More Like this

1. Comparative Fuel Yield from Anaerobic Digestion of Emerging Waste in Food and Brewery Systems

   https://doi.org/10.3390/en15041538  

   Herman, Tess; Nungesser, Emily; Miller, Kimberley E.; Davis, Sarah C. (February 2022, Energies)

   Food waste (FW), a major part of the US waste stream, causes greenhouse gases within landfills, but there is an opportunity to divert FW to anaerobic digestion (AD) facilities that produce biogas and digestate fertilizer. The composition of FW inputs to AD determines the value of these products. This study provides insight into the effect of waste composition on the quality of AD products by first characterizing the biogas and digestate quality of anaerobically digested FW from four diets (paleolithic, ketogenic, vegetarian, and omnivorous), and then estimating the difference in biogas produced from codigested FW and brewery waste (BW). Waste feedstock mixtures were incubated in lab-scale bioreactors for 21 days with live inoculum. Biogas quality was monitored for 21–30 days in four trials. Samples were analyzed using a gas chromatograph for detection of methane (CH4) and carbon dioxide (CO2). The composition of the waste inputs had a significant impact on the quality of biogas but not on the quality of the digestate, which has implications for the value of post-AD fertilizer products. Wastes with higher proportions of proteins and fats enhanced biogas quality, unlike wastes that were rich in soluble carbohydrates. Codigestion of omnivorous food waste with carbon-rich agricultural wastes (AW) improved biogas quality, but biogas produced from BW does not necessarily improve with increasing amounts of AW in codigestion. 

   more » « less
2. Molecular dynamics simulations of a hydrophilic MIL-160-based membrane demonstrate pressure-dependent selective uptake of industrially relevant greenhouse gases

   https://doi.org/10.1039/d1ma00468a  

   Chapman, Jordan; Garapati, Nagasree; Glezakou, Vassiliki-Alexandra; Duan, Yuhua; Hu, Jianli; Dinu, Cerasela Zoica (September 2021, Materials Advances)

   Continued integration of technologies capable of achieving higher degrees of sustainability while meeting global material and energy demands is of singular importance in halting human-caused climate change. Gas separation membranes composed of metal–organic frameworks (MOFs) are considered promising candidates for such integration; owing to their modular, scalable nature and high degree of tunability they are seen essential to maintain separation functionality. However, prior to sustainable implementation, both an evaluation of MOF characteristics and an intensive examination of MOF–gas molecule interactions are necessary to fully understand the fundamental separation criteria as well as to define suitable ranges of gas separation conditions. Herein, we present our findings on the greenhouse gas separation capabilities of the hydrophilic, Al-based MIL-160 in the selective uptake of carbon dioxide (CO 2 ) from other relevant greenhouse gases, i.e. , methane (CH 4 ), sulfur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), and nitric oxide (NO), including gravimetric solubility, permeability, and diffusivity calculations. We found that a MIL-160 membrane has excellent applicability in the separation of gases of varying electronegativities, with a diffusivity selectivity of 72.0, 9.53, and 13.8 for CH 4 , NO 2 , and NO, respectively, relative to CO 2 . Further, we demonstrate that the selectivity at which gas molecules diffuse through the MIL-160 membrane varies strongly with the simulation pressure, suggesting that such membrane system is potentially an ideal candidate for the development of pressure-swing adsorption processes that achieve gas separations efficiently while mitigating the emission of greenhouse gases. 

   more » « less
3. Quantifying the Potential of Renewable Natural Gas to Support a Reformed Energy Landscape: Estimates for New York State

   https://doi.org/10.3390/en14133834  

   Taboada, Stephanie; Clark, Lori; Lindberg, Jake; Tonjes, David J; Mahajan, Devinder (July 2021, Energies)

   null (Ed.)

   Public attention to climate change challenges our locked-in fossil fuel-dependent energy sector. Natural gas is replacing other fossil fuels in our energy mix. One way to reduce the greenhouse gas (GHG) impact of fossil natural gas is to replace it with renewable natural gas (RNG). The benefits of utilizing RNG are that it has no climate change impact when combusted and utilized in the same applications as fossil natural gas. RNG can be injected into the gas grid, used as a transportation fuel, or used for heating and electricity generation. Less common applications include utilizing RNG to produce chemicals, such as methanol, dimethyl ether, and ammonia. The GHG impact should be quantified before committing to RNG. This study quantifies the potential production of biogas (i.e., the precursor to RNG) and RNG from agricultural and waste sources in New York State (NYS). It is unique because it is the first study to provide this analysis. The results showed that only about 10% of the state’s resources are used to generate biogas, of which a small fraction is processed to RNG on the only two operational RNG facilities in the state. The impact of incorporating a second renewable substitute for fossil natural gas, “green” hydrogen, is also analyzed. It revealed that injecting RNG and “green” hydrogen gas into the pipeline system can reduce up to 20% of the state’s carbon emissions resulting from fossil natural gas usage, which is a significant GHG reduction. Policy analysis for NYS shows that several state and federal policies support RNG production. However, the value of RNG can be increased 10-fold by applying a similar incentive policy to California’s Low Carbon Fuel Standard (LCFS). 

   more » « less
4. Reductions in California's Urban Fossil Fuel CO ₂ Emissions During the COVID‐19 Pandemic

   https://doi.org/10.1029/2022AV000732  

   Yañez, C. C.; Hopkins, F. M.; Xu, X.; Tavares, J. F.; Welch, A.; Czimczik, C. I. (December 2022, AGU Advances)

   Key Points With COVID‐19 restrictions, carbon dioxide (CO 2 ) levels on Los Angeles (LA) freeways were reduced by 119 ppm (or 60%) in July 2020 relative to 2019 Plant radiocarbon analysis captured a 5 ppm reduction in LA' fossil fuel CO 2 levels during the Stay‐At‐Home order Mobile and plant‐based measurements of fossil fuel CO 2 can help quantify decarbonization progress in cities 

   more » « less
5. Assessing energy sources for powering “evakuula”

   https://doi.org/10.18697/ajfand.114.20600  

   Sempiira, EJ; Ononye, C; Robinson, J; Aralu, A; Mugisa, DJ; Katimbo A, A; Galiwango, J; Gomillion, C; Kisaalita, WS (November 2022, African Journal of Food, Agriculture, Nutrition and Development)

   Technologies that are appropriate, affordable, and sustainable are needed to increase incomes and resilience among sub-Saharan African smallholder farmers. A combination of thermization and low-cost evaporative cooling, termed Evakuuling, was developed to enable rural smallholder dairy farmers to preserve their evening milk in the absence of grid-electricity. The “EvaKuula” was configured to be powered by biogas. Biogas is used for the thermization process of the system. The evaporative cooling component is powered by wind. Use of biogas from domestic biogas plants add circularity value to smallholder farms. However, domestic biogas plant set-ups are relatively high capital investments and as such, a financial barrier to co-adoption with the EvaKuula. To lower this barrier, other energy sources have been considered. The purpose of this study was to assess alternative energy sources to power the thermization component of the EvaKuula. The list of energy sources considered included biogas, butane, kerosene, charcoal, and firewood. These energy sources were assessed with respect to the sum of the social and market costs. The product of a unit of fuel cost and the units consumed represented the “market cost.” The product of the long-term social carbon cost and total carbon dioxide emission equivalence represented the “social cost.” Regular and improved stoves were included in the charcoal and firewood analysis. As expected, biogas ranked on top of the list, followed by butane and kerosene. However, butane and kerosene are not easily accessible in rural setting. Approximated 76% of farmers in rural sub-Saharan Africa rely on firewood to meet domestic needs like cooking. Butane and kerosene are the fuel sources predominantly used in urban and peri-urban areas, due to accessibility and affordability. Incomes are typically higher among urban dwellers. Therefore, with butane and kerosene not readily available to the target EvaKuula users, the next best option was firewood, provided it is combusted in improved efficient stoves such as Lorena type. Key words: alternative energy, evaporative cooling, sustainable development, food security, circularity, smallholder farmers 

   more » « less