companies, supply chains and products
STEP 5: Verification and disclosure
Before reporting any GHG information, companies should try to verify their carbon footprint estimates to confirm their accuracy and consistency.
Verification minimizes the risk of human error and of decision makers forming the wrong judgements on the basis of misleading carbon foot-print information. The level of verification will depend on the main objec-tives of the carbon footprinting exercise. If the emissions data is only to be used internally, self-verification will usually suffice. This involves asking somebody else within the organization to check the collected documen-tation and all the calculations independently, in order to detect any errors or missing data. The verifier should be able to confirm that the carbon footprint information fulfils the criteria of relevance, completeness, accuracy, transparency and consistency.
If companies want to disclose the carbon footprint information publicly, independent verification by a third party is encouraged. The highest level of validation would be offered by an accreditation body providing official certification. Non-accredited third-party organizations also offer external validation services.
The final GHG report should present relevant information on GHG emissions, assessment boundaries, the methodology applied and the period of assessment. The required level of detail and scope of the report will also depend on the audience at which it is targeted and the main objective of the carbon footprinting process. However, it should always be based on the best available data at the time of publication, while being open and honest about its limitations (WBCSD/WRI, 2004). Additionally, if the carbon footprint is calculated periodically, information on trends in GHG emission levels should be enclosed.
suCCEss fACtors In CArbon footprIntIng
Measuring a carbon footprint is a challenging and time-consuming task, particularly if it covers the activities of more than one organization in the supply chain. It should be perceived as an ongoing long-term project that is likely to bring benefits to all the parties involved. Critical success factors for carbon footprinting include:
senior management support, devoting the necessary attention and
• resources;
buy-in from all partners involved and a good level of cooperation
• across the supply chain;
adoption of straightforward data collection procedures incorporating
•
standardized questions and data input formats that are aligned with other applications already in use;
a timetable for the project with firmly defined milestones for the
• different steps in the carbon footprinting exercise;
employee involvement and understanding of the environmental
• impact of the carbon auditing and reduction programme.
CAsE study: CArbon AudItIng of roAd frEIght trAnsport opErAtIons In thE uk
Although freight transport typically constitutes a relatively small part of the total carbon footprint of a product or service, it is an activity whose carbon intensity can be significantly reduced at little or no net cost (McKinnon, 2007). CO2 accounts for around 96 per cent of all GHG emis-sions from road transport (UK Air Quality Archive, 2008), thus the main focus should be on the CO2 element.
The carbon footprinting of road freight operations would normally include Scope 1 and Scope 2 emissions, with Scope 3 emissions left to the reporting entity’s discretion. All CO2 emitted by freight vehicles owned and/or controlled by the company will be considered as Scope 1 emissions. Scope 2 emissions would only arise from battery-powered operation of vans and small rigid vehicles recharged with purchased electricity from the grid. The transport of goods in vans or lorries owned or controlled by another entity would be classed as Scope 3 emissions (WBCSD/WRI, 2005).
Two approaches can be used to calculate CO2 emissions from road freight operations:
fuel-based;
• activity-based.
•
Fuel-based approach
The amount of fuel used in a carbon accounting period is multiplied by the standard CO2 conversion factor for each fuel type (Table 2.1). Data on fuel consumption can be obtained from the following sources:
Fuel receipts, showing the quantity and type of fuel purchased.
• Direct measurements of fuel use, for example readings from fuel
• gauges or storage tanks.
Financial records on fuel expenditures. Where no better data is
•
available, reports on fuel expenditures can be converted to fuel consumption by using average fuel prices.
When using fuel receipts as the source of fuel consumption data, it is important to remember that not all fuel purchased may have been used in a calculation period. Any stocks remaining at the end of this period should be excluded from the carbon footprint estimate. Similarly, any fuel in the vehicle tank(s) at the beginning of the accounting period but purchased previously should be included in the calculations.
Activity-based approach
Emissions can be calculated by using activity-based conversion factors.
In this case, data on activity level by vehicle type are needed. This should be available from a company’s records, based, for example, on tachograph readings, despatch notes and other sources (WBCSD/WRI, 2005). The UK government produces a series of conversion tables to enable companies to convert their road freight activity levels into carbon footprints (Table 3.1).
Table 3.1 illustrates the fact that in terms of carbon dioxide emissions, for each category of vehicle (either rigid or articulated) the higher the gross vehicle weight (GVW) the higher the emissions per vehicle-km but the lower the emissions per tonne-km, suggesting that use of fewer heavier vehicles is better for the environment than more lighter vehicles.
It is also interesting to note that on a tonne-km basis, rigid vehicles are actually more polluting than articulated ones. On a macro-level, it has been estimated that the heaviest articulated vehicles (with GVWs of over 33 tonnes) carry 72 per cent of all road tonne-kms (DfT, 2007) but are responsible for only around 47 per cent of all the external costs of road freight transport and for only 49 per cent of the total CO2 emissions from HGVs. Conversely, rigid vehicles account for 48 per cent of the total external costs and 47 per cent of the CO2 emissions while carrying only 24 per cent of all road tonne-kms (Piecyk and McKinnon, 2007). This is due to differences in the use patterns of these two categories of truck. Heavy articulated lorries move larger/heavier loads on long-haul, inter-urban trunk movements, where they achieve much higher energy efficiency than rigid vehicles, which typically distribute smaller, lighter loads on multiple-drop rounds within urban areas (DfT, 2008).
While vans (with a GVW of under 3.5 tonnes) run more kilometres per litre of fuel consumed than trucks, their much lower carrying capacity gives them a relatively high carbon intensity, expressed in terms of g CO2 per tonne-km (Table 3.2). Using a diesel-powered light commercial
Table 3.1CO2 conversion factors for heavy goods vehicles (vehicle km basis, based on UK average load for each vehicle type and tonne-km basis) vehicle type (gvW tonnes)total vehicle-kms travelled×Conversion factor (kg Co2 per vehicle-km)total kg Co2total t-km travelled×Conversion factor (kg Co2 per t-kmtotal kg Rigid >3.5t–7.5t×0.563×0.591 Rigid >7.5t–17t×0.747×0.336 Rigid >17t×0.969×0.187 All rigids (UK average)×0.895×0.276 Articulated >3.5t–33t×0.817×0.163 Articulated >33t×0.929×0.082 All artics (UK average)×0.917×0.086 All HGVs (UK average)×0.906×0.132 Source: DEFRA (2008b).
vehicle releases approximately the same carbon dioxide emissions as an average rigid vehicle per tonne-km, and a small petrol-engined van produces considerably more. However, one needs to be careful when applying the tonne-kms conversion factor for vans. The values shown in Table 3.2 are based on an assumption that the average van carries a 50 per cent payload. This appears rather high, as results of the Department for Transport’s survey of company owned vans for the period 2003 to 2005 shows that on 38 per cent of the distance travelled vans were less than one-quarter full (DfT, 2006). Also, when compared with the average lading factor of small rigid vehicles in the 3.5–7.5 tonne category (40 per cent) (DfT, 2008), the assumed 50 per cent load factor for vans seems to be too high.
The carbon footprint of road freight operations is strongly related to the capacity utilization of the vehicle. Table 3.3 shows its impact on carbon dioxide emissions for a typical articulated vehicle with a GVW over 33 tonnes. When a vehicle is empty, it still produces approximately two-thirds of the CO2-related pollution of a fully laden vehicle, and the higher the vehicle capacity utilization, the lower the emissions per tonne of goods carried. Measures to improve vehicle utilization are examined in Chapter 11.
When deciding on the method of calculating carbon footprint, the fuel-based approach should be the preferred option as the fuel consumption records tend to be more reliable. However, if data are only available for an organization as a whole, this can require the calculation of a top-down estimate of the CO2 emissions. In this case it may be difficult to disag-gregate impacts by vehicle class. The activity-based (bottom-up) approach should then be used to allocate emissions to different vehicle classes in order to identify the most promising areas for improving energy effi-ciency and reducing CO2 emissions. Disaggregated emissions data allow managers to target specific efficiency measures on particular categories of vehicles, types of operation or members of staff. Using both approaches simultaneously is not essential but it is a good way to validate calcula-tions and ensure the reliability of the results.
In essence, the CO2 emissions from road freight transport are a function of two factors: the nature of the vehicle and how it is used (Figure 3.4).
In order to reduce CO2 emissions from the road freight transport oper-ation, managers can manipulate both sets of factors. As CO2 emissions are directly proportional to the amount of fuel used, a reduction in fuel consumption will yield savings in CO2 levels. Measures to improve the fuel efficiency of trucking are discussed in Chapters 7 and 11.
Table 3.2Van/light commercial vehicle conversion factors based on a UK average vehicle vehicle type (gvW tonnes)total vehicle-km travelled×Conversion factor (kg Co2 per vehicle-km)total kg Co2total t-km travelled×Conversion factor (kg Co2 per t-km)total Co2 Petrol up to 1.25t×0.224×0.449 Diesel up to 3.5t×0.272×0.272 Source: DEFRA (2008b). Table 3.3Conversion factors for one particular vehicle class at various capacity utilizations % weight ladentotal vehicle-kms travelled×Conversion factor (kg Co2 per vehicle-km)total kg Articulated vehicle >33t GVW0×0.667 50×0.889 100×1.111 59 (UK average)×0.929 Source: DEFRA (2008b).
Vehicle:
• Vehicle type and age (class, engine, transmission)
• Tyres
• Type of fuel
• Body type
• Maintenance
How it is used:
• Road transport demand – Tonnes lifted
– Location of activities
• Management of transport resources
– Load factor – Empty running
• Traffic conditions – Congestion – Weather conditions
• Driver behaviour – Driver skills – Time pressures CO2 emissions from road freight transport
Figure 3.4 Factors affecting CO2 emissions from road freight transport
ConClusIons
Although still a relatively new concept, the carbon auditing of business activities has evolved rapidly in recent years. To date it has been conducted mainly at a company level, promoted both by government regulation and voluntary initiatives such as the Carbon Disclosure Project (www.
cdproject.net). It is now developing in vertical and horizontal dimensions (Figure 3.5). Its vertical extension involves the disaggregation of CO2 data by business unit, process, activity and even product, giving managers deeper understanding of the carbon-generating characteristics of their businesses. At the same time, carbon footprinting is being extended hori-zontally from individual companies across supply chains, making it possible to track the amounts of CO2 released at different stages in the production and distribution of individual products. Several attempts have been made to use this data to label consumer products such as potato crisps and fruit juice. Given the complexity and high cost of product-level carbon auditing of supply chains, and uncertainty about consumer responses to carbon labelling, it is doubtful that this practice will become widespread, at least for the foreseeable future. The case study of carbon auditing in the road freight sector, however, illustrates how the disaggregation of CO2 data to an activity, if not product, level can provide a quicker and more cost-effective means of finding opportunities for decarbonization within a logistics operation.
Company 1 Business unit Facility Process Activity Product
Company 2... Company X
Figure 3.5 Horizontal and vertical dimensions of carbon footprint
rEfErEnCEs
British Standards Institution (2008a) PAS 2050: Specification for the Assessment of the Life Cycle Greenhouse Gas Emissions of Goods and Services, BSI British Standards, London
British Standards Institution (2008b) PAS 2050: Guide to PAS 2050 – How to assess the carbon footprint of goods and services, BSI British Standards, London
Carbon Trust (2006) [accessed 11 February 2009] Carbon footprints in the supply chain: the next steps for business, November [online] www.
carbontrust.co.uk
Carbon Trust (2007) Carbon Footprinting: An introduction for organizations, The Carbon Trust, London
Department for Environment, Food and Rural Affairs (DEFRA) (2006) Environmental Key Performance Indicators, DEFRA, London
DEFRA (2008a) How to use Shadow Price of Carbon in Policy Appraisal, DEFRA, London
DEFRA (2008b) Guidelines to DEFRA’s GHG Conversion Factors, DEFRA, London
Department for Transport (DfT) (2006) Road Freight Statistics 2005, Department for Transport, London
DfT (2007) Road Freight Statistics 2006, Department for Transport, London
DfT (2008) Road Freight Statistics 2007, Department for Transport, London
Environmental Protection Agency (2006) Life Cycle Assessment: Principles and practice, EPA/600/R-06/060, May 2006
ISO 14064-1 (2006) Greenhouse Gases - Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emis-sions and removals, International Organization for Standardization, Geneva
ISO 14064-2 (2006) Greenhouse gases - Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements, International Organization for Standardization, Geneva
McKinnon, A (2007) CO2 Emissions from Freight Transport in the UK, Commission for Integrated Transport, London
Piecyk, M and McKinnon, A (2007) Internalising the External Costs of Road Freight Transport in the UK, Heriot-Watt University, Edinburgh
UK Air Quality Archive, (2008) [accessed 20 February 2009] Databases [online] http://www.airquality.co.uk/archive/reports/
cat07/0804161424_GBR-2008-CRF.zip
World Business Council for Sustainable Development and World Resources Institute (WBCSD/WRI) (2004) The Greenhouse Gas Protocol:
A corporate accounting and reporting standard, revised edition, World Business Council for Sustainable Development, Geneva and World Resources Institute, Washington, DC
WBCSD/WRI (2005) Calculating CO2 Emissions from Mobile Sources, World Business Council for Sustainable Development, Geneva and World Resources Institute, Washington, DC