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ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING
Asia-Pac. J. Chem. Eng. 2010; 5: 646?656
Published online 26 July 2010 in Wiley InterScience
(www.interscience.wiley.com) DOI:10.1002/apj.498
Special Theme Research Article
Carbon pollution (greenhouse gas) measurement
and reporting
Andrew Gunst*
Carbon Intelligence Pty Limited, Level 3, 2 Lyon Park Road, Macquarie Park, NSW, Australia
Received 2 December 2009; Revised 28 June 2010; Accepted 1 July 2010
ABSTRACT: The processes of Carbon Reporting and Emissions Trading in countries including the United States
and Australia have developed from appearing unlikely in 2007 to the implementation of mandatory data reporting
commencing in July 2008 in Australia and January 2010 in the United States. The onus is on emitting corporations to
determine whether they must report. The data reported will have financial importance if and when Australia and the
United States join Europe in placing a price on Carbon. To date, much of the public discussion in these countries has
centred on the financial aspects of a Carbon tax or Emissions Trading Scheme (ETS). However, significant challenges
exist in identifying and quantifying the emissions which the financial community seeks to trade, and business community
understanding of the details of greenhouse emissions is not strong. Greenhouse emission reporting regulations and
guidelines in Australia, where the first mandatory reports have been lodged by the 680 largest emitters, are outlined.
Industrial examples are used to illustrate the challenges of understanding greenhouse gas emissions and their estimation,
and how Chemical Engineering methodologies are useful in overcoming these challenges. ? 2010 Curtin University
of Technology and John Wiley & Sons, Ltd.
KEYWORDS: carbon pollution; greenhouse gas; measurement; reporting; greenhouse emissions
BACKGROUND
Development of an international body of work
on measurement and management of greenhouse
gases during the 1990s produced the widely used
joint World Resource Institute and World Business
Council for Sustainable Development?s Greenhouse
Gas Protocol: a corporate accounting and reporting standard,[1] and the International Organisation
for Standardisation?s Standard for Greenhouse Gases
ISO/AS 14 064.[2]
During the latter part of this decade, several countries
including Australia and the United States moved to create a series of discussion papers, and in some cases
legislation, based on this Protocol and Standard.
In Australia and the United States this process is
now at the stage of a mandatory reporting scheme in
place, and discussion and negotiations are occurring
on legislation to place a price on Carbon emissions,
possibly by way of a Carbon tax or a ?Cap and
Trade? ETS.
*Correspondence to: Andrew Gunst, Carbon Intelligence Pty Limited, Level 3, 2 Lyon Park Road, Macquarie Park, NSW, Australia.
E-mail: Andrew.Gunst@CarbonIntel.com.au
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
FROM VOLUNTARY TO COMPULSORY
REPORTING, TO A PRICE ON CARBON
Regulation and reporting of greenhouse gas emissions
and energy usage in Australia commenced in the mid1990s as voluntary ?Greenhouse Challenge? schemes
(first two bars, green in colour Fig. 1) and the semi
voluntary Energy Efficiency Opportunities reporting
scheme (third bar, orange in colour Fig. 1) in the mid2000s.
Mandatory reporting of greenhouse gas emissions in
Australia was made law in 2007 with the National
Greenhouse and Energy Reporting (NGER) Act 2007
(the Act) (sixth bar, red in colour Fig. 1) and the first
reports from the 680 largest emitters with some 7000
facilities were submitted in October 2009, for public
reporting in February 2010.
The regulator has been clear that the data collected
may be used in planning for the proposed Australian
ETS (the Carbon Pollution Reduction Scheme (CPRS)
Act) (eighth bar, red in colour Fig. 1), or a Carbon
tax if that becomes the preferred model. Essentially,
a price will be put on each tonne of carbon dioxide
equivalent (tCO2 -e; refer below for how this is defined
and calculated) reported, and corporations in certain
Asia-Pacific Journal of Chemical Engineering
CARBON POLLUTION MEASUREMENT AND REPORTING
Australian regulatory history.[3] This figure is available in
colour online at www.apjChemEng.com
Figure 1.
industries and over an annual emissions threshold would
be obligated to purchase permits, or otherwise pay a tax.
If a Carbon tax is in place the price of each tCO2 -e
is fixed, at perhaps $20 per tonne of carbon dioxide
equivalent. The more Carbon emitted nationally, the
more tax paid. An Emission Trading Scheme, called a
?Cap and Trade? system in the United States, is similar
but the quantity of permits is fixed (as a ?Cap? number
of tCO2 -e) and the price varies. In theory the price per
tonne increases to ?choke off? emissions over Cap.
Cap and Trade schemes are believed to be the
most economically efficient as they are market based,
are known to have delivered substantial emissions
reductions with the Acid Rain Program in the 1990s,
and are popular with governments as they directly
deliver a cap on carbon emissions, enabling them
to automatically achieve their international obligations
to agreements such as the Kyoto protocol. Cap and
Trade systems have been running in Europe and some
United States and Australian states since 2004. The
experience has been that the price per tCO2 -e varies
considerably ? in Europe from � to nearly �within
a year. This price fluctuation is seen by some as proof of
the success of the trading market mechanism, by others
as destabilising and not encouraging capital expenditure
for emissions reduction.
It should be noted that some data collected such as
emissions data from companies which are underneath
future thresholds for payments, and the Energy data
discussed below, will not be used in an ETS or Carbon
tax; and with the details of any ETS not yet firm,
additional or different data may be needed, as:
? An ETS or Carbon tax may have payment thresholds
different from the NGER reporting thresholds, which
themselves vary by year (discussed below).
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
? The payment rates may be on some sliding scale.
? Payment for some emissions such as refrigerants
will probably be levied at entry to Australia rather
than at the point of fugitive emission. All synthetic
refrigerants used in Australia are imported; there is no
domestic manufacturer; so levying payment though
Customs Australia is straight forward.
? Payment for emissions from combustion could be
levied as part of fuel excise and therefore based on
fuel consumption rather than emissions.
The United States has followed a similar path to Australia, starting mandatory reporting of carbon emissions
from 1 January 2010, and with discussions occurring
on placing a price on Carbon emissions via a Cap and
Trade ETS or a Carbon tax.
AUSTRALIAN REGULATIONS
AND GUIDELINES
The NGER Guidelines (2008)[4] summarises the regulatory framework:
?The NGER Act 2007 [5] establishes a national framework for corporations to report greenhouse gas emissions and energy consumption and production from 1
July 2008. The Act makes registration and reporting
mandatory for corporations whose energy production,
energy use or greenhouse gas emissions meet specified
thresholds.
The Act is administered by the Australian Government Department of Climate Change. The Act establishes the statutory position of the Greenhouse and
Energy Data Officer (GEDO), within the Department
Asia-Pac. J. Chem. Eng. 2010; 5: 646?656
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Figure 2. Australian legislative framework.[4] This figure is available in colour online
at www.apjChemEng.com
of Climate Change, to carry out certain regulatory
functions.
A number of pieces of subordinate legislation sit
under the Act, providing greater detail about corporations? obligations (Fig. 2)?.
The Reporting Regulations and Method Determination (second column of boxes, blue in colour Fig. 2)
are more specific than the Act in terms of which entities are reportable and how the emissions are to be
calculated, respectively.[6,7] The Guidelines (third column of boxes, brown in colour Fig. 2) explain these
documents and give examples.[4,8] Although the Guidelines have the least regulatory authority, they remain
a useful source of information by providing guidance
on the intent of the legislation. The Reporting Guidelines assist in the task of separating physical operations
into a set of Facilities, and deciding which one party
is considered to have Operational Control over each
Facility.[4] The party which is deemed to have Operational Control has legal responsibility to report on the
Facility?s emissions. The NGER Technical Guidelines[8]
then guides that party in how to measure and calculate
the Facility?s emissions. For key decisions, reference to
the Regulations, the Measurement Determination and
ultimately the Act is recommended. The delineation of
Facility boundaries and determining which single party
is deemed to have Operational Control can be challenging, requiring professional judgement.
The Australian legislation is principles-based rather
than rules-based, with four reporting principles determining how total emissions should be estimated[7] :
(a) Transparency: emission estimates must be documented and verifiable.
(b) Comparability: emission estimates using a particular method and produced by a registered corporation in an industry sector must be comparable
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
with emission estimates produced by similar corporations in that industry sector using the same
method and consistent with the emission estimates
published by the Department in the National Greenhouse Accounts.
(c) Accuracy: having regard to the availability of reasonable resources by a registered corporation and
the requirements of . . . [the Method] Determination, uncertainties in emission estimates must be
minimised and any estimates must neither be over
nor under estimates of the true values at a 95%
confidence level.
(d) Completeness: all identifiable emission sources . . .
must be accounted for.
Under principles-based legislation each corporation
is required to carry out a rational decision making process and to document the rationale for the major decisions: the declaration of Facilities, deciding who has
Operational Control, which emission sources will be
reported, and what level of measurement precision is
used.
The head regulator, the GEDO, will communicate
with reporting companies but, unlike most regulatory regimes, will not issue binding guidelines or rulings. It is up to the reporting company to decide
what and how to report. The head regulator controls
the audit function, and publically publishes the data
(Fig. 3).
Principles-based legislation is not common in Australia, and Australian industry is having some difficulty with the concept of an obligation to report
without binding guidelines and rulings on how to
report.
It is worth noting that the Australian legislation
also contains energy reporting requirements. Corporations over any one of several thresholds (refer below)
are obliged to report all three of Energy Produced,
Asia-Pac. J. Chem. Eng. 2010; 5: 646?656
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Asia-Pacific Journal of Chemical Engineering
CARBON POLLUTION MEASUREMENT AND REPORTING
KYOTO PROTOCOL GASES, GLOBAL
WARMING POTENTIAL (GWP) FACTORS
AND SCOPES
Relationships, principles-based regulations.
Industry Presentation by Greenhouse and Energy Data
Officer.[3] This figure is available in colour online at
www.apjChemEng.com
Figure 3.
Energy Consumed and Greenhouse Gas Emissions. The
definitions of Energy Produced and Energy Consumed
are broad. Oil, gas, coal and uranium extracted from
the ground must be reported as ?Energy Produced?;
and materials such as solvents, monomers and fertilizer
feedstocks which are removed from circulation when
incorporated into products must be reported as ?Energy
Consumed?.
Obtaining this information will enable the Australian
government to more accurately determine the sources
and sinks of energy in Australia (Fig. 4).
Under the Kyoto Protocol and the Australian regulatory
system, only some greenhouse gas emissions must be
reported. The list of reportable gases, including their
GWP relative to CO2 over a one hundred year period,
is shown in Table 1.
Emissions are categorised into three Scopes (Fig. 5).
Scope 1 emissions are those directly created by a corporation. Scope 2 emissions are those created by separate utilities providers to generate electricity, reticulated
steam or coolant consumed by the corporation. Scope
3 emissions are other emissions including other parties? Scope 1 emissions that the corporation is in large
measure responsible for. Major Scope 3 items are typically travel, waste processed by others and transmission
losses for Scope 2 electricity consumed.
In the United States, only Scope 1 emissions need to
be reported. In Australia, both Scope 1 and 2 need to be
reported. Scope 3 generally needs to be included before
making marketing claims such as ?Carbon Neutral?.
REPORTING THRESHOLDS
Australia has established a two-tier threshold reporting
system, with declining thresholds for a total corporation
over the first 3 years, and a lower threshold for any
single Facility within a corporation (Fig. 6).
Figure 4. Sources and Sinks of Energy in Australia over 2006?2007.[3] This figure is
available in colour online at www.apjChemEng.com
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
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Table 1. Kyoto Protocol Greenhouse gases, which are reportable under the Act, and their Global Warming
Potentials.[6]
Gas
Carbon dioxide
Methane
Nitrous oxide
Hydrofluorocarbons (HFCs)
HFC-23
HFC-32
HFC-41
HFC-43-10mee
HFC-125
HFC-134
HFC-134a
HFC-143
HFC-143a
HFC-152a
HFC-227ea
HFC-236fa
HFC-245ca
Perfluorocarbons (PFCs)
Perfluoromethane (tetrafluoromethane)
Perfluoroethane (hexafluoroethane)
Perfluoropropane
Perfluorobutane
Perfluorocyclobutane
Perfluoropentane
Perfluorohexane
Sulphur hexafluoride
Chemical formula
CO2
CH4
N2 O
Global Warming Potential
1
21
310
CHF3
CH2 F2
CH3 F
C5 H2 F10
C2 HF5
C2 H2 F4 (CHF2 CHF2 )
C2 H2 F4 (CH2 FCF3 )
C2 H3 F3 (CHF2 CH2 F)
C2 H3 F3 (CF3 CH3 )
C2 H4 F2 (CH3 CHF2 )
C3 HF7
C3 H2 F6
C3 H3 F5
11 700
650
150
1300
2800
1000
1300
300
3800
140
2900
6300
560
CF4
C2 F6
C3 F8
C4 F10
c-C4 F8
C5 F12
C6 F14
SF6
6500
9200
7000
7000
8700
7500
7400
23 900
produced and energy consumed if it exceeds any one of
the reporting thresholds of:
? 125 kt/year of Scope 1 + Scope 2 greenhouse
emissions expressed as CO2 equivalent or
? 500 TJ of ?Energy Produced?, broadly defined to
include the extraction of oil, gas, coal and uranium
from the ground or
? 500 TJ of ?Energy Consumed?, broadly defined to
include the incorporation of organic chemicals into
products or
if any single Facility within the corporation exceeds any
of the three facility reporting thresholds:
Figure 5. Emission scopes.[3] This figure is available in
colour online at www.apjChemEng.com
Thresholds exist at each tier for each of Greenhouse
Emissions, Energy Produced and Energy Consumed.
For example in the first year of reporting a corporation
must report all its greenhouse gas emissions, energy
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
? 25 kt/year of Scope 1 + Scope 2 greenhouse emissions expressed as CO2 equivalent or
? 100 TJ of ?Energy Produced?, broadly defined to
include the extraction of oil, gas, coal and uranium
from the ground or
? 100 TJ of ?Energy Consumed?, broadly defined to
include the incorporation of organic chemicals into
products.
Many corporations in Australia must report their
greenhouse emissions not because they are over an
emissions reporting threshold, but because they exceed
an Energy Produced or Energy Consumed threshold.
Asia-Pac. J. Chem. Eng. 2010; 5: 646?656
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Asia-Pacific Journal of Chemical Engineering
CARBON POLLUTION MEASUREMENT AND REPORTING
Figure 6. Australian reporting thresholds over the first 3 years.[9] This figure is
available in colour online at www.apjChemEng.com
For example even a modest size oil and gas company extracting less than 100 000 barrels of oil equivalent per year may exceed the Energy Produced corporate threshold of 500 TJ, and the Energy Consumed thresholds can be exceeded by a modest sized
paint, chemicals or plastics company. These reporting
requirements are not yet fully understood by Australian
industry.
The United States, in comparison, looks to be adopting a single tier, single parameter reporting threshold of
25 ktCO2 -e for Scope 1 emissions only. This is identical to the Australian Facility Emissions threshold, but
without including Scope 2 emissions, and without the
additional Corporate or Energy thresholds adopted in
Australia.
carbon dioxide equivalence, usually in metric tonne per
year. Historically, such emissions have generally not
been seen as of economic value, and hence many emission streams and sources are not routinely measured.
Direct metering will often not be in place. Even if volume flow metering is present, such as a simple orifice
plate with total and differential pressure taps in a flue
or vent pipeline, it is rare to have composition analyses
readily available to determine the mass flow of each gas
shown in Table 1 above (including CO2 , CH4 , N2 O but
not CO, C2 H6 or other NOx ). Emissions from pools of
liquid (such as open tanks or holding ponds) or solids
(such as methane from waste dumps) rarely have flow
metering available.
Challenge 2: visibility
CHALLENGES IN IDENTIFYING
AND QUANTIFYING GREENHOUSE
EMISSIONS
These standards and regulations appear to be a clear
and straightforward model, suitable for measurement
leading to emissions trading. However, significant
challenges exist in determining and measuring the
emissions.
Challenge 1: information on volume
As discussed above, greenhouse gas emissions are by
convention stated as annual mass flows converted to
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Emissions are often ?silent and invisible?. Flues, vents
and fugitive emissions such as leaks have little or
no visibility, literally and metaphorically. Literally,
because many emission streams are released to atmosphere as gases through vent or flue lines designed and
operated to direct the emissions away from humans
in a safe, unobtrusive manner. This is particularly
the case for low pressure vents and leaks, but even
high temperature combustion exhaust flues are often
designed and operated to rapidly disperse the exhaust
into the ambient atmosphere. Metaphorically, because
most emission streams have historically had no monetary value associated with them, and so do not appear
on most operational management and engineering lists
of importance.
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Challenge 3: large range of GWP values
not well appreciated
The range of GWP factors is larger than conventionally
assumed. It is not widely understood that, for example,
refrigerant GWP factors vary from a GWP of 1 for CO2
used as a refrigerant to 11 700 for Refrigerant 23, with
a corresponding proportionality to the value of a given
mass of each refrigerant. It is also a surprise to many
that the popular replacement refrigerant hydrofluorocarbon (HFC)-134a, used in most automobile and domestic
air conditioners for the last decade, has a relatively high
GWP factor of 1300.
Asia-Pacific Journal of Chemical Engineering
Challenge 1: information on volume
Emissions at the flue of the pump engine are not
metered for volumetric or mass flow, either in total
or by molecular component, as the flue gas is of no
economic value.
Fortunately however the fuel to the pump engine is
generally metered, and factors are available to estimate
the emissions of CO2 , CH4 and N2 O from combusting
the fuel used with an uncertainty of under 5% at a two
sigma (95%) confidence level.
Challenge 2: visibility
Challenge 4: inclusions vary
by protocol/regulatory regime
The gases which are counted under the Kyoto protocol
are only a subset of greenhouse gases, and greenhouse
accounting under national schemes such as Australia?s
is different in some aspects from the Kyoto protocol.
Refrigerant R-12 is a potent greenhouse gas with
a GWP of 10 200[10] but is not counted under the
Kyoto protocol because R-12 is being phased out
under the Montreal (ozone depletion) protocol. Also,
under Australian regulations emissions from refrigerant
gases that are counted under the Kyoto protocol may
not need to be counted unless they are from certain
industries and if the inventory of refrigerant is over
100 kg.
Following are two examples to illustrate the challenges to properly determining the sources and relative
importance of greenhouse emissions. Each example will
be developed in a manner similar to how a Carbon Footprint or Carbon Audit is developed.
EXAMPLE 1: OIL AND GAS INDUSTRY
A typical oil extraction well produces a mixture of
oil, gases and water. The mixture is pumped from
the ground, and the gases and water are separated
continuously by pressure reduction (flashing) into a
vessel. Water is removed from the bottom while the gas
mixture vents (and is sometimes flared) from the top.
Economic attention is naturally focussed on the oil, the
saleable product, and on the fuel used to drive the well
pump, the principal cost.
Ostensibly the emissions from this operation would
appear straightforward ? the creation of CO2 , CH4 and
N2 O by combusting fuel to drive the pump.
However, the challenges previously identified
show that there are complications in the identification and accurate measurement of greenhouse gas
emissions.
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Recall the vented, unwanted gas. This is a low pressure
release of gas through an elevated vent line, located
well away from human presence (for safety reasons)
and so having little physical visibility. It is currently
of no economic value, and so has little corporate
?visibility?.
However this vent stream can account for 20% or
more of greenhouse gas emissions, especially if not
flared. (Flaring will convert most of the methane with a
GWP of 21 to carbon dioxide with a GWP of 1.) Even
rejected water will contain and emit a small quantity of
greenhouse gases, because having been in equilibrium
with the oil and gas it contains (low) levels of CO2 and
CH4 .
Whilst measuring the flowrate and compositions of
these fugitive gas emissions can be difficult, the use
of gas?liquid equilibrium computerised simulations can
produce close estimates of the gas flow and composition
for the gas liberated from the oil and from the water.
Challenge 3: large range of GWP values
not well appreciated
A typical vent stream might be 20% CO2 and 60%
CH4 with the balance being mainly N2 . However, with
GWP factors of 1 and 21 for CO2 and CH4 respectively,
these gases have disproportionate impacts (as shown
in Table 2), with CH4 creating 98% of the greenhouse
impact of the vent stream.
Challenge 4: inclusions vary
by protocol/regulatory regime
Ethane, propane and heavier hydrocarbons present in
the vent gas in equilibrium with the oil are all active
greenhouse gases (albeit with low GWP factors), but
are not counted under Kyoto or Australian regulations.
First versions of the Australian NGER rules also
excused the reporting of CO2 from these oil operations,
meaning only CH4 need be reported.
Asia-Pac. J. Chem. Eng. 2010; 5: 646?656
DOI: 10.1002/apj
Asia-Pacific Journal of Chemical Engineering
CARBON POLLUTION MEASUREMENT AND REPORTING
Table 2. Contribution to emissions, typical gas vent
from an oil well, Australian data following the
CAPP/API methodology.[11,12]
Gas
%w/w
CO2
N2
N2 0
CH4
C2 H 6
C3 H 8
C4 H10
C5+
20%
10%
0%
60%
4%
3%
2%
1%
100%
GWP (Kyoto)
% GWP contribution
1
2%
0%
0%
98%
0%
0%
0%
0%
100%
310
21
and N2 O by combusting natural gas (predominantly
CH4 ) to power the boilers and fuel to power the forklift
trucks; and Scope 2 emissions to create the electricity
consumed.
However, several challenges are again present in this
example:
Challenge 1: information on volume
EXAMPLE 2: CHEMICAL INDUSTRY
A plant is manufacturing a variety of life science products, by chemical reaction, blending and phase separation. The site contains two natural gas (methane)
fired steam boilers, and consumes electricity. The main
chemical reaction on site does not produce a greenhouse
gas. The site also has warehouses, packaging rooms,
laboratories and offices, some of which are airconditioned. The Heating Ventilation and Air Conditioning
(HVAC) units are known to consume most of the electricity purchased by the site.
Example 2 is more complex than Example 1, and
will be used to present a sequential set of views
of the emissions profile as successive Challenges are
reviewed.
Ostensibly, the emissions from this operation appear
to be straightforward ? Scope 1 creation of CO2 , CH4
Emissions at the flue of the boilers and forklifts are not
metered for volumetric or mass flow, either in total or
by molecular component, as the flue/exhaust gas is of
no economic value.
Fortunately however, all fuels used are purchased
and therefore metered, and factors are available
to estimate the emissions of CO2 , CH4 and N2 O
from combusting the fuels used with an uncertainty
of under 5% at a two sigma (95%) confidence
level.
When consumption of fuels and electricity is totalled
and multiplied by relative emission factors, the annual
greenhouse emissions total ? sometimes called the
Greenhouse Gas Emissions Statement or Carbon Footprint of the operation ? for this example is shown in
Table 3.
Challenge 2: visibility
Another source of emissions, albeit one with little visibility, is the leaking of refrigerant from the HVAC
Table 3. Annual emissions (carbon footprint) for Example 2 after Challenge 1.
Emissions per year
Emissions source
Scope
Scope
Scope
Scope
2
1
1
1
?
?
?
?
stationary
stationary
transport
transport
Emissions factor
720 MWh electricity/year from black coal Mainly HVAC 0.89 kg CO2 -e/kWh
3300 GJ natural gas/year
2 Boilers
51.30 kg CO2 -e/GJ
6000 L diesel/year
Forklifts
2.82 kg CO2 -e/L
1300 kg LPG/year
Forklifts
1.53 kg CO2 -e/kg
Total
NGERS (tCO2 -e)
643
168
16
2
829
Table 4. Annual emissions (carbon footprint) for Example 2 after Challenge 2.
Emissions per year
Emissions source
Scope
Scope
Scope
Scope
Scope
Scope
2
1
1
1
1
1
?
?
?
?
?
?
stationary
stationary
transport
transport
fugitives
fugitives
720 MWh electricity/year from black coal
3300 GJ natural gas/year
6000 L diesel/year
1300 kg LPG/year
60 kg leaking at 16%/year = 10 kg/year
60 kg leaking at 59%/year = 35 kg/year
Total
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Emissions factor
Mainly HVAC 0.89 kg CO2 -e/kWh
2 Boilers
51.30 kg CO2 -e/GJ
Forklifts
2.82 kg CO2 -e/L
Forklifts
1.53 kg CO2 -e/kg
NGERS (tCO2 -e)
643
168
16
2
829
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(airconditioner) units. The rate of refrigerant leakage
can be determined over a number of years by the mass
of ?top up? refrigerant purchased or supplied by airconditioning maintenance contractors. If this data is not
available, for example if the units are too new to have
a maintenance purchases history, then average annual
loss percentage factors are available in the Method
Determination[7] , the Technical guidelines[8] and similar documents internationally.[1] For this example the
standard annual loss rate for industrial HVAC units of
16% of refrigerant inventory per year[8] is applied to
the refrigerant inventory of 60 kg to yield an annual
refrigerant loss of 10 kg of refrigerant per year.
However there exist a second, larger fugitive emission
source with even less visibility. Recall that a chemical
reaction is occurring. On investigation, the reaction is
exothermic, with reaction vessels being cooled by circulating cooling water, chilled in this case by a remote
refrigeration facility. The refrigerant leakage rate can be
measured or estimated in the same way as for the HVAC
units: measured by the top-up volumes used, or estimated by a percentage loss factor if true consumption
is not known. In this case the refrigeration unit has been
in service for many years and the annual top-up refrigerant purchase is known and averages 35 kg/year. The
refrigeration compressor has a 60 kg refrigerant working capacity, implying that some 59% (35 kg/60 kg) of
the refrigerant leaks out into the atmosphere each year.
Whilst this statistic may seem high, it is quite possible for an older refrigeration compressor such as in this
example. The replacement cost of this lost refrigerant
is not economically significant to the plant, and accordingly receives limited attention.
A fresh view of the operation?s carbon footprint is
shown in Table 4.
Challenge 3: large range of GWP values
not well appreciated
The mass of refrigerant leaking may not seem significant at a total of 45 kg compared to thousands of litre
and kilogram of fuels and GJ of electricity consumed.
However the GWP of refrigerants can be much greater
than CO2 and other products of fuel combustion. If the
leaking refrigerant is the most popular HFC-134a, with
a GWP of 1300 (Table 1), each kilogram lost is equivalent to 1300 kg of CO2 , or 14 560 kg of CO2 per year
for the refrigeration plant.
In this example, on examination, the HVAC and
refrigeration units all use refrigerant R22 with a GWP
of 1700,[10] so each kilogram lost is equivalent to
1700 kg of CO2 , or 60 tCO2 -e/year for the refrigeration
plant and a corresponding amount for the HVAC
units.
This data is included in a fresh view of the operation?s
annual emissions, in Table 5.
While it may not be conventionally intuitive, fugitive
refrigerant emissions can, in terms of CO2 equivalent
emissions (77 tCO2 -e in this example), be comparable
to the emissions from a small natural gas fired package boiler (168 tCO2 -e between two boilers in this
example).
Challenge 4: inclusions vary
by protocol/regulatory regime
Under Australian regulations, emission of Kyoto refrigerant gases need not be counted unless they are from
certain industries ? the list of which does not include
the chemical industry ? and if the inventory of refrigerant is over 100 kg. And if the refrigerant used and
leaking is Refrigerant R-22, commonly used in plants
from the 1980s, the emissions are not counted in most
Kyoto protocol countries.
The refrigerant emissions calculated above are therefore Scope 3 emissions, whose reporting is voluntary.
Table 6 also shows some other typical Scope 3
emissions, which sum to 200 tCO2 -e in this example
before some as yet unquantified Scope 3 emissions such
as employee travel and natural gas pipeline transmission
losses are included.
Table 5. Annual emissions (carbon footprint) for Example 2 after Challenge 3.
Emissions per year
Emissions source
Scope 2 ? stationary
Scope
Scope
Scope
Scope
1
1
1
1
?
?
?
?
stationary
transport
transport
fugitives
Scope 1 ? fugitives
720 MWh electricity/year
from black coal
3300 GJ natural gas/year
6000 L diesel/year
1300 kg LPG/year
60 kg leaking at 16%/year
= 10 kg/year
60 kg leaking at 59%/year
= 35 kg/year
Total
Emissions factor
Mainly HVAC
0.89
kg CO2 -e/kWh
643
CO2 -e/GJ
CO2 -e/L
CO2 -e/kg
CO2 -e/kg
168
16
2
2 Boilers
Forklifts
Forklifts
R22
51.30
2.82
1.53
1700.00
kg
kg
kg
kg
R22
1700.00
kg CO2 -e/kg
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
NGERS (tCO2 -e)
tCO2 -e
16
60
829
77
Asia-Pac. J. Chem. Eng. 2010; 5: 646?656
DOI: 10.1002/apj
All refrigerants
All refrigerants
+ Travel and gas loss
16
60
200
Transmission
Transmission
Employee travel
643
168
16
2
?
?
829
720 MWh electricity/year from black coal
3300 GJ Natural gas/year
6000 L diesel/year
1300 kg LPG/year
60 kg leaking at 16%/year = 10 kg/year
60 kg leaking at 59%/year = 35 kg/year
Total
stationary
stationary
transport
transport
fugitives
fugitives
?
?
?
?
?
?
2
1
1
1
1
1
Scope
Scope
Scope
Scope
Scope
Scope
Emissions source
Mainly HVAC
2 Boilers
Forklifts
Forklifts
R22
R22
0.89
51.30
2.82
1.53
1700.00
1700.00
CO2 -e/kWh
CO2 -e/GJ
CO2 -e/L
CO2 -e/kg
CO2 -e/kg
CO2 -e/kg
kg
kg
kg
kg
kg
kg
123
NA
NA
Main source
NGERS (tCO2 -e)
Emissions factor
tCO2 -e
Scope 3
Emissions per year
Table 6. Annual emissions (carbon footprint) for Example 2 after Challenge 4 including Scope 3 emissions typically included in a marketing claim.
Asia-Pacific Journal of Chemical Engineering
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
CARBON POLLUTION MEASUREMENT AND REPORTING
CHEMICAL ENGINEERING METHODOLOGIES
CAN ASSIST
Chemical Engineering methodologies can be useful
in addressing the challenges raised above, as these
methodologies have been developed (for other industrial
purposes) to enable:
? The awareness of, measurement and management
of ?low visibility? substances including emission
streams which may not have any other significant
economic importance.
? The identification of missing process components,
or concluding they must be present from thermal
or mass balance, such as the refrigeration facility in
Example 2.
? The understanding of chemical equilibrium, for
example that gas and water in contact with oil will
be in chemical equilibrium, in Example 1.
? Understanding the complexities of different reporting inclusions according to different standards and
regulations.
CONCLUSION
The emergence of mandatory greenhouse gas emissions
reporting in countries such as Australia and the United
States presents corporations with the new challenge of
determining their liability to report their greenhouse
emissions. This involves determining who has reporting
responsibility, then identifying and quantifying these
emissions. Challenges arise in the course of this process, typically involving consideration of factors which
would otherwise have been considered of little economic significance: lack of installed meters, low visibility emissions, the wide spread of GWP factors, and
differences in scope between the Kyoto and national
reporting requirements. Chemical Engineering methodologies can be useful in overcoming these challenges.
REFERENCES
[1] World Resource Institute and the World Business Council
for Sustainable Development. Greenhouse Gas Protocol:
A Corporate Accounting and Reporting Standard, revised
edition, March 2004.
[2] International Organisation for Standardisation. Standard for
Greenhouse Gases ? Part 1: Specification with Guidance at
the Organisational Level for Quantification and Reporting of
Greenhouse Gas Emissions And Removals (ISO/AS 14064-1).
[3] Australian Commonwealth Government. Presentation by the
Greenhouse and Energy Data Officer (GEDO) to Industry
Association APPEA, June 2009.
[4] Australian Commonwealth Government. National Greenhouse
and Energy Reporting Guidelines (2008) and National
Greenhouse and Energy Reporting Guidelines Correction, June
2009.
[5] Australian Commonwealth Government. National Greenhouse
and Energy Reporting Act 2007.
Asia-Pac. J. Chem. Eng. 2010; 5: 646?656
DOI: 10.1002/apj
655
656
A. GUNST
[6] Australian Commonwealth Government. National Greenhouse
and Energy Reporting Regulations, 2008.
[7] Australian Commonwealth Government. National Greenhouse
and Energy Reporting (Measurement) Determination, 2008.
[8] Australian Commonwealth Government. National Greenhouse
and Energy (Measurement) Technical Guidelines, v1.1,
October 2008.
[9] Australian Commonwealth Government. National Greenhouse
and Energy Reporting System Information Sessions Presentation, July 2008.
[10] U.S. Greenhouse Gas Inventory Program. Office of Atmospheric Programs, U.S. Environmental Protection Agency:
? 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Asia-Pacific Journal of Chemical Engineering
Greenhouse Gases and Global Warming Potential Values,
Excerpt from the Inventory of U.S. Greenhouse Emissions and
Sinks 1990?2000, April 2002.
[11] Canadian Association of Petroleum Producers. Estimation of
Flaring and Venting Volumes from Upstream Oil and Gas
Production Facilities, May 2002.
[12] American Petroleum Institute. Compendium of Greenhouse
Gas Emissions Methodologies For The Oil And Gas Industry,
February 2004.
Asia-Pac. J. Chem. Eng. 2010; 5: 646?656
DOI: 10.1002/apj
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