Introduction 

A range of greenhouse gas (GHG) monitoring and accounting protocols and guidelines currently exist for carbon capture and storage (CCS) activities, and various activities continue in this area. This report aims to provide a comparative review of how current GHG accounting rules apply to CCS activities worldwide. These include international, regional and national approaches employed under policies and measures such as mandatory GHG emissions reporting, carbon taxes and emission trading schemes (ETS). Twelve GHG accounting schemes and nine CCS-specific accounting schemes are reviewed. Based on the review, the report identifies issues, gaps and potential barriers

Key Messages

Three key GHG accounting requirements are found to be fundamental to all CCS activities:

1. Recognising captured CO2 for storage as “not emitted”. MRV rules need to allow for captured CO2 to be deducted from the relevant inventory (e.g. sector; installation).
2. Including transport and storage within the scheme accounting rules. MRV rules need to be developed also for monitoring of transport and storage, and these need to dovetail across the project chain.
3. A mechanism to address permanence. Appropriate accounting and MRV rules must provide assurances that the injected CO2 remains in the intended geological formation and isolated from the atmosphere over the long-term, and quantify any leaks that occur.

The review finds that these three key ‘fundamental’ requirements are addressed within existing CCS-specific accounting schemes. Hence the review therefore finds that existing GHG accounting rules are broadly able to account for emissions and emissions reductions associated with ‘standard’ CCS projects.

Some specific gaps, challenges and issues arise however when considering the following ‘special cases’ and these are discussed:

1. Recognition of negative emissions from bio-CCS.
2. Accounting for CO2-EOR.
3. Accounting for CO2 utilisation.