Life cycle assessment of bioethanol production from three feedstocks and two fermentation waste reutilization schemes

Accepted Manuscript Life cycle assessment of bioethanol production from three feedstocks and two fermentation waste reutilization schemes Fang-Chih Chang, Lang-Dong Lin, Chun-Han Ko, Hsin-Chuan Hsieh, Bing-Yuan Yang, Wen-Hua Chen, Wen-Song Hwang PII:

S0959-6526(16)32079-0

DOI:

10.1016/j.jclepro.2016.12.024

Reference:

JCLP 8599

To appear in:

Journal of Cleaner Production

Received Date: 3 May 2016 Revised Date:

13 November 2016

Accepted Date: 6 December 2016

Please cite this article as: Chang F-C, Lin L-D, Ko C-H, Hsieh H-C, Yang B-Y, Chen W-H, Hwang WS, Life cycle assessment of bioethanol production from three feedstocks and two fermentation waste reutilization schemes, Journal of Cleaner Production (2017), doi: 10.1016/j.jclepro.2016.12.024. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT

Life cycle assessment of bioethanol production from three feedstocks and two fermentation waste reutilization schemes

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Fang-Chih Chang a, Lang-Dong Lin b, Chun-Han Ko c,*, Hsin-Chuan Hsieh c, Bing-Yuan Yang c, Wen-Hua Chen d, Wen-Song Hwang d

a

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The Experimental Forest, College of Bio-Resources and Agriculture, National

Taiwan University, No.12, Section 1, Chien-Shan Road, Chu-Shan, Nan-Tou 55750,

b

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Taiwan

Department of Cultural Heritage Conservation, National Yunlin University of

Science and Technology, Yunlin 640, Taiwan c

School of Forest and Resources Conservation, National Taiwan University, Taipei

Chemistry Division, Institute of Nuclear Energy Research, AEC, Taoyuan, Taiwan

*

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d

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10617, Taiwan

Corresponding author.

Tel.: +886-2-33664615; fax: +886-2-23654520. E-mail: [email protected] (C.H. Ko)

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ACCEPTED MANUSCRIPT ABSTRACT More than 95% of energy supplies for Taiwan are imported. Conversely, approximately 150,000 ha half-fallow and 50,000 ha fallow paddy fields exist because of increasing labor costs and competition from rice imports. The potential for energy

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crop production from such underutilized paddy fields merits significant attention. However, selecting crops for optimal environmental performance when producing bioethanol is equally important. The life cycle assessments (LCAs) of rice straw

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(agricultural waste), Napier grass (energy crop), and Eucalyptus spp. (short rotation coppice) as bioethanol feedstocks in such fallow paddy fields were investigated in this

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study. The LCAs of two schemes for on-site fermentation waste utilization were also investigated as pellet fuel and molded pulp feedstocks. Experimental and field survey data were used in this study. Due to higher biomass yields, Napier grass and Eucalyptus spp. resulted in 47% and 28%, respectively, less weight-based negative

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impacts compared to rice. Pursuing high bioethanol production requires consideration of the overall environmental loading. Conversely, the rankings of the three crops based on acreage and bioethanol yield differed due to extensive farming practices and

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bioethanol conversion yields. On-site production of pellet fuel using fermentation

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waste was 7% and 31% higher than that of Eucalyptus biomass pellets and imported coal, respectively, for Taiwan. On-site production of molded pulp products using fermentation waste was 5% and 49% higher than that of recycled newspaper and virgin chemical pulp, respectively, for Taiwan. Thus, fermentation waste utilization schemes could provide a broader evaluation for planning alternative crops for bioethanol production. Keywords: Rice straw, Napier grass, Short rotation coppices, Eucalyptus spp., Bioethanol, Molded pulp, Pellet fuel, Life cycle assessment 2

ACCEPTED MANUSCRIPT 1. Introduction Second-generation biofuels from lignocellulosic biomass are highly regarded for their environmental, economical, and social sustainability (Liew et al., 2014; Ojeda et al., 2011). The cellulosic bioethanol process consists of four steps: pretreatment,

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hydrolysis, fermentation, and distillation (Ko et al., 2012; Portugal-Pereira and Lee, 2016). Pretreatment makes the cellulose accessible for hydrolysis and fermentation for conversion to fuels. The material’s lignin, hemicelluloses, and high-cellulose

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crystallinity are key factors for bioethanol production (Chundawat et al., 2011; Hendriks et al., 2009). Steam explosion methods are effective pretreatments to

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increase the accessible surface area for enzyme hydrolysis (Hendriks et al., 2009). Although all forms of renewable energy, including biofuel, wind power, and solar energy, are currently being researched in depth (Tilman et al., 2009), fossil fuels still comprise a large portion of the global energy supply. Development of renewable

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energy sources with lower resource exploitation and fewer negative energy impacts is currently being advocated; thus, life cycle assessments (LCAs) are very important (Hong et al., 2016; Kamp and Østergård, 2016; Silalertruksa et al., 2016). LCAs can

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compare various fuels based on their respective environmental impacts. Many LCA

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studies have already found that lignocellulosic ethanol is superior to petroleum fuels and corn-derived ethanol based on monitoring of GHG (greenhouse gas) emissions and fossil energy usage (Hong et al., 2016; Weldemichael and Assefa, 2016). Recently, different feedstocks have been used to produce biofuels and the

assessment of the environmental performance for the utilization of lignocellulosic bioethanol have been published. Perennial plants that are grown in degraded land that is no longer suitable for agricultural use can minimize competition with food crops. Planting these plants creates additional opportunities to improve soil carbon 3

ACCEPTED MANUSCRIPT sequestration, tillage water quality, and biodiversity (Field et al., 2008; Tilman et al., 2009). Currently, the potential for feedstock production from fast growing Napier grass is receiving significant attention (Alwi et al., 2016; Takata et al., 2014). The open field burning of corn straw increases air pollutants (CO2, NOx, SO2, and

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particulate matter) and the potential environmental burden (Hong et al., 2016). Crop

residues were originally considered essential for soil fertility and carbon sinking, but a recent report stated they could be a sustainable biomass resource (Tilman et al., 2009;

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Maraseni and Qu, 2016). Mechanized farming (green cane harvesting) along with integrated utilization of biomass residues (cane trash and vinasse) for fuels and

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fertilizers can also help reduce several environmental impacts (climate change, acidification, photooxidant formation, and particulate matter formation) of the sugar and ethanol derived from sugarcane (Silalertruksa et al., 2016). Additionally, the integration of farming and processing activities by utilizing residues for bioenergy

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production can be justified because it allows for reductions in energy demand, fossil energy use, and carbon emissions (Kamp and Østergård, 2016). The use of crop residues in a biorefinery system could reduce 50% greenhouse gas emissions and save

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more than 80% of nonrenewable energy (Cherubini and Ulgiati, 2010). The use of

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sugar cane residues could improve the efficiency in electricity generation and also reduce the greenhouse gas emissions (Nguyen et al., 2010). Sustainably harvested wood and forest residues using forestry operations such as thinning and slashing could reduce fire risks and improve timber quality, and thus has become another source of biofuels (Reinhardt et al., 2008; Giuntoli et al., 2015). However, the utilization of fermentation waste from these process has usually been restricted (Cherubini and Ulgiati, 2010; Nguyen et al., 2010). More than 95% of energy supplies for Taiwan are imported. However, 4

ACCEPTED MANUSCRIPT approximately 150,000 ha half-fallow and 50,000 ha fallow paddy fields exist because of increasing labor costs and competition from rice imports. The potential for energy crop production from such underutilized paddy fields merits significant attention. Thus, selecting crops for optimal environmental performance when producing

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bioethanol is equally important. This study employed LCA to investigate scenarios for plantation of three different crops in fallow paddy fields in Taiwan: rice straw

(agricultural waste), Napier grass (energy crop), and Eucalyptus spp. (short rotation

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coppice), for bioethanol production. The LCA of bioethanol produced from various

biomasses has been explored and compared. However, the analysis and discussion of

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such from a comprehensive perspective is very rare. Thus, the utilization schemes for the aforementioned wastes for pellet fuel as a secondary energy source and recycled molded pulp as a secondary product were also evaluated by LCA considering energy consumptions and environmental emissions for the processes of each utilization

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scenario.

2. Material and methods

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2.1. Goal and scope

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The goal of this study was to investigate the environmental impacts of bioethanol production via a bioconversion process using rice straw, Napier grass, and short rotated Eucalyptus spp. as bioethanol feedstocks in fallow paddy fields. This study used the IMPACT 2002+ model with midpoint evaluation. IMPACT 2002+ is one of the most widely used impact assessment methods in LCA. This method analyzes four different types of damage: human health, ecosystem quality, climate change, and resources, and the standard units for all categories are point (Pt) or millipoint (mPt). One kg of bioethanol-producing dry raw biomass was selected as the functional unit. 5

ACCEPTED MANUSCRIPT In addition, the environmental impacts from the on-site production of molded pulp and pellet fuel using fermentation wastes were evaluated with one dried kg of waste selected as the functional unit. Common materials, such as virgin pulp, recycled newspaper, and imported coals with the Taiwanese scenario, were selected as the

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feedstock to compare their environmental impacts with those of the fermentation wastes.

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2.2. System boundary

The system boundary is shown in Fig. 1. During the plantation stage, elements and

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energy inputs/outputs were considered with different process units, including machinery usage, fertilizer production, chemical production, irrigation, and facilities. This study excluded the influence of coproducts, such as rice hulls and white rice, during the plantation stage. Previous studies indicated that the yield of rice straw in

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Taiwan is approximately 2.13×109 kg/y and that rice straw was typically left on-site as fertilizer for subsequent cultivation. Therefore, the ground would be fertilized less

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Fig. 1. (P22)

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if the rice straw was removed for other purposes.

2.3. Assumptions

The proposed goal of this study was to compare different origins and extend the

overall product life cycle. The rice straw scheme in this study was a slight modification of that used for the case in Taoyuan County (Pan et al., 2008), which has the largest rice cultivation area proportion in northern Taiwan (31%) and generates the most rice straw as a result. Other raw materials were planted in fallow land and had a larger transport distance of up to 50 km by truck. On-site production of pellet fuel and 6

ACCEPTED MANUSCRIPT molded pulp products was assumed.

2.4. Inventory analysis This study used the inventory data in the Ecoinvent built-in database of the

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SimaPro 8.2 LCA software; the most relevant data for each inventory stage was

selected and then modified to reflect the real situation in Taiwan. The important data selections for each stage of the inventory analysis are described in the following

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sections. The inventory data are presented in Tables S1–S3.

Rice straw The cradle-to-grave system boundary of a rice straw biomass supply

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chain for bioethanol production is shown in Fig. 1. Removal of crop residues from farmland decreases the levels of soil organic carbon and nutrients, and thus crop yields, resulting in an increase in the greenhouse effect (Cherubini and Ulgiati, 2010; Cherubini et al., 2009). In this study, the effects of land-use changes caused by the

Fig. 1. (P22)

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removal of crop residues were investigated.

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Napier grass Napier grass, also known as Pennisetum purpureum or elephant grass,

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is a species of tropical grass native to Africa. It is a monocot C4 perennial grass that can be harvested 4–6 times/y and requires low nutrient inputs and water. The primary use for this crop in Taiwan is as forage for livestock. Recently, Napier grass has been used as an energy crop to reduce food competition. Inventory studies of Napier grass in Taiwan have focused primarily on converting biomass to electricity, and the plantation data were based on the results from Tsao (2009) and Li (2010). Other relevant field data were obtained from the experimental plots of the Taiwan Livestock Research Institute, Shinhua, Tainan, Taiwan. 7

ACCEPTED MANUSCRIPT Eucalyptus Eucalyptus is a diverse genus in the myrtle family, Myrtaceae, most of which is native to Australia. This species was first introduced to Taiwan in 1896. The Chung Hwa Pulp Corporation planted Eucalyptus grandis, Eucalyptus urophylla, and Eucalyptus camadulensis on Taiwan Sugar Corporation land in 1987. After 20 years,

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the growing stock reached 93.3–380.5 m3/ha (Shiu et al., 2010). Modifying

information from Australia (Paul et al., 2003) shows that the combined growing

volume was 70 m3/ha/y of wood from Taiwan, and the average density was 0.5 g/cm3

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(Food and Agriculture Organization of the United Nations, 2005).

Change in inland usage The total rice production was assumed 12,000 kg/ha/y

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from two crops, as discussed in a previous study (Huang et al., 2013). The GHG emissions of rice straw were reduced by 1.07×10-1 kg CO2eq/y (Cherubini et al., 2009). Other various emissions data from after the application of N fertilizer used in this study was based on a previous study (Huang et al., 2013).

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Emissions of N2O and CH4 from agricultural land The emissions data of N2O and CH4 for agricultural land based on previous studies (Cherubini et al., 2009; Cherubini and Jungmeier, 2010) was used in this study. Cherubini and Jungmeier (2010)

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discussed this based on their sensitivity analysis with different N2O emissions factors.

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The assessment also included volatilization of NH3 and the leaching of nitrates, which affected other environmental impacts such as acidification and eutrophication. Feedstock production stage inventory This study assumed that the raw materials

were treated with the same process. The basic devices used include various machines. Due to the lack of information about the full-scale processing equipment, certain alternative devices, such as a wood pelletizer, whose functions should be similar to devices used in the chipping process, were selected from the database for this study. Both the storage of bioethanol at a bioenergy center and the storage of collected 8

ACCEPTED MANUSCRIPT biomass were considered in this study. The inputs and outputs of land use, electricity consumption, and waste emissions were used by referring to relevant data in the database. Tables 1 and 2 describe the inventory of electricity in Taiwan in 2010 and 2011, respectively.

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Process of bioethanol production from different raw materials

In the base case, ethanol production includes milling, pretreatment and hydrolysis of the biomass, saccharification, fermentation, and purification of the ethanol or

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dehydration. The CO2 emitted from bioethanol use can be ignored because biomass

absorbs CO2 from the air during its growth. However, other GHGs (e.g., N2O and CH4)

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should be considered. Therefore, the coproduction of sugar from lignin and electricity from wastes was disregarded in this study (Fig. 1). Inventory data were obtained from a pilot-scale bioethanol experiment in Taiwan for LCA analysis (Ko et al. 2012; Chen et al., 2013). Based on the inventory data collected, LCA was performed for

Fig. 1 (P22)

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bioethanol production using different raw material processes.

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Utilization of wastes from bioethanol production

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Wood pellets can have a high energy density, which is an important factor of an energy source. Wood pellets are generally combusted. In this study, pellet fuel production and comparisons were modified from data from Italy (Fantozzi and Buratti, 2010). On-site production for pellet fuel was assumed, and the boundaries are shown in Fig. 1. Fig. 1 (P22)

Most molded pulp packaging products can be made from sources such as waste 9

ACCEPTED MANUSCRIPT printing paper, cartons, corrugated board boxes, paper pellets, and various waste paper sources; the processing of which results in a large variation in the quality of the products, which affects the performance and appearance of the molded pulp packaging products (Huo and Saito, 2009). The total paper and board production in

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Taiwan was 3.41×109 kg in 2008. Based on the Taiwan Technical Association of the Pulp and Paper Industry inventory data, the total GHG emissions in 2008 were 2 billion carbon dioxide equivalents (CO2eq). This study evaluated the Forest

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Eco-Technology Corporation’s mold factory in the city of New Taipei. Based on the

inventory data, 1 kg of molds was produced, which is equivalent to 64.5 products that

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required 0.97 kg of pulp and 8.4×10-2 h to produce. The production of molded pulp packaging products used 100 kWh of electricity and 10 kg of gas. The system boundary of the molded pulp factory modeled in this study is shown in Fig. 1.

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Fig. 1 (P22)

3. Results and discussion

The unused, 2-period, fallow land area occupies more than 50,000 ha in Taiwan.

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Therefore, the use of the fallow land of three different biomass plantation sites were

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investigated in this study and it was assumed that the average transportation distance was 50 km. The plantation schemes of the Napier grass and Eucalyptus spp. were based on a five-year rotation over 30 years (Table 1). Napier grass showed the largest overall production in a 1-ha plantation, followed by Eucalyptus spp., and then rice straw. Napier grass had a high biomass production rate of approximately 138,950 kg/ha/y and could be harvested 4–6 times/y. The raw material chemical components of rice straw, Eucalyptus spp., and Napier grass are also shown in Table 1. The ethanol yield from a 1 kg raw dry sample was significantly larger for rice straw and 10

ACCEPTED MANUSCRIPT Napier grass than it was for Eucalyptus spp. Eucalyptus spp. produced the most residue, followed by Napier grass, and then rice straw, because the higher lignin content in Eucalyptus spp. leads to more residue and thus a lower ethanol yield (Sarkar et al., 2012; Guo et al., 2013).

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Table 1. (P28)

Table 2 shows the energy input and ethanol production for rice straw, Eucalyptus

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spp., and Napier grass from a 1-ha plantation. The fuel and labor input for 1 L of

ethanol production was largest for rice straw, followed by Eucalyptus spp., and finally

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Napier grass. The required fertilizer inputs were largest for the Eucalyptus spp., followed by rice straw and then Napier grass. The results of this analysis show that fuel was the primary consumer of direct energy and fertilizer had the highest indirect energy consumption, which agree with the results found in a previous study

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(Bockari-Gevao et al., 2005). Rice straw had the highest total energy input for 1 L of

Napier grass.

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Table 2. (P29)

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ethanol production in the plantation process, followed by Eucalyptus spp., and finally

The fuel and ethanol productions were the same for rice straw, Eucalyptus spp., and

Napier grass (Table 2). The Eucalyptus spp. had the highest CO2 equivalent emissions, followed by rice straw, and then Napier grass. In terms of residue quantities, the Eucalyptus spp. produced the most, followed by Napier grass, and rice straw producing the least. The residues of Eucalyptus spp. can be reused for bioenergy production; whereas Napier grass requires low nutrient and water inputs and has relatively high ethanol yields. Thus, the CO2 equivalent emissions of the production 11

ACCEPTED MANUSCRIPT of ethanol from Napier grass were lower than those for rice straw or Eucalyptus spp. were. However, the CO2 equivalent emissions for bioethanol production from Eucalyptus spp. plantations were much higher than they were for Napier grass or rice straw because the Eucalyptus spp. plantations investigated in this study were

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approximately 5–7 years old, and the CO2 equivalent emissions from the

planting/weeding/tending processes were high. Additionally, the ethanol yields of Eucalyptus spp. were relatively low.

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Through evaluation of the conversion of 1 kg of biomass to ethanol, the most suitable energy resource was Napier grass (Fig. 2). Napier grass meets the

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requirements for lignocellulosic bioethanol production because it has a low lignin content and a relatively high herbage mass per year and per area (Yasuda et al., 2014). Rice straw contributes more to climate change because of its high transpiration rate. Elevated temperatures increase CH4 emissions rates and have a more pronounced

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effect on plants from flowering to maturity. The observed increase in emissions was increased further when rice straw was used (Gaihre et al., 2013; Pereira et al., 2013). In terms of ecosystem quality, Napier grass had a more pronounced effect because it is

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a non-native species and is considered to disrupt the balance of the ecosystem, as is

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shown by its weighted index. With regard to human health, although Eucalyptus spp. have certain advantages, such as carbon fixation and ecofriendliness, Eucalyptus spp. plantations are controversial due to their adverse effect on biodiversity, such as reduced biological diversity, a lack of food sources for mammals and birds, as well as an absence of hollows that provide shelter and nesting sites for birds, small mammals, and bees (Hiwale, 2015). Thus, the human health impacts of Eucalyptus spp. are relatively high. Rice straw was determined to have the largest total environmental influence followed by Eucalyptus spp. and Napier grass having the lowest. 12

ACCEPTED MANUSCRIPT Fig. 2. (P23)

Fig. 3 shows the life cycle impact assessment midpoint comparisons of rice straw, Eucalyptus spp., and Napier grass. The biomass in the field had the greatest effect on

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land occupation for the rice straw. The collection of biomass from the field had the lowest effect on all midpoint impacts for the rice straw. The application of the

fertilizer had the greatest effect on aquatic eutrophication, respiratory organics,

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mineral extraction, terrestrial acidification/nitrification, noncarcinogenic, aquatic

acidification, and global warming for rice straw and Eucalyptus spp. Saccharification

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& fermentation had the greatest effect on ionizing radiation and terrestrial ecotoxicity for the rice straw. Distillation and dehydration had the greatest effect on carcinogenic and ozone layer depletion for the rice straw. Saccharification & fermentation and distillation & dehydration accounted for more than 80% of the effects on all midpoint

Fig. 3. (P24-25)

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impacts (expect for aquatic eutrophication) for Napier grass.

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Comparison of the LCAs of raw wood, bioethanol waste reutilization, and imported

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hard coal is shown in Fig. 4. A previous study shows that lignocellulosic biorefineries can save up to 60% of GHG emissions compared to fossil fuel refineries (Singh et al., 2010). The utilization of by-products and wastes from the biorefining process has been broadly addressed for environmental sustainability (Nanda et al., 2015). The results show that using fermented waste to make wood pellets reduced environmental impacts by approximately 26.1% compared to imported hard coal. Additionally, using raw Eucalyptus spp. has similar environmental concerns as using fermented waste. However, the use of raw Eucalyptus spp. had a smaller effect on climate change as the 13

ACCEPTED MANUSCRIPT use of fermented waste did, because the current techniques require more energy inputs for fermented waste to produce ethanol. Fig. 4. (P26)

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The life cycle impact assessments for the environmental impacts of virgin pulp, fermentation waste, and recycled paper based on life cycle steps and impact

categories are shown in Fig. 5. The results show that using fermented waste to make

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molded pulp can reduce environmental impacts by more than 50% compared to virgin pulp. Additionally, the use of recycled newspapers had a similar effect on the

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environment as the use of fermented waste. Fermentation waste should thus be reused and reincorporated into the bioenergy system and eventually recovered from the waste stream. Thus, the reuse of fermentation waste from bioenergy production is important to mitigate a negative effect on the environment or human health when the final waste

Fig. 5. (P27)

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4. Conclusion

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is disposed.

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Biofuels generally have higher monetary costs than conventional fossil fuels do. To promote biofuels by highlighting their environmental value, the fermentation schemes from bioethanol production should be explored fully to enhance the total value of biofuels application. The LCAs for rice straw as an agricultural waste, Napier grass as an energy crop, and short rotation Eucalyptus spp., as bioethanol feedstocks in fallow paddy fields were investigated in this study. Additionally, LCAs for two schemes of on-site fermentation waste utilization (pellet fuel and molded pulp feedstocks) were also investigated. Experimental and field-surveyed data were used in 14

ACCEPTED MANUSCRIPT this study. Due to higher biomass yields, planting Napier grass and Eucalyptus spp. resulted in 47% and 28%, respectively, lower weight-based negative impacts compared to planting rice. Pursuing high bioethanol production requires consideration of the overall environmental loading. The rankings for the three crops by acreage and

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bioethanol yield impacts are different due to extensive farming practices and

bioethanol conversion yields. On-site production for pellet fuel using fermentation waste was 7% and 31% higher than that for Eucalyptus spp. biomass pellets and

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imported coals, respectively, in Taiwan. On-site production of molded pulp products using fermentation waste was 5% and 49% higher than that for recycled newspaper

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and virgin chemical pulp, respectively, in Taiwan. Thus, fermentation waste utilization schemes could provide a broader evaluation for planning alternative crops for bioethanol production. Therefore, the development of fermentation waste utilization

Acknowledgment

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will be suitable for regions that require high-energy imports.

The authors would like to thank the National Science Council, Taiwan for their

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financial support of project NSC100-2313-B-002-030-MY2 and Novozymes for their

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donation of enzymes.

References

Alwi, S.R.W., Klemeš, J.J., Varbanov, P.S.. 2016. Cleaner energy planning, management and technologies: Perspectives of supply-demand side and end-of-pipe management. J. Clean. Prod., doi:10.1016/j.jclepro.2016.07.181.

15

ACCEPTED MANUSCRIPT Bockari-Gevao, S.M., bin Wan Ismail, W.I., Yahya, A., Wan, C.C., 2005. Analysis of energy consumption in lowland rice-based cropping system of Malaysia. Energy 27,

RI PT

820-826. Chen, W., Tsai, C., Lin, C., Tsai, P., Hwang, W., 2013. Pilot-scale study on the acid-catalyzed steam explosion of rice straw using a continuous pretreatment system.

SC

Bioresour. Technol. 128, 297–304.

M AN U

Cherubini, F., Ulgiati, S., 2010. Crop residues as raw materials for biorefinery systems – A LCA case study. Appl. Energ. 87, 47-57.

Cherubini, F., Bird, N.D., Cowie, A., Jungmeier, G., Schlamadinger, B., Woess-Gallasch, S., 2009. Energy- and greenhouse gas-based LCA of biofuel and bioenergy systems:

TE D

Key issues, ranges and recommendations. Resour. Conserv. Recy. 53, 434-447. Cherubini, F., Jungmeier, G., 2010. LCA of a biorefinery concept producing bioethanol,

EP

bioenergy, and chemicals from switchgrass. Int. J. Life Cycle Assess.15, 53-66.

AC C

Chundawat, S.P.S., Donohoe, B.S., da Costa Sousa, L., Elder, T., Agarwal, U.P., Lu, F., Ralph, J., Himmel, M.E., Balan, V., Dale, B.E., 2011. Multi-scale visualization and characterization

of

lignocellulosic

plant

cell

wall

thermochemical pretreatment. Energ Environ Sci. 4, 973-984.

16

deconstruction

during

ACCEPTED MANUSCRIPT Fantozzi, F., Buratti, C., 2010. Life cycle assessment of biomass chains: Wood pellet from short rotation coppice using data measured on a real plant. Biomass Bioenerg.

RI PT

34, 1796-1804. Field, C., Campbell, J., Lobell, D., 2008. Biomass energy: the scale of the potential resource. Trends Ecol. Evol. 23, 65-72.

SC

Food and Agriculture Organization of the United Nations, 2005. Global forest resources

M AN U

assessment 2005. http://www.fao.org/docrep/008/a0400e/a0400e00.HTM (accessed 15.04.24)

Gaihre, Y.K., Wassmann, R., Villegas-Pangga, G., 2013. Impact of elevated temperatures on greenhouse gas emissions in rice systems: interaction with straw

TE D

incorporation studied in a growth chamber experiment. Plant Soil 373, 857-875. Giuntoli, J., Caserini, S., Marelli, L., Baxter, D., Agostini, A., 2015. Domestic heating

AC C

206-216.

EP

from forest logging residues: environmental risks and benefits. J. Clean. Prod. 99,

Guo, G., Li, S., Wang, L., Ren, S., Fang, G., 2013. Separation and characterization of lignin from bio-ethanol production residue. Bioresour. Technol. 135, 738-741.

Hendriks, A.T.W.M., Zeeman, G., 2009. Pretreatments to enhance the digestibility of lignocellulosic biomass. Bioresour. Technol. 100, 10-18.

17

ACCEPTED MANUSCRIPT Hiwale, S., 2015. Eucalyptus (eucalyptus sp.), in: Sustainable horticulture in semiarid dry lands, New Dehli, India, Springer Verlag, pp. 301-309.

straw utilization in China. J. Clean. Prod. 112, 1700-1708.

RI PT

Hong, J., Ren, L., Hong, J., Xu, C., 2016. Environmental impact assessment of corn

Huang, Y., Syu, F., Chiueh, P., Lo, S., 2013. Life cycle assessment of biochar cofiring

SC

with coal. Bioresour. Technol. 131, 166-171.

M AN U

Huo, L., Saito, K., 2009. Multidimensional life cycle assessment on various moulded pulp production systems. Packag. Technol. Sci. 22, 261-273.

Kamp, A., Østergård, H., 2016. Environmental sustainability assessment of fruit cultivation and processing using fruit and cocoa residues for bioenergy and compost.

TE D

Case study from Ghana. J. Clean. Prod. 129, 329-340. Ko, C., Wang, Y., Chang, F., Chen, J., Chen, W., Hwang, W., 2012. Potentials of

EP

lignocellulosic bioethanols produced from hardwood in Taiwan. Energy 44, 329-334.

AC C

Liew, W.H., Hassim, M.H., Ng, D.K., 2014. Review of evolution, technology and sustainability assessments of biofuel production. J. Clean. Prod. 71, 11-29.

Li, K.C., 2010. Costs and carbon emissions analysis of biomass supply logistics, in, Graduate Institute of Environmental Engineering. National Taiwan University, Taipei Taiwan.

18

ACCEPTED MANUSCRIPT Maraseni, T.N., Qu, J., 2016. An international comparison of agricultural nitrous oxide emissions. J. Clean. Prod. 135, 1256-1266.

RI PT

Nanda, S., Azargohar, R., Dalai, A. K., Kozinski, J.A., 2015. An assessment on the sustainability of lignocellulosic biomass for biorefining. Renew. Sust. Energ. Rev. 50, 925-941.

SC

Nguyen, T.L.T., Gheewala, S.H., Sagisaka, M., 2010. Greenhouse gas savings potential

M AN U

of sugar cane bio-energy systems. J. Clean. Prod. 18, 412-418.

Ojeda, K., Sánchez, E., Kafarov, V., 2011. Sustainable ethanol production from lignocellulosic biomass – Application of exergy analysis. Energy 36, 2119-2128. Pan, Y.J., 2008. Life cycle assessment of rice production in Taiwan, in, Institute of

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Natural Resource Management. National Taipei University, Taipei, Taiwan. Paul, K., Booth, T., Elliott, A., Jovanovic, T., Polglase, P, Kirschbaum, M., 2003. Life

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cycle assessment of greenhouse gas emission from domestic woodheating.

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http://utting.net.au/doc/lifecycle.pdf (accessed 15.08.31) Pereira, J., Figueiredo, N., Goufo, P., Carneiro, J., Morais, R., Carranca, C., Coutinho, J., Trindade, H., 2013. Effects of elevated temperature and atmospheric carbon dioxide

concentration on the emissions of methane and nitrous oxide from Portuguese flooded rice fields. Atmos. Environ. 80, 464-471.

19

ACCEPTED MANUSCRIPT Portugal-Pereira, J., Lee, L., 2016. Economic and environmental benefits of waste-to-energy technologies for debris recovery in disaster-hit Northeast Japan. J.

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Clean. Prod. 112, 4419-4429. Reinhardt, E.D., Keane, R.E., Calkin, D.E., Cohen, J.D., 2008. Objectives and considerations for wildland fuel treatment in forested ecosystems of the interior

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western United States. Forest Ecol. Manag. 256, 1997-2006.

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Sarkar, N., Ghosh, S.K., Bannerjee, S., Aikat, K., 2012. Bioethanol production from agricultural wastes: an overview. Renew. Energ. 37, 19-27.

Shiu, Y.R., Tsai, J.B., Chung, J.D., 2010. New thinking of plantations in the plain land fast-growing short rotation eucalyptus. Taiwan J. Forest Sci. 7, 5-9.

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Silalertruksa, T., Pongpat, P., Gheewala, S.H., 2016. Life cycle assessment for enhancing environmental sustainability of sugarcane biorefinery in Thailand. J. Clean.

EP

Prod., doi:10.1016/j.jclepro.2016.06.010.

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Singh, A., Pant, D., Korres, N.E., Nizami, A., Prasad, S., Murphy, J.D., 2010. Key issues in life cycle assessment of ethanol production from lignocellulosic biomass: challenges and perspectives. Bioresour. Technol. 101, 5003-5012.

Takata, E., Tsuruoka, T., Tsutsumi, K., Tsutsumi, Y., Tabata, K., 2014. Production of xylitol and tetrahydrofurfuryl alcohol from xylan in Napier grass by a hydrothermal

20

ACCEPTED MANUSCRIPT process

with

phosphorus

oxoacids

followed

by

aqueous

phase

hydrogenation. Bioresour. Technol. 167, 74-80.

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Tilman, D., Socolow, R., Foley, J.A., Hill, J., Larson, E., Lynd, L., Pacala, S., Reilly, J., Searchinger, T., Somerville, C., Williams, R., 2009. Beneficial biofuels—the food, energy, and environment trilemma. Science 325, 270-271.

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Tsao, H.J., 2009. Assessing carbon balance of biopower generation by municipal solid

University, Taipei, Taiwan.

M AN U

waste incinerators, in, Institute of Natural Resource Management. National Taipei

Velásquez-Arredondo, H.I., Ruiz-Colorado, A.A., De Oliveira Jr, S., 2010. Ethanol production process from banana fruit and its lignocellulosic residues: energy analysis.

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Energy 35, 3081-3087.

Weldemichael, Y., Assefa, G., 2016. Assessing the energy production and GHG

EP

(greenhouse gas) emissions mitigation potential of biomass resources for Alberta. J.

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Clean. Prod. 112, 4257-4264. Yasuda, M., Ishii, Y., Ohta, K., 2014. Napier grass (Pennisetum purpureum Schumach) as raw material for bioethanol production: pretreatment, saccharification, and

fermentation. Biotechnol. Bioproc. Eng. 19, 943-950.

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Fig. 1. System boundary of this study.

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Resources Climate change Ecosystem quality Human health

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mPt

16

0 Rice straw

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8

Eucalyptus spp.

Napier grass

Fig. 2. Life cycle impact assessment endpoint results for the conversion of 1 kg of

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straw to bioethanol.

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(a)

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(b)

Fig. 3. Characterization of the mid-point environmental effects of (a) Rice straw, (b) Eucalyptus spp., and (c) Napier grass. 24

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Fig. 3. Characterization of the mid-point environmental effects of (a) Rice straw, (b)

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Eucalyptus spp., and (c) Napier grass. (Continued)

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Resources Climate change Ecosystem quality Human health

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mPt

8

0

Raw eucalypt

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Fermentation waste Imported Hard coal

Fig. 4. Life cycle impact assessment endpoint results of wood pellets and reused

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pellets.

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0.010

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Resources Climate change Ecosystem quality Human health

0.008

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mPt

0.006

0.002

0.000 Virgin pulp

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Fermentation waste

Recycled paper

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Fig. 5. Life cycle impact assessment endpoint results of reused, fermentation waste,

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and original paper molds.

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Table 1

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Inventory of rice straw, Eucalyptus spp., and Napier grass on a 1-ha plantation. Material

Rice straw Eucalyptus spp. Napier grass 11,090

51,250

138,950

603

642

632

117

313

189

91

30

79

171

12

98

18

3

2

Ethanol yield (L/kg raw dry sample)

0.20

0.082

0.18

Residue (g/kg raw dry sample)

339

598

376

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Production (kg/ha/y) Raw material chemical components

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(g/kg raw dry sample) Holocellulose Lignin Extractives

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Others

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Ash

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Table 2

Life cycle impact assessment for energy inputs and ethanol production for rice straw, Eucalyptus spp., and Napier grass based on life cycle steps and impact categories on a

Rice straw

Plantation Dry weight (kg/ha/y/LEtOH) Fuel (L/ha/y/LEtOH) Labor (h/ha/y/LEtOH)

Ethanol production

5,000

12,200

5,560

326.22

165.52

6.23

63.95

34.57

1.26

180.20

261.90

6.94

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Fertilizer (kg/ha/y/LEtOH)

Eucalyptus spp. Napier grass

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Material

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1-ha plantation for 1 L of ethanol production (50 km transport distance).

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0.16

0.16

Ethanol (L/ha/y/LEtOH)

1.00

1.00

1.00

CO2 (kg eq/ha/y/LEtOH)

1,076.87

4,049.07

615.35

1.69

7.30

2.09

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Fuel (L/ha/y/LEtOH)

Residue (kg/ha/y/LEtOH)

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LCAs for pellet fuel and molded pulp of on-site fermentation waste utilization




Fermentation waste pellet fuel was 7% and 31% higher than Eucalyptus spp. and

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coal.

Fermentation waste utilization is suitable for regions with high-energy imports.




Fermentation waste molded pulp was 5% and 49% higher than recycled paper

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and pulp.