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3. Emission factors and methods 2007

3.1 Scope 1: Direct emissions

3.1.3 Stationary combustion of fuels

Scope 1 emissions from the stationary combustion of fuel occur from the combustion of fuels from sources owned or controlled by the reporting organisation. Table 1 contains emission factors for common fuels used for stationary combustion.

These emission factors are sourced from the Energy Greenhouse Gas Emissions 1990–2007 publication. The Energy Greenhouse Gas Emissions publication provides CO2, CH4 and N2O emission factors for a range of fuels used by the energy sector.

In line with the reporting requirements of ISO 14064-1 and The GHG Protocol, emission factors are provided to allow calculation of CO2, CH4 and N2O separately.

Table 1: Fuel combustion emission factors (fuels used for stationary combustion) – 2007

Emission Source User Unit Emission factor Total CO2-e*
(kg CO2-e/unit)
Emission factor CO2
(kg CO2/unit)
Emission factor CH4
(kg CO2-e/unit)
Emission factor N2O
(kg CO2-e/unit)

Stationary Combustion

  

Distributed Natural Gas

Commercial

Kwh

0.194

0.192

0.0000816

0.00231

GJ

54.0

53.3

0.0227

0.642

Coal – Bituminous

Commercial

Kg

2.53

2.51

0.00575

0.0119

Coal – Sub-bituminous

Commercial

Kg

2.01

2.00

0.00446

0.00921

Coal – Lignite

Commercial

Kg

1.49

1.48

0.00316

0.00653

Coal – Default**

Commercial

Kg

2.01

2.00

0.00446

0.00921

Diesel

Commercial

Litre

2.63

2.63

0.000538

0.00451

LPG***

Commercial

Kg

2.97

2.96

0.00109

0.00875

Heavy Fuel Oil

Commercial

Litre

2.99

2.98

0.00114

0.0037

Light Fuel Oil

Commercial

Litre

2.94

2.93

0.00114

0.0037

 

Distributed Natural Gas

Industry

KWh

0.192

0.192

0.0000953

0.000100

GJ

53.3

53.3

0.0265

0.0279

Coal – Bituminous

Industry

Kg

2.52

2.51

0.000406

0.0136

Coal – Sub-bituminous

Industry

Kg

2.01

2.00

0.000314

0.0105

Coal – Lignite

Industry

Kg

1.49

1.48

0.000223

0.00747

Coal – Default**

Industry

Kg

2.01

2.00

0.000314

0.0105

Diesel

Industry

Litre

2.63

2.63

0.000153

0.00451

LPG***

Industry

Kg

2.97

2.96

0.00109

0.00875

Heavy Fuel Oil

Industry

Litre

2.99

2.98

0.00245

0.0037

Light Fuel Oil

Industry

Litre

2.94

2.93

0.00162

0.00479

Wood

Industry

Kg

0.0178*****

1.26

0.00361

0.0142

Wood

Fireplaces****

Kg

0.0865*****

1.26

0.0723

0.0142

* Use the total CO2-e emission factor for calculating total CO2-e emissions, rather than summing the totals for CO2, CH4 and N2O.

** The default coal emission factor should be used if it is not possible to identify the specific type of coal.

*** Fuel-use data in litres can be converted to kilograms by multiplying by the specific gravity of 0.536 kg/l.

**** It is not expected that many commercial or industrial users will burn wood in fireplaces but this emission factor has been provided for completeness. It is the default residential emission factor.

***** The Total CO2-e emission factor (for wood) does not include the CO2 emission factor. Under ISO 14064-1 and The GHG Protocol reporting requirements, only CH4 and N2O emissions from the combustion of biomass are included as Scope 1 emissions. CO2 emissions, from the combustion of biologically sequestered carbon, are reported separately from the scopes.

Changes in Methodology from 2006

The 2006 emission factors for stationary combustion of distributed natural gas (industrial and commercial) were generated using a weighted average of natural gas from Kapuni treated and Maui gas streams. The 2007 distributed natural gas emission factor is the weighted average of natural gas from all gas streams. This change in methodology is outlined in Energy Greenhouse Gas Emissions 1990–2007.

Assumptions

The kg CO2-e per activity unit emission factors supplied in Table 1 are derived using calorific values sourced from the New Zealand Energy Data File 2008. The calorific values used can be found in Appendix 1.

All emission factors incorporate relevant oxidation factors which are sourced from New Zealand’s Greenhouse Gas Inventory1990–2006. Oxidation factors allow for the small proportion of carbon that remains unoxidised due to incomplete combustion, and remains as soot and ash. The oxidation factors used for each of the fuels can be found in Appendix 1.

The emission factors provided above account for the Scope 1 emissions resulting from fuel combustion. They are not full fuel cycle emission factors and do not incorporate Scope 3 emissions associated with the extraction, production and transport of the fuel.

The default coal emission factor is assumed to be the same as the sub-bituminous coal emission factor on the basis that the majority of coal use is of sub-bituminous coal.9

The Automotive Gas Oil-50 ppm Sulphur emission factor (provided in the Energy Greenhouse Gas Emissions 1990–2007 publication) has been used as the default emission factor for diesel.

Example calculation

A commercial organisation uses 1,400 kg of LPG to heat one of its office buildings in 2007.

CO2 emissions = 1,400 * 2.96 = 4,144 kg CO2/1000 = 4.14 tonnes CO2

CH4 emissions = 1,400 * 0.00109 = 1.526 kg CO2-e/1000 = 0.00153 tonnes CO2-e

N2O emissions = 1,400 * 0.00875 = 12.25 kg CO2-e/1000 = 0.0123 tonnes CO2-e

Total CO2-e emissions = 1,400 * 2.97 = 4,158 kg CO2-e/1000 = 4.16 tonnes CO2-e

3.1.2 Transport fuels (where fuel use data is available)

Scope 1 emissions from transport occur from vehicles which are owned or controlled by the reporting organisation. The most accurate way to quantify the emissions associated with transport is by using information on the quantity of fuel used.

Emission factors for combustion of transport fuels are reported in Table 2. The emission factors are sourced from the Energy Greenhouse Gas Emissions 1990–2007 publication.

Table 2: Fuel combustion emission factors (Transport fuels) – 2007

Fuel Unit Emission factor
Total CO2-e*
(kg CO2-e/unit)
Emission factor
CO2
(kg CO2/unit)
Emission factor
CH4
(kg CO2-e/unit)
Emission factor
N2O
(kg CO2-e/unit)

Regular Petrol

litre

2.32

2.29

0.0136

0.0155

Premium Petrol

litre

2.36

2.33

0.0137

0.0156

Petrol – Default**

litre

2.33

2.30

0.0136

0.0155

Diesel

litre

2.68

2.63

0.00305

0.0440

LPG

litre

1.61

1.59

0.0159

0.00469

* Use the total CO2-e emission factor for calculating total CO2-e emissions, rather than summing the totals for CO2, CH4 and N2O.

** The default petrol emission factor should be used if it is not possible to distinguish between regular and premium petrol use.

Assumptions

The kg CO2-e per activity unit emission factors supplied in Table 2 are derived using calorific values sourced from the New Zealand Energy Data File 2008. All emission factors incorporate relevant oxidation factors which are sourced from Energy Greenhouse Gas Emissions
1990–2007
.

The default petrol factor is a weighted average of regular and premium petrol based on 2007 sales volume data from the New Zealand Energy Data File 2008. It should be used when petrol use data does not distinguish between regular and premium petrol.

As with the fuels for stationary combustion these emission factors are not full fuel cycle emission factors and do not incorporate (the Scope 3) emissions associated with the extraction, production and transport of the fuel.

Example calculation

An organisation has 15 petrol vehicles. They used 40,000 litres of regular petrol in 2007.

CO2 emissions = 40,000 * 2.29 = 91,600 kg CO2 = 91.6 tonnes CO2

CH4 emissions = 40,000 * 0.0136 = 544 kg CO2-e = 0.544 tonnes CO2-e

N2O emissions = 40,000 * 0.0155 = 620 kg CO2-e = 0.620 tonnes CO2-e

Total CO2-e emissions = 40,000 * 2.32 = 92,800 kg CO2-e = 92.8 tonnes CO2-e

3.1.3 Transport where no fuel data is available (based on distance travelled)

If your records only provide information on kilometres travelled, and you do not have information on fuel use, the emission factors in the following table can be used. Note, however, that factors such as individual vehicle fuel efficiency and driving efficiency mean that kilometre-based estimates of CO2-e emissions are less accurate than calculating emissions based on fuel-use data. The emission factors in the below table should therefore only be used if information on fuel use is not available.

Table 3: Transport emission factors (based on distance travelled) – 2007

Vehicle size class* Unit Real world' petrol fuel use estimate
(L/100km)
Emission factor
Total CO2-e**
(kg CO2-e/unit)
Emission factor
CO2
(kg CO2/unit)
Emission factor
CH4
(kg CO2-e/unit)
Emission factor
N2O
(kg CO2-e/unit)

Car – Small (<1600 cc)

Km

7.53

0.175

0.173

0.00102

0.00117

Car – Medium (1600 – <2500 cc)

Km

10.4

0.241

0.238

0.00141

0.00160

Car – Large (>= 2500 cc)

Km

14.2

0.331

0.327

0.00194

0.00221

Car – Default***

Km

10.4

0.241

0.238

0.00141

0.00160

* Example (representative) vehicle models for each of the size classes are: Small = Toyota Echo, Medium = Honda Accord, Large = Holden Commodore.

** Use the total CO2-e emission factor for calculating total CO2-e emissions, rather than summing the totals for CO2, CH4 and N2O.

*** The default emission factor should be used if vehicle size class can not be determined.

Assumptions

The above emission factors in Table 3 assume that all vehicles are petrol. The emission factors are derived by multiplying the default petrol emission factor from Table 2 by ‘real world’ fuel consumption rates10 for the petrol light vehicle fleet, based on information from The New Zealand Light Vehicle Fleet: Light Fleet Statistics 2007 (Ministry of Transport, 2008). ‘Real world’ fuel consumption rates take into account ‘real world’ effects such as driver behaviour. Due to lack of data it is not currently possible to derive ‘real world’ fuel consumption rates for vehicles which use other fuels (eg, diesel, LPG).11 The above CO2-e emission factors should therefore be applied to all vehicles (for which only kilometre travelled information is available), regardless of the type of fuel used.

The above emission factors are averages and therefore do not reflect the variability in fuel consumption rates between individual vehicles.

The default emission factor (for vehicles of unknown size) is the same as that for medium vehicles (1600 – <2500 cc).12

Example calculation

An organisation has three vehicles which it owns. They are all large vehicles and travelled a total of 37,800 km in 2007.

CO2 emissions = 37,800* 0.327 = 12,360.6 kg CO2 = 12.4 tonnes CO2

CH4 emissions = 37,800* 0.00194= 73.332 kg CO2-e = 0.0733 tonnes CO2-e

N2O emissions = 37,800* 0.00221 = 83.538 kg CO2-e = 0.0835 tonnes CO2-e

Total CO2-e emissions = 37,800* 0.331 = 12,511 kg CO2-e = 12.5 tonnes CO2-e

3.1.4 Refrigerants

Greenhouse gas emissions from hydrofluorocarbons (HFCs) are associated with unintentional leaks and spills from refrigeration units, air conditioners and heat pumps. While quantities of HFCs reported in a business emissions inventory may be small, HFCs have very high global warming potentials (commonly 1,300 to 3,300 times more potent than CO2) and emissions from this source may therefore be material. In addition, emissions associated with this sector are growing significantly as they replace hydrochlorofluorocarbons (HCFCs)13 which are being phased out.

Scope 1 emissions from refrigeration occur from refrigeration units which are owned or controlled by the reporting organisation. If the unit is leased, associated emissions should be reported under Scope 3 emissions.

Methodologies

Three approaches can be taken to assess HFC leakage from refrigeration equipment. The approach taken should be dependant upon the type of equipment you are performing the calculation for, and the level of information available to you (see Choosing a Method below).

Method A – Lifecycle stage approach

E = (IE + S + DE) x GWP x CF

E      emissions from the piece of equipment in tonnes CO2-e (per year)
IE     installation emissions (refrigerant used to charge new equipment less the total full charge of new equipment. This is omitted if the equipment has been pre-charged by the manufacturer)
S      recorded quantity of refrigerant used to service equipment, also referred to as a “top-up”.
DE    disposal emissions (total full charge of retiring equipment less the refrigerant recovered from retiring equipment)
GWP the 100-year global warming potential of the refrigerant used in equipment (Table 5)
CF    kilograms to tonnes conversion factor = 1 tonne/1000 kg

This approach is detailed in the GHG Protocol HFC tool (WRI/WBCSD 2005). This method requires advice to be sought from service agents for the following information on each piece of equipment, truck or bus operated by the organisation:

  1. refrigerant type

  2. full refrigerant charge

  3. quantity used in installation of new equipment

  4. quantity used in servicing

  5. the quantity recovered from retired equipment.

The equations for installation, operation and disposal emissions are explained in more detail in the GHG Protocol HFC tool guide.

Method B – default annual leakage rate

E = (IE + OE + DE) x GWP x CF

E      emissions from equipment in t CO2-e

IE     installation emissions (as applicable – see above)

OE    operation emissions

DE    disposal emissions (as applicable – see above)

GWP the 100-year global warming potential of the refrigerant used in equipment (Table 5)

CF    kilograms to tonnes conversion factor = 1 tonne/1000 kg

IE= C x AEF

C original full refrigerant charge in equipment (kg)

AEF the default installation leakage for new equipment (%). This is omitted if the equipment has been pre-charged by the manufacturer

OE = C x ALR

C original full refrigerant charge in equipment (kg)

ALR the default annual leakage emission factor for equipment (%)

DE = (C x (1 – (ALR x S)) x (1 – R) – D)

C original full refrigerant charge in equipment (kg)

ALR the default leakage for equipment (%)

S time since last recharge of equipment (years)

R amount of charge recycled from equipment (%)

D amount of refrigerant destroyed from equipment (kg)

Default leakage rates for calculation of installation (IE) and operating emissions (OE) are contained in Table 4. When calculating disposal emissions (DE), a value of zero (ie, no recycling or destruction) must be assumed if the amount of recycled (R) or destroyed (D) refrigerant is unknown.

The type and quantity of HFC contained in the equipment will often be shown on the equipment compliance plate. If not, then this method requires service agents’ advice being sought for the refrigerant type and full refrigerant charge of each piece of equipment that is operated by the organisation.

Method C – default annual leakage rate and default refrigerant charge

E = (IE +(C x ALR)+DE) x GWP x CF)

E      emissions

IE     installation emissions (as per method B)

C     the default refrigerant charge in each piece of equipment (kg)

ALR   the default annual leakage emission factor for equipment (%)

DE    disposal emissions (as per method B)

GWP the 100-year global warming potential of the refrigerant used in equipment (Table 5)

CF    the tonnes from kilograms conversion factor = 1 tonne/1000 kg

Method C is the same as Method B except that it allows default refrigerant quantities to be used as well as default leakage rates. Table 4 contains default refrigerant amounts for the New Zealand refrigeration and air-conditioning equipment stock.

Choosing a method

The most accurate methodology is Method A – the life-cycle stage approach. The information required can be collected with the assistance of any service agents, vehicle fleet or building manager. Currently however, these quantities are seldom recorded but it would be good practice to encourage service agents to record these amounts for future reporting. If an organisation determines that emissions from equipment are significant then it should endeavour to move to a method A approach to estimate HFC emissions.

In some circumstances, gathering the information required for Method A may not be possible or may not be justifiable, due to the resource-intensive nature of collecting detailed information for a particular equipment type. If so, then Method B and C can be used in some circumstances (refer to guidance in Table 4) to measure leakage rates with the default factors also provided in Table 4. Method B and C are based on the “screening” method approach contained in the Greenhouse Gas Protocol HFC tool 2005viii.

In some cases, Method C is only suitable for investigating the approximate quantity of emissions when the refrigerant charge amount is unavailable. Screening provides a way of determining if the equipment should or should not be excluded based on significance of emissions from refrigerants. However, sometimes, depending on the equipment in question, Methods B and C would be so unreliable that they would be unacceptable even for a screening method.

Apart from office refrigerators, water coolers and car/van air-conditioning, Method A should be considered the recommended method (see Table 4). For most equipment, Method B would be acceptable, especially for factory and office situations where refrigeration and air-conditioning equipment is incidental rather than central to an organisation’s operations.

For supermarket refrigeration, commercial air-conditioning (above 20kW), dairy farming, industrial, commercial and laboratory cool stores, the size ranges and configurations are so varied that there will be no meaningful default refrigerant charge amounts or emission factors. In these cases there would be no reasonable alternative to Method A, relying on the leakage information available from service agents.

It is stressed that for all equipment and for all Methods, the type of refrigerant must be individually identified because the global warming potential (GWP) of various refrigerant mixes are widely variable (see Table 5). In addition, hydrocarbon and HCFC refrigerants (mainly R22) can be eliminated from the accounting as they have no GWP.

Organisations should also provide information on the approach used to quantify direct HFC emissions in their inventories to reflect the different levels of associated accuracy and uncertainty with each method.

Table 4: Default refrigerant charges and emission factors for refrigeration and air-conditioning equipment

Refrigeration Unit Type Default Refrigerant Charge (kg) Default (operating) Emissions Default Installation Emissions15

Guidance on Method Choice

Method A

Method B

Method C

Small refrigerator or freezer (up to 150 litres16)

0.07

3%

not applicable

unnecessary

recommended

acceptable

Medium refrigerator or freezer (up to 300 litres)

0.11

3%

not applicable

unnecessary

recommended

acceptable

Large refrigerator or freezer (more than 300 litres)

0.15

3%

not applicable

unnecessary

recommended

acceptable

Small commercial stand-alone chiller (up to 300 litres)

0.25

8%

not applicable

recommended

acceptable

screening method only

Medium commercial stand-alone chiller (up to 500 litres)

0.45

8%

not applicable

recommended

acceptable

screening method only

Large commercial stand-alone chiller (more than 500 litres)

0.65

8%

not applicable

recommended

acceptable

screening method only

Small commercial stand-alone freezer (up to 300 litres)

0.2

8%

not applicable

recommended

acceptable

screening method only

Medium commercial stand-alone freezer (up to 500 litres)

0.3

8%

not applicable

recommended

acceptable

screening method only

Large commercial stand-alone freezer (more than 500 litres)

0.45

8%

not applicable

recommended

acceptable

screening method only

Water coolers

0.04

3%

not applicable

unnecessary

recommended

acceptable

Dehumidifiers

0.17

3%

not applicable

unnecessary

recommended

acceptable

Small self-contained air-conditioners (window mounted or through-the-wall)

0.2kg per kW cooling capacity

1%

0.5%

recommended

acceptable

screening method only

Non-ducted and ducted split commercial air-conditioners (up to 20kW)

0.25kg per kW cooling capacity

3%

0.5%

recommended

acceptable

screening method only

Commercial air-conditioning (above 20kW)

wide range

wide range

wide range

recommended

unacceptable

unacceptable

Cars/vans

0.7

10%

not applicable

unnecessary

recommended

acceptable

Trucks

1.2

10%

not applicable

recommended

acceptable

screening method only

Buses

2.5
(but up to 10)

10%

not applicable

recommended

acceptable

screening method only

Refrigerated truck trailer units

10

25%

0.5%

recommended

acceptable

unacceptable

Self-powered or ‘cab-over’ refrigerated trucks

6

25%

0.5%

recommended

acceptable

unacceptable

‘Off-engine’ or ‘direct drive’ refrigerated vans and trucks

2.5

25%

0.5%

recommended

acceptable

unacceptable

Three-phase refrigerated containers

5.5

25%

0.5%

recommended

acceptable

unacceptable

Single-phase refrigerated containers

3

25%

0.5%

recommended

acceptable

unacceptable

Centralised commercial refrigeration eg, supermarkets

wide range

wide range

wide range

recommended

unacceptable

unacceptable

Industrial and commercial cool stores

wide range

wide range

wide range

recommended

unacceptable

unacceptable

Table 5: Detailed 100-year Global Warming Potentials for various refrigerant mixtures17

Refrigerant Type
(trade name)
HFC-23 HFC-32 HFC-125 HFC-134a HFC-143a HFC-152a PFC-218 Other* Total GWP

GWP 100yr (IPCC 1996)

11700

650

2800

1300

3800

140

7000

0

 

R23

100%

             

11700

R134a

     

100%

       

1300

R403B: 5% R290, 56% R22, 39% R218

           

39%

61%

2730

R404A: 44% R125, 52% R143a, 4% R134a

   

44%

4%

52%

     

3260

R407C: 23% R32, 25% R125, 52% R134a

 

23%

25%

52%

       

1526

R408A: 7% R125, 46% 143a, 47% R22

   

7%

 

46%

   

47%

1944

R410A: 50% R32, 50% R125

 

50%

50%

         

1725

R413A: 9% R218, 88% R134a, 3% R600a

     

88%

   

9%

3%

1774

R416A: 59% R134a, 39.5% R124,1.5% R600

     

59%

     

41%

767

R417A: 46.6% R125 50% R134a 3.4% R600

   

46.6%

50%

     

3.4%

1955

R422A: 85.1% R125, 11.5% R134a, 3.4% R600a

   

85.1%

11.5%

     

3.4%

2532

R507A: 50% R125, 50% R143a

   

50%

 

50%

     

3300

 

* Hydrocarbons (such as R290 and R600a) and HCFCs (mainly R22) are not considered to have GWPs for GHG accounting purposes. Refrigerant compositions are from AIRAH (2003).

Assumptions

The default factors for installation, operation and disposal of refrigerant equipment supplied in Table 4 are derived from the Assessment of HFC Emission Factors for GHG Reporting Guidelines, 2008. These are based on data for New Zealand refrigeration and air-conditioning equipment stock.

The greatest potential for significant emissions from refrigeration and air-conditioning equipment is in the disposal stage of the life cycle. Recycling efficiency is likely to be high (around 90 percent) for reputable service agents but in the absence of consistent information for New Zealand, the default assumption is zero percent recycling/destruction of the remaining charge in all sectors. It is assessed that there is no current justification for applying a lower default emission factor to any sector to reflect refrigerant gas collection for destruction. Refrigerants are often recycled within various sectors but the quantity currently shipped to Australia for destruction is relatively small.

In the absence of consistent information for New Zealand, the default assumption for the assembly emissions rate is the rounded-off IPCC 2006 mid-range value. This will not be applicable (relevant) for many pre-charged units.

For simplicity, the default operating emission factor does not take account of the variability associated with equipment age.

Example Calculations

A detailed example has been provided below.

Company A performs a stocktake of refrigeration-related equipment and identifies the following units:

  • two office refrigerators

  • one large commercial-sized refrigerator

  • one air-conditioning unit (which is retired in the reporting year and replaced by a new model)

  • two mobile air-conditioning (MAC) units in the company-owned car and delivery truck

  • one delivery truck owned by the company

  • two external delivery trucks operated by another company, but included in Scope 3 emissions.

To assess their emissions, the company takes the following approach for each type of equipment:

Two office refrigerators

Method B is the recommended approach and is relatively easy for newer equipment in this sector because compliance plates for refrigerators and freezers are nearly always accessible inside the fridge. (Alternatively, a Method C approach is acceptable, though less accurate, for refrigerant charges based on Table 1.)

Compliance plates inside the two large refrigerators confirm the refrigerant is R134A and the refrigerant amounts are 0.17 kg each.

Using Method B

E = (IE + OE + DE) x GWP x CF

 

E = 2(0 + (0.17 x 3/100) + 0) x 1300 x 1/1000

E = 2(0+0.0051+0) x 1300 x 0.001

E = 0.0133 tonnes CO2-e

One large commercial sized refrigerator

Method A is the recommended approach to capture the significant leakage rates for commercial-sized refrigerators. The company’s service agents have maintained refrigerant top-up records for each piece of equipment at the company’s request.

The large commercial refrigerator unit uses R404A refrigerant and the compliance plates show the refrigerant amount is 1.7 kg. Maintenance records for the refrigeration unit show it has been topped-up by the service agent during the year with 0.32 kg.

Using Method A

E = (IE +S+DE) x GWP X CF

E= (0 + 0.32 + 0) x 3260 x1/1000

E= 1.04 tonnes CO2-e

One commercial air-conditioning unit

Method A is recommended for all commercial air-conditioning units with the cooperation of service agents. Method B would be acceptable for all systems up to 20kW but above that rating, refrigerant amounts and leakage rates are so site-specific that there is no acceptable alternative to a Method A approach. Method C could be used as a screening test (Table 1) where the HFC refrigerant amount is not specified and the cooling capacity (up to 20kW) is known.

The old air-conditioning system for the company’s building (using R407C HFC refrigerant (GWP 1526)) was retired and replaced in August of the 2007 reporting (calendar) year. The service agent did the annual servicing in January 2007, topping-up the old system with 1.1 kg R407C to return it to the full charge of 8.5 kg (a high annual leakage rate of 13 percent). This represents the leakage for the current accounting year even though most of it would have occurred in the previous year. The service agent records show that 6.8kg (80 percent) of the original charge in the old equipment was collected for destruction (because its quality was too degraded for recycling).18

The service agent records show that used 7.1 kg of R410A was used to fill the new air-conditioning system. The full charge of the system is 7.0 kg of R410A (GWP 1725). Therefore, 0.1 kg of R401A was lost during installation. No top-up was required in the reporting year for the new system. Any leakage of the new system from August to December would not be accounted for until the following year if it is not topped-up until the following January.

Using Method A
E = (IE +S+DE) x GWP19 X CF

Installation Emissions (IE) = refrigerant used to charge new equipment – total full charge of new equipment
= (7.1 – 7.0) x 1725 x 1/1000
= 0.173 tonne CO2-e

Servicing Emissions (S) = quantity of refrigerant used to service old equipment
= 1.1 x 1526 x 1/1000
= 1.68 tonnes CO2-e

Disposal Emissions (DE) = total full charge of retiring equipment – refrigerant recovered from retiring equipment
= (8.5 – 6.8) x 1526 x 1/1000
= 2.59 tonnes CO2-e
E = 0.173 + 1.68 + 2.59
= 4.44 tonnes CO2-e

Mobile air-conditioning (MAC)

Method A is recommended for trucks and buses with the cooperation of service agents. Method B is recommended for cars and vans (and acceptable for trucks and buses) because information on refrigerant amounts should be relatively straightforward for service agents to gather during maintenance. Method C (see Table 1) is acceptable for cars and vans and can be used as a screening test for trucks and buses until a regular fleet monitoring scheme is established. This is the case for the company at this stage.

The company owns one delivery truck and one car that are fitted with MAC units. It uses R134A refrigerant (GWP 1300).

Using Method C:

Operation Emissions (truck) = (1.2 x 10/100 x 1300 x 1/1000) = 0.156
(car) + (0.7 x 10/100 x 1300 x 1/1000) = 0.091
= 0.247 tonnes CO2-e

Refrigerated transport

Method A is recommended due to the high potential for leakage from this sector. Where this is not practical (high turnover of a large number of refrigerated trucks or containers), a Method B approach is acceptable.

The company owns one refrigerated truck. It is a larger, self-powered unit (six litres) and the compliance plates show R404A refrigerant (GWP 3620). Service agents have topped up the refrigerant twice over the year to a total of 1.32 kg. The organisation also accounts for two large, three-phase refrigerated containers it operates that are owned by a contractor – one uses R22 and one R404A. The R22 refrigerated container is not included in the inventory. They are not able to collect service data and therefore use Method B to estimate emissions.

Using Method A for Scope 1:
Operation Emissions
= S x GWP x CF
= 1.32 x 3260 x 1/1000
= 4.78 tonnes CO2-e

Using Method B for Scope 3:
Operation Emissions
= (C x ALR) x GWP x CF
= (5.5 x 25/100) x 3260 x 1/1000)
= 4.48 tonnes CO2-e

Therefore total emissions for the company for refrigeration are:

Scope 1 Tonnes CO2-e

Office refrigeration

0.0133

Large commercial sized refrigerator

1.04

Commercial air-conditioning unit

4.44

Mobile air-conditioning (MAC)

0.247

Refrigerated transport

4.3078

SCOPE 1 TOTAL 10.52

Scope 3

 

Refrigerated transport

4.48

SCOPE 3 TOTAL 4.48

3.2 Scope 2: Electricity indirect emissions

3.2.1 Purchased electricity

An emission factor for the consumption of purchased electricity (by end users) is provided in Table 6. The emission factor is calculated on a calendar-year basis and accounts for the emissions from fuel combustion at thermal power stations which are associated with the consumption of purchased electricity from the grid. It also includes a relatively small proportion of fugitive emissions from geothermal generation.

The emission factor for the consumption of purchased electricity, as well as the emission factor for transmission and distribution line losses (included below, in Table 7), have been aligned with the definitions used in the GHG Protocol.

This emission factor is sourced from the Energy Greenhouse Gas Emissions 1990–2007 publication. This publication provides a historic record of (electricity) emission factors up to the previous calendar year.

The electricity emission factor covers purchased electricity which has been bought from an electricity supplier who sources its electricity from the national grid.20

Table 6: Emission factor for the consumption of purchased electricity – 2007

Emission Source Unit Emission factor Total CO2-e
(kg CO2-e/unit)

Purchased electricity

kWh

0.165

Assumptions

As with the fuels for stationary combustion emission factors, this emission factor does not incorporate emissions associated with the extraction, production and transport of the fuels burnt to produce electricity.

This emission factor does not account for the emissions associated with the electricity lost in transmission and distribution on the way to the end user. Under the reporting framework of The GHG Protocol the emissions associated with transmission and distribution line losses are Scope 3 emissions. Table 7 contains an emission factor for transmission and distribution line losses.

The emission factor in Table 6 is derived from the tCO2-e/MWh generation emission factor (as opposed to the consumption emission factor) in the Energy Greenhouse Gas Emissions
1990–2007
publication. This is explained in more detail in the section below covering the transmission and distribution line losses emission factor.

Notes on the use of electricity emission factors

The emission factor provided in Table 6 is an average over the calendar year for which the emission factor relates and is used for reporting the annual emissions associated with the consumption of purchased electricity.

A grid-average emission factor best reflects the CO2-e emissions associated with the generation of a unit of electricity, purchased from the national grid, in New Zealand.

Retailer-specific electricity factors for grid electricity may be considered in the future. At this stage, however, there is insufficient information to prepare such factors and no clear consensus on the advantages of this approach. In the meantime, use of a grid-average factor does not ignore or refute claims of carbon neutrality or similar by some electricity retailers. Rather, these claims should be accounted for separately. It is suggested users contact the Ministry for further advice on this issue.

This emission factor cannot be used for calculating abatement by intervention or reducing the use of thermal generation, for example for an offset project. A marginal emission factor is more appropriate in these circumstances, because it is designed to take into account the change in electricity generation at the margin. Users wanting more information on marginal electricity emission factors are advised to contact the Electricity Commission. A report on Carbon Abatement Effects of Electricity Demand Reductions is also now available on the Ministry for Economic Development’s website.21

It is also possible that a different emission factor may be used for determining allocation under the New Zealand emissions trading scheme. An allocation factor has yet to be determined at this stage, but it may need to take into account a number of different issues that could produce a different value to that listed in Table 6.

Example calculation

An organisation uses 800,000 kWh of electricity in 2007. Their Scope 2 emissions from electricity are:

Total CO2-e emissions = 800,000 * 0.165 = 132,000 kg CO2-e = 132 tonnes CO2-e

3.3 Scope 3: Other indirect emissions

3.3.1 Transmission and distribution line losses for purchased electricity

The transmission and distribution line losses emission factor accounts for emissions (from the generation) of the electricity lost in the transmission and distribution network due to inefficiencies in the grid. Under The GHG Protocol reporting framework emissions from the generation of electricity that is consumed in a transmission and distribution system should be reported as a Scope 3 emission by end users.

The emission factor for transmission and distribution line losses is the difference between the generation and consumption emission factors reported in Table 4.8 of the Energy Greenhouse Gas Emissions 1990–2007.22

Table 7: Transmission and distribution line losses for purchased electricity – 2007

Emission Source Unit Emission factor Total CO2-e
(kg CO2-e/unit)

Transmission and distribution line losses for purchased electricity

kWh

0.0142

Assumptions

This emission factor covers grid purchased electricity, bought by an end user. It is an average figure and therefore makes no allowance for distance from off-take point, or other factors that may vary between individual consumers.23

This emission factor accounts for emissions from the generation of the electricity lost in the transmission and distribution network, during delivery to end users. It does not incorporate the emissions associated with the extraction, production and transport of the fuels burnt to produce the electricity.

Example calculation

An organisation uses 800,000 kWh of electricity in 2006. Their Scope 3 emissions from transmission and distribution line losses for purchased electricity are:

Total CO2-e emissions = 800,000 * 0.0142 = 11,360 kg CO2-e = 11.4 tonnes CO2-e

3.3.2 Transmission and distribution losses for distributed24 natural gas

24

The transmission and distribution losses emission factor for distributed natural gas accounts for fugitive emissions, from the transmission and distribution system, which occur during the delivery of the gas to the end user.

This emission factor is derived based on information from the Energy Greenhouse Gas Emissions 1990–2007 and New Zealand Energy Data File 2008 publications.

Table 8: Transmission and distribution losses for distributed natural gas – 2007

Emission Source Unit Emission factor Total CO2-e
(kg CO2-e/unit)

Transmission and distribution losses for distributed natural gas

kWh

0.0285

GJ

7.91

Changes in methodology from 2007

The distributed natural gas emission factor for transmission and distribution losses is now based on a weighted average of all gas streams. In 2006, it was based on a weighted average of Maui and Kapuni treated natural gas only.

Assumptions

This figure represents an estimate of the average amount of CO2-e emitted from losses associated with the delivery (transmission and distribution) of a unit of gas per unit of gas consumed through local distribution networks for 2007. It is an average figure and therefore makes no allowance for distance from off-take point, or other factors that may vary between individual consumers.

This figure assumes that all losses are attributable to gas consumed via local distribution networks. A small amount (<1 percent) of emissions is attributable to losses occurring from delivery of gas to consumers who are directly connected to a high-pressure transmission pipeline.25

This emission factor is therefore appropriate for use by customers who receive their gas through a local distribution network, and is not intended for customers who receive gas directly from the transmission system, or directly from a gas producer via high-pressure transmission lines.

This emission factor covers the fugitive emissions which occur during the delivery of the gas to end users. It does not cover the emissions associated with the extraction and production of the gas.

Example calculation

An organisation uses 1,000 gigajoules of distributed natural gas in 2007. Their Scope 3 emissions from transmission and distribution losses are:

Total CO2-e emissions = 1,000* 7.91 = 7,910 kg CO2-e = 7.91 tonnes CO2-e

3.3.3 Taxis and rental cars

Business travel in taxis and rental cars are likely to be a common source of Scope 3 emissions for most businesses. As with Scope 1 emissions from transport, the most accurate way to calculate emissions is based on fuel consumption data. However this information may not be easily available, particularly for business travel in taxis. Table 9 provides emission factors for rental car and taxi travel, based on kilometres travelled, as well as an emission factor for taxi travel based on dollars spent.

Table 9: Emission factors for travel in taxis and rental cars (based on distance travelled) – 2007

Emission Source Unit Emission factor
Total CO2-e
(kg CO2-e/unit)

Rental car – Small (<1600cc)

Km

0.175

Rental car – Medium (1600 – <2500cc)

Km

0.241

Rental car – Large (>= 2500)

Km

0.331

Rental car – Default*

Km

0.241

Taxi travel – Distance travelled

Km

0.331

Taxi travel – Dollars spent (GST inclusive)

$

0.133

* The default emission factor should be used if the vehicle size class of rental cars can not be determined.

Assumptions

The emission factors for taxis and rental cars are the same as those found in Table 3 and so the underlying assumptions are the same.

The default emission factor for rental cars is the same as that for medium vehicles (1600 – <2500 cc) from Table 3. Data from the Motor Industry Association New Vehicle Sales database showed that for the period January 2002–July 2008, 60.0 percent of rental vehicles purchased were in the medium vehicle size class.

The default emission factor for taxis is the same as that for large vehicles (>= 2500 cc) from Table 3. Data from the Motor Industry Association New Vehicle Sales database showed that for the period January 2002–July 2008, 84.2 percent of taxis purchased were in the large vehicle size class.

The dollars spent emission factor is based on a national average figure of $2.50 per kilometre travelled. This figure is sourced from Taxicharge New Zealand and includes GST.

Example calculation

An organisation uses rental cars to travel 12,000 km in 2007. It also spends $18,000 on taxi travel.

Total CO2-e emissions from rental cars = 12,000* 0.241 = 2,892 kg CO2-e = 2.89 tonnes CO2-e

Total CO2-e emissions from taxi travel = $18,000*0.133 = 2,394 kg CO2-e = 2.39 tonnes CO2-e

3.3.4 Air travel

The emission factors provided in Table 10 are intended for use by organisations wishing to report their air travel emissions, based on the distance travelled per passenger. The emission factors provided below are based on emission factors published by the UK Department for Environment Food and Rural Affairs (DEFRA) in the 2008 Guidelines to DEFRA’s GHG Conversion Factors: Methodology Paper for Transport Emission Factors (DEFRA, 2008) These are deemed to be the most suitable emission factors currently available.26 The DEFRA publication discusses the emission factor methodology in more detail.

Table 10: Emission factors for air travel (based on distance travelled) – 2007

Emission Source Unit Emission factor Total CO2-e
(kg CO2-e/unit)

Domestic

pkm

0.1769

Short Haul International (<3700 km)

pkm

0.0992

Long Haul International (>3700 km)

pkm

0.1116

Changes in Methodology from 2006

DEFRA has recently published the 2008 guidelines to DEFRA’s GHG Conversion Factors: Methodology Paper for Transport Emission Factors which can be found at http://www.defra.gov.uk/environment/business/envrp/pdf/passenger-transport.pdf. The changes in methodology and assumptions have altered the emission factors from the 2006 version. These changes are explained in greater detail in the DEFRA guidelines.

In addition to changes in background assumptions and data, the emission factors now also include a 10 percent uplift to correct underestimation of emissions from climbing, cruising and descent. Note that this differs from the nine percent uplift for Great Circle distance (discussed below), which can be applied separately if an organisation decides to account for this in their inventory.

Assumptions

The underlying assumptions stated in the DEFRA publication are made here. Further discussion on the methodology used to derive the air travel emission factors can be found at http://www.defra.gov.uk/environment/business/envrp/pdf/passenger-transport.pdf.

The emission factors contained in Table 10 are based on representative flight distances of: domestic 463 km, short haul 1,108 km, and long haul 6,482 km. The domestic emission factor should be applied to all domestic flights; the short haul emission factor to flights less than 3,700 km; and the long haul emission factor should be applied to any flights greater in length than 3,700 km.

DEFRA endorses a nine percent Great Circle distance uplift factor to take into account non‑direct (ie, not along the straight line between destinations) routes and delays/circling. This figure comes from the IPCC’s Aviation and the Global Atmosphere, Section 8.2.2.3, and is based on studies on penalties to air traffic associated with the European ATS Route Network. This figure is likely to be overstated in New Zealand (initial estimates from Airways New Zealand is that this figure is likely to be less than five percent), however in the absence of a New Zealand-specific figure it is recommended that those wishing to take a conservative approach apply the nine percent uplift factor.

The DEFRA emission factors only take into account CO2 emissions. In line with ISO 14064-1 and The GHG Protocol reporting requirements, the emission factors provided in Table 10 are CO2-e emission factors. They have been scaled-up based on the default CH4 and N2O emission factors (for aviation fuels) sourced from the Energy Greenhouse Gas Emissions 1990–2007 publication. The percentage mark up (used to convert to CO2-e) is 0.9194 percent. The mark up assumes that all fuel burnt is jet fuel.

The emission factors provided above do not include radiative forcing (ie, non-CO2 climate change impacts). The total climate impacts of aviation due to radiative forcing have been estimated by the IPCC to be up to two to four times those of CO2 alone. However, the science in this area is currently uncertain and a multiplier is not used for New Zealand’s national greenhouse gas inventory reporting. As the emission factors contained in this guide are intended to be consistent with New Zealand’s national greenhouse gas inventory reporting, it is not currently deemed appropriate to apply a multiplier to account for radiative forcing.

Example calculation

An organisation makes a number of flights from Auckland to Sydney (2,171 km each way). The total distance travelled was 217,100 km.

Total CO2-e emissions from air travel = 217,000* 0.0983 = 21,331 kg CO2-e = 21.3 tonnes CO2‑e

3.3.5 Waste to landfill

The emission factors and methodologies provided below will help organisations in estimating their emissions from waste disposed of at a landfill. Emission factors are based on figures from New Zealand’s Greenhouse Gas Inventory 1990–2006 and methodologies are derived from IPCC good practice guidance. The (base equation) methodology provided below is termed “tier 1” under the IPCC 1996 guidelines and assumes all the potential emissions in a tonne of waste are released in the year of disposal.

Methodologies to determine emissions from wastewater treatment and solid waste incineration are not covered by this guide, as emissions are assumed to be negligible at the individual organisation level (with some exceptions for large industrial wastewater producers).

The anaerobic decomposition of organic waste in landfills generates methane (CH4). Inventories should be adjusted to account for the landfill gas that is collected and destroyed.27 The methodologies outlined below provide for such adjustment depending on whether an organisation’s waste is sent to a landfill with (or without) a landfill gas collection system.

Methodologies

Two methodologies for determining a solid waste emission factor are provided. Choice of methodology depends on organisational knowledge of waste composition. It is preferable to know the composition of waste as it allows emissions to be more accurately quantified.28

Base equation

The base equation used in deriving the waste emission factors, as taken from the 1996 IPCC Good Practice Guidelinesx, is as follows:

CO2-e emissions (kg) =

((MSWT x DOC x DOCF x F x 16/12) x (1– R) x (1-OX)) x 21

Where:

MSWT = total Municipal Solid Waste (MSW) generated (kg)

DOC = degradable organic carbon

DOCF = fraction of DOC dissimilated

F = fraction of CH4 in landfill gas

R = fraction recovered CH4

OX = oxidation factor

21 = GWP of methane (CH4)

Interpretation

Table 11 provides methodologies for four scenarios where composition of an organisation’s waste is or is not known, and is sent to a landfill that has or does not have a landfill gas collection system.

If the organisation has data on individual waste streams, but doesn’t know if the waste is going to a landfill with a gas collection system, then the default should be the factors for “without landfill gas recovery” ie, overestimate rather than potential to underestimate.

If the organisation does not know the composition of its waste but knows it is going to a landfill with a gas recovery system, then it should use the default “mixed waste” emission factor found in Table 11 unless it is an office-based organisation. Note that this will be an inaccurate emission factor at the organisation level, as it assumes the organisation’s waste matches the national average mixed municipal waste composition. If an organisation has an advanced diversion system (to recycling and composting) then this methodology will overestimate emissions. If an organisation has no diversion system, then it could underestimate emissions.

Default emission factors for “office waste” are provided in Table 11. These should be used by office-based organisations that do not have information on the composition of their waste. The higher emission factors reflect the higher proportion of organic matter (ie, paper and food) found in office waste. The default office waste emission factors assume no diversion has occurred so if an organisation has an advanced diversion system then this methodology will overestimate emissions.

Table 11: Emission factors for waste to landfill – 2007

Emission source Data input unit Kgs CO2e/unit Equation
Landfilled waste of known composition (without landfill gas recovery)

Paper and textiles

kg

2.520

(0.4 * 0.5 * 0.5 * 16/12) * (1-0.1) * 21

Garden and food

kg

0.945

(0.15 * 0.5 * 0.5 * 16/12) * (1-0.1) * 21

Wood

kg

1.890

(0.3 * 0.5 * 0.5 * 16/12) * (1-0.1) * 21

Landfilled waste of known composition (with landfill gas recovery)

Paper and textiles

kg

1.49

(0.4 * 0.5 * 0.5 * 16/12) * (1-0.40829) * (1-0.1) * 21

Garden and food

kg

0.559

(0.15 * 0.5 * 0.5 * 16/12) * (1-0.408) * (1-0.1) * 21

Wood

kg

1.11

(0.3 * 0.5 * 0.5 * 16/12) * (1-0.408) * 0.9 * 21

Landfilled waste – default values (without landfill gas recovery)

Mixed waste (national average)

kg

0.947

0.050130 * (1-0.1) * 21

Office waste

kg

1.55

((0.53631 * 0.4) + (0.20833 * 0.15) + (033 * 0.3)) * 0.5 * 0.5 * 16/12) * (1-0.1) * 21

Landfilled waste – default values (with landfill gas recovery)

Mixed waste (national average)

kg

0.560

0.0501 * (1-0.408) * (1-0.1) * 21

Office waste

kg

0.915

((0.53633 * 0.4) + (0.20833 * 0.15) + (033 * 0.3)) * 0.5 * 0.5 * 16/12) * (1-0.408) * (1-0.1) * 21

Assumptions

The emission factors provided in Table 11are based on 2006 data, however we recommend that they are used for the 2007 reporting period, as this is the most current data available.

Changes in methodology from 2006

The amount of greenhouse gas (methane) recovered from landfills is projected to increase more than gross emissions each year. Therefore, the emission factors for landfill waste with landfill gas recovery have decreased slightly.

Example calculation

An organisation disposes of 30 tonnes of garden waste to a landfill with a gas recovery system in 2007.

Total CO2-e emissions from waste to landfill = 30,000* 0.559 = 16,770 kg CO2-e = 16.77 tonnes CO2-e


9  Approximately 92 percent of the coal used by the commercial sector is sub-bituminous coal.

10  They have been calculated by multiplying the average Euro emissions dyno test cycle fuel consumption rate, for each vehicle size class, by a ‘real world’ scale-up factor of 1.207. The figures are based on consumption rates for new vehicles sold in New Zealand since 2005.

11  For purpose of comparison in 2007, approximately 15.2 percent of the light vehicle fleet was made up of diesel vehicles.

12  In 2007, 54.9 percent of light petrol vehicles sold in New Zealand were in the medium vehicle size class, 25.6 percent were small and 19.5 percent were large.

13  Whilst HCFCs have no GWP; they are an ozone-depleting substance and being phased out through the Montreal Protocol on Substances That Deplete the Ozone Layer.

14  ‘Total full charge’ refers to the full, original charge of the equipment rather than to the actual charge, which may reflect leakage.

15  In the absence of consistent information for New Zealand, the default assumption for the assembly (installation) emissions rate is the rounded-off IPCC 2006 mid-range value. It is not applicable (relevant) for many pre-charged units.

16  Internal dimensions up to 100 x 50 x 30cm for 150 litres, 150 x 50 x 40cm for 300 litres, 200 x 50 x 50cm for 500 litres.

17  For consistency until 2012, GWPs are set according to IPCC (1996) Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories, Intergovernmental Panel on Climate Change, www.ipcc.ch

18  This example is unlikely to happen for a few years until the relatively recent R407C and R410A equipment are being retired. R22 is more likely to be the retired refrigerant currently and this is omitted from the accounting because it is not a HFC.

19  As GWPs are different for the air-conditioning units they are calculated separately here.

20  It does not cover on-site, self-generation of electricity.

21  Carbon Abatement Effects of Electricity Demand Reductions.http://www.med.govt.nz/templates/MultipageDocumentTOC____33805.aspx

22  The electricity figures reported in the Energy Greenhouse Gas Emissions 1990–2007 are rounded figures. Calculations to derive the figure reported in Table 7 are sourced from unrounded figures available from the Ministry of Economic Development.

23  Major electricity users need to be aware that a losses allowance may already be included in their electricity invoices.

24  “Distributed” refers to natural gas distributed via low pressure, local distribution networks.

24  “Distributed” refers to natural gas distributed via low pressure, local distribution networks.

25  See p 16 of the Energy Greenhouse Gas Emissions 1990–2007 publication for more detail.

26  The Greenhouse Gas Protocol Initiative provides air travel emission factors which are in the process of being updated. The suitability of the air travel emission factors contained in this guide will be reviewed once these become available.

27  Where CH4 is recovered and flared or combusted for energy, the CO2 emitted from the combustion process is regarded as part of the natural carbon cycle.

28  It also allows you to take into account reductions in emission from altering the composition of your waste (as opposed to just reducing your waste). For example, reducing the amount of paper going to landfill will result in a significantly lower emission factor for waste.

29  This figure can be found by dividing the recovered methane per year by gross emissions as found in the supplementary CD of the New Zealand’s Greenhouse Gas Inventory 1990–2006.

30  This figure is published within the national greenhouse gas inventory supplementary table 6.1A as the methane generation potential of a Gg of solid waste.

31  These figures represent an assumed default composition (paper (53.6 percent), garden and food (20.8 percent) and wood (0 percent)) for office waste, based on waste data from government buildings.