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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Cellulosic ethanol: status and innovation

Although the purchase price of cellulosic feedstocks is competitive with petroleum on an energy basis, the cost of lignocellulose conversion to ethanol using today’s technology is high. Cost reductions can be pursued via either in-paradigm or new-paradigm innovation. As an example of new-paradigm innovation, consolidated bioprocessing using thermophilic bacteria combined with milling during fermentation (cotreatment) is analyzed. Acknowledging the nascent state of this approach, our analysis indicates potential for radically improved cost competitiveness and feasibility at smaller scale compared to current technology, arising from (a) R&D-driven advances (consolidated bioprocessing with cotreatment in lieu of thermochemical pretreatment and added fungal cellulase), and (b) configurational changes (fuel pellet coproduction instead of electricity, gas boiler(s) in lieu of a solid fuel boiler).

Lynd, Lee R.↗
DOE OSTI2018

Techno-Economic Evaluation of Cellulosic Ethanol Production Based on Pilot Biorefinery Data: a Case Study of Sweet Sorghum Bagasse Processed via L+SScF

Replacing fossil fuels with renewable fuels derived from lignocellulosic biomass can contribute to the mitigation of global warming and the economic development of rural communities. This will require lignocellulosic biofuels to become price competitive with fossil fuels. Techno-economic analyses can provide insights into which parts of the biofuel production process need to be optimized to reduce cost or energy use. Here, we used data obtained from a pilot biorefinery to model a commercial-scale biorefinery that processes lignocellulosic biomass to ethanol, with a focus on the minimum ethanol selling price (MESP). The process utilizes a phosphoric acid-catalyzed pre-treatment of sweet sorghum bagasse followed by liquefaction and simultaneous saccharification and co-fermentation (L+SScF) of hexose and pentose sugars by an engineered Escherichia coli strain. After validating a techno-economic model developed with the SuperPro Designer software for the conversion of sugarcane bagasse to ethanol by comparing it to a published Aspen Plus model, six different scenarios were modeled for sweet sorghum bagasse Under the most optimistic scenario, the ethanol can be produced at a cost close to the energy-equivalent price of gasoline. Aside from an increase in the price of gasoline, the gap between ethanol and gasoline prices could also be bridged by either a decrease in the cost of cellulolytic enzymes or development of value-added products from lignin.

Biofuel↗
DOE OSTI2013

NREL Proves Cellulosic Ethanol Can Be Cost Competitive [Fact Sheet]

Ethanol from non-food sources - known as "cellulosic ethanol" - is a near-perfect transportation fuel: it is clean, domestic, abundant, and renewable, and it can potentially replace 30% of the petroleum consumed in the United States, but its relatively high cost has limited its market. That changed in 2012, when the National Renewable Energy Laboratory (NREL) demonstrated the technical advances needed to produce cellulosic ethanol at a minimum ethanol selling price of $\$$2.15/gallon (in 2007 dollars). Through a multi-year research project involving private industry, NREL has proven that cellulosic ethanol can be cost competitive with other transportation fuels.

09 BIOMASS FUELS↗
DOE OSTI2015

Life Cycle Assessment of Switchgrass Cellulosic Ethanol Production in the Wisconsin and Michigan Agricultural Contexts

Spatial variability in yields and greenhouse gas emissions from soils has been identified as a key source of variability in life cycle assessments (LCAs) of agricultural products such as cellulosic ethanol. This study aims to conduct an LCA of cellulosic ethanol production from switchgrass in a way that captures this spatial variability and tests results for sensitivity to using spatially averaged results. The Environment Policy Integrated Climate (EPIC) model was used to calculate switchgrass yields, greenhouse gas (GHG) emissions, and nitrogen and phosphorus emissions from crop production in southern Wisconsin and Michigan at the watershed scale. These data were combined with cellulosic ethanol production data via ammonia fiber expansion and dilute acid pretreatment methods and region-specific electricity production data into an LCA model of eight ethanol production scenarios. Standard deviations from the spatial mean yields and soil emissions were used to test the sensitivity of net energy ratio, global warming potential intensity, and eutrophication and acidification potential metrics to spatial variability. Substantial variation in the eutrophication potential was also observed when nitrogen and phosphorus emissions from soils were varied. This work illustrates the need for spatially explicit agricultural production data in the LCA of biofuels and other agricultural products.

Acidification↗
DOE OSTI2025

Techno-economic analysis of sugarcane bagasse and straw conversion into cellulosic ethanol via consolidated bioprocessing

Cellulosic biofuels offer a sustainable alternative to fossil fuels and a means to mitigate climate change. Consolidated bioprocessing (CBP) featuring engineered thermophilic bacteria, combined with mechanical disruption during fermentation (cotreatment), has potential to lower production costs compared to featuring thermochemical pretreatment and added cellulase. A techno-economic analysis was conducted (230 million L ethanol/year) from sugarcane bagasse and straw at stand-alone facilities generating electricity from residues. Three scenarios were evaluated: Conventional, featuring hydrothermal pretreatment, fungal cellulase, and yeast fermentation (current commercial standard); Mid-term CBP, relying on bagasse solubilization without pretreatment or cotreatment; and Mature CBP, incorporating cotreatment but no pretreatment. Results for these scenarios in this order were: fixed capital investment (CapEx) $\$$589M, $\$$658M, and $\$$472M; net annual revenue (EBITDA) $\$$56M, $\$$96M, and $\$$94M; and minimum ethanol selling price 0.73, 0.61, and 0.48 US$\$$/L. Payback periods were 10.5, 6.9, and 5.1 years, while all scenarios showed <5 years at European prices for scales >100M L/year. Sensitivity and risk analysis highlighted ethanol price as the most critical variable. It is notable that Mid-term CBP had shorter payback times and better overall economic feasibility compared to Conventional. Our results underscore opportunities for research-driven innovation on low-cost cellulosic ethanol technologies in Brazil and elsewhere.

Consolidated bioprocessing↗
DOE OSTI2025

An Experimental and Computational Approach to Investigating CO 2 Uptake of Cellulose-producing Algae from Cellulosic Ethanol Production (Final Report)

This project combined experimental algal cultures with predictive quantum calculations to evaluate system-level CO 2 uptake and conversion efficiency of cellulose-producing Nannochloropsis sp. algae. Recently, Nannochloropsis sp. has garnered attention as a novel host organism for converting low-cost CO 2 produced from cellulosic ethanol fermentations into algal lipids for biodiesel production and microcrystalline cellulose as a high-value co-product. As depicted in the figure below, this project (1) optimized Nannochloropsis salina (N. salina) cultures on effluent gas produced directly from cellulosic ethanol fermentation, (2) characterized the fermentation products, quantify cellulose production, and calculate CO 2 uptake efficiency with predictive quantum calculations, (3) conducted a life cycle and techno economic analysis of the proposed integration, and (4) provided training opportunities to students attending UC Riverside.

09 BIOMASS FUELS↗
DOE OSTI2019

Selecting winter wheat straw for cellulosic ethanol production in the Pacific Northwest, U.S.A

Selection of the best wheat variety for cellulosic ethanol production is very important. With dozens of varieties available, information on the sugar yield of different straws is needed to help farmers choose the most profitable wheat variety, for both grain yield and straw yield. Thirty winter wheat lines from the Pacific Northwest of the US were chosen for analysis based on historical and current production. Two pretreatment methods, dilute acid and hot water, were compared to determine the optimum pretreatment condition for wheat straw. Using the optimum dilute acid pretreatment condition, sugar yields from the straw of the 30 wheat varieties were compared. The differences in variety performance were then evaluated based on relationships among several measured parameters, including straw yield, grain yield, and chemical composition of biomass. The ranges of chemical composition for the 30 wheat straw varieties were 33.7–36.3% glucan (proxy for cellulose), 16.8–19.5% xylan (proxy for hemicellulose), and 18.4–20.6% lignin. Results also showed significant differences in total sugar recovery, which varied between 0.239 and 0.401 g g -1 dry matter of raw biomass across wheat straw varieties. Among the 30 tested varieties, Weatherford was selected as the best for dual-purpose wheat because it ranked highest in straw yield and potential sugar production per area and 6th-highest in grain yield.

09 BIOMASS FUELS↗
DOE OSTI2013

2013 DOE Bioenergy Technologies Office (BETO) Project Peer Review—Biodiesel Cellulosic Ethanol Research Project (Hendry County Sustainable Biofuels Center)

The presentation provides an overview of the Biodiesel Cellulosic Ethanol Research Project (Hendry County Sustainable Biofuels Center). It summarizes the project history, timeline, budget, partners, objectives, goals, future plans and in closer detail reviews the used approaches and technical accomplishments. The main project goals were (1) developing strategies and tools that assist in the creation of economically and environmentally sustainable bioenergy industries within ecologically-sensitive regions such as South Florida and, in particular, the greater Everglades, (2) using these bioenergy strategies and tools in evolving the existing agricultural, urban, and ecological sectors towards more sustainable structures and practices and (3) using bioenergy as a focal point in the larger effort to mitigate climate change and sea level rise, realities with particularly catastrophic consequences for South Florida. The project started on Oct 1, 2010 and ended on Feb 28, 2013. It yearly average budget was $369,770, with the Dept. of Energy annual cost share of $317,167. The main project partners were Hendry County, University of Florida - Institute of Food and Agricultural Sciences, Intelligentsia International, Inc., Edison State College and University of South Florida. Used approaches, main accomplishments and results in the categories of (1) technical research, (2) education and (3) business development are presented in detail. The project uniqueness is mainly related to the use of system approaches and integrating several systems analyses. Relevance of the project applicable to sustainability of bioenergy, food production, & restoration is explained, critical success factors are challenges are outlined and future work drafted. Finally, the main publications and presentations catalogue list is presented.

09 BIOMASS FUELS↗
DOE OSTI2017

Biomass Production a Stronger Driver of Cellulosic Ethanol Yield than Biomass Quality

Core Ideas Fermentable sugars were greatest in corn stover > perennial grasses > polycultures. Corn stover had the highest ethanol content. Miscanthus had the highest ethanol yield potential on a per hectare basis. Ethanol yield potential per hectare of switchgrass ≥ corn stover. Biomass yield was the strongest driver of per hectare ethanol yield. Many crops have been proposed as feedstocks for the emerging cellulosic ethanol industry, but information is lacking about the relative importance of feedstock production and quality. We compared yield and sugar content for seven bioenergy cropping systems in south‐central Wisconsin (ARL) and southwestern Michigan (KBS) during three growing seasons (2012 through 2014). The cropping systems were (i) continuous corn stover ( Zea mays L.), (ii) switchgrass ( Panicum virgatum L.), (iii) giant miscanthus ( Miscanthus × giganteus Greef & Deuter ex Hodkinson & Renvoize), (iv) hybrid poplar ( Populus nigra × P. maximowiczii A. Henry ‘NM6’), (v) native grass mix, (vi) early successional community, and (vii) restored prairie. A high‐throughput pretreatment and fermentation assay showed corn stover with the highest sugar content (213 g glucose kg −1 [Glc] and 115 g xylose kg −1 [Xyl]) followed by the two monoculture perennial grass treatments (154 [Glc] and 88 [Xyl]) and then the herbaceous polycultures (135 [Glc] and 77 [Xyl]). Biomass production and sugar content were combined to calculate ethanol yields. Miscanthus had the highest per hectare ethanol yields (1957 l ha −1 yr −1 ARL, 2485 l ha −1 yr −1 KBS) followed by switchgrass (1091 l ha −1 yr −1 ARL, 1017 l ha −1 yr −1 KBS) and corn stover (1121 l ha −1 yr −1 ARL, 878 l ha −1 yr −1 KBS). Perennial grass cropping systems (i.e., switchgrass and miscanthus) had higher per hectare ethanol yields at both sites relative to diverse systems that included dicots. Despite feedstock differences in fermentable sugars, biomass production was the strongest driver of per hectare ethanol yield.

09 BIOMASS FUELS↗
DOE OSTI2012

A Case Study of Agricultural Residue Availability and Cost for a Cellulosic Ethanol Conversion Facility in the Henan Province of China

A preliminary analysis of the availability and cost of corn stover and wheat straw for the area surrounding a demonstration biorefinery in the Henan Province of China was performed as a case study of potential cooperative analyses of bioenergy feedstocks between researchers and industry in the US and China. Though limited in scope, the purpose of this analysis is to provide insight into some of the issues and challenges of estimating feedstock availability in China and how this relates to analyses of feedstocks in the U.S. Completing this analysis also highlighted the importance of improving communication between U.S. researchers and Chinese collaborators. Understanding the units and terms used in the data provided by Tianguan proved to be a significant challenge. This was further complicated by language barriers between collaborators in the U.S. and China. The Tianguan demonstration biorefinery has a current capacity of 3k tons (1 million gallons) of cellulosic ethanol per year with plans to scale up to 10k tons (3.34 million gallons) per year. Using data provided by Tianguan staff in summer of 2011, the costs and availability of corn stover and wheat straw were estimated. Currently, there are sufficient volumes of wheat straw and corn stover that are considered 'waste' and would likely be available for bioenergy in the 20-km (12-mile) region surrounding the demonstration biorefinery at a low cost. However, as the industry grows, competition for feedstock will grow and prices are likely to rise as producers demand additional compensation to fully recover costs.

09 BIOMASS FUELS↗
DOE OSTI2013

Land-use change and greenhouse gas emissions from corn and cellulosic ethanol

Background: The greenhouse gas (GHG) emissions that may accompany land-use change (LUC) from increased biofuel feedstock production are a source of debate in the discussion of drawbacks and advantages of biofuels. Estimates of LUC GHG emissions focus mainly on corn ethanol and vary widely. Increasing the understanding of LUC GHG impacts associated with both corn and cellulosic ethanol will inform the on-going debate concerning their magnitudes and sources of variability. Results: In our study, we estimate LUC GHG emissions for ethanol from four feedstocks: corn, corn stover, switchgrass, and miscanthus. We use new computable general equilibrium (CGE) results for worldwide LUC. U.S. domestic carbon emission factors are from state-level modelling with a surrogate CENTURY model and U.S. Forest Service data. This paper investigates the effect of several key domestic lands carbon content modelling parameters on LUC GHG emissions. International carbon emission factors are from the Woods Hole Research Center. LUC GHG emissions are calculated from these LUCs and carbon content data with Argonne National Laboratory’s Carbon Calculator for Land Use Change from Biofuels Production (CCLUB) model. Our results indicate that miscanthus and corn ethanol have the lowest (-10 g CO2e/MJ) and highest (7.6 g CO2e/MJ) LUC GHG emissions under base case modelling assumptions. The results for corn ethanol are lower than corresponding results from previous studies. Switchgrass ethanol base case results (2.8 g CO2e/MJ) were the most influenced by assumptions regarding converted forestlands and the fate of carbon in harvested wood products. They are greater than miscanthus LUC GHG emissions because switchgrass is a lower-yielding crop. Finally, LUC GHG emissions for corn stover are essentially negligible and insensitive to changes in model assumptions. Conclusions: This research provides new insight into the influence of key carbon content modelling variables on LUC GHG emissions associated with the four bioethanol pathways we examined. Our results indicate that LUC GHG emissions may have a smaller contribution to the overall biofuel life cycle than previously thought. Additionally, they highlight the need for future advances in LUC GHG emissions estimation including improvements to CGE models and aboveground and belowground carbon content data.

09 BIOMASS FUELS↗
DOE OSTI2022

Techno-economic analysis of cellulosic ethanol conversion to fuel and chemicals

In this paper, we describe multiple scenarios investigated to assess the techno-economic results of producing fuels from corn stover-derived ethanol and the impact of co-producing higher-value, ethanol-derived n-butanol and 1,3-butadiene to improve economic feasibility. An alternative approach that produces only chemicals from the lignocellulosic-derived ethanol while producing fuels from the residual cell mass, unconverted sugars and lignin using hydrothermal liquefaction and hydrotreating also is described. Our results indicate that the hydrothermal liquefaction pathway has cost advantages relative to pathways that burn lignin from the corn stover conversion process to make ethanol when the associated ethanol stream is used to make only chemicals.

09 BIOMASS FUELS↗
DOE OSTI2015

Fulton Cellulosic Ethanol Biorefinery

Final report on work performed by BlueFire on the deployment of acid hydrolysis technology to convert cellulosic waste materials into renewable fuels, power and chemicals in a production facility to be located in Fulton, Mississippi.

09 BIOMASS FUELS↗
DOE OSTI2022

Using Incremental Changes to Convert Lignocellulosic Feedstocks to Cellulosic Ethanol

One billion tons of biomass feedstocks have been identified for the production of renewable biofuels and biochemicals. This is one of the key carbon feedstocks to supply energy to the transportation sector for light duty, heavy duty and aviation fuels. Utilization of lignocellulosic feedstocks supports an improved energy security by reducing demand of petroleum imports, agricultural development, job creation, and reducing greenhouse gas emissions. To date, however, operational challenges have stymied the industrial production of large volumes of lignocellulosic-based fuels and chemicals. As a result, significant research investment has been led by the United States Department of Energy to understand and improve operational reliability at pioneer cellulosic biorefineries. In this perspective article lignocellulosic conversion technologies are described that have been adopted from the starch ethanol process. The developed process culminated in successful demonstration of 1,000-h integrated runs using several feedstocks, including switchgrass, energy sorghum, and two types of corn kernel fiber. This report highlights process development that solved several of the issues that plagued—and continue to plague—many in the cellulosic sugars space such as biomass feeding into equipment, high ash content, diversified co-product value, and others.

09 BIOMASS FUELS↗
DOE OSTI2018

Cellulosic Ethanol Potential of Feedstocks Grown on Marginal Lands

To examine the chemical composition and ethanol production of feedstocks grown on marginal lands, prairie cordgrass and switchgrass from waterlogged land, saline land, and saline water irrigated land were evaluated. Samples were pretreated using 1% w w -1 dilute acid at 160°C for 10 min, and simultaneous saccharification and cofermentation was conducted using industrial engineered . Samples grown on land irrigated with saline water had 2.8-fold higher total ash content compared to the other types of land, resulting in lower carbohydrate concentrations. Yeast fermented glucose and xylose simultaneously; almost all of the sugars were consumed, indicating that salts present in biomass ash did not inhibit yeast performance. Ethanol production from the waterlogged and saline lands was 2,500 to 4,700 L ha -1 , which is comparable to that of samples grown on other agricultural lands. Finally, prairie cordgrass and switchgrass grown on marginal lands could be potential feedstocks for cellulosic biofuel. Keywords: Irrigation, Marginal land, Prairie cordgrass, Saline, Simultaneous saccharification and cofermentation, Switchgrass, Waterlogging.

54 ENVIRONMENTAL SCIENCES↗