From 2027 the required Carbon Intensity Indicator (CII) tightens by 2.625 percentage points every year — 13.625 % below the 2019 reference in 2027, rising to 21.5 % in 2030 (Resolution MEPC.400(83)). A bulk carrier whose operating profile stays the same will drop roughly one rating band every two to three years. Ships rated D for three consecutive years, or E once, must add a corrective action plan to SEEMP Part III — and charterers, banks and vetting see the rating long before that.
What Is the CII?
The Carbon Intensity Indicator (CII) is the IMO’s annual operational carbon rating under MARPOL Annex VI regulations 26–28. It applies to cargo ships of 5,000 GT and above. Each year the ship’s attained CII is compared with a required CII and rated A to E. For bulk carriers and general cargo ships the metric is the Annual Efficiency Ratio (AER), in grams of CO₂ per deadweight-tonne nautical mile.
How the Rating Is Calculated
- Attained CII (AER) = total annual CO₂ ÷ (DWT × distance travelled)
- CO₂ = fuel consumed × CO₂ factor (e.g. HFO 3.114, MDO/MGO 3.206 t CO₂ per t fuel)
- Reference line: CIIref = a × DWT^−c. Bulk carrier: a = 4,745, c = 0.622 (MEPC.353(78))
- Required CII = (1 − Z/100) × CIIref
- Rating boundaries for bulk carriers = 0.86 / 0.94 / 1.06 / 1.18 × required CII (MEPC.354(78))
| Year | Reduction factor Z (vs. 2019) |
|---|---|
| 2026 | 11 % |
| 2027 | 13.625 % |
| 2028 | 16.25 % |
| 2029 | 18.875 % |
| 2030 | 21.5 % |
Worked Example: A 58,000 DWT Supramax
For a 58,000 dwt bulk carrier the reference CII is about 5.17 g CO₂/dwt·nm. The required values and the C/D boundary become:
| Year | Required CII | D starts above |
|---|---|---|
| 2026 | 4.60 | 4.88 |
| 2027 | 4.46 | 4.73 |
| 2028 | 4.33 | 4.59 |
| 2030 | 4.06 | 4.30 |
A ship with a constant attained AER of 4.75 is C in 2026 and D from 2027. After the third consecutive D, a corrective action plan becomes mandatory.
What a D or E Rating Triggers
- Regulatory: SEEMP Part III must be revised with a plan of corrective actions and verified by the Administration or RO.
- Commercial: charterers’ CII clauses (e.g. BIMCO CII Operations Clause), RightShip GHG rating and bank Poseidon Principles reporting all use the same data.
- Financial: the same fuel data drive EU ETS and FuelEU Maritime costs.
The Measures Toolbox for Bulkers
Operational — low or no capex
- Speed management: fuel per mile varies roughly with the square of speed — 10 % slower ≈ 19 % less main-engine fuel per mile
- Just-in-time arrival and reduced anchorage time — idle days add CO₂ without distance
- Weather routing and trim optimisation
- Hull cleaning and propeller polishing triggered by performance monitoring, not the calendar
- Auxiliary load control — fuel “not underway” is now reported separately
Technical — best at dry-dock
- Low-friction or foul-release hull coatings
- Energy-saving devices (pre-swirl ducts/stators, PBCF, rudder bulbs) with CFD justification and Class approval
- Propeller retrofit matched to the actual slow-steaming profile
- Variable frequency drives on engine-room fans and pumps; LED lighting
Data quality — protects the rating
- Accurate FAOP/EOSP events, distance and anchorage periods
- Fuel by consumer reconciled with bunker delivery notes
- Correction factors and voyage adjustments checked under MEPC.355(78)
In the Supramax example, a ~10 % speed reduction combined with hull and propeller care brings the AER from 4.75 to about 3.99 — back to C in 2030 before any capex.
Data: The Enhanced IMO DCS
From 2026 data, the IMO Data Collection System requires fuel per consumer and fuel type, fuel underway vs. not underway, laden distance and transport work. The first full report (calendar 2026) is due by 31 March 2027. The CII itself is still calculated on total annual CO₂ and total distance, but poor data can move a ship a full rating band.
A Five-Step Action Plan
- Run a 2027–2030 CII projection for each ship using verified 2025 data and 2026 year-to-date data.
- Agree a speed and consumption policy and charter-party terms with chartering.
- Build a measures plan per ship — operational now, technical at the next dry-dock.
- Put a DCS data-quality procedure in place before 1 January 2027.
- Where a ship reaches D×3 or E, prepare the corrective action plan and confirm the submission deadline with the RO.
What About the IMO Net-Zero Framework?
The global fuel standard and GHG pricing mechanism was not adopted in October 2025, and MEPC 84 continued negotiations without a timeline. CII remains the operative IMO carbon rule — do not delay measures waiting for it.
| The FleetPreserve Angle: Most CII problems are visible a year before the rating is issued. An independent projection on the ship’s own speed–consumption data shows which ships will cross into D, by how much, and which mix of speed, hull care and dry-dock measures closes the gap at the lowest cost — before the charterer’s screening does it for you. |
Conclusion
The CII is no longer a reporting exercise; from 2027 it is a moving target that most bulk carriers will miss without a plan. Owners who project, measure and act in Q4 2026 will keep their ships at C; those who wait for the 2027 rating will negotiate from a D. FleetPreserve provides CII projections, measures plans, SEEMP Part III and corrective action plans, and DCS data-quality audits for bulk carriers and general cargo ships. Contact info@fleetpreserve.com or visit fleetpreserve.com to request a CII projection for your fleet.
Download Technical Advisory FP-TA 03/2026 for the full rating tables by ship size and the measures toolbox.
