10 - Energy - Fuel Combustion

7/29/2019 10 - Energy - Fuel Combustion

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1A.1

CGEGreenhouse Gas Inventory

Hands-on Training Workshop

Energy Sector



1A.2

Outline – Fuel Combustion

Fuel combustion

References (slide ?)

Basic emission processes (slide ?)

Methodologies (slide ?)

Relationships with other sources and sectors (slide ?)

Uncertainty (slide ?)

Quality control and completeness (slide ?)



1A.3

Outline – Fugitive Emissions

Fugitives

Introduction

Coal mining and handling

Oil and natural gas systems

Data issues

References



1A.4

Survey says…?

Audience poll…

Who has prepared a national inventory for your

country?

Who has worked on the Energy Sector?

Please share…

Problems you have faced in preparing estimates for the

Energy Sector Your plans for the future to improve your inventory



1A.5

Reference materials

UNFCCC (COP decisions, reporting guidelines,

etc.)

IPCC

Revised 1996 IPCC Guidelines

IPCC Good Practice Guidance

IPCC Emission Factor Database (EFDB)

IPCC Working Group I Assessment Reports

Use “old” Second Assessment Report (SAR)

Global Warming Potential (GWP) values for reporting

International Energy Agency

http://unfccc.int/

http://www.ipcc-nggip.iges.or.jp/public/gl/invs1.htm

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

http://www.ipcc-nggip.iges.or.jp/EFDB/main.php

http://www.iea.org/

http://www.iea.org/

http://www.ipcc-nggip.iges.or.jp/EFDB/main.php

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

http://www.ipcc-nggip.iges.or.jp/public/gl/invs1.htm

http://unfccc.int/



1A.6

IPCC guidance

Fundamental methods laid out in 1996 Revised

Guidelines

IPCC good practice guidance clarifies some issues

(e.g. international bunker fuels) and provides someupdated factors…

…but no major changes made for fuel combustion!

2006 IPCC Guidelines provide new information onNon-Energy Use, new Tier 2 method for oil systems

fugitives, guidance on abandoned coal mines


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Key Category Analysis

Level assessment based on share of total nationalemissions for each source category

Trend assessment based on contribution of category to changes in emission trends

Qualitative criteria



Key Category Analysis

Idea of key sources based on a measure of

which sources contribute to uncertainty in

inventory

Most if not all source categories in theEnergy Sector will be Key Source Categories

Analysis only as good as original emissions

data

You probably already know your keycategories



Energy Sector –

Fuel CombustionEmissions



1A.10

Stationary sources

Energy Industries

Extraction, production and transformation

Electricity generation, petroleum refining

Autoproduction of electricity

Manufacturing Industries and Construction Iron and steel production

Non-ferrous metal production

Chemical manufacturing

Pulp, paper and print

Food processing, beverages and tobacco

Commercial/Institutional

Residential

Agriculture/Forestry/Fisheries





1A.12

Autoproducers

Note: p. 1.32 of the IPCC Guidelines, Reference Manual - Volume 3



1A.13

Mobile sources

Civil Aviation

Road Transportation

Cars

Light duty trucks

Heavy duty trucks and buses

Motorcycles

Railways

Navigation

International Bunker Fuels are reported separately



1A.14

Carbon dioxide (CO2)emissions

Methodology is mass-balance-based

Oxidation of the carbon in fuels during

combustion

In perfect combustion conditions, totalcarbon content of fuels would be converted

to CO2

Real combustion processes result in small

amounts of partially oxidized andunoxidized carbon



1A.15

Carbon flow for a typicalcombustion process

Most carbon is emitted as CO2 immediately

Small fraction emitted as non-CO2 gases

CH4, CO, non-methane volatile organic compounds

(NMVOCs) Ultimately oxidizes to CO2 in the atmosphere

Integrated into overall calculation of CO2 emissions

Each carbon atom has two atmospheric lifetimes

Remaining part of the fuel carbon is unburnt Assumed to remain as solid (ash and soot)

Account by using oxidation factors



1A.16

Non-CO2 emissions

Direct greenhouse gases

Methane (CH4)

Nitrous oxide (N2O)

Precursors and SO2

Nitrogen oxides (NOx)

Carbon monoxide (CO)

Non-methane volatile organic compounds(NMVOCs)

Sulfur dioxide (SO2)



1A.17

Require detailedprocess information

Combustion conditions

Size and vintage of the combustion

technology

Maintenance Operational practices

Emission controls

Fuel characteristics



1A.18

Methane (CH4)

Emissions a function of:

methane content of the fuel

hydrocarbons passing unburnt through engine

engine type post-combustion controls

Depends on temperature in boiler/kiln/stove

Highest emissions in residential applications

(e.g. small stoves, open biomass burning,

charcoal production)



1A.19

Nitrous oxide (N2O)

Lower combustion temperatures tend to lead tohigher N2O emissions

Emission controls (catalysts) on vehicles canincrease the rate of N2O generation, depending

on: driving practices (i.e. number of cold starts) type and age of the catalyst

Significant emissions for countries with a highpenetration of vehicles with catalysts

http://unfccc.int/resource/docs/2004/sbsta/inf03.pdf





1A.20

Methods for estimating CO2

Reference Approach (Tier 1)

Estimates based on national energy balance(production + imports - exports) by fuel type withoutinformation on activities

Performed quickly if basic energy balance sheet isavailable

Way of cross-checking emission estimates of CO2 withthe Sectoral Approach

Sectoral Approach (Tier 1)

Estimates based on fuel consumption data by sectoralactivity

Bottom-Up Approaches (Tier 2 or 3)

More detailed activity and fuel data



1A.21

Fundamental equation



1A.22

Six basic steps

1. Collect fuel consumption data

2. Convert fuel data to a common energy unit

3. Select carbon content factors for each fossil

fuel/product type and estimate the totalcarbon content of fuels consumed

4. Subtract the amount of carbon stored inproducts for long periods of time

5. Multiply by an oxidation factor 6. Convert carbon to full molecular weight of

CO2 and sum across all fuels



1A.23

1. Consumption data

Reference Approach

Estimate apparent consumption of fuelswithin the country

Sectoral Approach

Collect actual consumption statistics by fueltype and economic sector

Tier 2 or 3

Collect actual fuel consumption statistics byfuel type, economic sector and combustiontechnology type



1A.24

Data collection issues

IPCC sectoral approach can still be used even if

energy data are not collected using same sector

categories

Focus on completeness and use judgement or proxy

data to allocate to various subsectors Biomass combustion not needed for CO2 estimation,

but reported for information purposes

Informal sector fuel use is important issue if not

captured in energy statistics Household kerosene use can be approximated based

on expert judgement or proxy data



1A.25

2. Common energy unit

Convert fuel data into a common energy unit

Production and consumption of solid and liquid

fuels in tonnes

Gaseous fuels in cubic meters Original units converted into energy units using

calorific values (i.e. heating values)

Reference approach: use different calorific

values for production, imports and exports

Calorific values used should be reported



1A.26

3. Estimate total carboncontent of fuels consumed

Natural gas

Depends on composition (methane, ethane, propane,butane and heavier hydrocarbons)

Natural gas flared at the production site will usually be “wet’’ – its carbon content factor will be different

Typical: 15 to 17 tonnes C/TJOil

Lower carbon content for light refined petroleum productssuch as gasoline

Higher for heavier products such as residual fuel oil

Typical for crude oil is 20 tonnes C/TJ

Coal

Depend on coal's rank and composition of hydrogen, sulfur,ash, oxygen and nitrogen

Typical ranges from 25 to 28 tonnes C/TJ



1A.27

4. Subtract non-energy uses

Oil refineries: asphalt and bitumen for road construction,naphthas, lubricants and plastics

Natural gas: for ammonia production

Liquid petroleum gas (LPG): solvents and synthetic rubber

Coking: metals industry Attempt to use country-specific data instead of IPCC defaultcarbon storage factors.



1A.28

5. Oxidation factor

Multiply by an oxidation factor

to account for the small

amount of unoxidized carbon

that is left in ash or soot.

Amount of carbon remainingunoxidized should be low for

oil and natural gas

combustion…

…but can be larger and more

variable for coal combustion

When national oxidationfactors are not available, use

IPCC default factors



1A.29

Oxidation factor values

Natural gas Less than 1% left unburnt

Remains as soot in the burner, stack or environment

IPCC default oxidation factor = 99.5%

Higher for flares in the oil and gas industry

Closer to 100% for efficient turbines

Oil 1.5 ± 1 per cent left unburnt

IPCC default oxidation factor = 99%

Recent research has shown 100% in autos



1A.30

Coal Range from 0.6% to 6.6% unburnt

Primarily in the form of bottom and fly ash

IPCC default oxidation factor = 98%

Biomass Can range widely, especially for open

combustion

For closed combustion (e.g. boiler), the rangeis from 1% to 10%

No IPCC default

Oxidation factor values (cont.)



1A.31

6. Convert to full molecular weight and sum

Convert carbon to full molecular weight of

CO2 and add across all fuels

To express the results as CO2, multiply the

quantity of carbon oxidized by the molecular weight ratio of CO2 to C (44:12)



1A.32

International bunker fuels

CO2 emissions arising from fuels used inships or aircraft for international transport,not to be included in the national total

Fuels delivered to and consumed byinternational bunkers should be subtractedfrom the fuel supply to the country

Bunker fuel emissions should be mentionedin a separate table as a memo item

See IPCC decision trees on marine andaviation transport emission allocation



1A.33

Biomass fuels

CO2 emissions from biomass fuels should not be included

in national emission totals from fuel combustion

Reported for information only…

household fuelwood

ethanol and biodiesel for transport Account for mixed fuels (e.g. ethanol blends)

Net CO2 emissions implicitly accounted for under the Land

Use Change and Forestry Sector

Non-CO2 emissions from biomass combustion should be

estimated and reported under the Energy Sector!



1A.34

Methods for non-CO2 emissions

Tier 1

Multiply fuel consumed by an average emission factor

Does not require detailed activity data

Rely on widely available fuel supply data that assume anaverage combustion technology is used

Tiers 2/3

Multiply fuel consumed by detailed fuel type and technology-specific emission factors

Tier 2 methods use data that are disaggregated accordingto technology types

Tier 3 methods estimate emissions according to activitytypes (km traveled or tonne-km carried) and specific fuelefficiency or fuel rates

Use most disaggregated technology-specific and country-specificemission factors available



1A.35

Fundamental equation

Emissions =

Σ(Emission Factor abc

• Fuel Consumptionabc

)

Where,

a = fuel type

b = sector activity

c = technology type including emissions controls



1A.36

Stationary combustion

Default emission factors for CH4, N2O, NOx,CO and NMVOCs by major technology andfuel type are presented in the IPCCGuidelines

Most notable: CH4 emissions from openburning and biomass combustion

Charcoal production is likely to producemethane emissions at a rate that is several

orders of magnitude greater than from other combustion processes



1A.37

Mobile combustion

Major transport activity (road, air, rail and

ships)

Most notable: N2O emissions from road

transportation, affected by the type of emission control technologies

Non-Annex I Parties should focus their

efforts on collecting data on the number of

vehicles with catalytic emissions controldevices that operate in their country



1A.38

Mobile combustion (cont.)

Road transport activity data

Assume vast majority of motor gasoline used for

transport

Check data with equipment counts or vehicle

sales/import/export data Base assumptions of vehicle type and emission control

technology on vehicle vintage data (i.e. model year of

sale) and assumed activity level (i.e. vkt/vehicle)

Consider national emission standards, leaded gasoline

prevalence, and compliance with standards





1A.40

Relationships with other sources and sectors

Industrial Processes Sector Non-energy fossil fuel feedstocks data, if

available, may not be reliable

Petrochemical “feedstocks” may actually be

used for energy Coal purchased by iron and steel industry

may be used to make coke

Focus on petrochemical industry and metalproduction (e.g. iron and steel)

Conservative estimate: Assume plastics,asphalt, and some lubricants stored

Subtract carbon content from these products



1A.41

Relationships with other sources and sectors (cont.)

Waste Sector

Combustion of wastes for energy purposesincluded in Energy Sector

Incineration of plastics

Land-Use Change and Forestry Sector

Biomass carbon implicitly accounted for

Autoproduction of electricity

Fuel use for military purposes Mobile sources in agriculture



1A.42

Quality control andcompleteness checks

All gases (CO2, CH4 and N2O)

All source and sub-source categories

All national territories addressed

Bunker fuels and military operations

All fossil-fuel-fired electric power stations

Blast furnaces and coke production

Waste combustion with energy recovery

Black market fuels

Non-metered fuel use for pipelines by compressor

stations



1A.43

Uncertainty

Uncertainty in carbon content and calorific values for fuels is related to the variability in fuel compositionand frequency of actual measurements. Likely to besmall for all countries.

For most non-Annex I Parties the uncertainty inactivity data (i.e. fuel consumption data) will be thedominant issue!

Effort should focus on collection of fuel consumptiondata

Country-specific carbon content factors are unlikely toimprove CO2 estimates significantly

It is important to document the likely causes of uncertainty and discuss steps taken to reduceuncertainties.

UNFCCC f d



UNFCCC software andreporting tables

UNFCCC Software to aid in preparation of

greenhouse gas inventories

Provides IPCC default (i.e. Tier 1) methods

National factors can be used whereavailable

Documents

10 - Energy - Fuel Combustion