GREENHOUSE GAS (GHG)
CO2 CAPTURE AND GEOLOGICAL STORAGE QUANTIFICATION
The Greenhouse Gas (GHG) Verification Centre is a Government of Canada Action Plan 2000 initiative with
activities in the following 4 areas:
Serving as a central clearinghouse for collecting, maintaining, updating and sharing the latest
documentation and tools required for the measurement and verification of GHG emission reduction
projects and technologies;
Assisting in developing methodologies, protocols and standards for quantifying verifying, and
reporting emissions and emission reductions for various climate change initiatives;
Providing technical support services and coordinate the exchange of information between domestic
climate change initiatives and promote consistency in measurement and verification rules,
processes and procedures used by domestic initiatives;
Facilitating the establishment of trained and accredited verification entities that would perform
measurement, monitoring and verification.
Related to the second objective, the Centre has begun the development of GHG emission reduction
calculation protocols. These protocols provide guidance on how to complete facility-level greenhouse gas
inventories and project-level greenhouse gas emission reduction estimates. These protocols are drawn from
the accumulated knowledge in each area and are as consistent as possible with current international
reporting guidance for GHG emissions. They are made available for the use of Canadian climate change
initiatives and are not obligatory in any way.
It is also important to note that the GHG Verification Centre protocols are intended to give guidance on how
to perform GHG calculations and measurements but must be used within a broader systems approach to
quantifying GHG emission reductions. The current set of project-level protocols are designed to be used
within the systems approach used by the Technology Early Action Measures (TEAM) program, called the
System of Monitoring and Reporting to TEAM (SMART). This document can be obtained from the
Government of Canada climate change web site. Portions of the current protocol refer to elements that are
more fully defined in the SMART.
1.2 Purpose and Scope
This document provides guidance on the calculation of direct emission reductions that can be attributed to
the specific action of capturing a waste stream of CO2 and storing it in a geologic reservoir. The document
deals with GHG emission quantification issues that are applicable to three possible waste streams of CO2,
Purification of raw natural gas (also known as "sweetening");
Hydrogen production for upgrading synthetic crude oil;
Flue gas from a fossil fuel combustion process which may contain CO2 in fairly low concentrations
In addition, this document can be applied to three potential ways of storing this CO 2 in geologic reservoirs,
Storage in a depleted oil and natural gas reservoirs;
Use of the CO2 for enhancing recovery of oil from existing reservoirs;
Use of CO2 for enhancing recovery of coal bed methane.
The current document presents the key quantification issues that are common to all of the above cases and
illustrates how proponents can quantify these emission reductions.
1.3 Basic Principles
As with all Greenhouse Gas (GHG) Verification Centre quantification protocols, certain basic principles must
be adhered to. These principles are drawn from authoritative international guidance produced by the
Intergovernmental Panel on Climate Change (IPCC) in its Revised 1996 IPCC Guidelines for National
Greenhouse Gas Inventories (IPCC Guidelines) and related Good Practice Guidance and Uncertainty
Management in National Greenhouse Gas Inventories (Good Practice Guidance). These documents can be
accessed from the web at:
The rationale for maintaining consistency with this international guidance is to ensure information submitted
by project proponents is consistent with reporting guidelines for Parties to the Kyoto Protocol and the
reporting requirements for the Clean Development Mechanism (CDM) and Joint Implementation (JI).
These basic principles include:
Transparency: the assumptions and methodologies used for calculating an emission reduction should be
clearly explained to facilitate replication and assessment of the calculation by users of the reported
information. The transparency of emission calculations is fundamental to the success of the process for the
communication and consideration of this information.
Completeness: an emission reduction calculation covers all relevant sources and sinks as well as all
relevant greenhouse gases mentioned in the Revised 1996 IPCC Guidelines for National Greenhouse Gas
Consistency: an emission reduction estimate should be internally consistent in all its elements over a
period of years. An emission reduction estimate is consistent if the same methodologies are used for the
base and all subsequent years and if consistent data sets are used to estimate emissions or removals from
sources and sinks.
Comparability: estimates of emission reductions and removals reported by project proponents should be
comparable among all proponents .
Conservative: emission estimates should be produced in such a way that sources are not underestimated
and removals are not overestimated.
Representative: emissions are accounted for where and when they occur; double-counting is to be
For the purposes of this document, a representative glossary of terms can be found in section 3.18 of the
Good Practice Guidance.
1.4 Basic Conventions
International/domestic guidance has established basic conventions to make emission estimates more
comparable. Conventions which should be adhered to when using this protocol include:
Metric units: All emission reduction calculations should be made or converted to metric units prior to
completing the project reporting template.
Physical units of measure: To the extent possible, calculations should be made with physical units of
measure such as mass, volume, length. Ratios of one parameter to another or quantities of fossil fuel
measured in energy units should be avoided since they may contain systematic bias.
Emission reductions of individual GHGs should be calculated separately and then aggregated using Global
Warming Potentials (GWPs): Emission factors for most calculations are greenhouse gas specific and are not
presented in CO2 equivalent. For this reason emission calculations should be completed for each gas and
then GWPs should be applied to aggregate the total GHG emission reductions.
Emission Sources and Reduction Opportunities Through Capture and Storage
As mentioned above, various streams of CO2 are produced in the oil and gas and power generation sectors
and there are a number of ways these can be captured and stored geologically. However, there are
commonalties in how each of these efforts would calculate CO2 emission reductions. These include:
Calculation or measurement of the concentration of CO2 in the waste stream;
Calculation or measurement of the volume of waste gases being injected into the geologic
Characterization of the integrity of the geologic reservoir to establish an estimate of the long-term
Development of a leak measurement strategy that will minimize risks of a catastrophic leakage and
create confidence that the CO2 is, in fact, in long-term storage.
One of the critical elements of the above-mentioned quantification issues is the definition of "long-term"
storage. A number of questions surround the definition of a proper time scale and whether or not it should be
based on geologic time scales or other risk management principles.
In order to simplify debate with respect to "acceptable long-term storage", the GHG Verification Centre is
accepting initial guidance developed by a federal/provincial working group on CO2 capture and geologic
storage. This working group uses, as an initial definition for long-term storage, a period of 1000 years during
which the geologic reservoir must retain a minimum of 90% of the CO2 injected into it. While the selection of
this time frame is somewhat arbitrary, it is well beyond the time periods currently being considered by the
Intergovernmental Panel on Climate Change (IPCC) in their assessments of human-induced climate
change. These assessments are considering the effects of increased greenhouse gas (GHG) emissions on
the earth's climate system over the next 100 to 200 years. For this reason, it is felt that the 1000-year
timeframe is a sufficiently long timeframe for managing the risks associated with human-induced climate
The remainder of this document will deal with the different methods available for measuring or estimating the
four variables identified above.
Methodology for Calculating or Measuring the Concentration of CO2 in a Waste Stream
To begin quantifying GHG emission reductions, it is necessary to first identify a technology or scenario to
serve as the benchmark for the emission reduction project being considered. This benchmark should be as
comparable as possible to the project, in terms of its boundary definitions and technical specifications. It is
expected that most CO2 capture and geologic storage projects will establish the benchmark by defining a
system that excludes the installation and use of a CO2 capture and geologic storage system. For this
reason, it is logical to begin quantifying the possible CO2 emission reductions from the existing concentration
in the waste stream, which would be emitted to the atmosphere if no capture and geologic storage system
were in place.
The preferred method for establishing this concentration is the use of continuous emission monitoring
equipment which can be installed on the outlet of a waste stream and can track the concentration of CO 2
over time. Several manufacturers of this type of equipment exist and its application has been demonstrated
in the power generation sector in the United States.
There is the possibility, however, that the waste stream being considered is not amenable to continuous
emission monitoring, either due to the concentration levels of CO2 present in the waste stream (too high) or
because of other chemical species which may interfere with the accuracy of continuous measurement of
CO2. For these situations, estimation methods are preferred. Proponents can choose between using
established emission factors and activity data (e.g. total production of raw natural gas) to calculate these
estimates, or mass balance calculations may be used. In all cases, a rationale for the selection of a
particular methodology should be provided in the Project Scoping Report and a complete detailing of the
estimation methodology should be provided as an Attachment of the Project Reporting Templates.
Proponents of emission reduction projects may also decide to make their own periodic emission
measurements to establish project-specific emission factors and improve the accuracy of their estimates. In
these cases standard operating procedures should be respected for the emission measurement equipment
and a detailed explanation of the emission measurement protocol should be provided as an Attachment to
the Project Reporting Templates.
Methodology for Measuring or Estimating the Volume of Waste Gases Injected into the Geologic
Various commercially available flow measurement devices exist from suppliers to the petroleum and natural
gas sector. These devices are intended for measuring flows of liquids and gases being extracted from oil
and natural gas reservoirs. Proponents may choose to use similar devices to measure the flow of waste
gases being re-injected into these reservoirs. Measurements from these flow meters can be converted to
volumes injected by applying conversion factors (i.e. from imperial to metric units) and by multiplying by the
time over which injection occurred.
In some cases, proponents may be cryogenically trapping the waste gases before injecting them.
Appropriate flow measurement instruments should be selected for this application and, in both of the above
cases, standard operating procedures (SOP) should be provided as an Attachment to the Project Reporting
Methodology for Establishing the Integrity of the Geologic Reservoir
This step in the quantification protocol is the most critical for establishing the credibility of the emission
reductions achieved. The type of data which project documentation should contain includes, but is not
Location and history of the reservoir in question;
Seismic testing performed during the exploration phase which provides information on the size and
characteristics of the reservoir;
Any geophysical or geochemical testing which may have been performed on the reservoir which
may help in establishing its integrity;
Any history on the number and types of wells that have tapped this reservoir, including their status
(e.g. suspended, abandoned) and the well capping method used;
Any information or specifications on provincial or other jurisdictional requirements or regulations
which govern the injection of waste streams into geologic reservoirs;
Any attestation by a geophysicist or other recognized expert as to the integrity of the reservoir.
It is likely that authorities will use this information in their qualitative determination of whether the reservoir in
question meets the 90%, 1000 year specification. If this determination is positive, the proponent will be
assumed to have successfully injected and stored the full quantity of CO 2 (as determined by the
concentration and volume calculations above) through the implementation of the emission reduction project.
Authorities may reserve the right to request additional information to aid in making its determination.
Methodology for Monitoring of CO2 Post-injection
As an additional quality control step, project proponents must develop and implement a CO 2 monitoring
program that helps establish additional confidence that injected CO2 remains stored in the reservoir. While
the GHG Verification Centre recognises that a comprehensive monitoring program which would cover all
possible leak sites for a given reservoir is not feasible to implement for any given project, some form of
monitoring plan should be submitted with each project proposal to provide confidence that the project
proponent is exercising due diligence. This monitoring plan may include, but is not limited to:
Measurement of key pressure and flow variables at the injection site to ensure that reservoir
parameters are not exceeded;
Measurement of ambient CO2 fluxes, either on a continuous or periodic basis at the injection site
and any other potential leak site which has been identified. These leak sites could include:
particular geologic formations which have been known to leak in the past, improperly capped
suspended or abandoned wells, capped wells that are older than 50 years, etc.
The measurement plan should be designed so as to add confidence that risks of catastrophic or other
leakage are being minimised and that the project proponent is managing the project and surrounding site
Flexibility of Application of the Quantification Protocol
The GHG Verification Centre recognises that the current protocol does not provide extensive guidance to
project proponents on how to complete all these measurements. However, given the nature of the project
category and the state of research in this area, it is not possible at this time to offer complete and
comprehensive guidance to project proponents. The GHG Verification Centre hopes that project proponents
will be innovative in the application of the general guidance given above while at the same time ensuring
that credible emission reductions have resulted from their project.
Emission Reduction Calculation
The critical calculation parameters are:
= the average CO2 concentration of the waste stream for a given timeframe as determined by
measurement or estimation (percent by volume);
V = the total volume of waste gas injected (m );
The density, , of CO2 at the standard condition of 25 °C and 1 atmosphere pressure (atm) is found
from the ideal gas law:
p is the standard atmospheric pressure of 1 atmosphere (atm)
Ro is the universal gas constant, 0.08206 m -atm/kmole-K,
T is the absolute temperature in Kelvin (K = °C + 273.15), and
M is the molecular weight of carbon dioxide in kg.
If the flowmeter indicates the injection stream flow in standard cubic feet per minute (SCFM), multiplying by
0.02832 m /ft3 converts the flowrate to standard cubic meters per minute. Multiplying by the number of
minutes of operation in a day gives the total volume of gas injected (V) in a day.
The carbon dioxide concentration in the injection stream, (c) percent-by-volume, can be measured at the
emission source (e.g. stack) or estimated from reliable input data. These values should be averaged to give
the daily mean carbon dioxide concentration ( ). The product is then the daily volume of carbon
dioxide injected and the corresponding mass. Finally, no Global Warming Potential (GWP) needs to
be applied since the GWP for CO2 =1. The potential greenhouse gas emission reduction (r), in CO2
equivalent (CO2e) can be expressed as:
r= kg - CO2e/day
r, the potential emission reduction, will then be evaluated against the qualitative information on the integrity
of the geologic reservoir and the ambient monitoring program to determine the actual emission reduction. If
sufficient justification is provided on the integrity of the geologic reservoir and the rigour of the CO 2
monitoring program, the potential emission reduction, r, may be determined to be equal to the actual
Quality Assurance and Quality Control
Several quality assurance/quality control (QA/QC) steps have already been outlined in the sections above,
however, some general QA/QC procedures can also be applied to add confidence that all measurements
and calculations have been made correctly. These include:
following manufacturers specifications for instrument calibration and maintenance;
performing recalculations to make sure no mathematical errors have been made;
comparing current estimates with previous estimates as a "reality check";
requesting that another analyst (2nd or 3rd party) attempt to reproduce the calculations.
Third Party Verification
There is no consistent, authoritative guidance, within Canada, for conducting third party verification of
emission reduction claims. For the purposes of the current protocol, third party verification should be
obtained when submitting an emission reduction claim following a set time of operation of a given project.
This will increase the confidence that the emission reduction was achieved and is quantifiable.
Typical GHG emission reduction project-based reporting requires that proponents submit a report indicating
the project and benchmark elements included in the scope of the emission reduction calculation. Each
element of a project should have an associated GHG emission estimate. These estimates may be the same
or different in the benchmark and the project calculation.
In the case of a CO2 capture and geologic storage project, the main element which will differ between the
project and the benchmark is the measurement or calculation of CO2 injected. As stated above, the critical
element for determining the credibility of the emission reductions achieved is the determination of the
integrity of the geologic reservoir. Proponents should pay particular attention to the type and quality of
information reported out on the project. For reporting purposes the project proponent should include
attachments to the Project Reporting Templates that give additional detail on the calculated figures in the
Templates. For geological capture and storage these attachments should include:
daily records of average carbon dioxide concentrations for the reporting period;
daily average flow meter logs;
all raw data and studies relating to the justification of the integrity of the geologic storage reservoir;
sample measurement logs for the carbon dioxide leak monitoring program and daily average
monitoring data for the reporting period;
detailed sample calculations using actual data for the calculation of the emission reduction from a
These attachments should be verified by the third party verifier and included with the Project Reporting