LIFE-CYCLE GREENHOUSE GAS EMISSIONS OF CHINA S FOREST-TO-PULP SUPPLY CHAIN: A CASE STUDY ON WOOD PULP PRODUCED FROM EUCALYPTUS PLANTATIONS

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LIFE-CYCLE GREENHOUSE GAS EMISSIONS OF

CHINA’S FOREST-TO-PULP SUPPLY CHAIN:

A CASE STUDY ON WOOD PULP PRODUCED FROM EUCALYPTUS PLANTATIONS

Wei Xu, Gero Becker

Chair of Forest Utilization, University of Freiburg, Germany wei.xu@fobawi.uni-freiburg.de

Abstract

Climate change is one of the greatest environmental challenge facing the world. IPCC (2007) indicated that most of the temperature rise over the last 50 years is very likely caused by anthropogenic greenhouse gas (GHG) emissions.

Chinese wood pulp industry has experienced a remarkable development over the past two decades, and eucalyptus plantation is becoming the dominant pulpwood supply for the booming pulp industry. The objective of this study was to examine the GHG emissions of the

“forest-to-pulp” supply chain from a life-cycle perspective by using a case study approach.

The system boundary was divided into two sub-systems, including the forest sub-system with a leading eucalyptus plantation operator in Guangxi, and the pulp mill sub-system with a

“state of the art” pulp mill in Hunan province.

Site-specific data related to GHG emissions from the examined supply chain were gathered through field trips to the selected case study companies in 2009 and 2010. Some un-measurable emissions from the forest sub-system and transportation were calculated using the well-accepted approach proposed by IPCC (2003, 2006) by multiplying the on-site activity data with associated emission factors. Some un-measurable emissions from the studied pulp mill were estimated using the tool developed by NCASI (2005). System modelling and life-cycle inventory of GHG emissions were carried out with the program of Umberto 5.5. The inventoried GHG emissions were characterized into global warming impacts by applying the global warming potentials (GWP) suggested by IPCC (2007).

It was calculated that for producing one air-dried ton wood pulp ready at the pulp mill gate, 1.5 ton CO2-eq. greenhouse gas were released to the atmosphere. The mill’s on-site supportive units of CHP plant, chemical recovery unit and water treatment plant were identified as hot-spot emission sources contributing to the total global warming effects. The application of fertilizers in the eucalyptus plantation management was also identified as a great contributor leading to global warming impacts.

Keywords

Forest-to-pulp supply chain, life-cycle GHG emission, global warming potential, eucalyptus plantations

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1. INTRODUCTION

1.1 China’s forest-to-pulp supply chain

The Chinese wood pulp industry has experienced a remarkable development over the past two decades, and fast-growing eucalyptus plantations are becoming the dominant wood supply for the booming wood pulp industry (CPA, 2011).

In southern China, a total area of 1.6 million hectares eucalyptus plantations has been established mainly used as pulpwood. The integration of wood pulp industry with large-scale plantation establishment has become an important development pattern in China (NDRC, 2004). This integration was defined as ‘forest-to-pulp’

supply chain for sustainability impact assessment by Xu (2012).

1.2 Concerns for global warming impacts

Global warming has been identified as one of the greatest challenges facing the world over future decades. It was indicated that most of the temperature rise over the last 50 years is very likely caused by greenhouse gas (GHG) emissions through anthropogenic activities, such as fossil fuel combustion, chemical processing and transportation, etc (IPCC, 2006).

Many operations of the examined forest-to-pulp supply chain lead to direct or indirect emissions of greenhouse gas to the atmosphere, including the activities of plantation management, transportation and industrial operations in the pulp mill.

Therefore, an investigation of life-cycle GHG emissions along the entire forest-to-pulp supply chain has great significance.

The objective of this study was to eamine the GHG emissions along China’s forest-to-pulp supply chain from a life-cycle perspective, and to evaluate the environmental impact of global warming associated with the examined forest-to-pulp supply chain.

2. METHODOLOGY

The methodology of Life Cycle Assessment (LCA) was applied in this study, to identify all the relevant activities along the entire forest-to-pulp supply chain leading to GHG emissions, and to compile all these emissions from a life-cycle perspective. A case study approach was adopted to conduct this research.

2.1 Research boundary & functional unit

The research boundary was defined by adopting a “cradle-to-gate” perspective, covering the life cycle phases of raw material extraction from fast-growing eucalyptus plantations, through well-organized logistics of transportation, to the final product of manufacture Bleached Eucalyptus Kraft Pulp (BEKP) ready at the mill gate.

To allow a specific analysis, the system was divided into two sub-systems: the forest sub-system and the pulp mill sub-system. A leading eucalyptus plantation operator in Guangxi with more than 40,000 hectares eucalyptus plantations was taken as case study for the forest sub-system. A representative BEKP producer with the ‘state-of-art’ technique and facilities in Hunan province was taken as case study for the pulp mill sub-system. In this analysis, only the fossil-based GHG emissions were accounted into inventory. The biomass-based emission of CO2 released from

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biomass combustion and from biological processes (e.g. from soils) were excluded in this analysis.

The analysis results were referring to the functional unit (FU) of one air-dried ton of produced wood pulp.

2.2 Inventory of GHG emissions

The greenhouse gases taken into account in this study were carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) according to IPCC (2006). As explained before, many operations of the examined supply chain lead to direct or in-direct GHG emissions. An investigation of principal operations covering all the life cycle phases of the examined supply chain was conducted through field trips in 2009. Activities leading to GHG emissions were specified along the entire supply chain (see Table 1).

Table 1: GHG emission sources of the examined supply chain

Sub-system Operations Emission sources

Forest sub-system

Fertilization N-fertilizer urea

Harvest Fuel combustion in chain-saw Transport Log delivery Fuel combustion in vehicles Pulp mill

sub-system

On-site log transport Fuel combustion in log stacker

CHP plant Fuel combustion for power generation Chemical recovery Fuel combustion in the lime kiln Water treatment Anaerobic treatment

Landfill of solid waste Waste

Site-specific data of life-cycle GHG emissions was collected through company visits in 2009 and 2010. Some un-measurable emissions from the forest sub-system and transportation were calculated using the well-accepted approach proposed by IPCC (2003, 2006) by multiplying the on-site activity data with associated emission factors. For some un-measurable emissions from the studied pulp mill, estimated data was used based on the calculation tool for estimating GHG emissions from pulp and paper mills developed by the NCASI (2005). Subsequently, the inventoried data was processed with the professional LCA software of Umberto 5.5 (ifu, 2005).

2.3. Impact assessment of global warming

The inventoried GHG emissions of CO2, CH4 and N2O were characterized into global warming impact, by applying the characterization factors (see Table 2) suggested by IPCC (2007). The global warming impact is expressed by the indicator of global warming potential (GWP) for a time horizon of 100 years, and the aggregated result of GWP was measured in kg CO2-equivalent.

Table 2: Inventoried GHG emissions of the examined supply chain Greenhouse gas GWP for a time horizon of 100 year (kg CO2-eq )

CO2 1

CH4 25

N2O 298

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3. RESULTS

Results of the accounted GHG emissions from major contributing operations of the examined supply chain are presented in Table 3, and the presented results were referring to the functional unit (FU) of one air-dried ton of produced wood pulp.

Based on the inventory results, for producing one air-dried ton wood pulp, the total GHG emissions released from the supply chain reached up to 1.5 ton CO2-eqivalent.

Table 3: Inventoried GHG emissions of the examined supply chain

Sub-system Operations CO2 CH4 N2O GWP

kg/FU kg/FU kg/FU kg CO2-eq./FU

Forest sub-system Fertilization 28.94 - 0.35 133.24

Harvest 1.83 - - 1.83

Transport Log delivery 56.38 - - 56.38

Pulp mill sub- system

On-site log delivery 2.72 - - 2.72

CHP plant 376.92 0.89 0.39 515.39

Chemical recovery 115.57 0.41 0.04 137.74

Water treatment - 26.15 - 653.75

Total 582.36 27.45 0.78 1,501.05

Meanwhile, the relative contributions of major operations to the total global warming impacts were given in order to illustrate the hot-spot operations with major contributions to global warming impacts (see Figure 1).

Figure 1: Relative contributions of major operations of the entire supply chain to the total global warming impacts

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The pulp mill sub-system showed significant contribution to the total GHG emissions of the entire forest-to-pulp supply chain. Firstly, water treatment was identified as the most important source of GHG emissions by contributing 44% of the total global warming potential of the entire supply chain. This is mainly caused by the release of methane directly emitted to the atmosphere without any collection devices from the water treatment plant. Secondly, the mill’s CHP plant and the chemical recovery unit were identified as another two hot-spot GHG emission sources by accounting for 34% and 9% of the total global warming potentials, respectively. The generated GHG emissions were caused by coal combustion in the CHP plant for power generation and the diesel combustion in the lime kiln.

Furthermore, the forest sub-system which was responsible for 9% of the total global warming impacts was identified as a great GHG emission source, mainly due to the application of fertilizers in the eucalyptus plantation management.

4. CONCLUSIONS

This study examined the major GHG emission sources along the entire forest-to- pulp supply chain. The mill’s supportive units of water treatment, power generation and chemical recovery, and the operation of fertilizers in plantation management were identified as major contributors leading to global warming effects. Optimization measures with regard to these hot-spot operations can be taken in the future. The findings of this study set up a benchmark for China’s plantation operations and the pulp industry for achieving better environmental performance towards sustainable development.

ACKNOWLEDGEMENTS

The authors are grateful to the Landesgraduiertenfoerderung and the Graduate School “Environment, Society and Global Change” of the University of Freiburg for supporting this research.

REFERENCES

[1] Chinese Paper Association (CPA), ‘Annual report of the Chinese pulp and paper industry in 2010‘, 2011 (in Chinese). http://www.chinapaper.org/thread-122589-1-1.html

[2] National Development and Reform Commission (NDRC), ‘The program of plantation- pulp-paper integration establishment for the 10th-five year and special arrangement for 2010’, 2004 (in Chinese)

[3] National Council for Air and Stream Improvement (NCASI), ‘Calculation tools for estimating GHG emissions from pulp and paper mills’, 2005 (in Chinese)

[4] Institut für Umweltinformatik Hamburg GmbH (ifu), ‘Umberto user manual: a software tool for life cycle assessment and material flow analysis’, 2005

[5] IPCC, ’Good practice guidance for land use, land-use change and forestry’, 2003 [6] IPCC, ‘Guidelines for national greenhouse gas inventories’, 2006

[7] IPCC, ‘Climate change 2007: The physical science basis. Contribution of working group I to the fourth assessment report of the IPCC’, 2007

[8] W. Xu, ‘Sustainability impact assessment of China’s integrated forest-to-pulp supply chain: a case study of wood pulp production based on fast-growing eucalyptus plantations in South China’, 2012. Dissertation, University of Freiburg

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Cycle de vie des gaz à effet de serre de la chaine forêt-pâte à papier:

une étude de cas pour la pâte à papier fabriquée depuis les plantations d’Eucalyptus

Wei Xu, Gero Becker

Chair of Forest Utilization, University of Freiburg, Germany wei.xu@fobawi.uni-freiburg.de

Le changement climatique est actuellement le plus grand challenge de notre société. D’après l`IPCC (2007) le réchauffement récent de notre planète doit être largement attribué aux émissions liées à l’activité humaine.

L’industrie papetière chinoise essentiellement alimentée par des plantations d’Eucalyptus s’est remarquablement développée dans les deux dernières décades.

L’objectif de cette étude est d’examiner les émissions de gaz à effet de serre de la chaine forêt-pâte à papier d’un point de vue du cycle de vie, depuis l’approvisionnement de la matière première jusqu’au procédé industriel de transformation et aux opérations logistiques.

Dans cet objectif, nous avons divisé la de la chaine forêt-pâte à papier en deux sous-systèmes:

i) le sous-système forêt avec pour exemple une entreprise d’exploitation forestière d’Eucalyptus opérant en Guangxi

ii) le sous-système transformation de pâte avec pour exemple une entreprise de pointe de fabrication de pâte de la province de Hunan.

Des données spécifiques d’émissions de ces deux sites furent rassemblées lors d’études sur le terrain dans les entreprises respectives en 2009 et en 2010. Les émissions du sous-système forêt non-mesurables, ont été calculées par l’approche proposée pas IPCC (2203, 2006) en multipliant les indicateurs d’activité sur les sites par les facteurs respectifs d’émissions. Les émissions du système transformation de pâte non-mesurables dans l’usine de pâte et papier ont été estimées grâce à l’outil développé par NCASI (2005). Les émissions inventoriées ont enfin été caractérisées en termes d’impact sur le réchauffement global par les méthodes de Potentiels Réchauffement Global (GWPs) suggérées par IPCC (2007). Avec le programme Umberto (version 5.5), nous avons enfin modélisé le système et établi l’inventaire du cycle de vie des émissions. Il en résulte que pour produire une tonne de pâte à papier sèche, 1.5 tonnes de CO2- équivalent sont émises dans l’atmosphère. Les unités de génération d’énergie, de récupération de produits chimiques et de traitement des eaux usées sont des sources massives d’émission dans le sous- système pâte. L’utilisation intensive de fertiliseurs dans les plantations d’eucalyptus contribue également largement aux émissions et au réchauffement global. Des mesures d’optimisation de ces «points chauds» sont nécessaires dans le futur pour améliorer la performance environnementale de cette chaine de production.

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