About our greenhouse gas data

Controlled emissions: Exclusions

For controlled emissions we include our direct GHG data emissions for all significant companies that we operated or controlled. However, GHGs from certain sources emitted by these companies have not been included; namely, emissions from offices, transportation and depots controlled or operated by our downstream business. The volumes from these excluded sources are not significant. We believe they are less than 5%. During 2009 we will complete and publish a quantification of these exclusions.

Controlled emissions: Metering and estimation

Approximately 30% of the 75 million tonnes of CO2 equivalent in direct emissions we report currently come from companies that participate in regulatory cap and trade programmes or voluntary registers. These emissions data are mainly based on direct measurements using calibrated meters. These companies have also had on site data audits as required by the relevant regulatory authorities. For other reporting companies, data has been obtained through a combination of metering and estimation based on mathematical formulas. These data have greater uncertainty associated with them.

Equity emissions:

Reporting GHG data on an equity basis, where we do not have control or operate many of the entities involved, carries additional limitations. As for our controlled emissions sources such as transportation and depots are not included. Equity data is often reported only for entities where our ownership is above a certain percentage level. Being dependent on companies and joint ventures we do not operate or control means some data is not available in the desired time frame. The level of controls or verification are not always known. Accordingly, we cannot comment on the quality of this data. For example, our equity data for refining excludes 10 refineries (PDF, 15Kb KB) - opens in new window where we have an equity share. They represent approximately 3% of the total refining capacity we own. Our Gas and Power equity emissions include entities where our ownership share is 15% or more. Our Exploration and Production equity emissions include entities where our ownership share is 20% or more. Download an overview of companies in this category where we have been unable to secure GHG emissions data (PDF, 24 KB) - opens in new window.