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Assessing air pollution abatement co-benefits of energy efficiency improvement in cement industry: A city level analysis

Shaohui Zhang, Hongtao Ren, Wenji Zhou, Yadong Yu, Tieju Ma, Chuchu Chen

PII: S0959-6526(18)30631-0 DOI: 10.1016/j.jclepro.2018.02.293 Reference: JCLP 12240

To appear in: Journal of Cleaner Production Received Date: 1 November 2017

Revised Date: 22 February 2018 Accepted Date: 26 February 2018

Please cite this article as: Zhang S, Ren H, Zhou W, Yu Y, Ma T, Chen C, Assessing air pollution abatement co-benefits of energy efficiency improvement in cement industry: A city level analysis, Journal of Cleaner Production (2018), doi: 10.1016/j.jclepro.2018.02.293.

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.

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8[The [The [The [The number of words in this manuscript number of words in this manuscript number of words in this manuscript number of words in this manuscript is is is is 6589 6589 6589]]]] 6589

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Assessing Assessing Assessing

Assessing air pollution abatement co air pollution abatement co air pollution abatement co----benefits of energy efficiency air pollution abatement co benefits of energy efficiency benefits of energy efficiency benefits of energy efficiency

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improvement improvement improvement

improvement in cement industry: a city level analysis in cement industry: a city level analysis in cement industry: a city level analysis in cement industry: a city level analysis

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Shaohui Zhang1, Hongtao Ren 2*, Wenji Zhou1, Yadong Yu2, Tieju Ma1,2, Chuchu Chen3 6

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1 International Institute for Applied Systems Analysis, Schlossplatz 1, A-2361, Laxenburg, Austria 8

2 School of Business, East China University of Science and Technology, Meilong Road 130, 200237, 9

Shanghai, China 10

3 College of Materials Science and Engineering, Nanjing Forestry University, 210037, Nanjing, China;

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Abstract

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China is the world’s largest cement producer, contributing to 60% of the global total. Jiangsu 14

province takes the lead of cement production among China’s provinces, contributing to 8.4%

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of the national total cement output. In this study, a geo-graphical information system-based 16

energy model is developed to assess the potential of energy savings and associated 17

mitigation of CO2 and air pollutant emissions in Jiangsu’s cement industry during 2015–2030.

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Results show that 1) compared to 2015, energy consumption in the baseline scenario will 19

decrease by 54% at the provincial level. Economical energy saving potential for 2030 is 20

around 50 PJ, which equals to 35% of energy use in the baseline in 2030. 2) At the city level, 21

Changzhou, Wuxi, and Xuzhou are top three cities in terms of energy saving potential. 3) The 22

economical CO2 emission reductions will decrease by 4.4 Mt in 2030, while the emissions of 23

PM and NOx would decline by 30% and 56%, respectively. This study will help policy makers 24

develop integrated policies to support the coordinated development of Jiangsu and can also 25

enhance the effectiveness of the implementation of joint prevention and control of 26

atmospheric pollution to improve regional air quality.

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Keywords:

Keywords:

Keywords:

Keywords:

co-benefits; GIS-based energy model; energy efficiency; cement industry;

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emission reduction 30

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Nomenclature 32

33

Abbreviations 34

ECSC Energy conservation supply curves 35

CSC Conservation Supply Curve 36

GHG Greenhouse gases 37

SO2 Sulfur dioxide 38

NOx Nitrogen oxides 39

2 Corresponding author. Tel.: + 86 021 6425 0013 E-mail addresses: ren@ecust.edu.cn (Hongtao Ren)

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2 PM Particulate matter

1

Mt Million tons 2

kt Thousand tons 3

EJ Exajoule 4

GAINS–ECSC Greenhouse Gas - Air Pollution Interactions and Synergies (GAINS)- Energy 5

conservation supply curves 6

NSP New Suspension Preheater/Precalciner 7

t/d Tons per day 8

GIS A geo-graphical information system (GIS) 9

EECP Energy efficiency policy with cost effective energy saving potential scenario 10

EETP Energy efficiency policy with technical energy saving potential scenario 11

AEEI Annual autonomous energy efficiency improvement 12

BL Baseline scenario 13

NBS China National Bureau of Statistics 14

NDRC China National Development and Reform Commission 15

16

Symbols 17

CCE Cost of conserved energy for an energy efficiency measures 18

Cement production 19

Cement production in city i 20

New floor space in city i 21

Building cement material intensity 22

Highway cement material intensity 23

New length Highways in city i 24

Railway cement material intensity 25

New length Railways in city i 26

Ini Industrial Investment 27

ICI Industrial construction cement intensity 28

Ex Net export of cement 29

I Investment 30

AF Annuity factor 31

& Annual change in operation and maintenance fixed cost 32

& Annual change in operation and maintenance variable cost 33

ESP Annual energy saving potential 34

PE Energy price 35

d Discount rate;

36

n Lifetime of the energy efficiency measures 37

38

Subscript 39

i city 40

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1. Introduction 1. Introduction 1. Introduction 1. Introduction

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Chinese government announced the target “to achieve a peak of CO2 emissions around 2030 44

and to make the best efforts to peak early” for the Paris agreement (NDRC, 2015). Cement 45

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industry is one of the most energy intensive industrial sectors, and also one of the largest 1

contributors to CO2 emissions and air pollution (Morrow III et al., 2014; Worrell et al., 2013;

2

Worrell et al., 2001). China is the largest cement producer and consumer in the world, 3

accounting for 59% of the global total, consuming 6961 PJ of final energy, and emitting 1380 4

Mt CO2, 410 Mt of PM, 1.3 Mt of SO2, and 2.27 Mt of NOx, respectively, of the total sectors’

5

emissions (Zhang et al., 2015b). Recent studies have shown that the future energy 6

consumption of China’s cement industry in a reference scenario could continue increase to 7

8,500 PJ by 2020, 84% higher than 2010. This would result in increased projected annual 8

emissions of 1,719 Mt of CO2, 5,700 kt of PM, 1,400 kt of SO2, and 780 kt of NOx, 9

respectively (Zhang et al., 2015b,c). Jiangsu is China’s largest cement producer and 10

responsible for 8.4% of total China’s cement production. In 2015, Jiangsu’s cement industry 11

consumed around 261 PJ of final energy and emitted 98 Mt of CO2, 9 kt of SO2, 67 kt of PM, 12

and 74 kt of NOx (Jiangsu Provincial Bureau of Statistics, 2016).

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Various studies have shown that there is large potential to improve energy efficiency and 15

reduce emissions in China’s cement industry (Chen et al., 2015; Hasanbeigi et al., 2013a;

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Hasanbeigi et al., 2013b; Hasanbeigi et al., 2010b; Ke et al., 2012; Wen et al., 2015). Energy 17

efficiency measures can not only enhance the sustainability of the energy system but also 18

can reduce emissions of CO2 and other air pollutants (IEA, 2014a; IEA, 2014b). In this way, a 19

smart air quality policy that incorporates energy efficiency as a core approach can 20

simultaneously reduce energy use and greenhouse gas emissions, while achieving air quality 21

targets at lower costs. However, the current energy models only simulate the potentials of 22

energy efficiency improvement and emissions’ mitigation based on direct costs, which leads 23

to an underestimation of the full benefits of energy efficiency. The GAINS–ECSC model, 24

developed by Utrecht University, was used to assess the co-benefits of energy efficiency 25

measures for reducing greenhouse gas (GHG) and air pollutant emissions, in addition to 26

energy consumption in China’s cement industry (Zhang et al., 2015a,b). These studies 27

neglected the regional heterogeneity across China, especially for Jiangsu province. The co- 28

benefits of energy efficiency have not yet been systematically assessed for Jiangsu’s cement 29

industry, owing to limited data and few mature methodologies to measure their scope and 30

scale. As a result, there is lack of supporting tools for local policy makers to develop and 31

implement effective policies of adopting energy efficiency technologies in cement industry.

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Understanding the co-benefit of energy efficiency for air pollution in Jiangsu’s cement 33

industry at city level is an urgent necessity. This knowledge gap is the starting point of this 34

study, which aims to assess the potential of energy efficiency improvement in Jiangsu’s 35

cement industry to mitigate emissions of CO2 and air pollutants. Combining geographic data 36

as well as air quality data with energy modeling will allow a thorough analysis of the impacts 37

of energy efficiency improvement. Furthermore, the geographic modeling will allow 38

evaluation of the effects of different policies (including closure of outdated cement plants) 39

on local air quality. This paper can support the development of effective air quality policy 40

implemented by national and provincial authorities, and realizing the indirect climate 41

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4 benefits in the process.

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2. Overview of 2. Overview of 2. Overview of

2. Overview of the the the the cement industry cement industry cement industry cement industry in Jiangsu Province in Jiangsu Province in Jiangsu Province in Jiangsu Province

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Cement production in Jiangsu province has increased 1.8-fold since 2005, reaching 180 Mt 5

in 2015 (Fig. A-1 in Supplementary-A). However, the clinker production has only increased 6

by 30%, from 55 Mt in 2005 to 72 Mt in 2012, since when there has been a slight decrease, 7

at an average of 4% per year (China Cement Association, 2016; Jiangsu Provincial Bureau of 8

Statistics, 2016). The outdated kiln systems were almost completely replaced by New 9

Suspension Preheater/Precalciner (NSP) kilns before 2005 (Fig. A-2 in Supplementary-A). The 10

total production capacity of NSP kilns increased from 6 Mt before 2000 to 60 Mt in 2015.

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Meanwhile, the average clinker production capacity increased from 2,450 t/d before 2000 12

to 3,432 t/d in 2015. Compared to the growth of cement output, energy consumed in this 13

industry showed a mild increasing trend, from 216 PJ in 2005 to 286 PJ in 2013 (Fig. A-3 in 14

Supplementary-A), due to fast development of dry process, phase-out of smaller scale 15

cement plants, and import of clinker from surrounding regions. Coal plays a dominant role in 16

energy consumption in Jiangsu’s cement industry, accounting for 86% of the total, followed 17

by electricity.

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Total CO2 emissions in Jiangsu’s cement industry increased from 74 Mt in 2005 to 104 Mt in 20

2015, at an average annual growth rate of 4% (see Fig. 1.). The fuel combustion share of 21

total CO2 emissions ranges from 50–60%, followed by process emissions (30–40%).

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Interestingly, the contribution of process calcination to total CO2 emissions in Jiangsu’s 23

cement industry is comparatively 5–10% lower than the national average level due to the 24

ratio difference between clinker and cement.

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Fig. 1. Emissions CO2 and air pollutants from Jiangsu’s cement production 27

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Fig. 1 also shows that the historical trends of air pollutants emissions in Jiangsu’s cement 29

industry were completely different from those of energy-related CO2 emissions. Air 30

pollutant emissions decreased by two thirds from 2005 through 2011 and then declined 31

modestly over the next four years. PM is the largest contributor to air pollution in the 32

Jiangsu’s cement industry; the PM share of total air pollution decreased from 70% in 2005 to 33

45% in 2015, due to accelerating the implementation of NSP kilns, energy efficiency 34

improvement, and the phasing-out of small scale cement plants. Like the trend of PM 35

emissions, the SO2 emissions decreased by four fifths from 2005 to 2010 and then remained 36

at a stable level. However, the NOx emissions showed an opposite trend compared to the 37

PM and SO2 emissions.

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3. Methods 3. Methods 3. Methods

3. Methods and data and data and data and data

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3.1 3.1 3.1

3.1 G G General description of m G eneral description of m eneral description of model eneral description of m odel odel framework odel framework framework framework

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To support the development of an appropriate air quality policy that builds on energy 5

efficiency and assess the effect of changing regional productions of cement and clinker (by 6

closing or concentrating production at specific sites), a GIS-based energy model is developed 7

that can assess the impacts on air quality, energy use, and greenhouse gas emissions. Fig. 2 8

shows the simplified diagram of the model framework. This model can not only be used to 9

formulate effective policy strategies for the provincial government, but also be extended to 10

apply to other regions or industries.

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Fig. 2. Simplified diagram of model framework 13

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As the diagram shows, the framework comprises four parts, demand projection, GIS-based 15

modeling, and cost-benefit analysis. The demand projection part provides the future’s 16

development of cement industry in Jiangsu Province as well as in all the cities over the 17

period from 2015 to 2030. This serves the basic input for the overall scenario analysis. The 18

second step is to set up a GIS-based energy model based on the combination of provincial 19

energy conservation supply curves (ECSC) and the core model constructed with elaborated 20

spatial functions by applying ArcGIS, a geo-graphical information system (GIS) software. By 21

applying this model, the cost-benefit analysis can be conducted to assess the potential of 22

energy savings and associated mitigation of emissions of CO2 and air pollutants. More 23

details are provided as follows.

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3.2 3.2 3.2

3.2 Projection of the outputs of cement and clinker Projection of the outputs of cement and clinker Projection of the outputs of cement and clinker Projection of the outputs of cement and clinker

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Cement production is closely linked to new buildings, urbanization rates, and construction 28

of roads, highways, and railways (Hasanbeigi et al., 2017; Ke et al., 2012). For a better 29

projection of Jiangsu’s cement output, the current economy growth rate, the urbanization 30

process, future activities of new buildings, construction of roads, highways, and railways are 31

estimated. Also, the phase-out rate of outdated production, and other policies that aim to 32

control the overcapacity are considered. Set 2015 as the base year for analyzing the 33

historical trends of energy use, production structure, emissions. This step can provide more 34

evidence when estimating implementation rates of energy efficiency measures and the 35

potential needs to be assessed based on existing production capacities and production 36

structures. In the study, the urbanization rate of each city in 2015 is from the Jiangsu 37

Statistical Yearbook (Jiangsu Provincial Bureau of Statistics, 2016). The average floor area 38

per capita of each province in 2015 is from Wei’s study (Wei and Dong, 2011). The formula 39

for projecting the future cement production of each city is shown below (see Eq. (1)).

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= ∑ = ∑ ( ∗ + ∗ + ∗ + ∗ + ) Eq. (1) 1

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Where:

3

= cement production;

4

= cement production in city i;

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= New floor space in city i;

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= Building cement material intensity;

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= Highway cement material intensity;

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= New length Highways in city i;

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= Railway cement material intensity;

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= New length Railways in city i;

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Ini = Industrial Investment;

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ICI= Industrial construction cement intensity;

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Ex= Net export of cement.

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Note that the net export of cement in the base year is used to estimate the future cement 16

production at provincial level during the whole period. The provincial ratio of clinker and 17

cement production in 2015 is used to estimate the future clinker outputs up to 2030 at the 18

city level. The results of cement and clinker production of each city between 2015 and 2030 19

are listed in Table A-1 of Supplementary-A, which shows the peak of cement and clinker 20

production of each city appears in 2015 and then declines gradually. Detailed data 21

containing production capacities, production scales and technology distributions etc. for all 22

the cities of Jiangsu Province are provided in Supplementary-C.

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3.3 3.3

3.3 3.3 GIS GIS GIS----based energy model GIS based energy model based energy model based energy model

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A GIS-based energy model is constructed by incorporating energy conservation supply curve 27

into an ArcGIS-based distribution analysis platform. Energy Conservation Supply Curve is 28

used to assess the energy saving potential function of the marginal cost of conserved energy.

29

In this approach, the cost of conserved energy by dividing the net present value (NPV) of 30

annual costs over the study period (2015–2030) by the simple sum of annual energy saving 31

over the same period. Several studies illustrate that co-benefits from air pollutant emissions’

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reduction as a result of energy saving measures can reduce the CCE of those measures 33

(Hasanbeigi et al., 2013a; Ma et al., 2015; Price et al., 2008; Tomaschek, 2015; Worrell et al., 34

2013; Xi et al., 2013; Zhang et al., 2014). However, none of these studies quantified the co- 35

benefits of energy efficiency improvement and emissions’ reduction of GHG and air 36

pollutants through energy efficiency measures at a regional scale, especially at city level.

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The calculation of the costs of conserved energy for energy efficiency technology is 38

presented in Eq. (2), more details on the methodology for the construction of ECSCs are 39

presented in (Hasanbeigi et al., 2013a, 2013b, 2010b).

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= ×"#$ & %&'(#$ & %)*+,-./×/-

-./ Eq. (2) 1

Where:

2

CCE= Cost of conserved energy (CCE) for an energy efficiency measures, in $/GJ;

3

I= Investment;

4

AF= Annuity factor;

5

& = Annual change in operation and maintenance fixed cost;

6

& = Annual change in operation and maintenance variable cost;

7

ESP= Annual energy saving potential;

8

PE= Energy price ($/GJ).

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In this study, a discount rate of 10% is assumed. The annuity factor can be calculated from 11

Eq. (3).

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0 = 1

(2,(2#1)34) Eq. (3) 14

Where:

15

d= Discount rate;

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n= Lifetime of the energy efficiency measures.

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To construct ECSCs, a database that includes all the detailed techno-economic parameters 19

of energy efficiency measures (e.g., capital costs, operation and maintenance costs, lifetime, 20

etc.) is built up. Note that cement and clinker production facilities are treated individually, 21

characterizing them by production, energy use, and emissions. Integrating the outputs of 22

energy saving and emission mitigation potentials into ArcGIS. The model is employed to 23

simulate the dynamic potential of cost-effective energy savings and emission reductions of 24

CO2 and air pollutants (e.g. SO2, NOx, and PM) in Jiangsu’s cement industry both with and 25

without multiple benefits.

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3. 3.

3. 3.4 4 4 S 4 S Scenario S cenario cenario cenario design design design design

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In this study, we develop three scenarios in line with our previous research, to estimate the 30

co-benefits of energy efficiency improvement and associated mitigation of emissions of 31

CO2 and air pollutants in Jiangsu’s cement industry at the city level. The first one is the 32

baseline scenario, the second one considers energy efficiency policies only adopting cost- 33

effective energy saving potential (EEPCP scenario), and the third one considers energy 34

efficiency policies that can realize full potential of technical energy savings (EEPTP 35

scenario) (Zhang et al., 2015b). Fig. 3 defines the analysis scope of these three scenarios.

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Fig. 3. Analysis scope of the three scenarios 1

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One key innovation of this study is that eliminating older and small-scale cement plants is 3

considered when forecasting the dynamic distribution of clinker and cement for each city.

4

We assume that the discount rate, energy prices, the distribution of clinker and cement, and 5

fuel structures are the same in all scenarios. The baseline scenario assumes that annual 6

autonomous energy efficiency improvement (AEEI) is 0.2%, which is consistent with our 7

previous studies (Zhang et al., 2015b; Zhang et al., 2016). For the EEPCP scenario, we 8

assume that the cost-effective energy efficiency measures (the CCE of energy efficiency 9

measures below 0 $/GJ) with projected implementation rates would be implemented across 10

Jiangsu province. In this scenario, we calculate the cost-effective energy saving potential in 11

Jiangsu’s cement industry, based on 24 current commercially available energy efficiency 12

measures. We show how cost-effective energy saving and associated emissions mitigation 13

will be responsible for provincial targets. Additionally, we assume that all energy efficiency 14

measures will be fully implemented in energy efficiency policy with an EEPTP scenario. The 15

dynamic geographic distribution of energy consumption, GHG, and air pollution under 16

different scenarios are simulated; this can be used to ensure the highest air quality and 17

energy/GHG benefits with minimum costs. As a major advancement, the co-benefits of 18

energy efficiency are modeled. This allows for the evaluation of the synergies between 19

policies and of the resulting cost savings. The co-benefits of energy efficiency for emission 20

mitigation are further calculated to model how co-benefits would affect the cost-effective 21

potential of energy saving.

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3.5 3.5

3.5 3.5 Data sources Data sources Data sources Data sources

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The production data of cement and clinker in Jiangsu province are from the China Cement 26

Almanac (China Cement Association, 2016), the China Statistical Yearbook (NBS, 2016), and 27

the Jiangsu Statistical Yearbook (Jiangsu Provincial Bureau of Statistics, 2016). The historical 28

coal combustion and electricity consumption data in Jiangsu’s cement industry are obtained 29

from the China Energy Statistical Yearbook (NBS, 2017) and the Jiangsu Statistical Yearbook 30

(Jiangsu Provincial Bureau of Statistics, 2016) and are calibrated based on current literature 31

(Cai et al., 2016; Dai and Hu, 2013; Hasanbeigi et al., 2013a; Hasanbeigi et al., 2013b; Wen et 32

al., 2015; Xi et al., 2013; Xu et al., 2014; Zhang et al., 2015d). The historical data of the 33

population and urbanization of each city in Jiangsu Province are collected from the Jiangsu 34

Statistical Yearbook (Jiangsu Provincial Bureau of Statistics, 2016). The future population of 35

each city is calculated based on the projection in the GAINS database.

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The cement material intensity in the building industry is assumed to be 0.18 t/m2 floor area 38

(Liu, 2017). The cement material intensities for highway, railway, and construction 39

industries are obtained from the current literature (Hasanbeigi et al., 2017). Note that the 40

cement material intensity by end-users and the net export share of total cement production 41

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are assumed to be unchanged in the study period. Some key parameters including 1

production capacities, production scales and technology distributions etc. in the cities of 2

Jiangsu Province are provided in Supplementary Data.

3 4

Several studies indicate that many best energy efficiency technologies are already 5

implemented in Jiangsu’s cement industry. However, there is still room for improving energy 6

efficiency and reducing emissions of GHG and air pollutants, due to the scales of NSP line 7

have large difference in Jiangsu province. This study includes 37 best commercially available 8

energy efficient measures that includes four different processes (see Supplementary-B): fuel 9

and raw material preparation, clinker making, finish grinding, and general measures. The 10

parameters (i.e., fuel saving, electricity saving, capital cost, operating and maintenance costs, 11

lifetime, and current implementation rate in base year) of these energy efficiency measures 12

are obtained from our recent study (Zhang et al., 2015b,c), in addition to other recent 13

studies from (Tsinghua University, 2008; Hasanbeigi et al., 2013b; Wang et al., 2014; Wen et 14

al., 2015; Worrell et al., 2013). In addition, the implementation rates of each energy 15

efficiency measure are defined using a linear deployment approach and assumed to be fully 16

implemented by 2030. Note that cement production from the wet process in Jiangsu was 17

already phased out in 2015 (Economic and Information Commission of Jiangsu Province, 18

2016); therefore, energy efficiency measures for the wet process are not taken into account 19

in this study. The costs of each energy efficiency measure are priced at $2015, and the 20

prices of coal and electricity are taken from the China Cement Almanac (China Cement 21

Association, 2016).

22 23

The CO2 emission factors for electricity consumption in Jiangsu province are obtained from 24

regional grid baseline emission factors of China (NDRC, 2011). The CO2 emission factors for 25

coal and process are from our recent studies (Zhang et al., 2015b; Zhang et al., 2016). The 26

emission factors of SO2, NOx, and PM are calculated according to recent studies (Lei et al., 27

2011), and calibrated through running the GAINS model (for more information about GAINS, 28

http://gains.iiasa.ac.at/models/index.html). Note that the above emission factors are 29

assumed constant during the whole period. The energy efficient technologies and the 30

associated key techno-economic parameters are provided in Supplementary Data.

31 32

4. Results and discussion 4. Results and discussion 4. Results and discussion 4. Results and discussion

33 34

4.1 E 4.1 E 4.1 E

4.1 Energy consumption under different scenarios nergy consumption under different scenarios nergy consumption under different scenarios nergy consumption under different scenarios

35 36

The results of energy consumption in Jiangsu’s cement industry from 2015 to 2030 across 37

the three scenarios are shown in Fig. 4. In the baseline scenario, energy consumption is 38

expected to decline to 141 PJ in 2030, roughly 54% of the level in 2015. This reduction 39

reflects the effect from shrinkage of the production size of the industry. In contrast, the 40

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results of EEPCP and EEPTP indicate remarkable energy saving potential through the 1

adoption of energy efficiency technologies. Under the EEPCP scenario, in which all cost- 2

effective energy efficiency measures (represent economically feasible opportunities to 3

reduce energy consumption) are fully implemented, energy consumption will decrease by 4

35% compared to the baseline scenario. This potential is further enlarged in the more 5

stringent scenario of EEPTP, in which almost half of the energy use in BL scenario can be 6

reduced.

7 8

The regional distribution of energy saving potential, as measured by the gaps between the 9

baseline scenario and the other two scenarios, is significantly uneven, as shown in Fig. 4.

10

Apparently, this potential for each city is closely associated with their respective cement 11

production sizes. For example, Changzhou, Wuxi, and Xuzhou, as the top three cement 12

producing cities in Jiangsu, possess the most significant energy saving potential in the EEPCP 13

results for 2020. On the contrary, by virtue of their size, small producers such as 14

Lianyungang have much less potential. However, this relationship does not apply to all the 15

cases, because other factors, such as urbanization rate and technology level, also matter 16

with respect to reaching this potential. In particular, the results for 2030 in the EEPCP 17

scenario reveal that Huai’an replaces Wuxi as the third largest city in terms of energy saving 18

potential in cement production. An important reason for this is that Wuxi is currently more 19

urbanized than is Xuzhou, and its cement need in the future is, therefore, much smaller. The 20

results of Table A-1 show that cement output for Wuxi in 2030 will reduce to only 40% of its 21

2015 level in our prediction, whereas this ratio is 67% in Huai’an’s case. Another noteworthy 22

example is Suzhou. As one of the most affluent cities in China, Suzhou’s urbanization rate 23

reached as high as 75% in 2015, far higher than the national average level. As a result, its 24

potential demand for infrastructure and construction in the future will be much smaller than 25

will be the demands of less developed regions, which, in turn, affects the energy saving 26

potential within its cement industry. Despite this, the EEPTP scenario demonstrates notable 27

potential that is larger than 3 PJ for all the cities other than Lianyungang.

28 29

Fig. 4. Energy consumption and saving potential by city under different scenarios 30

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4.2 CO 4.2 CO 4.2 CO

4.2 CO

2222

emissions emissions emissions emissions for different scenarios for different scenarios for different scenarios for different scenarios

32 33

CO2 emissions from Jiangsu’s cement production in 2015 was roughly 104 Mt. Following the 34

same reduction rate as energy consumption, CO2 emissions in the baseline decrease to 57 35

Mt in 2030, or 54% of the level in 2015. Note that Fig. 5 shows that the reduction potential 36

of carbon emissions in EEPCP and EEPTP are much smaller compared to energy saving. The 37

main reason for this is that adopting energy efficient technologies reduces the energy- 38

related emissions; however, it has little impact on process-related emissions, which account 39

for roughly 40% of total emissions from cement production. Nevertheless, the absolute 40

term is still large, cost-effective energy efficiency measures will contribute to decreasing 41

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emissions by 4.4 Mt in 2030 compared to the baseline, and all the technologies, in total, 1

have a larger potential of 7.48 Mt, as shown in the EEPTP scenario.

2 3

Furthermore, this reduction potential is unevenly distributed across all the cities. Similar to 4

the energy saving profile, Changzhou, Xuzhou, and Huai’an take larger shares among the 5

cities, while Lianyungang has the smallest room for reduction. Not surprisingly, the results 6

from EEPTP show much larger reduction potential relative to EEPCP from the very beginning 7

to the end of this timespan. Apart from Lianyungang, all the cities can reduce emissions by 8

more than 0.4 Mt in 2030 with the adoption of technically viable technologies. In 9

particularly, Changzhou and Xuzhou show potential exceeding 1 Mt. Under the EEPCP 10

scenario, which adds the restraint of the economic profitable condition, the potential will 11

shrink to 60% of the EEPTP level.

12 13

Fig. 5. CO2 emissions and their reduction potential by city under different scenarios 14

15

4.3 4.3 4.3

4.3 Abatement of air pollution under different scenarios Abatement of air pollution under different scenarios Abatement of air pollution under different scenarios Abatement of air pollution under different scenarios

16 17

Fig. 6 illustrates that significant potential for air pollution reduction can also be realized. In 18

2015, SO2, NOx, and PM emissions from Jiangsu’s cement industry reached as high as 9.0, 19

74.2, and 67.1 thousand tons, respectively. In the baseline scenario, a decline of production 20

scale will reduce the emissions of the three pollutants to 4.9, 39.3, and 36.4 kt, respectively, 21

or 54%, 53%, and 54%, respectively, of the 2015 levels.

22 23

However, the reduction potential for the three pollutants varies remarkably in the EEPCP 24

and EEPTP scenarios. For example, in the EEPCP scenario, PM emissions are roughly 25.8 25

thousand tons in 2030, or 70% of the baseline scenario, indicating that 30% of PM can be 26

reduced through applying cost-effective technology. In contrast, NOx emissions can achieve 27

17.2 kt, just 44% of the baseline; in other words, 56% of NOx can be cut under the same 28

scenario. Furthermore, in the EEPTP scenario, the emissions can be as low as 8.9 kt, implying 29

that a reduction of 77% of the baseline emissions can be realized. The case of SO2 falls in the 30

middle of the range between NOx and PM. This notable difference indicates that the effect 31

of adopting these technologies is more significant in terms of NOx reduction, compared to 32

PM and SO2, which provides a feasible solution, particularly considering that the rate of 33

installation of NOx removal systems in China’s cement industry is currently low.

34 35

Fig. 6. Air pollutant emissions by city under different scenarios 36

37

Marked regional disparities also exist within Jiangsu in terms of the reduction potential of 38

the three pollutants, as shown in Fig. 7. A common characteristic across the profiles of the 39

three pollutants is that Xuzhou and Changzhou always rank in the first tier, and, therefore, 40

possess the largest potential for pollution alleviation, mainly because of their relatively 41

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larger production volumes. An interesting phenomenon is that, although Changzhou is 1

producing more cement and clinker than Xuzhou at present, its reduction potential will be 2

surpassed by that of Xuzhou in the near future. This can be attributed to the higher 3

urbanization rate of Changzhou, a more developed city (with almost twice the GDP per 4

capita of Xuzhou) that will, hence, need less cement production in the different scenarios.

5

Other cities, such as Wuxi, Nanjing, Huai’an, and Zhenjiang, can also benefit a lot, in terms of 6

reducing these pollutions, from applying energy efficient technologies. It is noteworthy that 7

the more affluent cities concentrated in the south part of Jiangsu, e.g., Nanjing, Wuxi, 8

Changzhou, and Zhenjiang, have severe problems of air pollutant emissions, while the 9

implementation of energy efficiency technologies offers not only a technically viable but 10

also cost-effective solution to address this issue in Jiangsu.

11 12

Fig. 7. Air pollution reduction potential under different scenarios 13

14

5. Sensitivity and uncertainty analysis 5. Sensitivity and uncertainty analysis 5. Sensitivity and uncertainty analysis 5. Sensitivity and uncertainty analysis

15 16

Sensitivity/uncertainty analysis remains an important part in the state-of-the-art energy 17

models, because current models cannot project the future precisely. In this paper, the key 18

factors of the future distribution of cement and clinker by cities, fuel prices, and discount 19

rates are discussed below.

20 21

To meet the requirement of cement demand for each city in Jiangsu, around 50% of clinker 22

is imported from surrounding regions (e.g., Anhui and Shandong), due to the availability of 23

raw material resources. The limestone resources in Jiangsu province are mainly located in 24

the northern cities, such as Xuzhou, and the southern cities, such as Nanjing, Suzhou, Wuxi, 25

and Changzhou (Wang et al., 2006). Therefore, we assume that the future distribution of 26

clinker production is mainly from these cities. Additionally, we use the average utilization 27

rate in the base year to forecast future activity levels and assume that the small-scale 28

cement/grinding plants will be phased out to address the problems arising from increased 29

excessive production capacity; thus, our approach might overestimate the potential benefits 30

in the cities with small scale plants. Additionally, increasing energy price is one of the most 31

important strategies to improve energy efficiency and mitigate CO2 emissions (Hasanbeigi et 32

al., 2013a; Tian and Liu, 2010). The energy price in Jiangsu province depends heavily on the 33

policy impacts from government and the relationship between supply and demand. Hence, 34

we assume that the future prices of coal and electricity remain unchanged, which should 35

result in underestimation of the cost-effective electricity saving potential. Discount rate is 36

another key factor in the cost and effectiveness analysis. In general, plants prefer to choose 37

a high discount rate (i.e., 30%) when making investment decisions, while policy makers 38

prefer to use a lower (social) discount rate (i.e. 4%) when projecting future pathways 39

(Hasanbeigi et al., 2010a). Considering the development progress in Jiangsu at a city scale, 40

the measures with higher marginal costs (e.g., high efficiency classifiers, high efficiency 41

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13

roller millers, and low pressure drop cyclones for suspension preheater) would be installed 1

firstly by the cities where the people have higher personal income, such as Nanjing and 2

Suzhou. Furthermore, if the co-benefits for mitigation of CO2 emissions and air pollution are 3

considered, the cost-effective energy saving potentials would increase across the province.

4

One should note that the adoption of other substitutive technologies including such as 5

geopolymers or SCC (self-consolidating concrete) materials has also very important impacts 6

on sustainable development of cement industry, and thus influences the energy 7

consumption in this industry to some extent. Though beyond the scope of this study 8

focusing on energy efficiency technologies, further investigation of these factors would need 9

to be explored in the future.

10 11

6. Conclusion 6. Conclusion 6. Conclusion 6. Conclusion

12 13

Jiangsu is the largest cement producer and consumer in China, accounting for 7.5% of 14

China’s total output. However, the Jiangsu’s cement industry only consumes 5% of the final 15

energy in China’s cement industry. The key feature for Jiangsu’s cement industry is that 16

approximately 50% of clinker is imported from surrounding regions, and uses grinding plants 17

to produce cement. The purpose of this study is to model the co-benefit potentials of 18

energy efficiency and emission reductions of CO2 and air pollutants in Jiangsu’s cement 19

industry at city level, using a GIS-based energy model that considers implementation of best 20

energy efficiency measures.

21 22

First, we present a comprehensive analysis of outputs of clinker and cement, production 23

capacity of NSP kilns, capital investment, energy consumption by fuel types, and emissions 24

of CO2 and air pollutants across the province. We find that the cement and clinker 25

production in Jiangsu province has increased 1.8-fold and 30% during 2005–2015, while 26

energy consumption and CO2 emissions only increased by 21% and 40%, respectively.

27

However, total air pollution decreased by two thirds during the same period.

28 29

Second, we develop a GIS-based energy model that includes provincial energy conservation 30

supply curves that show the cost-effective and technical energy saving potential and 31

emissions’ reduction potential through energy efficiency at city levels and ArcGIS, a GIS with 32

elaborated spatial functions. The model is used to assess the potential of energy savings and 33

associated emission mitigation of CO2 and air pollutants in Jiangsu’s cement industry during 34

2015–2030. The results clearly show that: 1) at the provincial level, energy consumption in 35

the baseline scenario will decrease by 54%, compared to the 2015 level. Under energy 36

efficient scenarios, energy consumption in Jiangsu’s cement industry will decline by 35% and 37

50% in EEPCP and EEPTP scenarios, respectively. 2) At the city scale we find that Changzhou, 38

Wuxi, and Xuzhou are the top three largest cities in terms of energy saving potential 39

between 2020 and 2030 in both scenarios; however, in 2030, Huai’an replaces Wuxi as the 40

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city with the third largest energy saving potential. Additionally, energy efficiency measures 1

can not only reduce energy consumption, but also lower emissions of CO2 and air pollution.

2

Hence, scenario analysis in this paper indicates that, compared to baseline, the CO2

3

emissions in EEPCP and EEPTP scenarios will decrease by 4.4 Mt and 7.5 Mt, respectively, in 4

2030. Similarly, the emissions of PM and NOx would decline by 30% and 56%, respectively, 5

in the EEPCP scenario. The main reason for this is that of the emissions from process has less 6

contribution than are those of than fuel combustion and electricity consumption. Another 7

key finding is that the distribution of co-benefits varies greatly among different cities and is 8

significantly affected by clinker output. Therefore, the policy makers of Jiangsu province, 9

and end users (especially for the less-developed cities), should consider the co-benefits of 10

energy efficiency measures when designing strategies for tackling issues of climate change 11

and air quality.

12

Finally, the findings of this study will help policy makers of Jiangsu province develop and 13

adopt an integrated policy to support the coordinated development of the Yangtze River 14

Delta Economic Region (which encompasses Shanghai, Jiangsu, Anhui, and Zhejiang 15

province), and can also enhance the effectiveness of the implementation of joint prevention 16

and control of atmospheric pollution to improve the region’s air quality.

17 18

Acknowledgements Acknowledgements Acknowledgements Acknowledgements

19 20

This research was supported by the Ministry of Education, China under Grant 222201718006;

21

National Natural Science Foundation of China under Grant 71571069; and Postdoctoral 22

fellowships at the International Institute for Applied Systems Analysis (IIASA), Austria..

23 24

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Fig. 1. Emissions of CO2 and air pollutants from Jiangsu’s cement production. (Panel a: CO2

emissions, Panel b: emissions of SO2, NOx, and PM)

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Demand projection

model

GIS-based model

Input

Population

Urbanization

Development of downstream industries

Production techs

Output

Output projection of cement/clinker

Change of production technology composition

Database

Techno-economic parameters:

Capital cost

Variable cost

Lifetime Saving potential

Savings of fuel/electricity

Savings of CO2, SO2, NOx, and PM

Solution

Increase of implementation rate

Distribution of technologies implementation at the city level

Cost-benefit analysis

Energy saving

CO2 emissions

Air pollution

ECSC

NPV

Total energy saving

Fig. 2. Simplified diagram of model framework

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Baseline EEPCP

(Economic-viable)

EEPTP (Technological-viable)

Energy saving

potential CO2 emissions

Air pollutants emissions (SO2,

NOx, PM)

Energy saving benefit

CO2 emissions mitigation benefits

Air pollutants emissions mitigation benefits

Co-benefit analysis

Fig. 3. Analysis scope of the three scenarios

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Fig. 4. Energy consumption and saving potential by city under different scenarios

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Fig. 5. CO2 emissions and reduction potential by city under different scenarios

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Fig. 6. Air pollutant emissions by city under different scenarios

0 20000 40000 60000 80000 100000 120000 140000 160000

BaseYear BL EEPCP EEPTP BL EEPCP EEPTP BL EEPCP EEPTP

2015 2020 2025 2030

Unit:[t]

PM NOx SO2

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Fig. 7. Air pollution reduction potential under different scenarios

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Highlights

1. Disparities in energy use and emissions are quantified for Jiangsu’s cement industry 2. A GIS-based energy model developed to assess co-benefits of energy efficiency 3. Energy efficiency would lead to huge reductions in air pollution in all cities

4. Co-benefits of energy efficiency should be integrated into air quality policy

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