Explore the vast range of titles available.

The seamless adoption of electric vehicles (EVs) in the United States necessitates the development of extensive and effective charging infrastructure. Various charging systems have been proposed, including Direct Current Fast Charging, Battery Swapping, and Dynamic Wireless Power Transfer. While many studies have evaluated the charging costs and greenhouse gas (GHG) intensity of EVs, a comprehensive analysis comparing these systems and their implications across vehicle categories remains unexplored. This study compares the total cost of ownership (TCO) and GHG-intensity of EVs using these charging systems. Based on nationwide infrastructure deployment simulations, the change to TCO from adopting EVs varies by scenario, vehicle category, and location, with local fuel prices, electricity prices, and traffic volumes dramatically impacting results. Further, EV GHG-intensity depends on local electricity mixes and infrastructure utilizations. This research highlights the responsiveness of EV benefits resulting from technology advancements, deployment decisions, and policymaking. Results show meaningful variations in electric vehicle costs and emissions benefits across the United States, differing by vehicle category and charging systems: Direct Current Fast Charging, Battery Swapping, and Dynamic Wireless Power Transfer.

In the current literature, the life cycle, technoeconomic, and resource assessments of microalgae-based biofuel production systems have relied on growth models extrapolated from laboratory-scale data, leading to a large uncertainty in results. This type of simplistic growth modeling overestimates productivity potential and fails to incorporate biological effects, geographical location, or cultivation architecture. This study uses a large-scale, validated, outdoor photobioreactor microalgae growth model based on 21 reactor- and species-specific inputs to model the growth of Nannochloropsis . This model accurately accounts for biological effects such as nutrient uptake, respiration, and temperature and uses hourly historical meteorological data to determine the current global productivity potential. Global maps of the current near-term microalgae lipid and biomass productivity were generated based on the results of annual simulations at 4,388 global locations. Maximum annual average lipid yields between 24 and 27 m ³·ha ⁻¹·y ⁻¹, corresponding to biomass yields of 13 to 15 g·m ⁻²·d ⁻¹, are possible in Australia, Brazil, Colombia, Egypt, Ethiopia, India, Kenya, and Saudi Arabia. The microalgae lipid productivity results of this study were integrated with geography-specific fuel consumption and land availability data to perform a scalability assessment. Results highlight the promising potential of microalgae-based biofuels compared with traditional terrestrial feedstocks. When water, nutrients, and CO ₂ are not limiting, many regions can potentially meet significant fractions of their transportation fuel requirements through microalgae production, without land resource restriction. Discussion focuses on sensitivity of monthly variability in lipid production compared with annual average yields, effects of temperature on productivity, and a comparison of results with previous published modeling assumptions.

Green infrastructure solutions can improve in-stream water quality in lieu of building electricity-consuming gray infrastructure. Permitted under the United States Clean Water Act, these programs allow regulated utilities to trade point-source water quality obligations with non-point source mitigation efforts in the watershed. Carbon financing can provide an incentive for water quality trading. Here we combine data on impaired waters, treatment technologies, and life cycle greenhouse gas emissions in the Contiguous United States, and compare traditional treatment technologies to alternative green infrastructure. We find green infrastructure could save$15.6 billion dollars, 21.2 terawatt-hours of electricity, and 29.8 million tonnes of carbon dioxide equivalent emissions per year while sequestering over 4.2 million tonnes CO2e per year over a 40 year time horizon. Green infrastructure solutions may have the potential to generate $ 679 million annually in carbon credit revenue (at $20 per credit), which represents a unique opportunity to help accelerate water quality trading.

Given the enormous impact of buildings on energy consumption, it is important to continue the development of net-zero energy districts. Opportunities exist for energy efficiency and renewable energy on a district level that may not be feasible in individual buildings. Due to the intermittent nature of many renewable energy sources, net-zero energy districts are dependent on the energy grid. The novelty of this work is to quantify and optimize the economic cost and grid independence of a net-zero energy district using the National Western Center (NWC) in Denver, CO, USA as a case study. The NWC is a 100+ ha campus undergoing a major redevelopment process with a planned 170,000 m2 of total building space, an emphasis on sustainability, and a net-zero energy goal. Campus plans, building energy models, and renewable energy performance models of on-site solar, biomass, and thermal renewable energy sources are analyzed in multiple energy scenarios to achieve net-zero energy with and without on-site energy storage. Levelized cost of energy (LCOE) is optimized as a function of variables defining the energy and economic relationship with the grid. Discussion herein addresses trade-offs between net-zero energy scenarios in terms of energy load, LCOE, storage, and grid dependence.

Decarbonizing the United States transportation sector has emerged as a critical objective to combat climate change due to its high greenhouse gas emissions, largely from light-duty vehicles. This study assesses the breakdown of life cycle emissions of various transportation options under average and maximum ridership scenarios and quantifies emissions reductions through mode shifts and technology advancements. Electrified transportation achieves half the greenhouse gas emissions of petroleum-fueled options in 2023, with projections indicating a reduction to one-fifth by 2050. Battery systems contribute up to one-fifth of lifetime emissions of electric vehicles and buses as of 2023, and this share is estimated to increase to half by 2050 as electricity emissions are greatly reduced with the decarbonization of electricity. The study concludes that shifting away from light-duty vehicles can achieve near-term greenhouse gas reductions, but these reductions are minimal in the long term when combined with transportation electrification powered by decarbonized electricity. In the United States, electrification can reduce greenhouse gas emissions from passenger transportation by half now and up to 85 percent by 2050 with a decarbonized grid, according to an analysis that uses life cycle assessment and ridership scenarios.

As the poultry industry works to become more sustainable and to reduce the volume of food waste, it is critical to consider points in the processing system that can be altered to make the process more efficient. In this study, we demonstrate that the method used during chilling (air versus water chilling) influences the final product microbial community, quality, and physiochemistry. The United States’ large-scale poultry meat industry is energy and water intensive, and opportunities may exist to improve sustainability during the broiler chilling process. By USDA regulation, after harvest the internal temperature of the chicken must be reduced to 40°F or less within 16 h to inhibit bacterial growth that would otherwise compromise the safety of the product. This step is accomplished most commonly by water immersion chilling in the United States, while air chilling methods dominate other global markets. A comprehensive understanding of the differences between these chilling methods is lacking. Therefore, we assessed the meat quality, shelf-life, microbial ecology, and techno-economic impacts of chilling methods on chicken broilers in a university meat laboratory setting. We discovered that air chilling methods resulted in superior chicken odor and shelf-life, especially prior to 14 days of dark storage. Moreover, we demonstrated that air chilling resulted in a more diverse microbiome that we hypothesize may delay the dominance of the spoilage organism Pseudomonas . Finally, a techno-economic analysis highlighted potential economic advantages to air chilling compared to water chilling in facility locations where water costs are a more significant factor than energy costs. IMPORTANCE As the poultry industry works to become more sustainable and to reduce the volume of food waste, it is critical to consider points in the processing system that can be altered to make the process more efficient. In this study, we demonstrate that the method used during chilling (air versus water chilling) influences the final product microbial community, quality, and physiochemistry. Notably, the use of air chilling appears to delay the bloom of Pseudomonas spp. that are the primary spoilers in packaged meat products. By using air chilling to reduce carcass temperatures instead of water chilling, producers may extend the time until spoilage of the products and, depending on the cost of water in the area, may have economic and sustainability advantages. As a next step, a similar experiment should be done in an industrial setting to confirm these results generated in a small-scale university lab facility.

Despite the many advantages of microalgae, the feasibility of large-scale cultivation requires significant amounts of carbon dioxide (CO2) to enable high growth rates. A synergistic union typically proposed for the supply of CO2 is the coupling of algal cultivation with emissions from power plants. This study investigates the sustainability of a novel microalgae platform coupled with coal-based flue gas. The proposed system consists of a novel photobioreactor (PBR) for the production of biomass followed by a two-stage dewatering process. A systems model, which quantifies the CO2 and energy consumption of the proposed system, was developed, and the minimum biomass selling price (MBSP) was determined by a techno-economic analysis (TEA). TEA results indicate that a facility with the capacity to capture 30% of the emissions from a 1-MW power plant requires a biomass production of 1280 metric ton per year, which when scaled to a nth of kind facility can produce biomass at a MBSP of $2322 per ton. The environmental impact of the proposed facility was determined by a life cycle assessment methodology, and results indicate a carbon capture potential of 1.16 × 104 metric tons of CO2 equivalent. In addition, an energy analysis indicates a desirable net energy ratio of 0.1, which is lower than conventional PBRs. Discussion focuses on the requirements to reduce biomass production cost, including research investment areas for increasing productivity while decreasing energy requirements.

Ultrasonic harvesting could reduce the energy consumption and costs associated with separating microalgae from growth media. The responsiveness of microalgae cells to an ultrasonic standing wave depends on the cell radius and acoustic contrast factor (ACF). The ACF can vary as cell composition (e.g. lipid, protein, carbohydrate content) varies depending on the algae strain, cultivation conditions, and growth stage. Two independent experimental methods were used to characterize the ACF of three algae ;strains—Nannochloropsis salina, Chlamydomonas reinhardtii, and Tetraselmis chuii—as a function of dynamic cellular composition over 9- to 14-day growth periods. For N. salina, lipid content increased from 25 ± 1% to 33 ± 1% ash-free dry weight (AFDW) and ACF decreased by 46% (from 0.041 ± 0.002 to 0.022 ± 0.002) between growth days 3 and 10. For C. reinhardtii, lipid content increased from 26 ± 1% to 40 ± 1% AFDW and ACF decreased by 33% (from 0.051 ± 0.013 to 0.034 ± 0.006) between growth days 3 and 9. For T. chuii, lipid content and ACF remained stable (~ 10% AFDW and ~ 0.3) over the growth period. ACF decreased as lipid content increased because lipids have a negative ACF in the growth media; however, cell size had a greater impact on cell responsiveness because the ratio of the acoustic radiation force to the drag force is proportional to cell radius squared.

Current assessments of the commercial viability and productivity potential of microalgae biofuels have been forced to extrapolate small-scale research data. The resulting analyses are not representative of microalgae cultivation and processing at industrial scale. To more accurately assess the current near-term realizable, large-scale microalgae productivity potential in the USA, this paper presents a model of microalgae growth derived from industrial-scale outdoor photobioreactor growth data. This model is combined with thermal models of the photobioreactor system and 15 years of hourly historical weather data from 864 locations in the USA to more accurately assess the current productivity potential of microalgae. The resulting lipid productivity potential of Nannochloropsis is presented in the form of a map that incorporates various land availability models to illustrate the near-term feasible cultivation locations and corresponding productivity potentials for the USA. The discussion focuses on a comparison of model results with productivity potentials currently reported in literature, an assessment demonstrating the scale of Department of Energy 2030 alternative fuel goals, and a critical comparison of productivity potential in several key regions of the USA.