The IMO DCS is a mandatory requirement, and the first step in a larger process to collect and analyse shipping emissions data, alongside the EU MRV.
Vessels are required to report their Distance travelled, the total amount of each type of fuel consumed, and the hours underway under their own propulsion. In addition, the SEEMP (Ship Energy Efficiency Management Plan) must be adjusted to document the data collection method and reporting process.
A vessel’s fuel oil consumption must be verified by the flag administration or Recognised Organisation (RO) - such as DNV - either annually or where there is a change of flag or owner. Then the flag state (or RO) reports the verified fuel oil consumption data to the IMO's GISIS database. This data is held anonymously – so that individual vessels and Flag States cannot be identified.