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 kinh tế - môi trường công nhận cơng cụ hiệu để đo lường tính bền vững xây dựng Nghiên cứu đề xuất số để đo lường hiệu kinh tế - môi trường cấp độ dự án cấp độ thành phần vịng đời đường giao thơng Tỉ số chi phí mức tiêu thụ lượng tỉ lệ chi phí lượng khí thải nhà kính hai số bật giai đoạn sản xuất vật liệu, tỉ lệ chi phí lượng chất thải rắn bật giai đoạn xử lý / tái chế Tỉ lệ chi phí mức tiêu thụ nguyên liệu bật giai đoạn xây dựng bảo trì Tỉ lệ chi phí mức tiêu thụ lượng tỉ lệ chi phí lượng khí thải nhà kính tỉ số phù hợp với giai đoạn công tác đất Các liệu từ dự án đường cao tốc Hà Nội-Lạng Sơn Việt Nam sử dụng để minh họa cho số Key words - eco-efficiency indicator; environmental cost; EMA; sustainable development; roadway project Từ khóa - số hiệu kinh tế - mơi trường; chi phí mơi trường; EMA; phát triển bền vững; dự án đường 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 Ecoefficiency 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 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 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 Conventional costs of roadways Material Production Construction Maintenance Disposal/ Recycling Material transportation Routine Demolition Equipment Periodic Transportation to landfill /recycling plant Figure 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 THE UNIVERSITY OF DANANG, JOURNAL OF SCIENCE AND TECHNOLOGY, NO 6(79).2014, VOL 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 nonproduct output Such environmental cost categories are shown in Table Table Environmental Cost Categories 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 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 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 Processing costs of non-products 2.2 Selection of Environmental Impact Factors World business council for sustainable development (WBCSD) developed a framework for identifying and measuring Eco-efficiency indicators and reporting Ecoefficiency 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 55 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 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 (1.Conventional; 2.Environmental ) (3.1) Impact ( a : Material ; b : Energy; c : Emissions; d : Waste ) 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 ecoefficiency 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 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 shows the most prominent indicators at the project and component levels According to the three criteria, the indicators in Table 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 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 HanoiLangson 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 Most Prominent Eco-Efficiency Indicators for Roadways Project, Pavement, bridge evel Stage Criteria Simplicity Data availability Environmenta l Impact Earthwork Simplicity Data availability Environmenta l impact High Medium Low High Medium Low High Medium Low High Medium Low High Medium Low High Medium Low Material production 1b, 1c 1d 2b,2c,2d 1b, 1c 1d 2b, 2c, 2d 1b, 1c, 2b, 2c 1d, 2d 1b, 1c 1d 2b, 2c, 2d 1b, 1c 1d 2b, 2c, 2d 1b, 1c, 2b, 2c 1d, 2d Construction Maintenance 1a 1a Disposal/ Recycling 1d 1a 1a 2d 1d 1a 2d 1d, 2d 1a 1b, 1c 1d 2b, 2b 1b, 1c 2d 1d 2b, 2c 1b, 1c, 2b, 2c 2d 1d, 2d Table Eco-Efficiency Indicators of Hanoi – Langson highway project Indicator (1a) Level Project Material production 27 Construction 51 Disposal/ recycling Maintenance 114 THE UNIVERSITY OF DANANG, JOURNAL OF SCIENCE AND TECHNOLOGY, NO 6(79).2014, VOL Conventional cost/Material consumption Earthwork 89 996 0 Pavement 20 23 100 Bridges 77 134 315 Project (1b) Conventional consumption cost/Energy cost/GHG cost/Solid 223 352 166 97 559 172 Pavement 15 112 292 166 Bridges 44 1,843 9,467 343 152 3,206 Earthwork 677 Pavement 121 Bridges 308 Project (1d) Conventional waste 20 Earthwork Project (1c) Conventional emissions 57 253 5,099 2,421 8,157 5,007 1,606 4,230 2,401 26,879 138,098 5,007 5,028 12,426 68 Earthwork 51,305 39,847 Pavement 178 2,657 11,416 115 1,903 5,678 21,240 Bridges 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 HanoiLangson highway pavement achieved better eco-efficiency than earthwork or bridges The Hanoi-Langson highway pavement presented better Eco-efficiency than bridges Conclusions Conventional cost and environmental cost are two kinds of economic performance metrics used for Ecoefficiency 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 12 impacts for roadways are material consumption, energy consumption, air emission and solid waste generation A potential environmental impact for roadway Ecoefficiency 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 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components... 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... 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,