Eco effciency analysis for roadway projects

54 Huynh Thi Minh Truc, Mai Anh Duc ECO EFFCIENCY ANALYSIS FOR ROADWAY PROJECTS PHÂN TÍCH HIỆU QUẢ KINH TẾ MÔI TRƯỜNG CHO CÁC DỰ ÁN ĐƯỜNG GIAO THÔNG Huynh Thi Minh Truc, Mai Anh Duc The University of[.]

54 Huynh Thi Minh Truc, Mai Anh Duc

ECO-EFFCIENCY ANALYSIS FOR ROADWAY PROJECTS

PHÂN TÍCH HIỆU QUẢ KINH TẾ - MÔI TRƯỜNG CHO CÁC DỰ ÁN

ĐƯỜNG GIAO THÔNG

Huynh Thi Minh Truc, Mai Anh Duc

The University of Danang, University of Science and Technology; Email: mtruc84@gmail.com, ducmaianh@gmail.com

Abstract - The eco-efficiency indicator is recognized as an

effective tool to measure sustainability in construction This study

proposes s indicators to measure eco-efficiency at project and

component levels during the roadway life cycle Conventional cost

over energy consumption and conventional cost over GHG

emissions are two most prominent indicators in the material

production stage, whereas conventional cost over solid waste is

the most prominent in the disposal/recycling stage Conventional

cost over material consumption is the most prominent in

construction and maintenance stages Conventional cost over

energy consumption and conventional cost over GHG emissions

are appropriate for earthwork’s construction stage The data from

Hanoi-Langson highway project in Vietnam are used to verify the

eco-efficiency indicators

Tóm tắt - Chỉ số hiệu quả kinh tế - môi trường được công nhận là

một công cụ hiệu quả để đo lường tính bền vững trong xây dựng Nghiên cứu này đề xuất những chỉ số để đo lường hiệu quả kinh

tế - môi trường ở các cấp độ dự án và cấp độ thành phần trong vòng đời đường giao thông Tỉ số chi phí trên mức tiêu thụ năng lượng và tỉ lệ chi phí trên lượng khí thải nhà kính là hai chỉ số nổi bật nhất trong giai đoạn sản xuất vật liệu, trong khi đó tỉ lệ chi phí trên lượng chất thải rắn là nổi bật nhất trong giai đoạn xử lý / tái chế Tỉ lệ chi phí trên mức tiêu thụ nguyên liệu là nổi bật nhất trong giai đoạn xây dựng và bảo trì Tỉ lệ chi phí trên mức tiêu thụ năng lượng và tỉ lệ chi phí trên lượng khí thải nhà kính là tỉ số phù hợp với giai đoạn công tác đất Các dữ liệu từ dự án đường cao tốc Hà Nội-Lạng Sơn tại Việt Nam được sử dụng để minh họa cho các chỉ

số này

Key words - eco-efficiency indicator; environmental cost; EMA;

sustainable development; roadway project

Từ khóa - chỉ số hiệu quả kinh tế - môi trường; chi phí môi trường;

EMA; phát triển bền vững; dự án đường

1 Introduction

There have been efforts in linking environmental

impacts and economic performance for roadways [4, 5, 8,

11] However, most of such studies just consider the

relationship between environmental impacts and economic

values of roadway materials Horvath assessed

environmental impacts and economic values of the use of

different materials and recycling for the construction and

maintenance of pavement [5] Keoleian integrated life

cycle assessment and life cycle costing method in selection

of material for bridge design [8] Tatari & Kucukvar

developed a framework utilizing life cycle costing and life

cycle assessment as numerator and denominator for

calculating the eco-efficiency ratio with the support of the

data envelopment analysis (DEA) model to calculate

Eco-efficiency ratios for external wall finishes [11] The

construction industry in general and roadway sector in

particular have not seen the emphasis on developing Eco

-efficiency indicators to measure the sustainability of

projects

2 Methodology

The research method adopted in this study is to propose

and analyze indicators Besides, the data of a case project

are used to verify the model and indicators

2.1 Economic performance metrics

Figure 1 shows the breakdown structure of

conventional costs during roadway life cycle There are

two costs concerned in the construction stage consisting of

transportation costs of construction material and

construction equipment and labor costs There are two

types of roadway maintenance costs including annual

routine and periodic maintenance cost Material

transportation and equipment are two sub-costs of periodic

maintenance The key activities of disposal or recycling stage are demolition and transport of roadway components

at the end-of-life to landfill or recycling plant Therefore, the main Costs of disposal/recycling are Demolition cost and Transport cost to landfill or recycling plant

Figure 1 Breakdown structure of conventional cost during

the roadway life-cycle

Environmental costs are generally defined as the costs connected with the actual or potential deterioration of natural assets due to economic activities [12] Environmental costs comprise both internal and external costs related to environmental damage and protection Jasch argued that in conventional cost, accounting for environmental costs taking into overhead accounts are

“hidden” from management [7] Therefore, it is necessary

to identify separately environmental costs beyond conventional costs

This study applies the environmental management accounting (EMA) to identify environmental costs EMA

is an integrated approach using data of financial

Conventional costs of roadways

Material Production Construction Maintenance

Disposal/ Recycling

Transportation

to landfill /recycling plant

Material transportation

Equipment

Routine

Periodic

Demolition

THE UNIVERSITY OF DANANG, JOURNAL OF SCIENCE AND TECHNOLOGY, NO 6(79).2014, VOL 1 55 accounting, cost accounting and material flow balances to

increase material efficiency, reduce environmental impacts

and costs of environmental protection [7] According to the

EMA approach, four categories of environmental costs

include waste disposal and emission treatment costs;

prevention and environmental management costs; wasted

material purchase costs; and production costs of

non-product output Such environmental cost categories are

shown in Table 1

Table 1 Environmental Cost Categories

2.2 Selection of Environmental Impact Factors

World business council for sustainable development

(WBCSD) developed a framework for identifying and

measuring efficiency indicators and reporting

Eco-efficiency performance [14] Seven environmental impacts

are appropriate for Eco-efficiency indicators, including

energy consumption, materials consumption, water

consumption, green house gas (GHG) emission,

ozonedepleting substance emission, acidification emission

to air, and solid waste

Among the above environmental impacts, ozone

depleting substance emissions and acidification emissions

to air have little relationship with construction [2] The

pavement life cycle assessment workshop by University of

California pavement research center in Davis and Berkeley

(UCPRC) in 2010 concluded some common environmental

impacts to roadways Such environmental impacts are

energy consumption, GHG emissions, material and water

consumption and waste [13] Besides, energy

consumption, emission and solid waste genration are studied mostly by research [9]

On-site construction uses of water include concrete mixing, coccrete curing, dust control, construction equipment washing, vegetation establishment, geotechnical borings, adding water to backfill material/soil compaction, pipe flushing and pressure testings and site clean up However, there is little information available on the amount of water used for roadways [9] This problem makes the calcualtion of water used for construction very difficult Therefore, for simplicity this study just considers four kinds of environmental impacts which are the most suitable for roadways: materials consumption, energy consumption, GHG emissions and waste

3 Results and Discussion

3.1 General Equation for Eco-Efficiency Indicators

The explanation of these eco-efficiency indicators is provided below

Eco efficiency indicators Cost Conventional Environmental Impact a Material b Energy c Emissions d Waste

(3.1)

The numerator of the above equation is the cost of a project or its components while the denominator is environmental impact Conventional and environmental costs are considered in developing Eco-efficiency indicators, whereas material consumption, energy consumption, GHG emissions and solid waste are the focus

of environmental performance The Eco-efficiency indicator measures how much of the cost is spent per unit

of environmental impacts As we knew, the objective of Eco-efficiency is maximizing value while minimizing resource use and adverse environmental impacts [14] In addition, saving cost is also a factor to maximize value, therefore, either component or project that spends less cost per one unit of environmental impact will achieve better eco-efficiency

When the numerator is conventional cost, the eco-efficiency indicator represents the environmental effectiveness of spending conventional cost If the numerator is conventional cost and denominator is material consumption, the indicator labeled 1a represents material efficiency [14] When the numerator is environmental cost, the indicator represents the environmental improvement of roadways For example: the indicator labeled 2c (Environmental costs to Emissions) The indicator 2c represents improvement of roadways in reducing GHG emissions resulted from spending environmental costs

3.2 Selection of Prominent Indicators for Roadway Projects

For the impacts of energy consumption and air emission, material production has on average 20 times the impacts of construction In addition, maintenance has around one-third the impacts of construction [9] According to the contribution level of environmental impacts, energy consumption and emission are prominent Eco-efficiency indicators in the stage of material production Energy consumption and GHG emissions are

1 Waste and emission treatment

1.1 Depreciation for related equipment

1.2 Maintenance, operating materials and services

1.3 Related personnel

1.4 Fees, taxes, charges

1.5 Fines and penalties

1.6 Insurance for environmental liabilities

1.7 Provisions for clean-up costs, remediation

2 Prevention and environmental management

2.1.External services for environmental Management

2.2.Personnel for general environmental

management activities

2.3 Research and development

2.4 Extra expenditure for cleaner technologies

2.5 Other environmental management costs

3 Material purchase value of non-products

3.1 Raw materials

3.2 Packaging

3.3 Auxiliary materials

3.4 Operating materials

3.5 Energy

3.6 Water

4 Processing costs of non-products

56 Huynh Thi Minh Truc, Mai Anh Duc the most important impacts from earthwork Therefore,

indicators related to energy consumption and GHG

emissions are prominent in the construction stage at

earthwork level, whereas the indicators related to material

consumption are prominent in the construction and

maintenance stages

For most roadway materials, waste created during the

placement of materials (Construction/Maintenance) is

almost negligible compared to that generated during the

manufacturing phase and at end-of-life [10] According to

the selection factor of the contribution level of

environmental impacts, Eco-efficiency indicators related

to total waste are prominent in material production and

disposal/recycling stage

This study adopts simplicity and data availability as

criteria of selecting the appropriate Eco-efficiency

indicators for roadway projects and components The

criteria of relevance is already considered in the selection

of Eco-efficiency indicators for projects and components

because all are about roadways Table 2 shows the most

prominent indicators at the project and component levels

According to the three criteria, the indicators in Table 2 are

assessed in three levels of prominence: high, medium, and

low At the project and component levels, indicators 1b

(Conventional cost over Energy consumption) and 1c

(Conventional cost over GHG emissions) are the most

prominent in the stage of material production because these

two indicators are assessed at a high level of simplicity,

data availability, and environmental impact contribution For project, pavement, and bridges, indicator 1a (Conventional cost over Material consumption) is the most prominent in the stage of construction and maintenance Indicators labeled 1b and 1c are the most prominent to measure Eco-efficiency of earthwork’s construction stage Indicator 1d (Conventional cost over Solid waste) is the most appropriate to measure Eco-efficiency in the disposal/recycling stage for both project and its components stages

3.3 Eco-Efficiency Analysis of the case project

Hanoi-Langson highway only discloses environmental costs in the construction stage In addition, environmental impacts which can be reduced are just GHG emissions and solid waste Therefore there are only indicators 2c (Environmental cost over GHG emissions reduced) and 2d (Environmental cost over Solid waste reduced) that are applicable in the construction stage Table 3 shows the indicators and values to analyze Eco-efficiency at the project level for the Hanoi-Langson highway Environmental impact values are calculated by Huynh [6] Indicators 2c (Environmental cost over Emission reduced) and 2d (Environmental cost over Waste reduced) just appear in the construction stage because the Hanoi-Langson highway does not disclose environmental costs in the remaining stages The Hanoi-Langson highway project spent US$95 to reduce one ton of air emissions and US$175 to treat one ton of solid waste

Table 2. Most Prominent Eco-Efficiency Indicators for Roadways

production Construction Maintenance

Disposal/ Recycling Criteria

Simplicity

Data

availability

Environmenta

l Impact

Low

Simplicity

Data

availability

Environmenta

l impact

Low

Table 3 Eco-Efficiency Indicators of Hanoi – Langson highway project

production Construction Maintenance

Disposal/ recycling

THE UNIVERSITY OF DANANG, JOURNAL OF SCIENCE AND TECHNOLOGY, NO 6(79).2014, VOL 1 57 Conventional cost/Material

(1b)

Conventional cost/Energy

consumption

(1c)

Conventional cost/GHG

emissions

(1d)

Conventional cost/Solid

waste

It can be seen from Table 3, material production of

earthwork spent the largest amount of conventional cost

per one GJ of energy (US$97/GJ), one ton of GHG

emissions (US$677/ton-CO2e), and one ton of solid waste

(US$51,305/ton of solid waste) In contrast, pavement

material production spent the smallest amount of

conventional cost on using one GJ of energy (US$15/GJ),

releasing one ton of GHG emissions (US$121/ton-CO2e),

and generating one ton of solid waste (US$178/ton of solid

waste) Overall, in the stage of material production

earthwork presented the worst Eco-efficiency, whereas

pavement showed the best Eco-efficiency In the

construction stage, through indicator 1a pavement

presented the better material efficiency than bridges

Indeed, pavement spent US$23 for one ton of construction

materials, whereas bridges had to pay US$134 for one ton

of construction materials This finding is also true for the

maintenance stage Pavement spent US$100 for one ton of

maintenance materials while bridges paid US$315 for one

ton of maintenance materials

In summary, material production for the

Hanoi-Langson highway pavement achieved better eco-efficiency

than earthwork or bridges The Hanoi-Langson highway

pavement presented better Eco-efficiency than bridges

4 Conclusions

Conventional cost and environmental cost are two

kinds of economic performance metrics used for

Eco-efficiency indicators at the project and component levels

In order to improve sustainability of roadways, it is

important to assess and determine the environmental costs

EMA is useful to identify environmental costs for roadway

project and components In order to have a more

comprehensive Eco-efficiency analyses, roadways should

report environmental costs in the roadway stages for its

components Among the seven environmental metrics for

Eco-efficiency indicators, four appropriate environmental

impacts for roadways are material consumption, energy consumption, air emission and solid waste generation A potential environmental impact for roadway Eco-efficiency indicators is water consumption Due to the lack

of information, this water impact is not considered in this study At both project and component levels, indicators of Conventional cost over Energy consumption and Conventional cost over GHG emissions are the two most prominent to assess Eco-efficiency in the material production stage, whereas the indicator of Conventional cost over Solid waste is the most prominent in the Disposal/Recycling stage The indicator of Conventional cost over Material consumption is the most prominent for Eco-efficiency analysis in the construction and maintenance stage of project, pavement, and bridges; while indicators of Conventional cost over Energy consumption and GHG emissions are the most appropriate for the earthwork’s construction stage

REFERENCES

[1] Burritt, R L., and Saka, “Environmental management accounting:

applications and eco-efficiency Case studies from Japan.” Journal

of Cleaner production, 14, 2006, 1262-1275

[2] Dickie, I., and Howard, N “BRE Digest 446: assessing environmental impacts of construction industry consensus

BREEAM and UK eco-points”, Built research establishment, 2000

[3] Holton, I., Glass, J., and Price, A D F “Managing for sustainability: findings from four company case studies in the UK precast concrete

industry.” Journal of Cleaner production, 18, 2010, 152-160

[4] Horvath, A., and Hendrickson, C “Comparison of environmental implications of asphalt and steel-reinforced concrete pavements.”

Transportation research record: Journal of the transportation research board, 1626, 1998, 105-113

[5] Horvath, A “Life-cycle environmental and economic assessment of

using recycled materials for asphalt pavements” Technical report

University of California Transportation Center, 2003

[6] Huynh Thi Minh Truc Studying the calculation of environmental impacts on the life cycle of highways (case study: Hanoi – Langson

highway in Vietnam) The university of Danang: Journal of science

and technology, 6(67), 2013, 86-92

58 Huynh Thi Minh Truc, Mai Anh Duc [7] Jash, C “The use of environmental management accounting for

identifying environmental costs.” Journal of Cleaner production,

11, 2003, 667-676

[8] Keoleian, G., Kendall, A., Dettling, J., Smith, V., Chandler, Lepech,

M., and Li, V “Life cycle modeling of concrete bridge design:

comparison of engineered cementitious composite link slabs and

conventional steel expansion joints.” Journal of infrastructure

system, 11(1), 2005, 51-60

[9] Muench, S T, Anderson, J L., Hetfield, J P., Koester, J R., and

Soderlund, M et al Greenroads Manual v1.5 Seattle, WA:

University of Washington, 2011

[10] Rajendran, S and Gambatese, J A “Solid waste generation in

asphalt and reinforced concrete roadway life cycle.” Journal of

infrastructure system, 13(2), 2007, 88-96

[11] Tatari, O., and Kucukvar, M “Eco-efficiency of construction

materials: a data envelopment analysis.” Journal of construction

engineering and management, 138(6), 2012, 733-742

[12] United Nations, New York Glossary of environment statistics, studies in methods, series F, No 67, 1997

[13] University of California pavement research center (UCPRC)

Pavement life cycle assessment workshop.2010

[14] World business council for sustainable development (WBCSD)

“Measuring eco-efficiency: a guide to reporting company performance”, 2000

(The Board of Editors received the paper on 10/04/2014, its review was completed on 28/05/2014)