ISO 19694-6:2023

Stationary source emissions — Determination of greenhouse gas emissions in energy-intensive industries — Part 6: Ferroalloys and silicon industry

This document provides a harmonized methodology for calculating GHG emissions from the ferro-alloys industry based on the mass balance approach. This document also provides key performance indicators over time for ferro-alloys plants. This document covers the following direct and indirect sources of GHG: — direct GHG emissions [see ISO 14064-1:2018, 5.2.4 a)] from sources that are owned or controlled by the company, such as emissions resulting from the following sources: — smelting (reduction) process; — decomposition of carbonates inside the furnace; — auxiliaries operation related to the smelting operation (i.e. aggregates, drying processes, heating of ladles, etc.); — indirect GHG emissions [see ISO 14064-1:2018, 5.2.4 b)] from the generation of purchased electricity consumed in the company’s owned or controlled equipment.

Émissions de sources fixes — Détermination des émissions des gaz à effet de serre dans les industries à forte intensité énergétique — Partie 6: Industrie des ferro-alliages et du silicium

General Information

• Status: Published
• Publication Date: 28-Feb-2023
• ICS: 13.020.40 - Pollution, pollution control and conservation
• ICS: 13.040.40 - Stationary source emissions
• Technical Committee: ISO/TC 146/SC 1 - Stationary source emissions
• Drafting Committee: ISO/TC 146/SC 1/WG 30 - GHG energy-intensive industries – Specific sectors
• Current Stage: 6060 - International Standard published
• Start Date: 01-Mar-2023
• Due Date: 16-Feb-2022
• Completion Date: 01-Mar-2023

Overview - ISO 19694-6:2023 (Ferroalloys and Silicon Industry)

ISO 19694-6:2023 is an international standard that defines a harmonized methodology for determining greenhouse gas (GHG) emissions from the ferroalloys and silicon industry. Focused on stationary source emissions, the standard uses a mass balance approach to quantify emissions from core metallurgical processes (notably carbothermic reduction in electric arc furnaces), ancillary operations and indirect sources such as purchased electricity. It also defines key performance indicators (KPIs) and reporting principles for plant-level GHG inventories.

Key topics and technical requirements

• Mass balance methodology: Calculate CO2 emissions based on inputs and outputs (reducing agents, ores, products, slag), consistent with IPCC-compatible approaches.
• Direct emissions covered: Smelting/reduction process (carbothermic CO/CO2 formation), decomposition of carbonates in furnaces, and auxiliaries related to smelting (dryers, ladle heating, aggregates).
• Indirect emissions: GHG from purchased electricity and from externally supplied heat are accounted for per ISO 14064-1 principles.
• Process vs combustion emissions: Guidance on distinguishing and quantifying process CO2 from fuel combustion, including fuel quantity determination, calorific values, oxidation factors and biomass considerations.
• Sampling and measurement: Minimum analysis frequencies and sampling approaches to support mass-balance calculations and uncertainty assessment.
• Reporting and KPIs: Recommended reporting periods, unit-based specific emissions denominators, recovery of waste gas/heat KPIs, and handling baselines, acquisitions and disinvestments.
• Uncertainty and quality: Procedures for assessing uncertainties of activity data, material parameters and aggregated mass-balance results.
• Supporting annexes: Tier 1 emission factors, minimum analysis frequencies, and country-specific electricity emission factors.

Practical applications and users

ISO 19694-6 is intended for:

• Plant operators and environmental managers in the ferroalloys and silicon industry who need consistent, auditable GHG inventories.
• Sustainability and compliance teams preparing regulatory reports, voluntary disclosures or carbon management plans.
• Third‑party auditors and consultants performing verification, benchmarking or emissions reduction assessments.
• Policy makers and regulators seeking harmonized methods for industry-level GHG accounting.

Use cases include site-level emissions accounting, performance benchmarking, tracking KPIs over time, designing emission reduction projects (e.g., electrode or reductant substitution, waste heat recovery), and preparing aligned sustainability disclosures.

Related standards

• ISO 14064-1:2018 (GHG accounting principles and organizational boundaries)
• IPCC 2006 Guidelines for National GHG Inventories (methodological compatibility)
• Other parts of the ISO 19694 series addressing energy‑intensive industries

Keywords: ISO 19694-6, ferroalloys, silicon industry, greenhouse gas emissions, GHG, mass balance, stationary source emissions, electric arc furnace, carbothermic reduction, emission factors, KPIs.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19694-6
First edition
2023-03
Stationary source emissions —
Determination of greenhouse gas
emissions in energy-intensive
industries —
Part 6:
Ferroalloys and silicon industry
Émissions de sources fixes — Détermination des émissions des gaz à
effet de serre dans les industries à forte intensité énergétique —
Partie 6: Industrie des ferro-alliages et du silicium
Reference number
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .v
Introduction . vi
1 S c op e . 1
2 Nor m at i ve r ef er enc e s . 1
3 Terms and definitions . 1
4 Abbreviated terms . 3
5 D etermination of GHGs — Principles . 4
5 .1 I nt r o duc t ion . 4
5.2 General . 4
5.3 D etermination based on mass balance . 4
5.4 U se of waste gas/heat recovery . 4
6 B ou nd a r ie s . 4
6.1 General . 4
6 . 2 O p er at ion a l b ou nd a r ie s . . 5
6 . 3 O r g a n i z at ion a l b ou nd a r ie s . 5
7 D irect emissions and their determination. 6
7.1 G eneral . 6
7.2 M ass balance approach . 6
7.2.1 G eneric approach . 6
7. 2 . 2 S a mpl in g . 7
7. 2 . 3 A lt er n at e appr o ac h. 7
7. 3 P r o c e s s em i s s ion s . 9
7. 3 .1 O ver v iew . 9
7. 3 . 2 Me t ho d s . 9
7.4 C ombu s t ion em i s s ion s . 10
7.4 .1 O ver v iew . 10
7.4 . 2 Me t ho d s . 10
7.4.3 Calculation of the quantity of fuel . 11
7.4.4 D etermination of the lower calorific value and the emission factor .12
7.4.5 D etermination of the oxidation factor .12
7.5 Combustion of biomass fuels .12
8 I ndi r e c t emi s s ions .12
8.1 General .12
8 . 2 CO from external electricity production .12
8.2.1 General .12
8.2.2 G HG from heat transfer .13
9 B aselines, acquisitions and disinvestments .13
10 R ep or t i n g .13
10.1 G eneral .13
10 . 2 R epor t i ng per io d s . 14
10 . 3 Per f or m a nc e i nd ic at or s . 14
10.3.1 General . 14
10.3.2 Denominator for specific, unit-based emissions .15
10.3.3 Denominator for other ratio indicators . 15
10.3.4 Key performance indicators . 15
10.3.5 Recovery of waste gas and waste heat . 15
11 Uncertainty of GHG inventories .16
11.1 I ntroduction to uncertainty assessment . 16
11.1.1 B a s ic c on s ider at ion s . 16
11.1.2 Materiality thresholds . 17
iii
11.2 U ncertainty of activity data . 17
11.2.1 Measuring instruments for the determination of fuel and material
quantities . 17
11.2.2 Aggregated uncertainties in case of mass balances . 17
11.3 U ncertainties of fuel and material parameters . 18
11.4 E valuation of the overall uncertainty of an GHG inventory . 18
Annex A (normative) Tier 1 emission factors .19
Annex B (normative) Minimum frequency of analyses.21
Annex C (normative) Country-wise emission factors for electricity .22
Bibliography .26
iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 1,
Stationary source emissions.
A list of all parts in the ISO 19694 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
0.1 Overview of the ferro-alloy manufacturing process
Ferroalloy production involves a metallurgical reduction process that results in significant carbon
dioxide emissions. These emissions are the results of a carbothermic reaction which is intrinsic to
the process. In ferroalloy production, ore, carbon materials and slag forming materials are mixed and
heated to high temperatures for smelting.
Smelting in an electric arc furnace is accomplished by conversion of electrical energy to heat. An
alternating current applied to the electrodes creates current to flow through the charge between the
electrode tips. The heat is produced by the electric arcs and by the resistance in the charge materials.
Emissions from the smelting process are therefore not to combustion emissions. The furnaces can be
open, semi-closed or closed. Submerged electric arc furnaces with graphite electrodes or self-baking
Søderberg electrodes are used (see Figure 1).
The reduction process is the main source of direct CO emissions. Other CO sources include direct
2 2
emissions from calcination of calcium, magnesium and other carbonates (e.g. limestone) in some
processes and from non-smelting fuels (e.g. dryers for ladles and refractory linings), room heating and
indirect emissions from, for example, external power production.
Figure 1 — Submerged electric arc furnace
0.2 CO from the smelting of raw materials
In the smelting process, CO is released due to the carbothermic reduction of the metallic oxides
occurring with the consumption of both carbonaceous reductants and carbon-based electrodes. The
carbon in the reductants reacts with oxygen from the metal oxides to form CO and then CO (in different
ways depending on the process), and the ores are reduced to molten base metals. For the calculation,
the assumption is that all CO is assumed to be converted in the furnace to CO .
vi
The reductant carbon is used in the form of coke, coal, pet coke, anthracite, charcoal and wood chips.
The first four are fossil-based and the charcoal and wood chips are bio-carbon.
In the carbothermic process, only the fixed carbon content is used as a reducing agent, which means
that volatile matter, ashes and moisture mostly leave the furnace with the off-gas and slag.
The nature of reducing agents, price and electrodes depends on the localization of the plant, the raw
material availability and it is presented in Table 1. It is variable from one site to another and from one
year to another and also from one ferro-alloy to another.
Table 1 — Type of reducing agents and electrodes used in the electrometallurgy sector
Reducing agents Electrodes
Crude petroleum coke Graphite electrode
Calcinated petroleum coke Prebaked electrodes
Coal coke Søderberg paste
Coke from coal Composite electrode
Wood —
Calcinated wood —
Charcoal —
Graphite powder —
Anthracite —
CO emissions are estimated with and calculated from the consumption of the reducing agents and
electrodes, their carbon content, and the carbon content of the final products.
NOTE The basic calculation methods used in this document are compatible with the 2006 IPCC Guidelines
[1]
for National Greenhouse Gas Inventories issued by the Intergovernmental Panel on Climate Change (IPCC) .
Ores and reducing agent react to form ferro-alloys or metal, CO and dust and other by-product (i.e.
slags); amount of carbon can be found in the products
Default emission factors suggested in these documents are used, except where more recent, industry-
specific data has become available.
vii
INTERNATIONAL STANDARD ISO 19694-6:2023(E)
Stationary source emissions — Determination of
greenhouse gas emissions in energy-intensive industries —
Part 6:
Ferroalloys and silicon industry
1 S cope
This document provides a harmonized methodology for calculating GHG emissions from the ferro-
alloys industry based on the mass balance approach. This document also provides key performance
indicators over time for ferro-alloys plants. This document covers the following direct and indirect
sources of GHG:
— direct GHG emissions [see ISO 14064-1:2018, 5.2.4 a)] from sources that are owned or controlled by
the company, such as emissions resulting from the following sources:
— smelting (reduction) process;
— decomposition of carbonates inside the furnace;
— auxiliaries operation related to the smelting operation (i.e. aggregates, drying processes,
heating of ladles, etc.);
— indirect GHG emissions [see ISO 14064-1:2018, 5.2.4 b)] from the generation of purchased electricity
consumed in the company’s owned or controlled equipment.
2 Normat ive references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 14064-1:2018, Greenhouse gases — Part 1: Specification with guidance at the organization level for
quantification and reporting of greenhouse gas emissions and removals
ISO/IEC 17025, 2005, General requirements for the competence of testing and calibration laboratories
ISO 19694-1:2021, Stationary source emissions — Determination of greenhouse gas emissions in energy-
intensive industries — Part 1: General aspects
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 19694-1:2021 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
For the purposes of this document, the terms and definitions in and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
auxiliary
equipment consuming electricity/power related to the smelting (3.5) process
EXAMPLE Fans, pumps, gas abatement systems (filter bags, venture scrubbers, etc.).
3.2
silica fume
amorphous silicon dioxide particles from the volatilization and vaporization of furnace feed materials
in the manufacture of ferrosilicon and silicon (3.4)
Note 1 to entry: The process off-gas that contains silica fumes beings cleaned in a baghouse using fabric filters of
the open or semi-closed SEAF (3.8).
3.3
ferro-alloy
alloy of iron and one or more metals such as silicon (3.4), manganese, chromium, molybdenum,
vanadium and tungsten
3.4
silicon
metalloid produced by carbo-thermic reduction of quartz in an electric submerged arc furnace
3.5
smelting
industrial process where one or more ores or ore concentrates are heated and reduced (i.e. chemically
modified) by, for example, aluminino-carbo-silico thermic reduction, to manufacture and mix the
metals in one step
Note 1 to entry: Examples of smelted alloys are ferro-alloys (3.3).
3.6
gross GHG emission
absolute fossil direct GHG emission excluding GHG emissions from on-site power production
3.7
absolute gross GHG emission
total direct emission of GHGs within the boundaries excluding GHG emissions from biogenic CO from
biomass (i.e. wood chips and charcoal)
3.8
submerged electric arc furnace
SEAF
electric arc-heating furnace in which the arcs are completely submerged under the charge
Note 1 to entry: The arc forms between the electrode [graphite electrodes or self-baking Søderberg electrodes
(3.12)] and metal surface or bottom lining. The heat being produced by the electric arcs and by the resistance in
the charge materials initiates the reduction process. The furnaces can be open, semi-closed or closed, which can
depend upon the ferro-alloy (3.3) to be produced.
3.9
biomass fuel
fuel with only biogenic carbon
3.10
petroleum coke
petcoke
carbon-based solid fuel derived from oil refineries
3.11
sinter
sintering
process to form a coherent mass by heating without melting
3.12
Søderberg electrode
continuously self-baking carbon electrode used in electro-metallurgical furnaces for production of
ferroalloys and silicon (3.4)
Note 1 to entry: The “Søderberg paste” is a preparation of coal tar pitch and carbonaceous dry aggregate.
3.13
composite electrode
electrode where the core is composed of graphite while the exterior is a self-baking carbon paste (which
is a “Søderberg paste”)
3.14
prebaked electrode
carbonaceous paste baked so as to carbonize coal tar pitch in order to form a solid pitch coke binder
phase
Note 1 to entry: A carbonaceous paste is a mixing of coal tar pitch with a dry carbonaceous aggregate.
4 Abbreviated terms
For the purposes of this document, the following abbreviations apply.
CO Carbon monoxide
CO Carbon dioxide
EF Emission factor
FA Ferro-alloys
GHG Greenhouse gases
HCV High calorific value
IEA International Energy Agency
IPCC Intergovernmental Panel on Climate Change
KPI Key performance indicator
SEAF Submerged electric arc furnace
UNFCCC United Nations Framework Convention on Climate Change
5 De termination of GHGs — Principles
5.1 Introduction
This document shall be used in conjunction with ISO 19694-1:2021 which contains generic, overall
requirements, definitions and rules applicable to the determination of GHG emissions for all energy-
intensive sectors, provides common methodological issues and specifies the details for applying the
rules. The application of this document to the sector-specific standards ensures accuracy, precision and
reproducibility of the results and is for this reason a normative reference standard.
5.2 General
The determination of CO emissions can be in principle done either through calculation (mass balance
method) or through stack emission measurement.
The methodology described in this document for GHG emissions determination is based on the mass
balance method (see 7.1).
CO is the only GHG relevant for the ferro-alloys industry. The emissions of CH and of N O are extremely
2 4 2
low. Therefore, they are both neglected in the calculation of carbon emissions.
The measurements of the concentrations of CH and N O have been demonstrated to be near or below
4 2
the detection limits during the field tests performed to develop this document with independent
[7]
laboratories .
5.3 Det ermination based on mass balance
In installations where carbon stemming from input materials used remains in the products or other
outputs of the production, for example, for the reduction of metal ores, a mass balance approach is
applied. In installations where this is not the case, combustion emissions and process emissions are
calculated separately.
Emissions from source streams are calculated from input or production data, obtained by means of
measurement systems and additional parameters from laboratory analyses including calorific factor,
carbon content and biomass content. Standard factors can also be used; references to these factors are
provided in ISO 19694-1:2021.
5.4 Use of w aste gas/heat recovery
GHG emissions related to waste gas and heat recovery are reported as direct GHG emissions. Waste
gas including CO and CO can be subtracted from the direct emission, when exported outside the
boundaries of the location, as a negative carbon flow in the mass balance (e.g. when exporting waste
gas to another installation).
6 Bo undaries
6.1 General
Drawing appropriate boundaries is one of the key tasks in an emissions inventory process.
6.2 Operational boundaries
Operational boundaries refer to the types of sources covered by an inventory. A key distinction between
direct and indirect emissions is the following.
a) Direct emissions [see ISO 14064-1:2018, 5.2.4 a)] are emissions from sources that are owned or
controlled by the reporting company. For example, emissions from smelting are direct emissions of
the company owning (or controlling) the furnace.
b) Indirect emissions [see ISO 14064-1:2018, 5.2.4 b) to f)] are emissions that result as a consequence
of the activities of the reporting company but occur at sources owned or controlled by another
company. For example, emissions from the generation of grid electricity consumed by a ferro-alloy
company qualify as indirect.
Clause 7 provides detailed guidance on the different sources of direct emissions occurring in ferro-
alloys plants. Indirect emissions are addressed in Clause 8.
Companies shall use the operational boundaries outlined in Table 2 and the relevant process steps
in Table 3, for the determination of the GHG emissions for the smelting/carbo-thermic reduction
operations part of the ferro-alloy plant. Any deviation from these boundaries shall be reported and
explained.
Table 2 — Operational boundaries
Included within boundaries Excluded
Smelting (carbo-thermic reduction): Mobile transport
— electrodes
— reducing agents
— non-furnace fuels
Electricity consumption for whole production process Room heating / cooling (negligible)
Onsite power production: waste heat recovery Mobile transport in plant
Stock inventories carbon materials —
Table 3 — Process steps
Process step Scope Inclusion GHG emission category
ISO 14064-1:2018, 5.2.4 a)
Smelting Scope 1 Yes a
Electricity consumption for whole
Scope 2 Yes b
production process
Onsite power production Scope 1 Yes a
Waste heat recovery Scope 1 Yes a
Room heating / cooling Scope 1 Yes, but negligible a
Stock changes Scope 1 Yes a
6.3 Organizational bou ndaries
The major source of GHG emissions in the ferroalloys sector is the process-related emissions from the
submerged electric arc furnaces operations, the reduction of the metallic oxides and the consumption of
the electrodes during the process. There are practically no fuel related process emissions and heat is a
negligible input factor in the production. The operational boundaries for this document GHG emissions
cover only the smelting/carbo-thermic reduction operations considered as core activities and the
related auxiliaries.
7 Dir ect emissions and their determination
7.1 General
Direct emissions are emissions from sources of the respective plant. In ferro-alloys plants, direct GHG
emissions can result from the following sources:
a) CO emissions from reducing agents and electrode use in the smelting process,
b) raw materials (e.g. decomposition of limestone, dolomite, and carbon containing metal ores and
concentrates),
c) combustion of conventional fuels (e.g. natural gas, coal and coke, or fuel oil), and
d) combustion of biomass fuels.
In installations where carbon stemming from fuels or input materials used at this installation remains
in the products or other outputs of the production, for example, for the reduction of metal ores, a mass
balance approach is applied.
Generally, companies are encouraged to measure the required parameters at plant level for specific raw
materials. Where plant- or company-specific data are not available, standard or default factors should
be used.
7.2 Mass balanc e approach
7.2.1 Generic approach
In the mass balance approach, the CO quantity corresponding to each source stream included in the
mass balance has to be calculated by multiplying the activity data related to the amount of material
entering or leaving the boundaries of the mass balance, with the emission factor for each material.
The methodologies for determining activity data and emission factors are referred to as tiers. The
increasing numbering of tiers from one upwards reflects increasing levels of accuracy, with the highest
numbered tier as the preferred tier.
For emission sources which emit more than 10 % of the total annual emissions of the installation
the operator shall preferably apply the highest tier given the less uncertainty. For all other emission
sources, the operator shall apply at least one tier lower than the highest tier.
In case the application of the highest tier is technically not feasible or incurs unreasonable costs, a next
lower tier shall be used for the relevant emission source, with a minimum of tier 1.
For marginal flows, which jointly emit 1,000 t CO ,eq or less, or less than 2 % of the “total of all
monitored items” (whichever is highest and not exceeding 20,000 t CO ,eq), it is allowed to calculate
activity data and emission factors using a conservative estimation, instead of using tiers (unless it is
possible to use tiers without additional effort or costs) with:
a) Activity data: The operator shall analyse and report the mass flows into and from the installation
and respective stock changes for all relevant fuels and materials separately (generally in GJ for
energy, in t for mass or m for volume).
n
— Tier 1: Activity data over the reporting period are determined with a maximum uncertainty of
less than ±7,5 %.
— Tier 2: Activity data over the reporting period are determined with a maximum uncertainty of
less than ±5 %.
— Tier 3: Activity data over the reporting period are determined with a maximum uncertainty of
less than ±2,5 %.
— Tier 4: Activity data over the reporting period are determined with a maximum uncertainty of
less than ±1,5 %.
b) Emission factors: Emission factors are expressed as tCO eq/GJ, tCO eq/t or as tCO eq/m .
2 2 2 n
— Tier 1 International reference for emission factors (IPCC data): The emission factor of input or
output streams shall be derived from reference emission factors for fuels or materials named in
Annex A.
— Tier 2 National reference: The operator applies country-specific emission factors for the
respective fuel or material as reported by the respective country in its latest national inventory
submitted to the Secretariat of the United Nations Framework Convention on Climate Change.
— Tier 3 Industry specific reference: The emission factor of input or output stream shall be
derived following the provisions of this document in respect to representative sampling
of fuels, products and by-products, the determination of their carbon contents and biomass
fraction. These emission factors are usually determined by analysis of the carbon content. For
the conversion of carbon content into the respective emission factor for CO , a factor of 3,664 t
CO /t C shall be used.
Requirements for analysis should retain the preference for the use of laboratories meeting the
requirements of ISO/IEC 17025. Company measurements are carried out by applying methods based
on suitable ISO standards (e.g. ISO 9001) or national standards, or on industrial best practices, limiting
sampling and measurement bias.
7.2.2 S ampling
The operator shall provide evidence that the derived samples are representative and free of bias. The
respective value shall be used only for the delivery period or batch of fuel or material for which it was
intended to be representative.
Generally, the analysis will be carried out on a sample which is the mixture of a larger number (e.g. 10
to 100) of samples collected over a period of time (e.g. from a day to several months) provided that the
sampled fuel or material can be stored without changes of its composition.
The sampling procedure and frequency of analyses shall be designed to ensure that the annual average
of the relevant parameter is determined with a maximum uncertainty of less than 1/3 of the maximum
uncertainty which is required by the approved tier level for the activity data for the same source stream.
If the operator is not able to meet the allowed maximum uncertainty for the annual value or unable to
demonstrate compliance with the thresholds, the operator shall apply the frequency of analyses as laid
down in Annex B as a minimum, if applicable.
7.2.3 Alternate approach
The alternate approach for the Tier 3 method is to use emission factors for the reducing agents only,
which is adopted in this subclause. The simplified adopted formula given in Formula (1):
EU=×EF (1)
CO2 RA/E RA/E
where
E is the emissions of CO , in t;
CO2 2
U is the total consumption of reducing agents/electrodes, in t;
RA/E
EF is the emission factor of reducing agents of electrodes, in t CO /t.
RA/E 2
The emission factor of the reducing agent is based on its carbon content (see Formula (2)]:
EF =×C 3,664 (2)
RA/E Ci,,RA
The total C-contents of reducing agents is calculated by Formula (3):
CF=+FC× (3)
Ci,,RA Fix Cv,,iiolatiles v
where
C is the carbon content in reducing agent i, in tonne C/tonne reducing agent;
C,RA, i
F is the mass fraction of Fix C in reducing agent i, in tonne C/ tonne reducing agent;
Fix C,i
F is the mass fraction of volatiles in reducing agent i, in tonne volatiles/ tonne reducing agent;
volatiles,i
C is the carbon content in volatiles, in tonnes C/tonne volatiles.
v
NOTE Unless other information is available, C = 0,65 is used for coal and 0,80 for coke.
v
Instead of calculating the carbon content using Formula (3), it is also possible to analyse the total
[5]
carbon content directly using ISO 29541 .
In case of humidity, H, in the reducing agent, Formulae (2) and (3) become Formulae (4) and (5):
()1−w
H
C = ×+FF ×C (4)
()
Ci,,RA Fix Cv,,iiolatiles v
1−w
()
H
EF = ×+FF ×C ×3,664 (5)
()
RA Fix Cv,,iiolatiles v
where w is the mass fraction of humidity contained in the reducing agent or electrode.
H
Therefore, for the tier 3 method, it is necessary to determine the carbon contents of the reducing
agents used in the production processes. But most ferroalloys producers analyse only on the basis of
percentage of ash and volatiles, and calculate (dry basis calculation (db)) Formula (6):
w =−1 w − w (6)
FixC ashvolatiles
where
w is the mass fraction of fixed carbon in reducing agent;
Fix C
w is the mass fraction of ash contained product (reducing agent);
ash
W is the mass fraction of volatiles contained product (reducing agent);
volatiles
as received basis calculation (ar) [see Formula (7)]
ww=−1 −−ww (7)
FixC H ashvolatiles
where
w is the mass fraction of fixed carbon in reducing agent;
Fix C
w is the mass fraction of ash contained product (reducing agent);
ash
w is the mass fraction of volatiles contained product (reducing agent);
volatiles
w is the mass fraction of humidity contained in reducing agent or electrode.
H
The frequency of analyses of the raw materials/products for determining the emission factors are made
as a minimum according to Annex B. They are determined based on internal analysis and suppliers to
calculate their carbon content, except for wood.
An option is also to use certificates issued by independent laboratories at loading ports. Such certificates
are supplied by the producer or trader of raw materials.
In the absence of data analysis for one year and for the installation concerned, the factors used are from
the average of measurements made on the site or sites in the corresponding year. When the number of
analyses is insufficient (not shown), the factors used are from the average of the analyses conducted
from 2005 to 2008 for the whole or the sites.
Requirements for analysis should retain the preference for the use of laboratories meeting the
requirements of ISO/IEC 17025. Company measurements are carried out by applying methods based
on on suitable ISO standards (e.g. ISO/IEC 9001) or national standards, or on industrial best practices,
limiting sampling and measurement bias (see Table 4).
Table 4 — Relevant standards for analysis
Standards
[9] [10] [12] [13]
Moisture ISO 579:2013 , ISO 589:2008 , ISO 687:2010 , ISO 11722:2013
[12]
Ash ISO 1171:2010
[8]
Volatile matter ISO 562:2010
Fixed carbon NA
[5]
Total carbon ISO 29541
Key
NA : not available
7.3 Process emissions
7.3.1 Overview
The calcination of limestone (CaCO ) or dolomite (CaMg(CO ) is considered under the process emission.
3 3 2
These processes are used for the production of Mn and CaSi alloys.
7.3.2 Methods
For each type of input material used, the amount of CO shall be calculated as follows:
E = Σ × EF × CF
CO2 AD
where
AD is the activity data:
— Tier 1: Amounts (t) of input material and process residues used as input material in the
process over the reporting period are determined with a maximum uncertainty of less than ±5,0 %;
— Tier 2: Amounts (t) of input material and process residues used as input material in the
process over the reporting period are determined with a maximum uncertainty of less than ±2,5 %;
EF is the emission factor tier 1; for carbonates, use of stoichiometric ratios given in Table 5;
CF is the conversion factor:
— Tier 1: Conversion factor: 1. Based on the principle that process emissions are coming from
reducing agents, therefore the total carbon of the raw materials is converted to CO .
— Tier 2: The amount of non-carbonate compounds of the relevant metals in the raw
materials, including return dust or fly ash or other already calcined materials, shall be
reflected by means of conversion factors with a value between 0 and 1 with a value of 1
corresponding to a full conversion of raw material carbonates into oxides.
Table 5 — Stoichiometric emission factors
Ratio
Carbonate Remarks
t CO /t Ca-, Mg-
or other carbonate
CaCO : limestone 0,440 —
MgCO : Mg carbonate Does not exist as natural carbonate
0,522
Intermediate between CaCO and MgCO that typi-
3 3
MgCO -CaCO : dolomite
3 3
cally contains 30 % of Mg and 20 % of CaO
where
X is the metal;
M is the molecular weight of X, g/mol;
X
EF = M / (Y * M + Z * M )
General: X Y (CO ) Z CO2 X 2−
M is the molecular weight of CO g/mol;
3 CO CO2 2,
2-
M is the molecular weight of CO , g/mol;
2− 3
CO
Y is the stoichiometric number of X Z is
2-
the stoichiometric number of CO .
These values shall be adjusted for the respective moisture and gangue content of the applied carbonate
material.
The carbon content of sinter, slag or other relevant output as well as in filtered dust shall be derived
following the provisions of this document in respect to representative sampling and the determination
of the carbon contents. In case filtered dust is re-employed in the process, the amount of carbon (t)
contained shall not be accounted for in order to avoid double counting.
7.4 Combustion emissions
7.4.1 Overview
Combustion emissions concern auxiliaries' operations to the smelting/carbo-reduction process such as:
— mobile gas burner,
— radiators (heat),
— drying of granules, and
— hooding.
7.4.2 Methods
7.4.2.1 General
The uncertainty thresholds in Table 6 shall apply to tiers relevant to activity data requirements for
which the operator shall use metering results based on measurement systems under its own control at
the installation and carry out an uncertainty assessment so as to ensure that the uncertainty threshold
of the relevant tier level is met.
The uncertainty thresholds shall be interpreted as maximum permissible uncertainties for the
determination of source streams over a reporting period.
7.4.2.2 Production or processing of ferro-alloys
Table 6 — TIER overview activity data
Source Tier 1 Tier 2 Tier 3 Tier 4
Process Each input material or process residue
±5 % ±2,5 % — —
emissions used as input material in the process, t
Mass balance
Each input and output material, t ±7,5 % ±5 % ±2,5 % ±1,5 %
methodology
Tier 2 for the carbon content is used by the operator by deriving it from country specific emission
factors (standard factors used by a country for its national inventory submission to the UNFCCC) for
the respective fuel or material.
Activity data are based on fuel consumption. The quantity of fuel consumed is expressed as energy
content, i.e. in TJ. The emission factor is expressed as tCO /TJ. When a fuel is consumed, all the carbon in
the fuel is oxidized to CO . The imperfections of the combustion process result in incomplete oxidation.
Some carbon is burned or partly oxidized as soot or ash. The carbon not oxidized or partially oxidized
is reflected in the oxidation factor, which is expressed as a fraction.
CO emissions (E ) from combustion plants are calculated using Formula (8). The calculation shall be
2 CO2
performed for each fuel and for each activity.
EC=×CLCV*××EF OF (8)
CO2
where
CC is the quantity of fuel consumed during the reporting period (t or m );
n
LCV is the lower calorific value (TJ/t or TJ/ m );
n
EF is
...