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At least 91 records · Page 5

Capabilities Development at the University of Texas at El Paso for Hydrogen Generation Research and Education

Gasification-based systems have recently received much attention due to their capability of converting wastes into useful fuels. The gasification of biomass, municipal solid waste (MSW), plastics, and other sustainable resources has shown promise in hydrogen production. When coupled to a CCU or CCS unit, these systems have the potential to achieve carbon neutrality or carbon-negative emissions. In addition, these systems have an edge over conventional incineration or landfill systems by reducing greenhouse gas emissions and recovering useful energy. However, the gasification of MSW and other wastes is still in its early stages. In particular, co-gasification of wastes with biomass has significant unknowns in optimizing the reaction kinetics, operability, design and performance improvements. Currently, Supercritical Water Gasifiers (SCWG) and Plasma Gasifiers are the major systems that are capable of producing high hydrogen amounts from Biomass and MSW, respectively. However, both systems have high capital and operating costs, adversely affecting efficiency and the hydrogen production cost. Additionally, due to lower temperatures, SCWGs are prone to tar formation and fouling in the heat exchangers. Hence, there is a need to look for alternative solutions for MSW and biomass gasifications, particularly in co-gasification. The current effort aims to develop a strategic plan to establish a sustainable gasification facility for hydrogen research at the University of Texas at El (UTEP). A major part of this effort involves an extensive literature survey to identify technological gaps and potential areas of interest. Several concepts were developed in accordance with the current demands from the literature survey. Based on the concepts, a center-wide capability assessment was conducted to measure the current capacity and feasibility of establishing hydrogen research. Afterward, a strategic research plan was developed, and a list of required resources was made for the expansion of hydrogen research at UTEP. In addition, successful partnerships with the local county and the city were developed to pursue hydrogen research. The strategic goal setting and planning of UTEP Aerospace Center resulted in securing $2.5 million in external support to expand the hydrogen research during the project performance period. In addition, during the project period, a course in Hydrogen Energy Systems was developed to expand the energy curriculum at the UTEP Aerospace and Mechanical Engineering Department. The course focused on hydrogen production, storage, supply and delivery and application. The cross-listed course was offered at both undergraduate and graduate levels during the Spring 2024 semester and had 27 enrolled students. Moreover, the students supported under this award were trained in gasification process modeling, CAD, CFD and FEA during the project period. The training enabled the students to move into new projects to support gasification design, integrated gasification combined cycle process plant analysis, gasifier structural and operational analysis, and digitally threading the systems.

08 HYDROGEN↗

Sustainable Aviation Fuel: Review of Technical Pathways

The 106-billion-gallon global (21-billion-gallon domestic) commercial jet fuel market is projected to grow to over 230 billion gallons by 2050. Cost-competitive, environmentally sustainable aviation fuels (SAFs) are recognized as a critical part of decoupling carbon growth from market growth. Renewable and wasted carbon can provide a path to low-cost, clean-burning, and low-soot-producing jet fuel. Research shows an opportunity to produce fuel in which aromatics are initially diluted with the addition of renewable iso-alkanes, aromatics are later fully replaced with cycloalkanes, and finally high-performance molecules that provide mission-based value to jet fuel consumers are introduced. Key to this fuel pathway is sourcing the three SAF blendstocks - iso-alkanes, cycloalkanes, and high-performing molecules - from inexpensive resources. When resourced from waste carbon, there are often additional benefits, such as cleaner water when sourcing carbon from wet sludges or less waste going to landfills when sourcing the carbon from municipal solid waste or plastic waste. Jet fuel properties differ from gasoline and diesel, so research will be most successful if it begins with the end result in mind.

09 BIOMASS FUELS↗

Reinventing CEMENT: Carbonation-Enabled Mineralization to Engender Novel Technology

Cement is the most important building material used in civil infrastructure but it is extremely energy intensive to produce. We developed novel ways to make cements at low temperatures by mimicking the chemistry of the calcium silicate mineral pseudowollastonite. Pseudowollastonite is interesting because when it is exposed to hot (90-150oC), alkaline conditions with CO2 and water it reacts to form mineral phases that are much stronger than commercial cements. The resulting phases are also much more resistant to acid attack and have lower permeability, which will make them last longer. Many of the mineral phases in our cements are similar to those that exist in ancient Roman cements that have lasted thousands of years. Our objective was to understand how waste materials from industrial processes (such as power production, municipal solid waste treatment, or power plants) can be used to replicate the conditions that give pseudowollastonite cement its remarkable properties. We worked to optimize our formulations and incorporate the cements into concrete blends that the industry can test and consider using in different applications. Our cements could be used in pre-cast cement structural elements, which makes up nearly 20% of the total cement market and is growing rapidly. This work supports ARPA-E program objectives to significantly improve the industrial efficiency of materials production.

36 MATERIALS SCIENCE↗

Biogas Biocatalysis

Biogas derived from anaerobic digestion of waste streams such as biorefinery wastewater, animal, agricultural, and municipal solid waste, offers a versatile renewable energy source. Total domestic methane potential from landfill material, animal manure, wastewater, and organic waste, combined with biogas generated from AD of lignocellulosic biomass, is estimated to offer >4 quadrillion Btu potential energy. This energy could displace nearly half of current domestic natural gas consumption in the electric power sector and all consumption in the transportation sector. However, despite this promise of this feedstock, its gaseous state prevents facile integration with extant transportation and industrial infrastructure. Microbial conversion of biogas to liquid fuel and chemical intermediates offers valorization potential. However, biogas biocatalysis is currently limited by poor substrate gas-to-liquid mass transfer, low conversion efficiencies, and incomplete biogas utilization. To this end, the Biogas Biocatalysis AOP aims to develop a carbon- and energy-efficient biogas bioconversion process via techno-economic-informed strain and fermentation engineering strategies. Efforts here will improve both process economics and sustainability via process-intensified, carbon-efficient biogas bioconversion to value-added platform molecules, enabling bolt-on deployment for valorization of biogas derived from standalone AD infrastructure.

BASIC BIOLOGICAL SCIENCES,BIOMASS FUELS↗

Introducing Small Scale Waste-to-Energy Technology in Microgrids (Cooperative Research and Development Final Report, CRADA Number CRD-17-00703)

Cogent has developed an innovative, proprietary waste-to-energy (WTE) system, the HelioStorm(TM) Gasifier, capable of efficiently operating on small amounts of heterogeneous municipal solid waste feedstocks, converting them into a clean syngas that can be used to fuel an electricity generator, all with rapid on/off cycle times. NREL will work with Cogent to complete a computer simulation of an integrated HelioStorm(TM) plasma gasifier system and dual fuel diesel generator. Cogent will test the performance of an actual HelioStorm(TM) WTE system and dual fuel diesel generator at their test facility using steady state electrical loads and provide a report describing the performance of the integrated system.

09 BIOMASS FUELS↗

Port Authority of New York and New Jersey Sustainable Aviation Fuel Logistics and Production Study

The Port Authority of New York and New Jersey (PANYNJ) sustainability commitment is to meet the goals set by the Paris Agreement, with an interim greenhouse gas reduction target of 35% by 2025 and 80% by 2050. PANYNJ is seeking sustainable solutions to reduce carbon emissions for all public forms of transportation, including aviation. Similarly, the global aviation industry adopted the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), which seeks to cap net carbon dioxide (CO 2 ) aviation emissions at 2020 levels through 2035. Industry has also set a goal of reducing CO 2 emissions by 50% compared to 2005 levels by 2050. Sustainable aviation fuel (SAF), made from non-petroleum feedstocks, is a near-term alternative fuel that reduces emissions from air transportation. The National Renewable Energy Laboratory (NREL) conducted a resource assessment and a techno-economic analysis to identify the potential for production in the port district. Although SAF could be sourced from other areas of the United States or imported, an evaluation of local production was conducted due to the potential positive impacts of a circular economy by converting local waste feedstocks into SAF for use at nearby airports. The study found that the highest volumes of feedstock nearby were municipal solid waste and woody biomass. SAF must be blended with Jet A up to certain percent determined by ASTM International fuel quality standards prior to use in aircraft. SAF from a stand-alone facility could be delivered by barge, rail, or truck to a Linden, New Jersey based terminal for blending with Jet A or it could be blended in the Gulf region and shipped via the Colonial pipeline to one of the terminals. The investment will take place at the terminal(s) to accommodate SAF/Jet A blends and it will be business as usual for the airports in how they receive fuel and distribute it to aircraft.

09 BIOMASS FUELS↗

Evaluation of mixed #3–7 plastic waste from material recovery facilities (MRFs) in the United States

Plastic recycling rates are still low in the United States (U.S.), with less than 10% of municipal solid waste (MSW) plastic being recycled. Most unrecycled plastics are identified by Resin Identification Codes (RIC) from #3–7, which are commonly destined for landfill or waste-to-energy facilities (WTE). Therefore, the composition and quality of outbound bales containing #3–7 plastics were assessed to understand the potential to increase recycling rates. Three bales were sourced from three different Material Recovery Facilities (MRFs) located in the United States. Each bale was manually sorted and characterized for quality and performance via multiple plastic characterization techniques. Considerable differences in bale composition were observed between MRFs, which correlated with the technology used by each MRF in the sorting process. The differences were substantial in the residual levels of poly(ethylene terephthalate) (PET) and high-density polyethylene (HDPE), which are highly desired for mechanical recycling processes and not expected in #3–7 plastics bales. Traditional recycling processes including washing, extrusion, and injection molding of the sorted material were employed prior to the physical, thermal, and molecular characterization. Despite differences in bale composition by plastic type, some polymer properties were similar across MRFs. Here, this research suggests that landfill-diverted mixed plastic waste can be utilized in the mechanical recycling of currently unrecycled materials, as processes can be designed to work with consistent polymer properties. It also highlights the need to upgrade the sorting systems to prevent waste feedstocks, which can be recycled with current technologies, from contaminating other plastic streams or reach landfills.

36 MATERIALS SCIENCE↗

Integrated Urban Services: Program Impact and Business Plan Summary

The Integrated Urban Services (IUS) program, launched in 2021 and funded by the U.S. State Department under the United States-Association of Southeast Asian Nations (US-ASEAN) Smart Cities Partnership, aimed to bolster resilience in ASEAN cities by addressing challenges across food, energy, and water systems. Led by the National Renewable Energy Lab (NREL) with support from Regenerative Impact Ventures, the program focused on demonstrating the socio-economic benefits of integrated urban planning, educating stakeholders on circular economy principles, providing technical assistance to two ASEAN cities, and attracting private sector involvement. The program facilitated peer learning events, engaging public and private sector participants and leveraging knowledge from a group of global experts to inform approaches and best practices. Technical assistance was provided to two pilot cities, Iskandar Malaysia and Cagayan de Oro, Philippines, resulting in the development of market-driven business plans for resilient, circular, and regenerative energy-water-food system projects. The Iskandar Malaysia pilot focused on development of a state-of-the-art AgriTech Innovation Hub and Modern Farming Complex to enhance agricultural productivity and produce enough renewable energy to power the facilities. The Cagayan de Oro project aimed to enhance urban agricultural productivity and waste management through development of an Urban Precision Agricultural Complex featuring aeroponics, hydroponics, aquaponics, agrivoltaics, and a Black Solider Fly Facility for converting municipal solid waste into commodities. The success of the IUS program sets a precedent for replicating integrated urban service models globally, offering valuable insights for cities aiming to enhance their resilience and sustainability.

ASEAN↗

Challenges in Tracking Waste Reduction Performance Improvement in Manufacturing Plants

The recently released Circularity Gap Report 2023 by the Circle Economy Foundation states that the circularity score for the global economy is declining. The US Environmental Protection Agency (EPA) tracked municipal solid waste from 1960 to 2018 and found that 50% of the waste was destined for landfills. EPA estimates that US industry is responsible for 2.7 Gt of solid nonhazardous waste annually in the US mostly linear economy model. The circular economy framework aims to decouple economic value generation from the extraction of virgin materials from nature. The linear model of material extraction and disposal at the end of life is highly unsustainable. Manufacturing companies are adopting ambitious waste reduction targets to achieve sustainability. Through the Better Plants program, US DOE has established the Waste Reduction Network, which offers technical assistance to partners to achieve their ambitious waste reduction goals. Basic requirements of establishing a target include identifying a baseline, quantifying waste performance, and measuring progress over time. One problem faced by industry is unstandardized metrics for quantifying waste performance that may not be well suited to demonstrate progress. This paper studies traditional methods used to measure waste performance and highlights advantages, disadvantages, and limitations of each method. It also examines the suitability of applying the methods in different manufacturing circumstances. Finally, the paper presents a case study of a large manufacturer that faced inconsistencies in its tracked measurement metric. A solution was proposed and implemented to alter the methodology to enable more accurate waste performance tracking against a baseline.

circular economy↗

Hydrogen production from high-volume organic construction and demolition wastes

The Energy & Environmental Research Center (EERC) has partnered with Simonpietri Enterprises, LLC (SEL) with the objective of developing an integrated waste preparation, gasification, and syngas cleanup process capable of using a high-volume, negative-value, highly contaminated feedstock consisting of construction and demolition (C&D) waste to economically produce 99+% pure hydrogen. The target is to achieve $\$$1/kg H2 at a modular scale ranging from 5- to 50-MWe-equivalent size by testing the gasification of organic C&D debris containing treated waste lumber and construction materials, permanently sequestering contaminants into the ash. C&D debris waste is one the largest-volume waste streams in the United States; is already aggregated and available across the country, lending itself to hub operations; and has fewer alternatives for energy conversion than are available for coal, biomass, and municipal solid waste because of contamination from treated lumber and other construction materials.

08 HYDROGEN↗

Escalating trends in the urban metabolism of Hong Kong: 1971-1997

Urban metabolism measures quantitatively a city's load on the natural environment. We update the Newcombe et al. (3) pioneering study of Hong Kong's urban metabolism in 1971, highlighting trends in resource consumption and waste generation. Per capita food, water and materials consumption have surged since the early 1970s by 20%, 40%, and 149%, respectively. Tremendous pollution has accompanied this growing affluence and materialism, and total air emissions, CO2 outputs, municipal solid wastes, and sewage discharges have risen by 30%, 250%, 245%, and 153%. As a result, systemic overload of land, atmospheric and water systems has occurred. While some strategies to tackle deteriorating environmental quality have succeeded, greater and more far-reaching changes in consumer behavior and government policy are needed if Hong Kong is to achieve its stated goal of becoming "a truly sustainable city" in the 21st century.

Environmental Pollution↗

Life-Cycle Greenhouse Gas Emissions and Human Health Trade-Offs of Organic Waste Management Strategies

Waste-to-energy systems can play an important role in diverting organic waste from landfills. However, real-world waste management can differ from idealized practices, and emissions driven by microbial communities and complex chemical processes are poorly understood. This study presents a comprehensive life-cycle assessment, using reported and measured data, of competing management alternatives for organic municipal solid waste including landfilling, composting, dry anaerobic digestion (AD) for the production of renewable natural gas (RNG), and dry AD with electricity generation. Landfilling is the most greenhouse gas (GHG)-intensive option, emitting nearly 400 kg CO 2e per tonne of organic waste. Composting raw organics resulted in the lowest GHG emissions, at -41 kg CO 2e per tonne of waste, while upgrading biogas to RNG after dry AD resulted in -36 to -2 kg CO 2e per tonne. Monetizing the results based on social costs of carbon and other air pollutant emissions highlights the importance of ground-level NH3 emissions from composting nitrogen-rich organic waste or post-AD solids. However, better characterization of material-specific NH 3 emissions from landfills and land-application of digestate is essential to fully understand the trade-offs between alternatives.

54 ENVIRONMENTAL SCIENCES↗

Challenges in Tracking Waste Reduction Performance Improvement in Manufacturing Plants

The recently released Circularity Gap Report 2023 by Circle Economy Foundation found that the circularity score for the global economy is declining. This indicates that material extraction from virgin sources is climbing over earlier years. As per data released by US Geological Survey, material use in the US economy has increased exponentially with the expanding US economy over last century. EPA tracked municipal solid waste from 1960 to 2018 and found that 50% of the waste is destined for landfills. EPA estimates that US industry is responsible for 2.7 billion ton of solid non-hazardous waste annually in our mostly linear economy model. The circular economy framework aims at decoupling economic value generation from virgin materials extraction from nature. The linear model of material extraction and disposal at end of life is highly unsustainable. Manufacturing companies have realized this and in their commitments to sustainability are adopting ambitious waste reduction targets. Through Better Plants program US Department of Energy has established Waste Reduction Network where it is offering technical assistance to partners to achieve these ambitious waste reduction goals. Basic requirements of establishing a target include identifying a baseline, quantifying waste performance, and measuring progress over time. One problem faced by industry is the unstandardized metrics to quantify waste performance that may not be well suited to demonstrate progress. In this paper, we research methods traditionally used to measure waste performance and highlight advantages, gaps and limitations of each method. Suitability of the methods applicable to different manufacturing circumstances are also examined. Finally, we present a case study of a large manufacturer that faced inconsistencies in their tracked measurement metric. A solution was proposed to alter the methodology to enable more accurate waste performance tracking against a baseline.

Chaudhari, Subodh↗

Planning decentralized urban renewable energy systems using algal cultivation for closed-loop and resilient communities

To tackle climate challenges, communities need to harvest renewable energy and resources on site locally to close the loops for enhancing the resilience of communities facing unpredictable and uncertain future changes. A decentralization planning of urban renewable energy systems is proposed by treating urban waste streams and producing biomass through applying algal biotechnology. When applying algal technology as a renewable and decentralized energy source in urban systems, the overall performance can vary by levels of urban nutrients, solar and CO 2 resources, and the transportation cost when considering its application to different urban densities, urban form, and the spatial scale of urban settings. This research explores three potential impacts on the algal system’s energy performance: (1) urban density, (2) urban form in different contexts, and (3) spatial scale. The research examines the impacts by testing urban settings given in actual contexts in Atlanta, Georgia, USA. Four neighborhoods representing the high-density urban, mid-density urban, mixed suburban, and typical suburban areas are investigated. The density-scale–performance relationships are explored through testing different urban forms of neighborhoods in both hypothetical and actual neighborhood settings. A GIS-based model is developed to estimate the overall energy performance of the decentralized renewable energy system in urban environments. Results show that the energy performance is positive mainly for high-density urban neighborhoods with small-to-medium scales, up to 0.36 MJ per ton of municipal solid wastes for actual settings and 0.37 MJ for hypothetical cases. Neighborhoods with higher density have higher energy performance while up scaling has negative effects on the energy performance with a low degree of significance. Optimal scales are found as a 1-km radius in real test beds and 1.3 km in hypothetical settings, in which the results show trade-offs between scaling effects in the system efficiency gain and the transportation cost increase.

Quan, Steven Jige↗

Algebraic expressions for estimating the impact depths of a surface barrier over a homogeneous soil

Engineered surface barriers are used to isolate subsurface contaminants for effective long-term containment of municipal solid waste, other nonhazardous solid and liquid waste, hazardous and toxic wastes, and radioactive waste. The impact depths of a surface barrier are affected by the pre-barrier recharge rate and the properties of the soil beneath the barrier. In this paper, the pore-size-specific (PSS) water velocity is defined and an algebraic expression of PSS velocity is derived based on the stream tube concept and the Brooks and Corey hydraulic retention model. Algebraic expressions are developed to estimate drainage velocities and barrier impact depths after the emplacement of a surface barrier. Four impact depth terms are used to convey the protective effect: drainage front, average drainage, the location with 50% impact, and drainage tail. The drainage front depth is the deepest point at which the barrier has a detectable impact at a specific time (also called the near zero-impact depth). The average-impact depth is the depth at which average drainage occurs. At the 50% impact depth, the water flux rate is reduced by half because of the surface barrier. Lastly, the drainage tail depth (also called the full-impact depth) is the deepest depth at which the water conditions above it are in equilibrium with the barrier. The algebraic expressions show that the average-impact depth is no more than 1/3 of near zero-impact depth, while the 50% impact depth is slightly larger than 1/2 of the near zero-impact depth. The full-impact depth, depending on the final recharge rate from the surface barrier, is usually much smaller than the other impact depths. These differences lead to a very large transition zone beneath a surface barrier. Numerical simulations were conducted to replicate the same conditions. The numerical results corroborated the analytical models by predicting very similar water content profiles and near zero-, average-, 50%, and full-impact depths. The algebraic expressions provided in this paper are useful for quickly identifying sites where the depth of the existing contaminants could be beyond the protection of a surface barrier.

54 ENVIRONMENTAL SCIENCES↗

Sustainability assessment of alternative jet fuel for the U.S. Department of Defense

The United States Department of Defense (DoD) is considering replacing the 2.8 billion gallons of petroleum jet fuel consumed within the continental United States (CONUS) annually with alternative jet fuels to reduce vulnerability to price and supply fluctuations and improve sustainability. We evaluate the feasibility of replacing DoD CONUS jet fuel with alternative jet fuel from domestic feedstocks and assess the cost, greenhouse gas (GHG) emissions, energy balance, land, water, and fertilizer impacts of nine alternative jet fuel pathways. The feedstocks include terrestrial crops (soy, corn, wood, and grass), marine microalgae, and by-products (forestry residue, municipal solid waste, and waste oil) converted by extraction, fermentation, or thermo-chemical conversion, paired with upgrading steps. We found that domestic biomass feedstocks can meet the DoD CONUS jet fuel demand without significantly affecting food supply. Alternative pathways cost more than petroleum jet fuel ($0.78 l -1 and emitting 89 g CO 2 equivalent (CO 2e ) MJ -1 ), but many lowered GHG emissions. The forestry residue and waste oil pathways yielded the lowest costs ($\$0.92$ and $\$0.82$ l -1 , respectively), decreased emissions (23 and 35 g CO 2 e MJ -1 , respectively), and had negligible effects on land, water, and fertilizer resources. Finally, tradeoffs among sustainability metrics are further explored with a sensitivity analysis and by evaluating carbon-cost scenarios.

09 BIOMASS FUELS↗