Methodology for Estimating Carbon Footprint of Road Projects

Case Study: India

,

• Publisher: Asian Development Bank
• Year: 2015
• Print ISBN: 9789290920274
• eBook ISBN: 9789290920281
• Topic: Biological Sciences
• Subtopic: Global Warming & Climate Change
• Index: Biological Sciences

Carbon footprint is a tool commonly used to describe the total amount of carbon dioxide and other greenhouse gas emissions for which an individual or organization is responsible. South Asia Department of the Asian Development Bank carried out this study to explore possible approaches and methods to calculate the carbon footprint from its road activities and their total contributions on its overall SARD activities in India. India was selected for this study because it represents all types of SARD activities (highways, national roads, and rural roads) and the project locations range from urban to rural areas with different ecological conditions. A model of calculating carbon footprint---construction, operation, and maintenance---of road projects was developed, and this model was tested and presented using data from its projects in India.

FINDINGS

Carbon Footprint of Selected Roads

Carbon Footprint of Construction Phase

The carbon footprint of the construction phase for all sample projects was calculated from primary data collected from the road construction contractors. The direct sources of CO₂ emissions during the construction phase include on-site use of diesel, furnace oil, and light diesel oil (LDO) in construction machinery, vehicles, and power generators. The transport of construction materials to the site also contributes to CO₂ emissions. The indirect emissions are attributed to the embodied carbon in construction materials and fuels used on-site. Use of vegetation removed from construction site as fuel wood also contributes to direct CO₂ emissions.² Table 4 summarizes the amount of electricity purchased from the grid, diesel used on-site, and the number of trees cut for the four sample projects. Table 5 summarizes the amount of different types of construction materials used per kilometer during construction of the four sample roads, and Table 6 gives the total quantity of diesel used for transporting construction materials and/or fuels to the construction site.

Table 4. Electricity and Fuels Used On-Site and Vegetation Removed

kl = kiloliter, km = kilometer, kWh = kilowatt-hour, LDO = light diesel oil, MP = Madhya Pradesh, NH = national highway, RR = rural road, SH = state highway, UP = Uttar Pradesh.

Note: The electricity purchased per kilometer for the NH, MP/UP construction is less compared with the SH, MP construction because the NH, MP/UP depends on electricity from two sources: grid and diesel generators. Therefore, though it purchases less electricity from the grid, this road project generates its own electricity on-site to meet the construction demand. The diesel used per kilometer of road construction to generate electricity on-site is therefore highest for the NH, MP/UP. SH, MP meets all of its electricity needs by purchasing electricity from the regional grid. Also, the number of trees cut during NH, MP/UP construction is the highest compared with all other roads because this NH passes through forest areas and the construction activity required clearing of a number of trees.

Source: Road construction contractors, project documents, and bills of quantities.

Table 5. Construction Materials Used per Kilometer

km = kilometer, MP = Madhya Pradesh, mt = metric ton, NH = national highway, RR = rural road, SH = state highway, UP = Uttar Pradesh.

Source: Road construction contractors, project documents, and bills of quantities.

Table 6. Diesel Used for Transportation of Construction Materials/Fuels

Road Project	Total Diesel Used for Transportation of Construction Materials/Fuels to the Site (kl)
NH, MP/UP	4,331.9
SH, MP	774.9
SH, Uttarakhand	148.7
RR, W. Bengal	60.5

kl = kiloliter, MP = Madhya Pradesh, NH = national highway, RR = rural road, SH = state highway, UP = Uttar Pradesh.

Source: Road construction contractors, project documents, and bills of quantities.

The total quantum of fuel and electricity consumed (for road construction and transport of construction materials and/or fuels to the site) was converted to equivalent CO₂ emissions using India-specific emission factors. Similarly the embodied CO₂ in construction materials and/or fuels used was estimated using India-specific values. The sources for emission factors and embodied energy values are discussed in the appendix. The CO₂ estimation results for the construction phase of all sample projects are found in Table 7.

Table 7. CO₂ Emissions from the Entire Construction Phase

Road Project	CO2 (ton/km)
NH, MP/UP	2,115.2
SH, MP	377.9
SH, Uttarakhand	109.6
RR, W. Bengal	48.4

CO₂ = carbon dioxide, km = kilometer, MP = Madhya Pradesh, NH = national highway, RR = rural road, SH = state highway, UP = Uttar Pradesh.

Source: This study.

Carbon Footprint of Operation Phase

The transport fuels used in vehicles during road operations contribute to direct and indirect CO₂ emissions on account of fuel combustion in vehicle engines and embodied carbon in fuels respectively. The cumulative GHG emissions are attributable to the increasing number of vehicles on the road, the number of kilometers traveled by each vehicle, the fuel consumed for each kilometer traveled, and the carbon content of the different fuels used.

Vehicular movement for the entire life period of the sample roads was estimated by using the data from detailed project reports (DPRs) and economic analysis of these sample projects. ADB accepts these vehicular projections in the DPRs for justifying the economic viability of the road construction. Since the road construction activity is based on these future vehicular projections, it is appropriate to use these traffic numbers for the entire project life. The vehicular projections in DPRs include the vehicular growth resulting from population increase and economic growth in the region (natural growth). This natural traffic growth is considered to be the normal growth of traffic that would have taken place with or without the road construction project. In addition to the natural growth of traffic volumes, road improvements also generate new traffic on account of better driving conditions. The projections for this “induced traffic” or “newly generated traffic” due to road improvements and diversion of traffic to these roads are also included in the DPR future traffic projections (sometimes explicitly, sometimes implicitly).

The DPRs of the sample road projects either give yearly projections for different transport modes or the growth rates for these modes. The vehicle projection data and/or growth rates from DPRs were used to derive the vehicle volumes for the design life of sample projects. The operation phase duration or the design life for the sample projects was taken as assumed in the DPRs (for national highway, Madhya Pradesh/Uttar Pradesh – 22 years; state highway, Madhya Pradesh – 30 years; state highway, Uttarakhand – 16 years; and rural road, ...

Table of contents

• Front Cover
• Title Page
• Copyright Page
• Contents
• Foreword
• Abbreviations
• Weights and Measures
• Prologue
• Introduction
• Methodology
• Findings
• Final Notes
• Appendix
• Back Cover