The pulp and paper industry (PPI) is an integral part of the manufacturing industry in the United States. Despite the industry’s success in reducing energy use, it remains an energy-intensive industry, accounting for 11% of the manufacturing sector’s energy consumption. There have been many initiatives to decarbonize the PPI and many novel innovations to make it more energy efficient. One of the novel approaches to decarbonizing this industry is through converting existing pulp and paper mills into integrated biorefineries.

Integrated biorefineries have been defined as ‘facilities that integrate biomass extraction and conversion processes and equipment to produce fuels, power, heat, and value-added chemicals’. The PPI can be converted into an integrated biorefinery by adding different routes, such as gasification, anaerobic digestion, pyrolysis, and fermentation, to transform wastes or lower-value by-products into value-added products. Biorefineries can expand the product portfolio, increasing industry resiliency by taking advantage of the already invested capital and established logistics and services. However, a more comprehensive understanding of these diverse biorefineries, including their feasibility and comparativeness in terms of costs, environmental impacts, and energy use, is essential.

In this study, we use life cycle assessment (LCA) and techno economic analysis (TEA) to investigate and compare the costs, resource depletion, carbon, and energy impacts of different biorefinery approaches chosen based on their applicability. This study has two objectives: (a) to identify different biorefinery options for the PPI and show their feasibility through market demand; and (b) to evaluate the embodied energy, carbon footprint, resource depletion, and production costs for different products in the chosen biorefinery using LCA and TEA.

Based on initial findings on applicability from a literature review, we focus on modifying an existing kraft paper mill into an integrated biorefinery that produces (a) carbon fiber, (b) fertilizers, and (c) bioplastics, along with the pulp production. Since there are multiple products with multiple functions, 1 metric ton of pulp was chosen as the functional unit, and the system expansion methodology with substitution was used to account for the avoidance of conventionally produced products.

Our expected LCA and TEA results will identify the most cost-effective biorefinery concept, determine the technologically superior performer, assess their different environmental impacts, evaluate market viability, and identify their comparative ranking. Furthermore, the results will also highlight the carbon/ energy hotspots in the processes that can be improved.

PPI-based biorefineries are industrial symbiosis systems which share materials and energy between the production processes of pulp and value-added products. This results in reduced usage of virgin materials, energy use, emissions, and waste generation. Therefore, targeting specific product markets could lead to net improvements in the total environmental impacts of the system. Lower production costs could also contribute to a more competitive market. The value-added products produced can replace petroleum-based, virgin materials, impacting material and resource consumption of multiple industries. Thus, the results of this study will help decision makers in choosing the best valorization path based on economic and life-cycle impacts, determining the most feasible, environmentally friendly, and profitable alternative.

In an era where environmental sustainability is paramount, the effective management of wood waste emerges as a pivotal factor in ecological innovation. This research delves into the intricate dynamics of wood's lifecycle, aiming to redefine its sustainability impact in emerging forest-based bioeconomy scenarios. By reassessing the fate of wood waste, particularly from sectors like construction, we seek to extend the lifecycle of wood products, thereby significantly impacting our carbon footprint.

Our project adopts a multifaceted approach to transform wood waste management, emphasizing the principles of a circular economy and sustainable resource efficiency. Beginning with a Stock-driven Material Flow Analysis, we meticulously traced the entire lifecycle of wood, from its origin to end-of-life, with a keen focus on its role as a carbon sink. Simultaneously, we incorporate Life Cycle Assessment (LCA) methodologies to identify potential environmental implications associated with different pathways of wood waste management.

The research identifies gaps and inefficiencies in the current wood waste management system, with a commitment to prioritizing recycling and repurposing over conventional disposal methods. Our goal is to revolutionize the approach to wood waste, ensuring that its use as an energy source is considered only after all other options have been exhausted. By maximizing the carbon storage potential of wood, we aim to reduce the pressure on our forests, promoting a sustainable future.

The methodology employed encompasses a comprehensive Material Flow Analysis, LCA, and an in-depth examination of wood decay rates to gauge material longevity. By understanding how long wood can serve as a carbon sink, we contribute valuable insights to the field. This approach is further complemented by an exploration of broader ecological impacts, particularly the influence of changes in land use on emissions.

As the research unfolds, we strive to provide a holistic view of the ecological footprint of wood waste management. The findings will culminate in actionable recommendations aimed at refining the Life Cycle Assessment framework and steering the industry towards a more sustainable, circular approach in managing wood waste. This project transcends the conventional notion of finding new uses for wood waste; it signifies a paradigm shift in our relationship with this critical resource, fostering a future where sustainability and resource efficiency are at the heart of environmental stewardship.

The chemical industry is transitioning from relying on fossil fuels to renewable biomass as feedstocks for chemical production. Compared to traditional petrochemicals, these bio-based chemicals have the potential to reduce greenhouse gas (GHG) emissions and energy consumption throughout manufacturing processes. Life cycle assessment (LCA) has been widely utilized by researchers to assess the potential environmental impacts of biochemicals. However, the diversity in biorefinery features (e.g., the choice of feedstocks, platforms, and conversion processes) and LCA modeling assumptions (e.g., allocation methods, system boundary, and locations) will affect the environmental outcomes of bio-based chemicals, leading to high uncertainty in estimating their true environmental benefits.

Our research provides a comprehensive analysis of Global Warming Potential (GWP) results for the production of 19 priority bio-based chemicals. We employed a system harmonization approach to minimize variations in functional unit and system boundary across 85 LCA case studies, resulting in 160 harmonized data points. The harmonized GWP results for each biochemical were then visualized by violin graphs and compared to their fossil-based counterparts. The results showed that most bio-based chemicals exhibited lower GWP results, mainly attributed to two mechanisms of GHG emissions reduction: (1) carbon sequestration credit through biomass growth, and (2) reduced emissions from the manufacturing processes (e.g., reduced energy consumption or direct GHG emissions).

In addition, a meta-regression analysis (MRA) was conducted to analyze and contextualize the variability in observed environmental impacts of biochemical production. The GWP results for producing 1 kg bio-based chemical (kg CO2-eq/kg) were designated as the dependent variable. The biorefinery characteristics and LCA methodological choice, by contrast, serve as 37 binary or continuous explanatory variables. The results indicated that GHG emissions from biochemical processes (e.g., fermentation) are statistically higher than those from chemical (e.g., hydrolysis, catalysis) and electrochemical conversion pathways. Moreover, the meta-regression model can be utilized to estimate the GHG emissions of each bio-based chemical. We found that predicted GWP results showed a narrower range of variation compared to the original values, thanks to the benefits of standardizing study-level characteristics through the model.

In this research project, we reviewed the biorefinery processes and the environmental impact of 19 selected bio-based chemicals. We compared the GWP results of biochemicals with the fossil-based benchmarks to identify their potential environmental benefits. Finally, we synthesized the LCA studies through meta-regression analysis to predict GWP results for each chemical. Our findings will give recommendations for enhancing current biorefinery processes and provide an LCA dataset for future research.

Background: Lignocellulosic biomass is an abundant and recalcitrant material primarily composed of cellulose, hemicellulose, and lignin. Due to its recalcitrance, biomass pretreatment is becoming a key part of the biorefinery process to enhance sugar production for biofuels and biomaterials. This step determines the conversion efficiency, production cost, and potentially the product's environmental impact.

Methods: Here, we explore the environmental life cycle analysis (LCA) of four pretreatment methods, namely hot water extraction, hot water extraction combined with disc milling, dilute acid, and steam explosion of willow biomass followed by enzymatic hydrolysis. The system boundary includes the activities associated with the willow biomass production system, transportation to the biorefinery, biomass pretreatment, hydrolysis, and sugar concentration. The functional unit is 1 kg of sugar (C5 and C6 combined) produced. The mass and energy balance data are derived from a robust process simulation model developed in SuperPro Designer based on our laboratory experiments and published studies. The life cycle inventory data for background processes (e.g., electricity) are sourced from the DATASMART and the Ecoinvent database. The impact assessment was conducted in SimaPro using the Tool for Reduction and Assessment of Chemicals and other Environmental Impacts (TRACI 2.1).

Results: The preliminary results indicate that hot water extraction pretreatment has the lowest global warming potential (0.0097 kg CO2eq) while steam explosion has the highest impact (0.0438 kg CO2eq). Combining disc milling with hot water extraction led to an increased impact but was lower than the dilute acid pretreatment. Over the next few months, our team will explore the implications for the other impact categories and identify the most influential factors affecting our results.

Conclusions: Lignocellulosic biomass pretreatment to enhance sugar yield from willow biomass affects climate change and other impacts of the produced sugars. This research will help researchers understand the impact of sugars produced from willow biomass for biofuels, biochemicals, and bioproducts production.

Livestock are the greatest contributors to nutrient runoff in the Chesapeake Bay Watershed, with dairy farms being of particular interest. Developing high-efficiency nutrient management systems is imperative for the sustainable growth of the livestock industry. Duckweeds, small, free-floating aquatic plants, possess the ability to hyper-accumulate nutrients from agricultural runoff and nutrient pools. This capability positions duckweed as a promising approach for manure management and the recirculation of nutrients back into the farm system. Using duckweed for nutrient absorption, retention, and reuse could open avenues to a circular nitrogen bioeconomy, though it has not received much attention in the US agricultural system. This study applied the method of life cycle assessment (LCA) to evaluate the environmental impact of a duckweed-based manure treatment system (DMTS) and compares it with the conventional manure management (CMM) system on the farm. The study considered farms with a herd size of 1300 cattle where 85 percent of the manure was treated through an open pond cultivation system. Following treatment, harvested duckweed was pelletized, and an analysis was conducted on its use as a soil amendment. The results of the LCA indicate that DMTS has lower impacts than CMM for climate change, marine eutrophication, and terrestrial acidification, at 63.8%, 84.6%, and 89.5% of CMM's impacts, respectively. In the category of terrestrial ecotoxicity, DMTS shows a 103% reduction in impact relative to CMM. However, for freshwater ecotoxicity and marine ecotoxicity, CMM impacts are lower, at 86.7% and 68.2% of DMTS's impacts, respectively, while water depletion is notably higher at 100%. The observed reductions in terrestrial acidification, global warming potential, and marine eutrophication by DMTS are critically relevant, particularly for addressing the challenge of nutrient runoff and pollution in the Chesapeake Bay.

Bioresource utilization is expected to perform a pivotal role while complementing other renewable energy pathways en route to deep decarbonization. Mitigating carbon using bioresource coupled with carbon capture and storage (CCS) provides additional opportunities for decarbonization. Replacing conventional fossil-based fuels requires technological update and adoption of new energy forms. Though certain liquid biofuels are infrastructure compatible, others may need technology update while keeping fuel form consistent, relative to fossil fuels. For realization of greenhouse gas (GHG) emissions reduction benefits through bioenergy pathways, consideration of production cost and GHG avoidance cost is critical to screen realistic pathways in terms of engineering, economic and environmental efficacy. In this analysis, we present the use of a harmonization framework to assess select biomass-based pathways (with and without CCS) which produces biofuels, bio-electricity, and biohydrogen to assess their relative GHG reduction potential, their minimum fuel selling price, and marginal cost of carbon avoidance. Further, we utilize U.S. biomass feedstock availability projections at various price-points to estimate the scale-up potential of the selected pathways. We also present an assessment of how a decarbonized electric grid may influence the pathways’ performance. In our study, we consider woody biomass and herbaceous biomass types as feedstocks for the conversion pathways. A total of 22 pathways are analyzed, a subset of which include CCS technology. Our analysis shows that the pathways have higher relative carbon reduction potential when CCS is implemented for a marginal increase in cost of production (10-25% depending on CCS technology and CO2 concentration). The marginal cost of avoidance for studied pathways ranges from $32 to $600 per metric ton (MMT) CO2e avoided relative to current incumbents. The preliminary scale-up study shows carbon reduction potential in scale of 10 MMT CO2e for herbaceous biomass and 10-1000 MMT CO2e for woody biomass, for a farm to biorefinery gate feedstock cost of $70/dry ton of biomass (including production, collection, and processing costs). The best use of biomass framework implemented for the analysis was presented at the 2023 ISSST Conference. This year, we elucidate results obtained from the analyses of pathway-level harmonization as well as extension of the framework to perform a scale-up study.