GHG Protocol guidance on uncertainty assessment in GHG inventories and calculating statistical parameter uncertainty

One element of GHG emissions data quality management involves quantitative and qualitative uncertainty analysis. For example, several emissions trading proposals require that participants provide basic uncertainty information for emissions from their activities (e.g. the proposed European Emissions Allowance Trading Scheme). The GHG Protocol Initiative has developed this guidance along with a calculation tool based on Excel spreadsheets. This calculation tool automates the aggregation steps involved in developing a basic uncertainty assessment for GHG inventory data.

The purpose of this document is to describe the functionality of the tool, and to give companies a better understanding of how to prepare, interpret, and utilize inventory uncertainty assessments. The guidance on the tool is embedded in this overview. The guidance is based on the IPCC Guidelines for National GHG Inventories and should be considered as an addition to the calculation tools provided by the GHG Protocol Initiative, as well as to the chapter on Managing Inventory Quality in the standard document.

Section 2 gives a short overview on the different types of uncertainty associated with corporate GHG Inventories and specifies the limitations of the GHG Protocol Uncertainty Tool. In section 3 follows a short introduction to the approach used in the tool for presenting and aggregating statistical uncertainties. Sections 4 through 8 then provide a step by step discussion on collecting uncertainty information and aggregating it using the first order error propagation method. Section 9 provides recommendations on how to document and interpret the results of an uncertainty assessment. Finally, section 10 gives a short guidance on how to use the uncertainty tool.