 at room temperature, without the need for added heat. This would allow DAC to take place at ambient temperatures, greatly increasing the range of conditions where DAC systems could be deployed. Yang and her team will identify and test various kinds of electrochemical CO2 capture materials using computational chemistry methods and then use chemistry modeling techniques to determine how well different materials might perform as ambient temperature DAC filter systems. Promising materials will be tested in laboratory-scale CO2 separation chambers to determine their performance under various conditions.

This grant supports an interdisciplinary project led by Laura Lindsey at Ohio State University to study how various agricultural practices might promote the uptake and storage of carbon dioxide (CO2) in soils, plants, and crops. Lindsey and her team of soil scientists, biologists, and environmental scientists drawn from multiple institutions will focus on examining three practices that could be deployed in commercial agriculture. The first is the application of biochar into crop systems. Biochar is a charcoal-like material that is applied to soils to improve carbon uptake from the atmosphere. The second process is the use of cover crops, which are plants designed to help maintain carbon fixation in soils. The third process is the implementation of better nitrogen management practices that reduce nitrous oxide emissions. In addition to laboratory research, Lindsey and her team will conduct five field studies across Kentucky, Ohio, and Michigan, testing different combinations of these three agricultural practices (biochar, cover crop, nitrogen management) to determine their relative impact, alone and in combination, on carbon sequestration in agriculture systems.

Weatherization and mineralization are natural processes by which rocks of certain chemical compositions react with carbon dioxide (CO2)Сeither from ambient air or from concentrated CO2 streams collected during industrial processesСand undergo reactions that lead to the CO2 binding to the rock. These processes thus represent a potential pathway for decarbonization, an opportunity to use natural processes to sequester large amounts of atmospheric carbon in mineralized form. This grant supports research by Christine McCarthy and Ah-Hyung Park that will investigate key questions about the basic physics and chemistry of rock weathering and mineralization, with an aim toward understanding how these processes can be enhanced and accelerated. For example, mineralization can result in an effect called Тreactive crackingУ in which pores or fissures in the rock open, creating more surface area that allows for additional mineralization. This generates a positive CO2 solidification feedback loop. Sometimes, however, mineralization does not result in reactive cracking. Instead, as a rock mineralizes, pores within the rock become clogged by carbonated minerals, leading the rock pores to become ТcloggedУ and hindering further mineralization. The team led by McCarthy and Park will study what factors lead to differences between these ТcrackingУ versus ТcloggingУ effects, and they will assess how these reactions might impact larger-scale efforts to mineralize CO2 in geologic systems. This study will include a series of laboratory experiments that will examine a range of different stress, temperature, and acidity conditions that might hinder or accelerate such cracking or clogging processes, with these lab-based results used to model how such findings might scale up in real-world field conditions.