FAQs

Emission Reduction Methods

• For what emission sources does the 1605(b) Program provide approved methods?
  

The 1605(b) Program cites approved emissions methods for the following sources:

• Stationary Combustion;
• Mobile Sources;
• Industrial Processes;
• Agricultural Sources;
• Fugitive Emissions associated with Geological Reservoirs;
• Indirect Sources; and
• Forestry Sources.

• How are emission methods rated?

EIA uses an ordinal rating system to grade emission estimation methods and achieve accurate, reliable, and verifiable emission results. The Technical Guidelines usually identify more than one acceptable method of measuring or estimating greenhouse gases emissions for each category. Therefore, each acceptable method is rated A, B, C, or D, with A methods corresponding to the highest quality method available and D representing the lowest quality method hat may be used. Furthermore, each letter is assigned a numerical rating reflecting its relative quality, 4 for A method, 3 for B method, 2 for C methods and 1 for D. See Appendix G of the Instructions for Form EIA-1605 for a complete list of emission methods and ratings by source.

Table 2 provides a general description of the criteria used to set the four ratings for particular sources within the Technical Guidelines.

Table 2: Description of Ratings for Measurement & Estimation Methods

Source: United States, Department of Energy, Office of Policy and International Affairs.Technical Guidelines Voluntary Reporting of Greenhouse Gases 1605(b) Program. January 2007.p.6

• What is the minimum quality rating required for entities intending to register emission reductions?

Entities that intend to register emission reductions must use emission inventory methods that result in a quantity-weighted average quality rating of at least 3.0.

• How do I estimate emission reductions?

Emission reductions must be estimated using the following methods, which are outlined in the Guidelines for Voluntary Greenhouse Reporting:

• Changes in Emissions Intensity;
• Changes in Absolute Emissions;
• Changes in Carbon Storage;
• Changes in Avoided Emissions;
• Energy Generation and Distribution (Integrated method); and
• Action-specific Emissions Reductions.
• General Guidelines, §300.8(h)
• Technical Guidelines, Section 2.4
  

• What is emissions intensity?

Emissions intensity indicates the emissions per unit of output, where output is defined as the quantity of physical output, or a non-physical indicator of an entity's or subentity's productive activity. The Changes in Emissions Intensity reduction method measures the change in emissions form the Base Period to the Reporting Year, per unit of output. Entities are encouraged to calculate reductions using emissions-intensity methods when feasible. Using emissions-intensity methods is usually feasible when the following are applicable:

• There is a clear physical measure of output associated with, or the service provided by, the emissions.
• The same measure of output is likely to be used for at least several years (that is, the basic product being produced, the output metric, is not likely to change substantially in the near future).
• It is not likely that significant elements of the covered process will be outsourced (or "in-sourced") in the near future.
  

 

General Guidelines, §300.8(h)(1)
Technical Guidelines, Section 2.2.2.1

• What are absolute emissions?

Absolute emissions are an entity's total emissions calculated in units of carbon dioxide equivalents. The Changes in Absolute Emissions reduction method measures the change in total emissions of CO2 equivalents produced between an entity's Base Period and its Reporting Year.

Any entity may use changes in the quantity of absolute emissions (for the entity as a whole or a specific subentity) to determine emission reductions reported to EIA. However, entities that intend to register their reductions may use this method only if they can demonstrate that the output associated with covered emissions did not decline from the identified Base Period to the Reporting Year. Entities may use one or more physical or economic measures of output (such as quantity of product or total value of shipments) to demonstrate that the affected output has not declined.

Technical Guidelines, Section 2.4.2

• What is carbon storage?

Carbon storage is the quantity of carbon stored in biological and physical systems including: trees, products of harvested trees, agricultural crops, plans, wood and paper products and other terrestrial biosphere sinks, soils, oceans, and sedimentary and geological sinks. The Changes in Carbon Storage reduction method measures changes in the quantity of carbon stock stored in biological and physical systems between the entity's Base Period and Reporting Year.

General Guidelines, §300.2
Technical Guidelines, Section 2.4.3

• What are avoided emissions?

Avoided emissions are those emissions that do not occur within the boundaries of the reporting entity due to the use of non- or low-emitting sources (e.g., wind power, hydropower, or solar power). The Changes in Avoided Emissions method should be used when an energy product (including electricity, hot water, steam, and chilled water) produced by a non- or low-emitting source is distributed to customers that would have otherwise purchased a comparable energy product generated by a higher-emitting source. This method may be used exclusively if the reporting entity has no emissions associated with such energy exports in their Base Period; that is, either all of its distributed energy were generated by non-emitting sources or it distributed no energy during its chosen Base Period.

General Guidelines, §300.2
Technical Guidelines, Section 2.4.4

• What is the Energy Generation and Distribution (or integrated) method?

Energy Generation and Distribution is a reduction method used for entities or subentities that produce electricity, steam, or hot/chilled water for export (sale) to other entities (and that also have emissions in the Base Period). Also known as the "integrated method," this method simultaneously calculates emission reductions by evaluating changes in both emission intensity and avoided emissions.

This method calculates emission intensity reductions based on Base Period sales levels, and avoided emission reductions on incremental sales levels above Base Period sales levels. Most electric utilities will be required to use this method to calculate emission reductions.

• What are action-specific methods to calculate reductions?

Action-specific methods are methods for estimating reductions from specific sources or situations that result from actions not covered by any other method, including landfill methane recovery, coal mine methane recovery, geologic sequestration, and transmission and distribution losses.

The action-specific methods included in the Technical Guidelines and on Form EIA-1605 include:

• Coal Mine Recovery
• Landfill Methane Recovery
• Geological Sequestration
• Electricity Transmission and Distribution Improvements
• Anaerobic Digestion at wastewater Treatment Facilities
• Anaerobic DIgestion of Animal Waste
• Recylcing of Fly Ash
• Demand-Side Management and Other Emissions Reduction Programs
• Combined Heat and Power
• Destruction of Chlorofluorocarbons
• Guidance on how to apply each of these methods is provided in Section 2.4.5 of the Technical Guidelines.

General Guidelines, §300.8(h)(5)

• What is the difference between the emissions intensity and absolute emissions reduction methods?

The fundamental difference between the Changes in Emissions Intensity and Changes in Absolute Emissions reduction methods is that the absolute emissions method measures the difference between actual Base Period and Reporting Year emissions, while the emissions intensity method demonstrates the difference between Base Period and Reporting Year emissions in relation to the emissions intensity, which is the amount of emissions per unit of output.  The unit of output can be a physical, economic, or indexed output measure. 

The Changes in Absolute Emissions method can only be used to register reductions if the output associated with covered emissions did not decline from the Base Period to the Reporting Year.  The Changes in Emissions Intensity method may be used when it is feasible.  A reporter may register reductions using the Changes in Emissions Intensity method and also report but not register reductions using the Changes in Absolute Emissions method in the same report. 

Technical Guidelines, Sections 2.4.1 and 2.4.2

Form EIA-1605, Addenda B1 and B2

• Can the absolute emission method be used for power generation?

Yes. Electricity generators are required to use either the integrated method (a combination of the emissions intensity and avoided emissions methods) or the absolute emission method in calculating reductions. It is important to note, however, that to register reductions, the absolute emission method cannot be used if the output of your entity or subentity, whichever the method is applied to, is declining.

Technical Guidelines, Section 2.2.2

• Can I use more than one reduction calculation method to estimate reductions?
  

In some cases you may need to use two or more reduction estimation methods because of the disparate nature of your various emission sources.   To do this, you will need to define and specify the portion of the entity (i.e., “subentity”) to which each method will be applied. If you intend to use more than one method to calculate emission reductions, or intend to use different output measures for the Changes in Emissions Intensity method, your entity must be divided into two or more subentities.  The methods used must cover all the entity’s emissions sources and must be clearly reported in the analysis of reductions.

 

Technical Guidelines, 2.2.1

General Guidelines, §300.8

• Should large emitters intending to register reductions calculate emission reductions at the entity level?

Large emitters intending to register reductions must estimate their reductions at the entity-level.  Large emitters intending to register reductions must include all emission sources, with the exception of de minimis sources, in their emissions inventory and base the emission reductions they register on the total emissions for the entity.  Emission reductions may be calculated using a single method applied to total entity-wide emissions.  Alternately, an entity may be divided into several subentities using different emission reduction methods, output measures, or Base Periods; however, the total emissions of the subentities combined must equal the total emissions of the entity.

Instructions for Form EIA-1605, pp.6

General Guidelines, §300.3(b)

• Should small emitters intending to register reductions calculate all emission reductions using the same method?

Small emitters intending to register reductions should calculate reductions according to each activity on which they have decided to report.  An activity of a small emitter is defined by its ability to be assessed with a single emission reduction calculation method.  As a result, if the entity chooses to report only one type of activity, it would only use one reduction method.  If more that one activity is reported, multiple reduction methods may be used. 

Instructions for Form EIA-1605, pp.6

General Guidelines, §300.5(e)

• How would an entity report reductions for landfill methane recovery if the entity were already reducing emissions in the Base Period?

The reporter may only report reductions for actions occurring since the Base Period.  The reductions would be based on the increase in methane captured and destroyed since the Base Period. 

 

Technical Guidelines, Section 2.4.5.6.2

Form EIA-1605, Addendum B7

• How would an entity report reductions for landfill methane if it closed a landfill, and therefore reduced its overall emissions?

Reductions associated with landfill closure are not recognized, for the following reasons:

• Reductions associated with landfill methane are calculated based on the difference in the quantity of methane captured in the Base Period and the Reporting Year. 
• If the amount of methane captured in the Reporting Year is less than the quantity captured in the Base Period due to landfill closure, this would show up as an emission increase rather than a reduction, provided the landfill is still within the entity’s organizational boundaries. 
• Additionally, any reductions associated with closing a landfill are not recognized, since waste is likely to be diverted to a different landfill, where emissions will increase.

 Technical Guidelines, Section 2.4.5.6.2

• According to the 1605(b) geological sequestration guidelines, does the capture and sale of CO2 yield a reduction?

The capture and sale of anthropogenic CO2 does not, in itself, yield a reduction; it is only through the long-term storage of CO2 that a reduction may be generated.  For the purpose of calculating emission reductions, all sales or other transfers of CO2 to another entity must be treated as emissions in the year of the transfer.  Entities that capture and sell CO2 to a third party that permanently sequestered the CO2 by injection into geologic formations may report reductions only if there is a written agreement with the third party.

Alternatively, if the reporting entity both captures and stores the CO2, it has primary ownership of the reductions, and therefore would not need to obtain a written agreement.