Environmental sustainability of bioethanol production from wheat straw in the UK
Open accessAbstract
A UK-based environmental sustainability study on bioethanol production from wheat straw was conducted using a Life Cycle Assessment (LCA) approach. Five pathways with leading pretreatment technologies (dilute acid, steam explosion with and without catalyst, liquid hot water, and wet oxidation) were modelled using process simulation software AspenPlus™, and their advantages and disadvantages were evaluated from an environmental perspective. In a contribution analysis of the environmental profiles for the near-term prospective scenarios, results indicated that the enzyme is a main contributor in all pathways. In addition to enzyme production, acid catalyst and base for its subsequent neutralisation also cause significant environmental burdens for dilute acid and steam explosion with catalyst pathways. By comparing the five wheat straw production pathways with petrol, it was suggested that those using pretreatment with steam explosion, liquid hot water and wet oxidation can be environmentally favourable over petrol. However, a sensitivity analysis conducted by expanding the ethanol system boundary to include the consequential effects of removing wheat straw from the field, suggested an increase in the overall environmental burdens of ethanol life cycles but certain wheat straw ethanol pathway (i.e. with steam explosion pretreatment) still remain environmentally favourable over petrol.
AI snapshot
Written from the paper’s full text.
TL;DR
This UK life-cycle assessment models five wheat straw-to-bioethanol pathways and compares them with petrol, finding that enzyme production is a major environmental hotspot and that steam explosion, liquid hot water, and wet oxidation pathways can be environmentally favourable over petrol. When wheat straw removal effects are included, burdens rise but steam explosion ethanol still remains favourable over petrol.
Key findings
- Enzyme production is the dominant contributor to abiotic resource depletion in all five pathways, ranging from 50% to 80%, and accounts for 40%–60% of net GHG emissions.
- Net GHG emissions per functional unit (“drive 1 km in a flexible-fuel vehicle”) are 0.26 kg CO₂ eq. for dilute acid (DA), 0.21 for steam explosion with acid catalyst (SEAC), 0.13 for steam explosion without catalyst (SE), 0.16 for liquid hot water (LHW), and 0.17 for wet oxidation (WO).
- Compared with petrol, SE, LHW, and WO pathways are overall environmentally favourable; SEAC is similar to petrol but advantageous in ADP, GWP₁₀₀, ODP, and HTP; DA is less favourable in most impact categories. Baseline savings versus petrol are 11%–45% in GHG emissions and 13%–75% in abiotic resources depletion potential.
- In the wheat straw removal sensitivity analysis, pathway rankings remain unchanged, but SE, LHW, and WO still outperform petrol, while SEAC becomes worse than petrol overall though still advantageous in ADP, ODP, and HTP; savings fall to up to 25% for GHG emissions and 60% for abiotic resources depletion potential.
Methods
- Well-to-wheel LCA with functional unit “to drive 1 km in a Flexible-fuel vehicle (FFV)”; fuel use is 114 g E100 and 70 g petrol per km, based on assumed engine efficiency and energy contents.
- Five pretreatment pathways (DA, SEAC, SE, LHW, WO) were modelled in AspenPlus™ for a plant processing 2000 dry metric tonnes of wheat straw per day, with enzymatic saccharification using Cellic Ctec at 10 FPU/g glucan and fermentation by *Zymomonas mobilis*.
- Inventory data came from literature, supplier questionnaires, Ecoinvent v2.2, IPCC, and EMEP-EEA; LCIA used CML baseline 2000 v2.05 in SimaPro v7.3. A sensitivity analysis expanded the system boundary to include additional fertiliser production/use, field emissions, and soil carbon loss of 0.275 t C/ha over 20 years (13.75 kg C/ha/year).
Limitations
- The paper states that soil carbon change is highly dependent on soil type, climate conditions, and field operations, and that obtaining better-quality data may be of interest for further research.
- The paper states that conclusions are affected by the definition of the ethanol system boundary, which may or may not include the consequences of wheat straw removal.
- Evident from the text: the study reports only a system-boundary sensitivity analysis, not a broader parameter uncertainty analysis, and relies on process simulation plus literature/questionnaire inventory data with near-term prospective assumptions such as reduced enzyme loading.
Model-written summary. Check it against the paper before relying on it.
Integrity signals
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Cites
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Claims the paper makes
0 of 12 cited sources checked · 0 supported · 0 flagged
- Findingown data
The wheat straw bioethanol pathways using pretreatment with steam explosion, liquid hot water and wet oxidation can be environmentally favourable over petrol.
“By comparing the five wheat straw production pathways with petrol, it was suggested that those using pretreatment with steam explosion, liquid hot water and wet oxidation can be environmentally favourable over petrol.”
Quote in the paperSubstantial claim- The authors state this as an assumption: All carbon in bioethanol is converted to CO2 during combustion in the FFV.
- Findingown data
Wheat straw cultivation contributes between 30% and 60% to net GHG emissions, due to N2O emission from fertiliser application.
“Wheat straw cultivation contributes between 30% and 60% to the net GHG emissions, which is due to N 2 O emission by applying fertiliser.”
Quote in the paperSubstantial claim - Findingreasoning
Enzyme production is the dominant contributor to ADP in all five cases ranging from 50% to 80%.
“It is shown in Fig. 4(a) that the enzyme production is the dominant contributor to ADP in all five cases ranging from 50% to 80%.”
Quote in the paperSubstantial claim- The authors state this as an assumption: A commercial enzyme cocktail Cellic Ctec with an enzyme activity of 120 FPU/ml is used at a relatively low enzyme loading (e.g. 10 FPU/g glucan) that is expected to be achievable in the near-term in industry scale.
- Findingown data
Expanding the ethanol system boundary to include consequential effects of removing wheat straw from the field increases the overall environmental burdens of ethanol life cycles.
“However, a sensitivity analysis conducted by expanding the ethanol system boundary to include the consequential effects of removing wheat straw from the field, suggested an increase in the overall environmental burdens of ethanol life cycles but certain wheat straw ethanol pathway (i.e. with steam explosion pretreatment) still remain environmentally favourable over petrol.”
Quote in the paperSubstantial claim- The authors state this as an assumption: The wheat straw removed is supposed to otherwise have degraded in the field.
- Findingnone given
A significant amount of surplus electricity (25.8 MW) is obtained from bioethanol production using steam explosion (SE) pretreatment.
“A significant amount of surplus electricity (25.8 MW) is obtained from bioethanol production using steam explosion (SE) pretreatment.”
Quote in the paperSubstantial claim
- Findingown data
Enzyme production is the dominant contributor to overall AP burdens due to SO2 emissions from fossil fuel consumption.
“Enzyme production is found to be the dominant contributor to the overall burdens due to SO 2 emissions from fossil fuel consumption.”
Quote in the paperNot a substantial claim - Findingown data
Acid catalyst and base for its subsequent neutralisation cause significant environmental burdens for dilute acid and steam explosion with catalyst pathways.
“In addition to enzyme production, acid catalyst and base for its subsequent neutralisation also cause significant environmental burdens for dilute acid and steam explosion with catalyst pathways.”
Quote in the paperSubstantial claim - Findingnone given
Production of sulphuric acid and ammonia used in DA and SEAC pretreatment are the main contributors to burdens in the pretreatment process.
“Production of sulphuric acid and ammonia used in DA and SEAC pretreatment are the main contributors to burdens in the pretreatment process.”
Quote in the paperNot a substantial claim - Findingown data
Enzyme production is a main contributor to environmental burdens in all five wheat straw bioethanol pathways.
“In a contribution analysis of the environmental profiles for the near-term prospective scenarios, results indicated that the enzyme is a main contributor in all pathways.”
Quote in the paperSubstantial claim- The authors state this as an assumption: A commercial enzyme cocktail Cellic Ctec with an enzyme activity of 120 FPU/ml is used at a relatively low enzyme loading (e.g. 10 FPU/g glucan) that is expected to be achievable in the near-term in industry scale.
- Findingown data
The wheat straw ethanol pathway with steam explosion pretreatment remains environmentally favourable over petrol after expanding the system boundary to include wheat straw removal effects.
“However, a sensitivity analysis conducted by expanding the ethanol system boundary to include the consequential effects of removing wheat straw from the field, suggested an increase in the overall environmental burdens of ethanol life cycles but certain wheat straw ethanol pathway (i.e. with steam explosion pretreatment) still remain environmentally favourable over petrol.”
Quote in the paperSubstantial claim- The authors state this as an assumption: All carbon in bioethanol is converted to CO2 during combustion in the FFV.
- The authors state this as an assumption: The wheat straw removed is supposed to otherwise have degraded in the field.
- Findingreasoning
Enzyme production accounts for 40%-60% of the overall net GHG score.
“Another 40%-60% of the overall net score is accounted for by enzyme production which is a highly energy intensive process.”
Quote in the paperNot a substantial claim - Findingown data
Wheat straw ethanol produced with SE, LHW and WO pretreatment methods is overall favourable over petrol, particularly in ADP, GWP100, ODP, ecotoxicity and POCP impacts.
“It is shown that wheat straw ethanol produced with SE, LHW and WO pretreatment methods are overall favourable over petrol, particularly in ADP, GWP 100 , ODP, ecotoxicity and POCP impacts.”
- Also stated in: § 4. Conclusions · plain
“These five wheat straw-to-bioethanol cases are further compared with conventional petrol, from which it is found that the pathways with steam explosion, liquid hot water and wet oxidation pretreatment are environmentally favourable over petrol.”
Quote in the paperSubstantial claim - Also stated in: § 4. Conclusions · plain
- Findingown data
The wheat straw cultivation process is the dominant contributor to the above-the-line EP score.
“In Fig. 4(d), the wheat straw cultivation process is the dominant contributor to the 'above-theline' score.”
Quote in the paperNot a substantial claim - Findingreasoning
Bioethanol production using DA pretreatment is less favourable over petrol in most impact categories.
“In contrast, bioethanol production using DA pretreatment is less favourable over petrol in most impact categories.”
Quote in the paperSubstantial claim - Findingnone given
In DA and SEAC pathways, ammonia production contributes over 90% of ODP burdens in pretreatment.
“In DA and SEAC pathways, ammonia production contributes to over 90% of the burdens in pretreatment.”
Quote in the paperNot a substantial claim - Findingnone given
For FATEP, NOx emissions from landfill of bottom ash are the main cause.
“For FATEP, NO x emissions from landfill of bottom ash are the main cause.”
Quote in the paperNot a substantial claim - Findingnone given
CO2 emissions from lost soil carbon caused by wheat straw removal enlarge the GWP100 score.
“Furthermore, CO 2 emissions from the lost soil carbon caused by wheat straw removal enlarge the GWP 100 score.”
Quote in the paperSubstantial claim - Findingnone given
For DA and SEAC pathways, WWT burdens are due to NaOH production used to neutralise nitric acid resulting from ammonia neutralising acid during pretreatment.
“For DA and SEAC pathways, the burdens for WWT are due to the production of sodium hydroxide (NaOH) that is used to neutralise nitric acid (HNO 3 ) as a result of ammonia neutralising acid during pretreatment.”
Quote in the paperNot a substantial claim - Findingown data
In DA and SEAC pathways, WWT is the biggest contributor to all toxicity categories due to NaOH production used in WWT.
“In DA and SEAC pathways where acid is used in pretreatment, WWT is the biggest contributor to all toxicity categories due to the production of NaOH which is used in WWT (Fig. 4(g), (h) and (i)).”
Quote in the paperSubstantial claim - Findingnone given
Burdens in wheat straw cultivation for AP are mainly caused by field operation emissions from diesel consumption.
“The burdens in wheat straw cultivation are mainly caused by the field operation emissions from diesel consumption.”
Quote in the paperNot a substantial claim - Findingown data
In combustion, sulphur contained in wheat straw feedstock and other inputs is converted to SO2 and accounts for 23-40% of the overall net AP score.
“In the combustion process, the sulphur contained in wheat straw feedstock and other inputs is converted to SO 2 and accounts for 23-40% of the overall net score.”
Quote in the paperNot a substantial claim - Findingown data
Credits from surplus electricity offset above-the-line burdens considerably, resulting in relatively low net burdens for SE, LHW and WO pathways.
“The credits from surplus electricity offset the 'above-the-line' burdens considerably, resulting in relatively low net burdens for these three pathways.”
Quote in the paperSubstantial claim - Findingreasoning
Increased field emissions from additional fertiliser are reflected in EP and GWP100 scores.
“In addition, the increased field emissions caused by using this additional fertiliser are reflected in EP and GWP 100 score.”
Quote in the paperSubstantial claim - Findingown data
By replacing petrol with wheat straw bioethanol using the pretreatment methods studied here, with exception for DA pretreatment, savings of 11-45% in GHG emissions and 13-75% in abiotic resources depletion potential can be achieved.
“Overall, it can be concluded that by replacing petrol with wheat straw bioethanol using the pretreatment methods studied here, with exception for DA pretreatment, savings of 11-45% in GHG emissions and 13-75% in abiotic resources depletion potential can be achieved.”
Quote in the paperSubstantial claim - Findingown data
In DA and SEAC pathways, sulphuric acid production is the main contributor to pretreatment AP burdens, accounting for 86% and 81% respectively.
“In DA and SEAC pathways, the production of sulphuric acid is the main contributor to the pretreatment process, accounting for 86% and 81% respectively.”
Quote in the paperNot a substantial claim - Premisecitation
The fugitive loss of methane from anaerobic digestion is estimated as 3%.
“The fugitive loss of methane from anaerobic digestion is estimated as 3% [39].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [39] Møller, 2009, Anaerobic digestion and digestate use: accounting of greenhouse gases and global warming contirbution, Waste Management and Research source
Not checked in the free run.
- Premisecitation
The UK annual wheat straw yield has been estimated to be between 8 and 10 million tonnes.
“The UK annual wheat straw yield has been estimated to be between 8 and 10 million tonnes [2].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [2] Brander M, Hutchison C, Sherrington C, Ballinger A, Beswick C, Baddeley A, et al. Methodology and evidence base on the indirect greenhouse gas effects of using wastes, residues, and by-products for biofuels and bioenergy—appendix 10 wheat straw case study—Data and Assumptions, In: Davis G, (editor). Report to RFA and DECC. Ecometrica; 2009.
Not checked in the free run.
- Premisecitation
The average yield of wheat straw is 3.2 t/ha.
“The average yield and price of wheat grain (with 16% water content) are 7.8 t/ha and 133 d/tonne (time period: 2007-2011) [28] while those for wheat straw are 3.2 t/ha and 52 d/tonne [3].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [3] Hay F., Straw. Eng & Wales Average Prices—Monthly 2000 to date, UK. Available from: 〈http://www.farminguk.com/defrastats 2012〉; 2012.
Not checked in the free run.
- Premisecitation
Soil carbon loss due to wheat straw removal is 0.275 t C/ha in 20 per years (13.75 kg C/ha/year).
“It was reported that the soil carbon loss due to wheat straw removal is 0.275 t C/ha in 20 per years (13.75 kg C/ha/year) and used in this study [19].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [19] Cherubini, 2010, Crop residues as raw materials for biorefinery systems—a LCA case study, Applied Energy source
Not checked in the free run.
- Premisereasoning
There is currently relatively little research focused on assessing the 'well-to-wheel' environmental profile with full impact categories of wheat straw-derived bioethanol.
“Review of the literature as summarised above indicates that there is currently relatively little research focused on assessing the 'well-to-wheel' environmental profile with full impact categories of wheat straw-derived bioethanol.”
Quote in the paperSubstantial claim - Premisecitation
Except for a few literature reports, the effects caused by wheat straw removal for bioethanol production purposes are neglected in most bioethanol LCA studies.
“Except for a few literature reports [19,20], the effects caused by wheat straw removal for bioethanol production purposes are neglected in most bioethanol LCA studies.”
Quote in the paperSubstantial claim0 of 2 sources checked - Interpretationreasoning
DA and SEAC pathways result in higher impacts (ADP, toxicities, GWP100 and POCP) than other pretreatments because of the use of acid and sodium hydroxide.
“In general, DA and SEAC pathways result in higher impacts (i.e.ADP, toxicities, GWP 100 and POCP) than other pretreatments because of the use of acid and sodium hydroxide.”
Quote in the paperSubstantial claim - Interpretationreasoning
Additional fertiliser requirement increases burdens in ADP, FAETP and TEP significantly because fertiliser production is fossil fuel intensive.
“Fertiliser production is a fossil fuel intensive process and therefore the additional requirement of fertiliser increases burdens in ADP, FAETP and TEP significantly.”
Quote in the paperSubstantial claim
- May combine two claims. 20
- Classified as probably not a substantial claim. 9
May combine two claims.
FindingreasoningNet overall GHG emissions per functional unit are 0.26 kg CO2 eq for DA, 0.21 kg CO2 eq for SEAC, 0.13 kg CO2 eq for SE, 0.16 kg CO2 eq for LHW, and 0.17 kg CO2 eq for WO.
“Therefore the net overall GHG emissions per functional unit are 0.26 kg CO 2 eq.for DA, 0.21 kg CO 2 eq.for SEAC, 0.13 kg CO 2 eq.for SE, 0.16 kg CO 2 eq.for LHW, and 0.17 kg CO 2 eq.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataFor HTP and TEP, pretreatment burdens are due to acid production while wheat straw cultivation burdens are due to pesticide production.
“For HTP and TEP, burdens in pretreatment are due to acid production while those in wheat straw cultivation are because of pesticide production.”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown dataFor GWP100 and ADP, wheat straw bioethanol can save only up to 25% and 60% respectively in GHG emissions and abiotic resources depletion potential compared to petrol even by considering consequential effects of removing wheat straw from the field.
“For GWP 100 and ADP, wheat straw bioethanol can save only up to 25% and 60% respectively in GHG emissions and abiotic resources depletion potential compared to petrol even by considering the consequential effects of removing wheat straw from the field.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataCompared with baseline scenarios, wheat straw production with SE, LHW, WO pretreatment continues to have better environmental performance than petrol, while SEAC pretreatment is worse than petrol but still has advantages in ADP, ODP and HTP impact categories.
“Compared with the baseline scenarios (Fig. 5), wheat straw production with SE, LHW, WO pretreatment continues to have a better environmental performance than petrol, while SECA pretreatment is worse than petrol but still has advantages in ADP, ODP and HTP impact categories.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataContribution analysis for near-term scenarios indicates enzyme production is a significant contributor to most impact categories, whilst wheat straw cultivation also contributes considerably to global warming, eutrophication and eco-toxicity potentials.
“The contribution analysis for the near-term scenarios of bioethanol production indicates that enzyme production is a significant contributor to most of the impact categories, whilst wheat straw cultivation also contributes considerably to global warming, eutrophication and eco-toxicity potentials.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataIncluding additional fertiliser production/use and soil carbon change in the system boundary leaves the rankings of the five bioethanol pathways unchanged, while altering their comparison with petrol particularly in GWP100, FATEP and TEP.
“It is shown that the rankings of five bioethanol pathways remain unchanged, while their comparison results with petrol are altered, particularly in GWP 100 , FATEP and TEP impact categories.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataIn POCP, burdens in enzyme production are due to fossil fuel consumption emissions while those in combustion are due to SO2 emissions.
“In Fig. 4(f), burdens in enzyme production are due to emissions from fossil fuel consumption while those in combustion are due to SO 2 emissions.”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown dataIn SE, LHW and WO pathways, enzyme production is the dominant contributor to HTP and FATEP while wheat straw cultivation contributes most to TEP.
“In SE, LHW and WO pathways, enzyme production is the dominant contributor to HTP and FATEP while wheat straw cultivation contributes most to TEP.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataIn Distribution & end use, fugitive ethanol emissions (0.5 g/kg fuel) in ethanol storage account for 30% of POCP burdens, and CO and SO2 emissions in ethanol distribution account for the remainder.
“In the 'Distribution & end use' module, the fugitive ethanol emissions (0.5 g/kg fuel) in ethanol storage account for 30% of its burdens, whilst CO and SO 2 emissions in ethanol distribution are responsible for the remainder.”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown dataIn addition to enzyme production, wheat straw cultivation causes considerable ODP burdens from pesticide production (40%) and fertiliser production (50%).
“In addition to enzyme production (shown in Fig. 4(e)), wheat straw cultivation causes considerable burdens caused by pesticide production (40%) and fertiliser production (50%).”
Quote in the paperNot a substantial claimMay combine two claims.
FindingreasoningBy considering consequent effects, burdens for most impact categories are increased considerably, though the steam explosion pathway still remains environmentally favourable over petrol.
“By considering these consequent effects, burdens for most impact categories are increased considerably, though certain ethanol pathway (i.e.steam explosion) still remains environmentally favourable over petrol.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataThe SEAC pretreatment pathway is environmentally similar to petrol but delivers advantages in ADP, GWP100, ODP and HTP impacts.
“The pathway with SEAC pretreatment is environmentally similar to petrol but delivers advantages in ADP, GWP 100 , ODP and HTP impacts.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataIn wheat straw cultivation, N2O emissions contribute over 60% to EP burdens, wheat seed production accounts for around 20%, and the rest is from fertiliser production.
“In this process, N 2 O emissions contribute to over 60%, while wheat seed production accounts for around 20% of burdens and the rest is from fertiliser production.”
Quote in the paperNot a substantial claimMay combine two claims.
InterpretationreasoningThe considerable credits obtained by replacing national grid electricity offset its environmental burdens and gives the lowest overall ADP score.
“Therefore, the considerable credits obtained by replacing national grid electricity offset its environmental burdens and gives the lowest overall ADP score.”
Quote in the paperSubstantial claimMay combine two claims.
PremisereasoningDue to rising gasoline prices and the availability and relatively low cost of wheat straw compared with other lignocellulosic biomass, wheat straw serves as a potentially attractive feedstock for producing bioethanol.
“However, due to rising gasoline prices and particularly the availability and relatively low cost of wheat straw compared with other lignocellulosic biomass, it serves as a potentially attractive feedstock for producing bioethanol.”
Quote in the paperSubstantial claimMay combine two claims.
PremisecitationThe main environmental impacts related to the removal of wheat straw include the requirement of additional fertiliser to balance the nutrients removed with wheat straw, the change in soil organic carbon and the decrease in field emissions from wheat straw.
“The main environmental impacts related to the removal of wheat straw include the requirement of additional fertiliser to balance the nutrients removed with wheat straw, the change in soil organic carbon and the decrease in field emissions from wheat straw [19].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [19] Cherubini, 2010, Crop residues as raw materials for biorefinery systems—a LCA case study, Applied Energy source
Not checked in the free run.
May combine two claims.
PremisecitationPhosphorous and nitrogen leaching to soil were estimated to be 1.5 kg/ha and 2.0 kg/ha.
“Phosphorous (P) and nitrogen (N) leaching to soil were estimated to be 1.5 kg/ha and 2.0 kg/ha based on Williams et al. [31].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites Williams et al. [31] Williams RB. Biofuels from municipal wastes-background discussion paper. California Biomass Collaborative; 2007.
Not checked in the free run.
Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).
InterpretationreasoningBioethanol production from wheat straw is viewed as a potentially economically attractive pathway.
“These established biorefineries suggest that bioethanol production from wheat straw is viewed as a potentially economically attractive pathway.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing), S4 (based).
Interpretationnone givenThe change in soil carbon is highly dependent on soil type, climate conditions and field operations etc.
“However, the change in soil carbon is highly dependent on soil type, climate conditions and field operations etc.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S4 (based). May combine two claims.
Interpretationnone givenEnzyme production is an energy intensive process, with consumption mainly of natural gas.
“This is because enzyme production is an energy intensive process, with consumption mainly of natural gas.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationPolicy support in the form of tax exemptions and the access to the wheat straw prices of d35/tonne or lower could significantly enhance competitiveness of bioethanol with petrol.
“It also indicated that policy support in the form of tax exemptions and the access to the wheat straw prices of d35/tonne or lower could significantly enhance competitiveness of bioethanol with petrol.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [21] Littlewood J, Murphy RJ, Wang L. Importance of policy support and feedstock prices on economic feasibility of bioethanol production from wheat straw in the UK. Renewable and Sustainable Energy Reviews; 2013, 17:291–300. source
Not checked in the free run.
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationBioethanol production with steam explosion or liquid hot water, with a production cost at d0.28/L, can be economically competitive with petrol in a prospective scenario with a reduced enzyme loading.
“It was found that bioethanol production with steam explosion or liquid hot water, with a production cost at d0.28/L, can be economically competitive with petrol in a prospective scenario with a reduced enzyme loading [21].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [21] Littlewood J, Murphy RJ, Wang L. Importance of policy support and feedstock prices on economic feasibility of bioethanol production from wheat straw in the UK. Renewable and Sustainable Energy Reviews; 2013, 17:291–300. source
Not checked in the free run.
Probably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductcitationThe LCA study was conducted with regard to ISO 140440 and its related standards.
“The LCA study was conducted with regard to ISO 140440 and its related standards [22].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [22] ISO 14040. Environmental management-life cycle asssessment-principles and framework; 2006.
Not checked in the free run.
Classified as probably not a substantial claim.
PremisecitationNutrient loadings and fermentation sugar conversion efficiencies (95% for glucose, 85% for xylose and arabinose) are adopted from the NREL process.
“Nutrient loadings and fermentation sugar conversion efficiencies (95% for glucose, 85% for xylose and arabinose) are adopted from the NREL process [36].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [36] Humbird, 2011
Not checked in the free run.
Classified as probably not a substantial claim.
Interpretationnone givenThese conclusions are affected by the definition of the ethanol system boundary, which may or may not include the consequences of wheat straw removal.
“However, these conclusions are affected by the definition of the ethanol system boundary, which may or may not include the consequences of wheat straw removal.”
Quote in the paperSubstantial claimMay combine two claims.
InterpretationreasoningFor AP and EP, higher environmental burdens from bioethanol pathways than petrol are due to combustion emissions in the CHP process and utilisation of fertilisers in the agricultural process, respectively.
“For AP and EP, higher environmental burdens from bioethanol pathways than petrol are due to the combustion emissions in the CHP process and the utilisation of fertilisers in the agricultural process, respectively.”
Quote in the paperSubstantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
Interpretationnone givenUsing wheat straw to produce ethanol instead of ploughing back into the field may cause consequential effects on the LCA comparison results with petrol.
“However, as discussed in Section 1, using wheat straw to produce ethanol instead of ploughing back into the field may cause consequential effects on the LCA comparison results with petrol; these are discussed in the sensitivity analysis.”
Quote in the paperNot a substantial claimMay combine two claims.
Interpretationown dataEthanol production from wheat straw shows great potential to replace petrol by saving GHG emissions of up to 45% and fossil fuel usage of up to 75%.
“Overall, the ethanol production from wheat straw shows great potential to replace petrol by saving GHG emissions of up to 45% and fossil fuel usage of up to 75%.”
Quote in the paperSubstantial claim
The authors state this as an assumption.
All sulphur in feedstock and WWT streams is completely converted into hydrogen sulphide (H2S) and oxidised into sulphur dioxide (SO2) during combustion.
“All Sulphur in feedstock and WWT streams are assumed to be completely converted into hydrogen sulphide (H 2 S) and oxidised into sulphur dioxide (SO 2 ) during combustion.”
The authors state this as an assumption.
1% of SO2 becomes sulphuric acid (H2SO4).
“1% of SO 2 is also assumed to become sulphuric acid (H 2 SO 4 ).”
The authors state this as an assumption.
All carbon in bioethanol is converted to CO2 during combustion in the FFV.
“The CO 2 emissions from bioethanol combustion in the FFV were estimated theoretically by assuming all carbon in bioethanol is converted to CO 2 .”
The authors state this as an assumption.
The wheat straw removed is supposed to otherwise have degraded in the field.
“It should be noted that the wheat straw removed is supposed to otherwise have degraded in the field.”
The authors state this as an assumption.
A commercial enzyme cocktail Cellic Ctec with an enzyme activity of 120 FPU/ml is used at a relatively low enzyme loading (e.g. 10 FPU/g glucan) that is expected to be achievable in the near-term in industry scale.
“In saccharification, a commercial enzyme cocktail Cellic Ctec with an enzyme activity of 120 FPU/ml is assumed to be used at a relatively low enzyme loading (e.g. 10 FPU/g glucan) that is expected to be achievable in the near-term in industry scale.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The high GWP value (6.72E-01 kg CO2 eq) was also due to CO2 given off when fermenting agave juice.
“The high value of GWP (6.72E-01 kg CO2 eq) was also due to the CO2 given off when fermenting agave juice (Table 3) (Amores et al. 2013; González-García et al. 2012; Wang et al. 2013).”
From Environmental and economic analysis of bioethanol production from sugarcane molasses and agave juice (2021) · cites this paper as Wang et al. 2013
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
Figure labels saccharification as Area D rather than Area C
MinorThe process description places saccharification and fermentation in Area C, while the Figure 3 flow labels saccharification as Area D.
“To Saccharification (Area D)”
“The treated wheat straw is sent to separate hydrolysis and fermentation (Area C)”
The citation lists haven’t been fetched yet
References 31 · Cited by 144
Research works printed but not linked: 1
- Luo, 2009, Udo de Haes H. Allocation issues in LCA methodology: a case study of corn stover-based fuel ethanol, The International Journal of Life Cycle Assessment, 14, 529, 10.1007/s11367-009-0112-6 · DOI
- Authors
- Wang, L., Littlewood, J., & Murphy, R. J.
- Affiliations
- Imperial College London (GB)
- University of Surrey (GB)
- Corresponding author
- Wang, Lei
- ORCID
- Wang, Lei
- Venue
- Renewable and Sustainable Energy Reviews
- Publisher
- Elsevier BV
- Published
- 2013-12
- Volume
- 28
- Pages
- 715-725
- ISSN
- 1364-0321 (ISSN-L)
- OpenAlex
- W2007758797
- Semantic Scholar
- 79df4bc76a3cd41e57dadd4a2c5f1307b4b3edbb
- Cited by
- 144
- References
- 31
- Citations by year
- 2026: 3 · 2025: 6 · 2024: 7 · 2023: 14 · 2022: 17 · 2021: 15 · 2020: 16 · 2019: 12 · 2018: 19 · 2017: 12 · 2016: 9 · 2015: 5 · 2014: 9
- FWCI
- 4.23
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Locations
- Renewable and Sustainable Energy Reviews (publishedVersion, cc-by)
- RePEc: Research Papers in Economics (submittedVersion)
- Open Research (University of Surrey) (submittedVersion)
- Surrey Research Insight Open Access (The University of Surrey) (submittedVersion)
- Topics
- Physical Sciences › Engineering › Biomedical Engineering › Biofuel production and bioconversion
- Physical Sciences › Environmental Science › Environmental Engineering › Environmental Impact and Sustainability
- Life Sciences › Agricultural and Biological Sciences › Agronomy and Crop Science › Bioenergy crop production and management
- Keywords
- bioethanol, wheat straw, environmental sustainability, life cycle assessment, pretreatment technologies, dilute acid pretreatment, steam explosion, liquid hot water pretreatment, wet oxidation, enzyme production, acid catalysts, contribution analysis
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.
Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
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