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UK GHG Inventory QA/QC System
AEA manages the inventory QA system to comply with the Tier 1 procedures outlined in the IPCC Good Practice Guidance (IPCC, 2000). The system is being developed and the range of activities extended so that the system complies with Tier 2.
The inventory is based on a live database system into which Quality Assurance and Quality Control (QA/QC) procedures have been built over several years. The database consists essentially of a table of activity data and a table of emission factors for the GHGI source categories which are multiplied together to produce emission estimates according to IPCC and CORINAIR formats.
The GHGI is subject to BS EN ISO 9001:2000 and is audited by Lloyds and AEA internal QA auditors to test elements including: authorisation of personnel to work on inventories, document control, data tracking and spreadsheet checking, project management.
DECC is in the process of implementing an EU Decision 280/2004/EC on a mechanism for monitoring Community greenhouse gas emissions and for implementing the Kyoto Protocol. This process includes the development of more formal memoranda of understanding for all the major data providers, to include specific criteria for QA/QC.
Referencing and Documentation Schematic
The existing QA/QC system incorporates the following activities, which are carried out each year as the inventory is compiled:
1. Documentation
Tick Data received by AEA are logged, numbered and are traceable to their source.
Tick The inventory is held as a database of activity data and emission factors, each of which are referenced to the data sources.
Tick An on-line QA manual defines timetables, document control, checking procedures and procedures for updating the methodology manual.
Tick The on-line methodology manual contains details of the methodology used, emission factor and activity data sources, discussion of the rationale for choice of methodology and emission factors.
Tick Data processing spreadsheets are customised to incorporate required documentation of data sources, spreadsheet functions and outputs, to ensure traceability of dataflows.
Tick An annual report outlining the methodology of the inventory, data sources and changes made is produced.
2. Database
Tick The classification of source categories is controlled by a formatting table in the database, used to generate emissions tabulated in the IPCC format. Database queries are used to compare tabulated outputs to check that all sources are acounted for and that the totals are correct. Consistency checks are made between outputs in IPCC, CORINAIR and CRF formats and compared against database totals.
Tick All fields in the database are labelled automatically with an NAEI source/fuel category, CORINAIR SNAP code and the appropriate units. Comment fields link to each data entry to provide further description of data sources and calculation methods.
3. Checking
Tick Spreadsheet calculations are checked using internal consistency calculations, and data sources are referenced within spreadsheets.
Tick Spreadsheet completion and data entry to the database are peer-checked.
Tick Database queries are tailored to abstract and total fuel consumption data for each fuel. These totals are then checked against the totals reported in the DBERR publication DUKES.
Tick For historic data, consistency checks are made to compare emission totals against the previous inventory. A designated auditor identifies sources where there have been significant changes or new sources and inventory staff are required to explain these changes in the inventory to satisfy the auditor.
Tick A final check is made on the inventory comparing the emissions of the latest year with those of the previous year. A designated checker identifies sources where there have been significant changes and inventory staff are required to explain these changes in the inventory to satisfy the checker.
4. Recalculation
Tick When revisions are made to the methodologies of the estimates, emissions for all previous years are recalculated.
5. Uncertainties
Tick Estimates are made of the uncertainties in the estimates according to Tier 1 and Tier 2 procedures.
Tick A ranking exercise is performed according to Tier 1 procedures to identify key source categories.
6. Archiving
Tick At the end of each reporting cycle, all the database files, spreadsheets, on-line manual, electronic source data, paper source data, output files are in effect frozen and archived. An annual report outlining the methodology of the inventory and data sources is produced. Electronic information is stored on hard disks that are regularly backed up. Paper information is archived with a simple database of all items in the archive.
Checking Within the UK GHGI Compilation Process
The figure below illustrates the system of data checks used within the UK greenhouse gas inventory, with the vertical bars symbolising ‘gates’ through which data should not pass until the appropriate checks have been performed.
Checking Schematic
Specific QA/QC activities undertaken in recent years
Data Processing and Storage Systems of the Inventory Agency
The data processing systems and GHG inventory database used by the Inventory Agency have been significantly improved, leading to a number of QC system improvements such as: a reduction in errors made when data is entered into the database; more stable data storage and management systems; and an improved data audit trail.
Key Data Provider Meetings
Meetings have been held between AEA and several key organisations to identify areas for GHGI improvements including:
Bullet The DBERR team that compile the UK’s consumptions of solid, liquid and gaseous fuels;
Bullet The Environment Agency Pollution Inventory team;
Bullet The Scottish Environmental Protection Agency EPER team;
Bullet UKOOA to discuss data used to compile emission estimates from oil and gas.
Development of Agreements with Data Providers
UK DECC is in the process of implementing an EU Decision 280/2004/EC on a mechanism for monitoring Community greenhouse gas emissions and for implementing the Kyoto Protocol. Specific developments to meet the requirements of the UK National Inventory System include the arrangements with key data providers to ensure quality, timely, secure data provision to the UK GHG inventory.
Compliance of National Statistical Agencies
Many of the data received by AEA come from other government departments, agencies, research establishments or consultants. Some of these organisations (e.g. DBERR, North Wyke Research and BGS) would qualify as the National Statistical Agencies referred to in the Guidance. Other organisations (e.g. CEH) compile significant parts of the Inventory; data complied by other organisations are used to compile significant parts of the inventory (e.g. the Pollution Inventory). These organisations are to prepare documentation to show how their QA/QC systems comply with IPCC Good Practice Guidance.
External Peer Reviews
Tier 2 of the Good Practice Guidance requires that key sources should be subjected to external peer review. During 2002, the UK implemented a programme of peer reviews by experts outside of the organisation responsible for the estimates. The first peer review on CO2 emissions from fossil fuel has been completed (Simmons, 2002). Recommendations from this Peer Review, which have now been implemented, include: an improved method for estimating emissions from domestic and international civil aviation; a review of the carbon emission factors used in the UK GHG inventory; and a review of the proportion of recycled lubricants burnt.
The second Peer Review on agriculture was carried out in March 2005. The external reviewers were Prof. Ulrich Daemmgen (Institute of Agroecology, Germany) and Ulrike Doering (Federal Environmental Agency, Germany). Both Prof. Ulrich Daemmgenm and Ulrike Doering are internationally recognised experts in the technical area of agriculture. The review team also included the GHG agricultural expert from UK IGER (Lorna Brown) and John Watterson and Chris Dore from AEA (representing the Inventory Agency). The review covered: the methods used to estimate agricultural emissions, including emissions from agricultural soils (N2O), manure management (N2O) and enteric fermentation (CH4S); the underlying activity data and emission factors; uncertainties; and the QA/QC of the emission estimates. The recommendations of the review will be used to help improve the accuracy of the emission estimates from the agricultural sector.
In Country Review
In March 2007, the UK GHGI underwent a UNFCCC in-country review, in accordance with Decision 19/CP.8. The purpose of the review was to ensure that the UK was following IPCC Good Practice for inventory compilation and to certify that the National Inventory System met with the requirements defined in the Marrakesh Accords of the Kyoto Protocol.
After reviewing each sector of the inventory in detail, the expert review team concluded that the UK's institutional arrangements were well organised and well functioning, leading to a high-quality, transparent, consistent, comparable, complete and accurate report in accordance with the Revised 1996 IPCC guidelines and the IPCC good practice guidance.
Verification is covered as part of the QA/QC checks and by the background research undertaken by DECC. In addition DECC contributes support and analysis of the continuous high-frequency observations of the Kyoto gases at the Mace Head Atmospheric Research Station on the Atlantic Ocean coastline of Ireland. The UK Met Office employs the Lagrangian dispersion model NAME (Numerical Atmospheric dispersion Modelling Environment) driven by 3D synoptic meteorology from the Unified Model to sort the observations made at Mace Head into those that represent Northern Hemisphere baseline air masses and those that represent regionally-polluted air masses arriving from Europe. The Lagrangian dispersion model is then used to estimate the magnitude and spatial distribution of the European emissions that best support the observations. The technique has been applied to 3-yearly rolling subsets of the data.

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