Consultative Group of Experts (CGE) CGE Training Materials National Greenhouse Gas Inventories Key...

Consultative Group of Experts (CGE)

CGE Training MaterialsNational Greenhouse Gas Inventories

Key Category Analysis

Version 2, April 2012

Training Materials for National Greenhouse Gas Inventories

Target Audience and Objective of the Training Materials

These training materials are suitable for people with beginner to intermediate level

knowledge of national greenhouse gas (GHG) inventory development.

After having read this presentation, in combination with the related documentation, the

reader should:

Have an overview of how key category analyses are conducted

Have a general understanding of the methods available, as well as of the main

challenges in that particular area

Be able to determine which methods suits their country’s situation best

Know where to find more detailed information on the topic discussed.

These training materials have been developed primarily on the basis of

methodologies developed, by the IPCC; hence the reader is always encouraged to

refer to the original documents to obtain further detailed information on a particular

issue.

2



Acronyms and Abbreviations

AD Activity Data

GHG Greenhouse Gas

GPG Good Practice Guidance

GWP Global Warming Potential

KCA Key Category Analysis

LULUCF Land Use, Land-Use Change and Forestry

QA/QC Quality Assurance/Quality Control

3



Definition

A key category is one that is prioritised within the national inventory system because its

estimate has a significant influence on a country’s total inventory of GHG, in terms of the:

Absolute level

The trend, or

The uncertainty in emissions and removals.

Also, national circumstances may point at additional key categories (relevant even if they

do not fully meet the requisites above) based on a qualitative analysis.

4



Rationale

It is good practice to:

Identify national key categories in a systematic and objective manner, i.e. to

undertake key category analysis

Use the results of the key category analysis as a basis for methodological and

resource allocation choices.

5

Improved inventory quality, as well as greater confidence in the estimates that are developed.



Key Category Analysis

Non-Annex I Parties are encouraged to fulfil this good practice only if they:

Have the AD needed to apply the higher level methodology and

Can collect relevant data without jeopardizing the financial resources required for the

whole inventory process.

If not, the level of detail must be reduced until a balance with the available AD is reached:

Tier 3 > Tier 2 > Tier 1

Keep in mind that KCA is a tool that helps you prioritize limited resources by:

Focusing on the most important sources/sinks of emissions in the country

Determining the most appropriate methodological approach (more detailed, higher-

tier methods should be selected for key categories).

6



General Guidance

The current guidelines for national communications (NCs) from non-Annex I Parties

encourage the use of the GPG-2000 and the GPG-LULUCF for KCA analysis.

GHG inventory compilers are required to perform KCA twice:

The key (source) categories should first be identified excluding LULUCF (i.e., key

categories should be identified for the energy, industrial processes, solvent and other

product use, agriculture, and waste sectors) following the guidance in GPG2000,

Chapter 7 (Methodological Choice and Recalculation).

The key category analysis should then be repeated for the full inventory including the

LULUCF categories.

7



Caution!

It is possible that some non-LULUCF categories identified as key in the first analysis will

not appear as key when the LULUCF categories are included:

These categories should still be considered as key.

In a few cases, in countries with small net LULUCF emissions or removals, the integrated

analysis may identify additional non-LULUCF categories as key:

The analysis performed for the non- LULUCF sectors should be used to identify the

key categories in those sectors, and the additional non- LULUCF categories

identified in the combined analysis should not be considered as key.


Training Materials for National Greenhouse Gas Inventories 8

Identifying Key Categories

Any inventory agency that has prepared a national GHG inventory will be able to identify

key categories in terms of their contribution to the absolute level of national emissions.

For those inventory agencies that have prepared a time series, the quantitative

determination of key categories should include evaluation of both the absolute level and

the trend of emissions and removals.

Some key categories may only be identified when their influence on the trend of the

national inventory is taken into account.

9Consultative Group of Experts (CGE)


10

Quality of estimates:

Box 3 > Box 2 > Box 1

KCA is done for the inventory as a whole

Box 1

Box 3

Box 2



Decision tree to choose a method in a way that is consistent with good practice

Identifying Key Categories

Good practice in determining the appropriate level of disaggregation of categories:

Use subcategory disaggregation suggested by IPCC (see sector guidance)

Consider separately each GHG for each category (default choice unless otherwise

appropriate)

If data are available, undertake a separate analysis for emissions and removals.

11

Table 5.4.1 of the GPG-LULUCF provides information on the recommended level of aggregation for all sectors.



Identifying Key Categories (continued)

12



Determination of Significant Subcategories

For each key category, determine whether certain subcategories are particularly

significant:

A subcategory is significant when it has a high contribution to the key category

emissions

If information on subcategories is available, those potentially significant ones could

be included in the key category analysis at the level of categories.

It is good practice to estimate emissions from significant subcategories applying the

most detailed and specific methodology alllowed by the available activity data.

Non-significant subcategories can be treated with Tier 1 methods.

13



Approaches

Quantitative approaches to determining key categories:

Basic Tier 1 approach (level and trend) and

Tier 2 approach (level and trend), which takes uncertainties into account.

In addition to making a quantitative determination of key categories, it is good practice to

consider qualitative criteria, particularly when a Tier 1 assessment is performed or lower

tier estimation methods are used.

The good practice guidance provided in the two GPGs is applicable to the full inventory of

emissions and removals.


Training Materials for National Greenhouse Gas Inventories 14

Start Here!

If it is the first time, prepare a preliminary inventory for the year of interest applying Tier 1

methods for all categories.

If you already have a GHG inventory, then use the available GHG data for the most

recent year.

List source and sink categories separately.

Express emissions in carbon dioxide equivalent (CO2 eq) (using the IPCC GWP values).

15



Quantitative Approach Tier 1: Level Assessment

16

Based on assessing the influence of various categories of sources and sinks on the level,

of the national GHG inventory:

Key categories are those that, when summed together in descending order of magnitude, add up to 95 % of the sum of all Lx,t.



Estimate GHG Emissions and Removals

LULUCFLULUCF

17



Step 1: Only consider emissions

18



Step 2: Order activities in descending order

19



Step 3: Sum up all emissions

20



Step 4: Find percentage contribution

21



Step 5: Add up to 95% of total emissions

95%95%

22



But, this is only half of the work!

LULUCFLULUCF

23



Step 6: Convert removals into “emissions”

LULUCFLULUCF

24



Step 7: Sum up all “emissions”

25



Step 8: Order all activities in descending order

26



Step 9: Find percentage contribution of all activities

27



Step 10: Add up to 95% of “total emissions”

95%95%

28



Key Categories

KCA (only emissions): Activity 4

Activity 1

Activity 3

Activity 2

Activity 5

Activity 6

KCA (emissions and removals) Activity 9

Activity 4

Activity 1

Activity 3

Activity 2

Activity 5

Activity 6

Activity 10

29



Example from the GPG-LULUCF

30



Quantitative approach Tier 1: Trend Assessment

31

Categories that may not be large enough to be identified by the level assessment,

but whose trend is significantly different from the trend of the overall inventory.

Categories whose trend diverges most from the total trend should be identified as key, when this difference is weighted by the level of emissions or removals of the category in

the base year.




32

Example 2: Calculate the % contribution to the trend for the variable below

Refrigeration and air conditioning




33

Example 2: Step 1

Calculate (Ex,t - Ex.0)/ │Ex,0│ (5-10)/ │10│ = - 0.5





34

Example 2: Step 2

Calculate

(Total inventory t - Total inventory 0) / │ Total inventory 0 │ (76-95) / │95│ = - 0.2





35

Example 2: Step 3

Calculate the trend assessment for refrigeration and AC

(0.09) * │- 0.5 - (-0.2)│ = 0.0261





36

Example 2: Step 4


Calculate the contribution to the trend from refrigeration and AC 0.0261 / 0.122 = 21.4%




Example 2: Steps 5, 6 and 7

37

Variable Value

Emissions from refrigeration and AC in year 0 (Gg CO2eq) 10

Total inventory emissions in year 0 (Gg CO2eq) 95

|Emissions from refrigeration and AC | / Sum |individual emissions| 9%

Emissions from refrigeration and AC in year t (Gg CO2eq) 5

Total inventory emissions in year t (Gg CO2eq) 76

Trend assessment total 0.122

(Ex,t – Ex,0)/|Ex,0| -0.5

(Total inventory t – Total inventory 0) / Total inventory 0 -0.2

Trend assessment for refrigeration and AC 0.0261

% contribution to the overall trend 21.4%


Repeat for all sources and sinks and then …

5. Rank sources according to their contribution to the trend

6. Calculate cumulative contribution

7. Identify sources contributing to 95% of the trend (Key Categories)



Quantitative approach Tier 2: Level Assessment with uncertainties

38

Key categories are based on uncertainty analysis, level assessment

Results should be sorted according to decreasing order of magnitude.

Key Categories are those that add up to 90 % of the sum of all LUx,t.

They should be added to the KC identified with Tier 1 and can inform inventory improvements.



Quantitative approach Tier 2: Trend Assessment with uncertainties

39

Key categories are based on uncertainty analysis, trend assessment

Results should be sorted according to decreasing order of magnitude.

Key Categories are those that add up to 90 % of the sum of all TUx,t.

They should be added to the KC identified with Tier 1 and can inform inventory improvements.




Example 3: Identify Key Categories based on Tier 2 (including uncertainty) level

assessment

40

IPCC category GHG Emissions (Gg CO2eq)

/Ext/ (Gg CO2eq)

Lxt

Energy industries: gas CO2 25 25 25%

Manufacturing industries and construction: solid CO2 20 20 20%

Road transport CO2 15 15 15%

Solid waste disposal CH4 15 15 15%

Forest land remaining forest land CO2 -10 10 10%

Direct N2O emissions from managed soils N2O 10 10 10%

Refrigeration and air conditioning HFCs, PFCs 5 5 5%




Example 3: Step 1

41

Add uncertainty data


/Ext/ (Gg

CO2eq)

Lxt Ux

Energy industries: gas CO2 25 25 25% 10%Manufacturing industries and construction: solid CO2 20 20 20% 15%Road transport CO2 15 15 15% 10%Solid waste disposal CH4 15 15 15% 25%Forest land remaining forest land CO2 -10 10 10% 40%Direct N2O emissions from managed soils N2O 10 10 10% 50%

Refrigeration and air conditioningHFCs, PFCs 5 5 5% 45%




/Ext/ (Gg CO2eq)

Lxt Ux Lxt * Ux

Energy industries: gas CO2 25 25 25% 10% 2.5%Manufacturing industries and construction: solid CO2 20 20 20% 15% 3.0%

Road transport CO2 15 15 15% 10% 1.5%

Solid waste disposal CH4 15 15 15% 25% 3.8%

Forest land remaining forest land CO2 -10 10 10% 40% 4.0%

Direct N2O emissions from managed soils N2O 10 10 10% 50% 5.0%

Refrigeration and air conditioning HFCs, PFCs 5 5 5% 45% 2.3%


Example 3: Step 2

42

Multiply % uncertainty by the % contribution




/Ext/ (Gg CO2eq)

Lxt Ux Lxt * Ux

Energy industries: gas CO2 25 25 25% 10% 2.5%Manufacturing industries and construction: solid CO2 20 20 20% 15% 3.0%Road transport CO2 15 15 15% 10% 1.5%Solid waste disposal CH4 15 15 15% 25% 3.8%Forest land remaining forest land CO2 -10 10 10% 40% 4.0%Direct N2O emissions from managed soils N2O 10 10 10% 50% 5.0%

Refrigeration and air conditioning HFCs, PFCs 5 5 5% 45% 2.3%Total 80 100 22%


Example 3: Step 3

43

Calculate Total




Example 3: Step 4

44

IPCC category GHG Emissions (Gg

CO2eq)

/Ext/ (Gg

CO2eq)

Lxt Ux Lxt * Ux

% of total

Energy industries: gas CO2 25 25 25% 10% 2.5% 11.4%Manufacturing industries and construction: solid CO2 20 20 20% 15% 3.0% 13.6%Road transport CO2 15 15 15% 10% 1.5% 6.8%Solid waste disposal CH4 15 15 15% 25% 3.8% 17.0%Forest land remaining forest land CO2 -10 10 10% 40% 4.0% 18.2%Direct N2O emissions from managed soils N2O 10 10 10% 50% 5.0% 22.7%

Refrigeration and air conditioningHFCs, PFCs 5 5 5% 45% 2.3% 10.2%

Total 80 100 22%

Calculate % of Total

e.g. 0.025/0.22 = 11.4%Consultative Group of Experts (CGE)



Example 3: Step 5

45


CO2eq)

/Ext/ (Gg

CO2eq)

Lxt Ux Lxt * Ux

% of total

Direct N2O emissions from managed soils N2O 10 10 10% 50% 5.0% 22.7%Forest land remaining forest land CO2 -10 10 10% 40% 4.0% 18.2%Solid waste disposal CH4 15 15 15% 25% 3.8% 17.0%Manufacturing industries and construction: solid CO2 20 20 20% 15% 3.0% 13.6%Energy industries: gas CO2 25 25 25% 10% 2.5% 11.4%

Refrigeration and air conditioningHFCs, PFCs 5 5 5% 45% 2.3% 10.2%

Road transport CO2 15 15 15% 10% 1.5% 6.8%Total 80 100 22%

Rank

high

Low




Example 3: Step 6

46


CO2eq)

/Ext/ (Gg

CO2eq)

Lxt Ux Lxt * Ux % of total cumulative % of total

Direct N2O emissions from managed soils N2O 10 10 10% 50% 5.0% 22.7% 22.7%Forest land remaining forest land CO2 -10 10 10% 40% 4.0% 18.2% 40.9%Solid waste disposal CH4 15 15 15% 25% 3.8% 17.0% 58.0%Manufacturing industries and construction: solid CO2 20 20 20% 15% 3.0% 13.6% 71.6%Energy industries: gas CO2 25 25 25% 10% 2.5% 11.4% 83.0%

Refrigeration and air conditioningHFCs, PFCs 5 5 5% 45% 2.3% 10.2% 93.2%

Road transport CO2 15 15 15% 10% 1.5% 6.8% 100.0%

Calculate cumulative and identify 90% contribution



Qualitative Criteria

Mitigation techniques and technologies: If emissions from a category are being

reduced or removals increased through the use of climate change mitigation techniques,

it is good practice to identify these categories as key.

High expected growth of emissions or removals: If the inventory agency expects

emissions or removals from a category to grow significantly in the future, they are

encouraged to identify that category as key. Some of these categories will be identified

by the Trend Assessment or will be identified in the future. Because it is important to

implement a higher tier good practice method as soon as possible, however, early

identification using qualitative criteria is important.

High uncertainty: If the inventory agency is not taking uncertainty explicitly into account

by using the Tier 2 method to identify key categories, they may want to identify the most

uncertain categories as key. This is because the largest reductions in overall inventory

uncertainty can be achieved by improving estimates of highly uncertain categories.




Unexpectedly high or low emissions or removals: When emissions or removals are

far higher or lower than would be expected using the methods in the IPCC Guidelines,

these categories should be designated as key. Particular attention to QA/QC.

Large stocks: When a small net flux results from the subtraction of large emissions and

removals, the uncertainty can be very high. Thus, when moving from the Tier 1 to higher

tier estimation methods the order of IPCC Source Categories may change and previously

insignificant categories may become significant.

Deforestation: In the quantitative key category analysis, deforestation is spread out

under the different land- use change categories (e.g., Lands converted to grassland are

considered separately from Lands converted to cropland). To ensure consistency with the

IPCC Guidelines, countries should identify and sum up the emission estimates

associated with forest conversion to any other land category. “Deforestation” should be

considered key if the sum is larger than the smallest category considered key in the

quantitative analysis.




Completeness: Neither the Tier 1 nor the Tier 2 approach gives correct results if the

inventory is not complete. The analysis can still be performed, but there may be key

categories among those not estimated. In these cases it is good practice to qualitatively

examine potential key categories applying the qualitative considerations above. The

inventory of a country with similar national circumstances can also often give good

indications on potential key categories.



Reporting and Documentation

It is good practice to:

Clearly document the results of the KCA in the inventory report

List the criteria by which each category was identified as key

e.g. Level, trend or qualitative

Indicate the method used to undertake quantitative KCA

Tier1 and/or Tier 2

Report results using the IPCC tables

50Consultative Group of Experts (CGE)


Reporting Tables



Key Category Analysis – Summary/Checklist

If first time, prepare a preliminary inventory for the year of interest applying Tier 1 methods for all

categories

If you already have a GHG inventory, the use the GHG data for the most recent year

List source and sink categories separately

Express emissions in CO2 eq (using the IPCC GWP values)

Sort categories according a decreasing order or magnitude of emissions/captures

Calculate the relative contribution of each category to the total emissions/captures

Calculate the cumulative relative contribuition of categories and draw a threshold level at the point

when 95% of national emissions/capture is reached

Key categories are those that integrate the group of categories that accumulate the upper 95% of

national GHG emissions

52



Thank you

53



CASE STUDY: CHILE

54



Example

2000 GHG inventory of Chile (Gg CO2-equivalent)

Sector/subsectorCO2 Emissions

(Gg/year)CO2 Removal

(Gg/year)CH4

(Gg eq/year)

N2O (Gg eq/year)

Total

Total National 53.623,5 -29.819,20 11.755,8 7.812,0 43.372,11. Energy 48.730,0 0 2.190,3 341,0 51.261,31.A. Fuel Combustion 48.730,0 840,0 341,0 49.911,01.A.1. Energy Industries 15.842,8 6,3 62,0 15.911,11.A.2. Manufacturing, construction and mining

12.142,6 14,7 31,0 12.188,3

1.A.3. Transport 16.013,3 56,7 62,0 16.132,01.A.4. Commercial, Institucional, Residential

4.146,7 18,9 0,0 4.165,6

1.A.5. Fishing 584,7 4,2 0,0 588,91.A.6 Wood and biomass (no-CO2) 741,3 217,0 958,31.B. Fugitive emissions from fuel 1.350,3 0,0 1.350,31.B.1. Solids fuels 71,4 0,0 71,41.B.2. Oil and natural gas 1.278,9 0,0 1.278,92. Industrial processes 4.153,6 0 123,9 155,0 4.432,52.A. Mineral products 2.336,8 0,0 0,0 2.336,82.B. Chemical industry 0 123,9 155,0 278,92.C. Metal production 1.816,8 0,0 0,0 1.816,82.D. Other (Pulp & Paper, Food & Drinks)

NA NA NA NA

2.E. SF6 and PFC production 2.F. SF6 and PFC consumption 2.G. Other (specify) NE NE NE NE3. Solvent use and other product NE 0,0 NE NE

55



Example

2000 GHG inventory of Chile (Gg CO2-equivalent) cont.4. Agriculture 6.207,6 6.882,0 13.089,64.A. Enteric Fermentation 4.796,4 0,0 4.796,44.B. Manure management 1.241,1 310,0 1.551,14.C. Rice cultivation 115,5 0,0 115,54.D. Agricultural soils 0,0 6.572,0 6.572,0

4.E. Prescribed burning of savannas NO NO NO

4.F. Agricultural residue burning 54,6 31,0 85,6

4.G. Other (specify) NE NE NE5. LULUCF 703,1 -29.819,2 1.331,4 341,0 -27.443,75.B. Changes in forest and other woody biomass stocks.

613,5 0 0,0 0,0 613,5

5.B. Forest and grassland conversion 0 -1.033,6 12,6 0,0 -1.021,0

5.C. Abandonment of managed lands 0 0,0 0,0 0,0

5.D. CO2 Emissions and removals from soils 86,3 -28.785,5 0,0 0,0 -28.699,2

5.E. Other (specify) NE NE NE NE NE6. Waste 36,9 1.902,6 93,0 2.032,5

6.A. Solid waste disposal on land 1.797,6 0,0 1.797,6

6.B. Wastewater treatment 105,0 0,0 105,06.C. Waste incineration 36,9 0,0 0,0 36,9

6.D. Other (N2O indirects emissions) NA 93,0 93,0

7. Other (specify) NE NE NE NE NE

Memo items

International bunkers 3.059,8 2,1 0,0 3.061,9Aviation 1.045,1 2,1 0,0 1.047,2Marine 2.014,7 0,0 0,0 2.014,7CO2 Emissions from biomass 16.721,5 0,0 0,0 16.721,5

56



Up-down Ranking of Categories

Gas Key categories Sector Emissions (without

LULUCF) Gg/year

CO2 eq

% Cumulative

(without LULUCF)

Emissions (with LULUCF)

Gg/year CO2 eq

% Cumulative

(with LULUCF)

CO2 Forest land remaining forest land

LULUCF 28.784,2 28,0%

CO2 Stationary combustion (Solids) Energy 15.842,8 22,4% 43,4%

CO2Mobile combustion: road transportation

Energy 15.002,3 43,7% 58,0%

CO2Manufacturing, construction and mining

Energy 12.142,6 60,8% 69,8%

N2O

Agricultural soils (direct and indirect)

Agriculture 6.562,5 70,1% 76,2%

CH4

Enteric fermentation Agriculture 4.796,0 76,9% 80,8%

CO2 Other sectors: residential Energy 3.508,8 81,9% 84,3%

CO2 Iron and steel industryIndustrial Processes

1.816,8 84,5% 86,0%

CH4

Solid waste disposal sites Residues 1.796,8 87,0% 87,8%

CO2 Cement productionIndustrial Processes

1.638,4 89,4% 89,4%

CH4

Fugitive emissions from oil and natural gas operations

Energy 1.277,9 91,2% 90,7%

CH4 Manure management Agriculture 1.241,1 93,0% 91,9%

CH4Forest land remaining forest land

LULUCF 93,0% 1.233,1 94,1%

CO2 Land converted to forest land LULUCF 93,0% 1.026,2 94,1%CH4 Other (energy) Energy 741,0 94,0% 94,8%CO2 Mobile Combustion: aviation Energy 663,0 94,9% 95,4%

CO2 Lime productionIndustrial Processes

653,3 95,9%

57



Significant Subcategories Determination MODULE AGRICULTURE

SUBMODULE METHANE AND NITROUS OXIDE EMISSIONS FROM DOMESTIC LIVESTOCK

ENTERIC FERMENTATION AND MANURE MANAGEMENT

WORKSHEET 4-1

SHEET 1 OF 2 METHANE EMISSIONS FROM DOMESTIC LIVESTOCK ENTERIC

FERMENTATION AND MANURE MANAGEMENT

STEP 1 STEP 2 STEP 3

A B C D E F

Livestock Type Number of

Animals

Emissions Factor for Enteric

Fermentation

Emissions from

Enteric Fermentation

Emissions

Factor for

Manure

Management

Emissions from

Manure Management

Total Annual Emissions

from

Domestic

Livestock

(1000s) (kg/head/yr) (t/yr) (kg/head/yr) (t/yr) (Gg)

C = (A x B) E = (A x D) F =(C + E)/1000

Dairy Cattle 550 81 44.550 19 10.450 55,00

Non-dairy Cattle 2750 49 134.750 13 35.750 170,50

Buffalo 0 55 0 7 0 0,00

Sheep 2500 5 12.500 0,16 400 12,90

Goats 500 5 2.500 0,17 85 2,59

Camels 125 46 5.750 1,9 237,5 5,99

Horses 75 18 1.350 1,6 120 1,47

Mules & Asses 25 10 250 0,9 22,5 0,27

Swine 5030 1 5.030 7 35.210 40,24

Poultry 15000 NE NE 0,018 270 NE

Totals 206.680 82.545 288,96

22%22%

65% SIGN.65% SIGN.

<3%<3%

6%6%

13%13%

43% SIGN.43% SIGN.

<1%<1%

43% SIGN.43% SIGN.

<1%<1%

<1%<1%

<1%<1%

<1%<1%

<3%<3%

<3%<3%

<3%<3%

<3%<3%

<1%<1%

58

Useful Supporting Material

IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse

Gas Inventories

http://www.ipcc-nggip.iges.or.jp/public/gp/english/

US-EPA – Template Workbook for Developing a National GHG Inventory System

http://epa.gov/climatechange/emissions/ghginventorycapacitybuilding/templates.html

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