Rechargeable batteries are necessary for the decarbonization of the energy systems, but life‐cycle environmental impact assessments have not achieved consensus on the environmental impacts of ...producing these batteries. Nonetheless, life cycle assessment (LCA) is a powerful tool to inform the development of better‐performing batteries with reduced environmental burden. This review explores common practices in lithium‐ion battery LCAs and makes recommendations for how future studies can be more interpretable, representative, and impactful. First, LCAs should focus analyses of resource depletion on long‐term trends toward more energy and resource‐intensive material extraction and processing rather than treating known reserves as a fixed quantity being depleted. Second, future studies should account for extraction and processing operations that deviate from industry best‐practices and may be responsible for an outsized share of sector‐wide impacts, such as artisanal cobalt mining. Third, LCAs should explore at least 2–3 battery manufacturing facility scales to capture size‐ and throughput‐dependent impacts such as dry room conditioning and solvent recovery. Finally, future LCAs must transition away from kg of battery mass as a functional unit and instead make use of kWh of storage capacity and kWh of lifetime energy throughput.
Rechargeable batteries are necessary for the decarbonization of the energy systems, but life‐cycle environmental impact assessments have not achieved consensus on the environmental impacts of producing these batteries. This article highlights underlying reasons for the discrepancies in energy and environmental impact estimates and recommends better practices for more transparent, interpretable battery life‐cycle assessments.
Biomanufacturing has the potential to reduce demand for petrochemicals and mitigate climate change. Recent studies have also suggested that some of these products can be net carbon negative, ...effectively removing CO2 from the atmosphere and locking it up in products. This review explores the magnitude of carbon removal achievable through biomanufacturing and discusses the likely fate of carbon in a range of target molecules. Solvents, cleaning agents, or food and pharmaceutical additives will likely re-release their carbon as CO2 at the end of their functional lives, while carbon incorporated into non-compostable polymers can result in long-term sequestration. Future research can maximize its impact by focusing on reducing emissions, achieving performance advantages, and enabling a more circular carbon economy.
Future biomanufacturing studies must recognize the important distinction between greenhouse gas mitigation relative to the status quo and processes that result in true carbon dioxide removal.The potential for biomanufacturing to serve as a carbon dioxide removal strategy is limited because many target products are re-oxidized to CO2 at the end of their useful life, yet this is not accounted for in recent studies.Many precursors to commodity polymers can be made biologically and polymers offer the largest opportunity to achieve carbon dioxide removal through biomanufacturing.Bio-based materials do reduce reliance on petroleum and may offer performance advantages relative to conventional petrochemical alternatives.Instead of focusing on net carbon negativity, future research should focus on using biotechnology to enable a more circular and sustainable carbon economy.
The dynamics of microbial communities involved in anaerobic digestion of mixed organic waste are notoriously complex and difficult to model, yet successful operation of anaerobic digestion is ...critical to the goals of diverting high-moisture organic waste from landfills. Machine learning (ML) is ideally suited to capturing complex and nonlinear behavior that cannot be modeled mechanistically. This study uses 8 years of data collected from an industrial-scale anaerobic co-digestion (AcoD) operation at a municipal wastewater treatment plant in Oakland, California, combined with a powerful automated ML method, Tree-based Pipeline Optimization Tool, to develop an improved understanding of how different waste inputs and operating conditions impact biogas yield. The model inputs included daily input volumes of 31 waste streams and 5 operating parameters. Because different wastes are broken down at varying rates, the model explored a range of time lags ascribed to each waste input ranging from 0 to 30 days. The results suggest that the waste types (including rendering waste, lactose, poultry waste, and fats, oils, and greases) differ considerably in their impact on biogas yield on both a per-gallon basis and a mass of volatile solids basis, while operating parameters were not good predictors of yield at this facility.
Technoeconomic analysis for biofuels and bioproducts Scown, Corinne D; Baral, Nawa Raj; Yang, Minliang ...
Current opinion in biotechnology,
February 2021, 2021-02-00, 20210201, 2021-02-01, Letnik:
67, Številka:
C
Journal Article
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•Technoeconomic analysis involves process design and simulation.•New studies have expanded to incorporate market size, policy incentives, and use.•There is a trend toward lightweight ...open-source TEA tools.•Inclusion both fuels and co-products complicates methods and performance metrics.•Integration of TEA with high-throughput experimental pipelines is promising.
Technoeconomic analysis (TEA) is an approach for conducting process design and simulation, informed by empirical data, to estimate capital costs, operating costs, mass balances, and energy balances for a commercial scale biorefinery. TEA serves as a useful method to screen potential research priorities, identify cost bottlenecks at the earliest stages of research, and provide the mass and energy data needed to conduct life-cycle environmental assessments. Recent studies have produced new tools and methods to enable faster iteration on potential designs, more robust uncertainty analysis, and greater accessibility through the use of open-source platforms. There is also a trend toward more expansive system boundaries to incorporate the impact of policy incentives, use-phase performance differences, and potential impacts on global market supply.
Plug-in electric vehicle (PEV) use in the United States (US) has doubled in recent years and is projected to continue increasing rapidly. This is especially true in California, which makes up nearly ...one-third of the current US PEV market. Planning and constructing the necessary infrastructure to support this projected increase requires insight into the optimal strategies for PEV battery recycling. Utilizing life-cycle perspectives in evaluating these supply chain networks is essential in fully understanding the environmental consequences of this infrastructure expansion. This study combined life-cycle assessment and geographic information systems (GIS) to analyze the energy, greenhouse gas (GHG), water use, and criteria air pollutant implications of end-of-life infrastructure networks for lithium-ion batteries (LIBs) in California. Multiple end-of-life scenarios were assessed, including hydrometallurgical and pyrometallurgical recycling processes. Using economic and environmental criteria, GIS modeling revealed optimal locations for battery dismantling and recycling facilities for in-state and out-of-state recycling scenarios. Results show that economic return on investment is likely to diminish if more than two in-state dismantling facilities are constructed. Using rail as well as truck transportation can substantially reduce transportation-related GHG emissions (23-45%) for both in-state and out-of-state recycling scenarios. The results revealed that material recovery from pyrometallurgy can offset environmental burdens associated with LIB production, namely a 6-56% reduction in primary energy demand and 23% reduction in GHG emissions, when compared to virgin production. Incorporating human health damages from air emissions into the model indicated that Los Angeles and Kern Counties are most at risk in the infrastructure scale-up for in-state recycling due to their population density and proximity to the optimal location.
Decarbonizing the air transportation sector remains one of the most challenging hurdles to mitigating climate change. Lignocellulosic biomass-derived jet fuel blendstocks can contribute to the shift ...toward renewable, low-carbon energy sources for aircrafts. Producing these renewable jet fuel molecules from biomass requires advanced pathways with the potential for efficient and affordable conversion routes. This paper presents a detailed techno-economic analysis and sensitivity analysis, including estimated minimum selling price (MSP), and life-cycle greenhouse gas (GHG) mitigation costs for five routes to four potential bio-jet fuel molecules – limonane via limonene, limonane via 1,8-cineole, tetrahydromethylcyclopentadiene dimer (RJ-4), bisabolane, and epi -isozizaane. The simulated biorefineries utilize biomass sorghum and an integrated high-gravity ionic liquid-based biomass deconstruction process. We present results reflecting the current state of the technology and potential future scenarios with improved yields. Among the conversion pathways and the fuel molecules evaluated in this study, limonane, bisabolane, and epi -isozizaane could reach an MSP of $0.73–$0.91 per L-Jet A ($2.75–$3.45 per gal-Jet A) in optimized future cases, without a hypothetical lignin-derived co-product. RJ-4 requires a more costly upgrading process and catalysts, resulting in a comparatively higher MSP ($1.33 per L-Jet A or $5.04 per gal-jet A). Based on the GHG footprints of each fuel, the minimum achievable carbon mitigation cost relative to conventional Jet-A is $29 per metric ton CO 2e , which is just under double the current cap-and-trade market price in California. In the absence of any policy support, the economics could be improved through high-value uses for lignin. To reach a target selling price of $0.66 per L-Jet A ($2.50 per gal), lignin-derived products would need to be sold for at least $1.9 per kg. However, the higher energy density of these bio-based blendstocks offers valuable improvements in aircraft efficiency/range; we find that commercial airlines may be willing to pay a 4–14 cent per L premium for these bio-jet fuels. Our results highlight the need for improvements beyond currently-reported yields for the biologically produced intermediates, identification of ideal microbial hosts, selection of metabolic pathways to achieve competitive production costs, and a focus on fuels with attractive properties that increase their value.
Successfully interfacing enzymes and biomachinery with polymers affords on-demand modification and/or programmable degradation during the manufacture, utilization and disposal of plastics, but ...requires controlled biocatalysis in solid matrices with macromolecular substrates
. Embedding enzyme microparticles speeds up polyester degradation, but compromises host properties and unintentionally accelerates the formation of microplastics with partial polymer degradation
. Here we show that by nanoscopically dispersing enzymes with deep active sites, semi-crystalline polyesters can be degraded primarily via chain-end-mediated processive depolymerization with programmable latency and material integrity, akin to polyadenylation-induced messenger RNA decay
. It is also feasible to achieve processivity with enzymes that have surface-exposed active sites by engineering enzyme-protectant-polymer complexes. Poly(caprolactone) and poly(lactic acid) containing less than 2 weight per cent enzymes are depolymerized in days, with up to 98 per cent polymer-to-small-molecule conversion in standard soil composts and household tap water, completely eliminating current needs to separate and landfill their products in compost facilities. Furthermore, oxidases embedded in polyolefins retain their activities. However, hydrocarbon polymers do not closely associate with enzymes, as their polyester counterparts do, and the reactive radicals that are generated cannot chemically modify the macromolecular host. This study provides molecular guidance towards enzyme-polymer pairing and the selection of enzyme protectants to modulate substrate selectivity and optimize biocatalytic pathways. The results also highlight the need for in-depth research in solid-state enzymology, especially in multi-step enzymatic cascades, to tackle chemically dormant substrates without creating secondary environmental contamination and/or biosafety concerns.
As the use of plug-in electric vehicles (PEVs) further increases in the coming decades, a growing stream of batteries will reach the end of their service lives. Here we study the potential of those ...batteries to be used in second-life applications to enable the expansion of intermittent renewable electricity supply in California through the year 2050. We develop and apply a parametric life-cycle system model integrating battery supply, degradation, logistics, and second-life use. We calculate and compare several metrics of second-life system performance, including cumulative electricity delivered, energy balance, greenhouse gas (GHG) balance, and energy stored on invested. We find that second-life use of retired PEV batteries may play a modest, though not insignificant, role in California's future energy system. The electricity delivered by second-life batteries in 2050 under base-case modeling conditions is 15 TWh per year, about 5% of total current and projected electricity use in California. If used instead of natural gas-fired electricity generation, this electricity would reduce GHG emissions by about 7 million metric tons of CO2e per year in 2050.
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•We model potential second-life use of retired PEV batteries for stationary storage.•Second-life batteries in California may deliver ∼15 TWh per year in 2050.•Enabled renewable electricity generation may displace ∼7 Mt CO2e per year in 2050.•There is significant uncertainty in PEV adoption and battery degradation scenarios.•We calculate ESOI and discuss appropriate metrics for large-scale storage systems.
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 CO2e per tonne of organic waste. Composting raw organics resulted in the lowest GHG emissions, at −41 kg CO2e per tonne of waste, while upgrading biogas to RNG after dry AD resulted in −36 to −2 kg CO2e 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 NH3 emissions from landfills and land-application of digestate is essential to fully understand the trade-offs between alternatives.
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