Expert Meeting on Use of Models and Measurements in GHG Inventories
9-11 August 2010, Sydney
Co-Chairs Summary
1. The expert meeting considered the use of models and measurements for all sectors in greenhousegas emission inventories. In the light of experience to date, the meeting compiled a report onexperience and the lessons learnt, particularly related to transparency so that inventory compilers
addressing these issues can benefit from this experience.
2. Measured data underlie both models and facility level data. Measurements may be made atindividual plant covering all of part of specific sub-sectors, and the meeting noted that there are anincreasing number of reporting systems that combine such measured data with other facility level
information. In general, models, use measured data for calibration, evaluation and validation toestimate those emissions or removals that cannot be easily otherwise obtained, and so extend
limited information to cover national emissions and removals.
3. The use of both models and facility level data in inventories provides significant opportunities toimprove the overall quality and, usually, accuracy of the inventory, through, amongst other things,(i) reducing uncertainty and improving uncertainty estimates in the national inventory; (ii) improving
spatial and temporal resolution of data and further disaggregating data categories; or (iii) improving
potential to correctly estimate impacts of mitigation on national inventories by, for example,
reflecting any mitigation effects from measurements or by improving inventory stratification.
Therefore their use in the national inventory should be encouraged.
4. The key issue identified in the use of both models and facility level data, is transparency. Whileapproaches to ensuring transparency, documenting and reporting lower Tier approaches areclearly given in the IPCC Guidelines, the use of models and facility level data is only discussed
more generally as the specifics depend on national circumstances. The 2006 IPCC Guidelines doprovide the overall approach to transparently documenting and reporting these types of data. The
meeting noted that clearer descriptions of the approaches used to derive national emissions would
help ensure the results understandable and credible and that recent experience provides usefulguidance to inventory compilers on how to do this.

5. The meeting compiled lists of typical items that, when reported, may lead to improved
transparency. These include:
ModelsFacility Level Data
Institutional arrangements• Basis and type of model• Legal basis• Application and adaptation of the model• Elements covered• Main equations/processes• Criteria for data selection• Key assumptions• QA/QC• Domain of application• Confidentiality• How the model parameters were estimatedCategory-specific• Description of key inputs and outputs• Category emissions• Details of calibration & model evaluation• Implied emission factor• Uncertainty and sensitivity analysis• Uncertainty• QA/QC procedures adopted• How completeness and time series• References to peer-reviewed literature
consistency are ensured
6. The meeting also considered some of the factors inventory compilers need to consider in the use ofmodels and facility level data.
7. For models considerations include: reasons for model selection; interpretation of model results;
calibration and parameterisation; evaluation of model methods, processes and results;
comparisons with lower tiers and measurements; uncertainty and sensitivity analysis.
8. For facility level data considerations include: do the facility level data definitions match those of theinventory and how has this matching been achieved; does the dataset completely cover a reporting
category and if not how this gap has been filled; how has time series consistency between thefacility level data and estimates for earlier years has been achieved; and how might these dataenhance the quality of inventories
9. The meeting also considered how the use of these methods can be encouraged. The main barriers
to the adoption of complex models are the need for enhanced financial resources and institutional
capacity. Access to suitable models, and the ability to modify them, remains a barrier to their use.
The participants also noted that the use of models requires a significant, sustained and dedicatedeffort over the lifetime of the model to collect and update high quality and reliable data at a suitable
resolution and to maintain and adapt suitable models.

Thelma KrugTFB Co-Chair

Taka Hiraishi
TFB Co-Chair