Reducing onboard energy consumption is an effective way of complying with the IMO GHG fuel intensity targets that will apply to 5,000+ GT ships from 2028. Solutions are available that help owners comply, save money, and contribute to low-emission shipping. In April 2025, the 83rd session of the IMO’s Marine Environment Protection Committee approved the IMO Net-Zero Framework, introducing new emission rules: As of 1 January 2028, all ships above 5,000 GT (except ships trading solely domestically and platforms including FPSOs, FSUs, and drilling rigs, and semi-submersible vessels) must report their GHG fuel intensity (GFI) – and if they do not meet the IMO targets, owners will face economic consequences. The decision is a big step towards lower GHG emissions from shipping.
What are the consequences?
Under the upcoming regulations, shipowners must submit emission reports once a year. The reported figures (calculated using a well-to-wake approach) are compared to targets defined by the IMO.
There are two targets. The most stringent one is the direct compliance target. As shown below, a vessel meets this target in 2028 if it has reduced emissions by 17% or better compared to a 2008 baseline. There is also a less stringent base target; for 2028, this is a 4% reduction compared to 2008.
What happens next depends on which target the ship is able to meet:
- If the ship meets (or outperforms) the direct compliance target, there is no cost to the owner. In fact, the owner receives surplus units (SUs) which can offset the Tier 2 compliance deficit of other ships (see below) or be saved for use within the next two years.
- If the ship does not meet the direct compliance target but meets the base target, the owner must purchase remedial units (RUs) from the IMO at USD 100 per ton of CO2 equivalents emitted by the ship. These Tier 1 RUs cannot be offset by using SUs from other vessels.
- If the ship does not meet the base target, either, the owner must purchase Tier 1 RUs and Tier 2 RUs at a combined cost of USD 480 per ton of CO2 equivalents emitted by the ship. Instead of buying Tier 2 RUs, shipowners can offset the Tier 2 deficit by transferring SUs from other vessels, if any, but the owner must still buy Tier 1 RUs.
As the reduction levels for both direct compliance and base targets increase every year, ships must constantly reduce emissions to stay compliant – and the cost of purchasing RUs quickly adds up. A calculation example from ClassNK shows that a ship consuming around 4,000 tons of LNG annually will cost its owner USD 112,560 a year – even if it meets the base target.
Solution: reducing energy consumption
On almost any ship, it is possible to drive down fuel consumption and emissions by reducing onboard energy consumption. One efficient way of doing this is to operate pumps, engine room fans, compressors, and other equipment based on current requirements instead of design conditions (which are worst-case scenarios intended to prepare the ship for extreme conditions that rarely occur in actual operation).
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DESMI calculations show that on a Panamax bulker with three main sea water pumps, for example, it is possible to save 79% of pump-related HFO consumption by adjusting pump speeds. Similar savings can be achieved on other ships, saving thousands of dollars, reducing CO2 emissions, and making it easier to comply with the base or direct compliance target. DESMI solution facilitates compliance with GFI targets and other requirements. Based on sensor input, variable frequency drives, and decades of experience, the DESMI OptiSave™ solution enables this by automatically optimising equipment operation. It requires no major rebuilding or refitting, making it easy to retrofit and improve efficiency, and it is already operating successfully in more than 700 installations on more than 450 vessels globally.
By improving energy efficiency and reducing carbon emissions, OptiSave™ helps shipowners comply with the IMO’s base and direct compliance targets. It also helps them comply with regional emission regulations such as the emission trading system (ETS) used in the European Union. Finally, higher energy efficiency also helps improve the vessel’s CII rating so the owner does not have to develop a SEEMP Corrective Action Plan. Like the GFI targets, CII requirements become stricter year by year, and shipowners need to take action to stay compliant.
Conclusion
The new IMO MEPC83 GHG requirements will be considered for adoption as amendments to MARPOL Annex VI at an MEPC session in October 2025. Though many details are still unclear, it is evident that shipowners must increasingly take steps to reduce emissions or face economic consequences.The high cost of RUs makes energy optimisation retrofit solutions like DESMI OptiSave™ an attractive option. Not only can they help shipowners comply with the IMO targets; they also help meet other emission standards and improve vessel CII ratings – and the technology is proven, reliable, and available today.
For more information about OptiSave™, visit desmi.com, or contact us today, for example to get vessel-specific calculations of how much fuel, energy, and money it is possible to save.
