Draft accounting rules for carbon capture and storage technology

In this chapter, a framework of accounting rule of carbon dioxide capture and storage (CCS) technology is proposed based mainly on leakage estimation using newly developed models. These rules follow identified priority factors with which emphasize estimation and accounting of yearly leakage in the near term as a conservative basis for rule making. In avoided emission estimation methodology, the net stored amount of CO₂ is defined and a three-level-methodology is proposed for estimating yearly physical leakage. The proposed accounting rules for CCS consists of avoided emission estimation methodology, accounting rules for national inventories, and accounting rules for project-based activities. In suggesting accounting rules for use in national inventories, an accounting method is recommended that presumes 100% of stored CO₂ at the time of injection with summing up of emissions afterwards when gradual leakage or sudden release occurs. In establishing accounting rules for project-based activities, a compensation rule is proposed for CCS in general or a discounting rule for geologic CCS with a very rigid structural seal.