When wells reach the end of their productive life, the plugging and abandonment process becomes crucial. Orphaned wells, lacking an accountable owner, pose a variety of environmental and health hazards, threatening water sources and emitting air pollutants [1]. The conventional plugging approach involves cementing and sealing to create an impermeable barrier. However, Portland cement, a primary component, contributes significantly to carbon dioxide emissions and resource consumption [2]. This study explores the potential of carbon sequestration in well plugging operations, specifically through the integration of biochar derived from abundant beetle-killed pine trees in Colorado.

The life cycle analysis assesses key stages, including transporting beetle-killed pine wood to the biochar facility, chipping, pyrolysis, and subsequent transportation of the formed biochar to a cement facility. The cement and biochar are then transported to the orphan well site for plugging, where biochar is integrated into spacer fluids, balance plugs, and well-squeezing operations. Comparative analyses reveal that incorporating biochar into standard well plugging operations results in an 11% reduction in greenhouse gas emissions per well plugged, highlighting biochar's role in mitigating the environmental impact traditionally associated with Portland cement. The findings contribute to ongoing discussions on sustainable practices within the oil and gas industry, positioning biochar as a promising avenue for reducing greenhouse gas emissions and fostering a more sustainable future.

[1] Raimi, D., Krupnick, A. J., Shah, J. S., & Thompson, A. (2021). Decommissioning Orphaned and Abandoned Oil and Gas Wells: New Estimates and Cost Drivers. In Environmental Science and Technology (Vol. 55, Issue 15, pp. 10224–10230). American Chemical Society. https://doi.org/10.1021/acs.est.1c02234

[2] Suarez-Riera, D., Restuccia, L., & Ferro, G. A. (2020). The use of Biochar to reduce the carbon footprint of cement-based materials. Procedia Structural Integrity, 26, 199–210. https://doi.org/10.1016/J.PROSTR.2020.06.023

Abstract: To meet the global greenhouse gas (GHG) emissions reduction goal, a priority concern is given to the building sector as the industry typically uses emission-intensive materials. Thus, various strategies are gradually adopted to reduce the embodied GHG emissions from buildings such as the adoption of design for manufacturing and assembly, increasing reuse and recycling of materials based on the circular economy (CE) principle, renovation of existing buildings, and increasing use of regenerative resources (e.g., bio-based materials). Using regenerative resources can substantially aid in reducing non-renewable resource consumption and subsequent GHG emissions. In addition, the use of wood-based resources can significantly promote the adoption of CE considering its adaptive mode and function. This study scrutinizes the recent trends, adoption, and functions of using wood-based resources in buildings based on the comprehensive literature review. Over a thousand relevant articles including scientific papers, conference papers, book chapters, reports, and thesis were preliminary analyzed based on the Scopus search, and then 180 articles were finalized according to the pre-defined criteria such as wood-based construction, buildings, lifecycle assessment, geographic coverage, applications, distinct features and specificity, evaluation methods and indicators, adopted databases and tools, etc. After synthesizing the selected studies, the key findings were summarized and discussed critically. Though recent studies showed substantial embodied carbon emissions reduction from buildings using bio-based materials compared to conventional materials [1-3], several aspects such as biogenic carbon accounting, multiple impact categories, the use of consistent methodology and databases, and CE adoption and its influence on environmental impacts of buildings need further attention. The existing gaps along with future research direction on how bio-based materials can substantially enhance CE adoption and the sustainability performance of buildings, are highlighted.

Keywords: Building, Sustainability, Wood-based resources, Circular economy, GHG emissions.

References

[1] Andersen C.E., Hoxha E., Rasmussen F.N., Sørensen C.G., Birgisdóttir H. (2024). Evaluating the environmental performance of 45 real-life wooden buildings: A comprehensive analysis of low-impact construction practices. Build. Environ. doi: https://doi.org/10.1016/j.buildenv.2024.111201.

[2] Churkina G., Organschi A., Reyer C.P.O, Ruff A., Vinke K., Liu Z., Reck B.K., Graedel T.E., Schellnhuber H.J (2020). Buildings as a global carbon sink. Nat. Sustain. 3, 269–276.

[3] Andersen C.E., Rasmussen F.N., Habert G., Birgisdóttir H. (2021). Embodied GHG emissions of wooden buildings—challenges of biogenic carbon accounting in current LCA methods. Front. Built Environ. 7:729096.

The southwestern states of California, New Mexico, and Utah, share many commonalities: a semiarid climate, water management challenges, changing hydroclimatic conditions, a growing competition for scant water supplies, and the production of alfalfa hay. Alfalfa greatly contributes to the economies of these states and the United States (US) overall each year. In 2022, the tristate areas collectively harvested 1.45 million acres to produce seven million tons of alfalfa hay valued at $2.1 billion. To cultivate alfalfa on this scale, large amounts of inputs (e.g., water, fertilizers, fuel, and pesticides) are applied, resulting in season-long high forage yields and profits but also risking water security, degrading water quality, impacting soil health, and emitting greenhouse gases (GHGs). This study aims to quantify the water use and other environmental impacts of alfalfa production systems, per cutting and life cycle stage, in the tristate area using a life cycle assessment (LCA). This study is the first LCA of alfalfa in the southwestern US. The cradle-to-farm gate system boundary includes stand establishment, forage production, and forage harvest. The functional unit is one ton of alfalfa hay corrected to 90% dry matter (DM). The primary data sources include the US Department of Agriculture’s National Agricultural Statistics Service (NASS), the University of California extension Cost & Return Studies, the New Mexico State University extension publications, the Utah State University extension publications, and state and county agriculture reports. Data analysis and modeling will be conducted using the LCA software SimaPro 9.2. Preliminary analyses indicate that water use in California, per cutting, is lower than water use in New Mexico and Utah. Results from this study can enable growers to assess tradeoffs between interconnected farm-management decisions using relevant data, charting a course toward a more resilient agricultural future. The findings of this study are scalable to other forage crops and regions with similar climate and water challenges and are especially important as the world moves toward achieving sustainable water use in a changing climate.

Achieving global climate goals is a copper-intensive endeavor. The rise of electrification trends and the widespread deployment of clean energy contribute to a growing demand for copper and the looming threat of a copper supply shortage. With annual copper demand expected to grow by 50% and reach 35 Mt by 2035, the world will need new sources of copper supply. While the development of new mining projects could increase copper production, declining ore grades leads to greater energy and land use for copper production, conflicting with global decarbonization goals and often environmental protection measures. Recycled copper, which has a significantly smaller carbon impact, can play a vital role in meeting present and future demand. Furthermore, enhanced secondary copper systems contributes to a circular economy while mitigating social and environmental risks. In this paper, we analyze opportunity scenarios to meet growing copper demand via increased end-of-life scrap collection and improved sorting efficiencies across six major waste streams: construction and demolition, municipal solid waste, waste electronic and electrical equipment, end of life vehicles, industrial electrical waste, and industrial non-electrical waste. We use an economic model of the copper system to quantify supply evolution while incorporating price feedback between demand and supply. The model quantifies the impact of the increased scrap collection on the displacement of mining production and demonstrates how increasing recycling can reduce supply risks, copper prices, and CO2-equivalent (CO2e) emissions. We benchmarked our findings against existing literature on future copper flows and found that there is an opportunity to increase scrap supply in 2035 by over 50% compared to the current baseline. From a regional analysis, optimized recycling and collection rates lead to an 110% increase in China’s copper supply alone. Building upon these collated results, we suggest strategies through policy and economic initiatives to help seize this end-of-life scrap opportunity.

Population growth in the United States has caused a massive uptick in building construction, both residential and commercial. Given the threat of climate change, it is necessary to understand the environmental impacts of these buildings to encourage sustainable practices. This study aims to quantify the impacts of the Curtis Media Center on UNC-Chapel Hill’s campus through a life cycle assessment (LCA). This study is cradle-to-grave and analyzes utility usage, construction processes, building materials, and transport. Two end-of-life scenarios are considered to highlight the importance of sustainable demolition. University utility data and construction documents, as well as the architect’s materials list, are used to determine quantities of each material used in the construction of the Curtis Center. Life cycle impact assessment (LCIA) values have been obtained from ecoinvent and aggregated to find the total environmental and human health impacts of the building.

Building LCAs are common, yet not much research has been done regarding buildings on college campuses. The Curtis Media Center has rooftop solar panels and is mostly accessible on foot, both of which help to decrease the building’s environmental footprint. This LCA uses the TRACI method to determine human health impacts of each life cycle stage. These impacts are discussed in the study and provide occupational health information that is often omitted in environmental LCAs. This study compares a best-case and worst-case scenario for the building’s end-of-life, which can be used to guide sustainable demolition of other buildings. The Curtis Center’s Energy Star profile is calculated and its implications are discussed in this study. Finally, life cycle impacts of the Curtis Center are compared to other similarly-used buildings to determine the relative “greenness” of the building. This LCA of the Curtis Media Center can be used to guide sustainable building development on other college campuses. More comprehensive statistical analysis must be done to understand the effects of random variables and uncertainty on the results of this study.