JUST MEETING EEXI REQUIREMENTS RISKS MISSING CII POTENTIAL

Dr. Chris Craddock, Head of LR’s Technical Advisory & Ship Performance Team, says power limitation is fully permitted by the IMO to improve the attained EEXI and is expected to be the most popular choice for shipowners. It is typically very effective in reducing the EEXI, relatively straightforward to install, relatively inexpensive and relatively non-invasive on commercial operations. It also allows for reserve power to be used up to the total installed power in the case of an emergency, so it does not compromise safety.

However, it does involve a number of additional statutory requirements in terms of verification and approval from the Flag Administration or Recognised Organisation (RO). In some cases, it can increase ship vibration, and, critically, in many cases it will be ineffective in reducing operational carbon intensity (carbon intensity indicator (CII)), and other improvement measures will be required to achieve this.

Operators of EEDI certified vessels will need to ensure they know the required EEXI (which may differ from the required EEDI), he says. “If it is equal to or higher than the attained EEDI (which has been verified by the Flag Administration or RO) then these vessels will only require an International Energy Efficiency Certificate. However, if it is not, then these ships will first need to undergo the full process of calculating the attained EEXI, evaluating and implementing any required improvement measures, compilation of the EEXI Technical file and obtaining statutory verification.”

Equipment manufacturers are offering a range of services to support shipowners. “There is an old and tired joke in the marine industry that if an owner actually totalled up all the fuel savings offered by suppliers that most vessels would actually produce fuel rather than burn it,” says Jon Jackson, Product Manager, Caterpillar. While there’s no doubt that multi-million-dollar industry research efforts increase owner profits and benefit the environment, he says sometimes these benefits fail to replicate on a vessel or the benefits are so deeply muffled within the vessel that they are hard to document.

Caterpillar’s Multi-Engine Optimizer (MEO) uses proprietary fuel maps and algorithms to maximise fuel, emissions or response efficiency on vessels with multiple power sources and multiple load factors through engine prioritisation and the capability to select differentiated engine specific load points. A key benefit, says Jackson, is that MEO can document the fuel savings it generates by comparing MEO driven fuel usage to simulated usage based on previous behaviour or the customer can turn MEO off and observed the increased fuel usage.

“You cannot turn off a hull coating; you cannot turn off your drive motors; you cannot turn off your propeller design, but you can turn MEO off and see the consequences.”

Operators can use technologies to improve vessel efficiency, lower operating costs, and provide total optimisation with support from Caterpillar’s expertise and solutions, such as MEO. “MEO can precisely choose the times and depths of battery cycles that bring the most benefit to a customer. This is achieved with MEO’s access to fuel maps, the use of customer operating mode indicators, our optimization indicators, and MEO’s ability to anticipate daily load profiles based on customer and operational input,” says Jackson.

Giulio Tirelli, Director of Business Development at Wärtsilä, describes a case where the inclusion of energy from solar panels seems beneficial, but without appropriate power management can cause a ship’s engines to run below optimum, negating any emissions’ benefits.

Limiting engine power doesn’t automatically imply a corresponding effect in emissions reduction, because many vessels are already operating at lower speeds. Tirelli says the potential loss of efficiency of having a main engine running below its optimum can be countered by tuning the propulsion system to the new operating point or by adding energy saving devices, above and below the water, including renewable energy sources such as Flettner rotors. Despite the current focus on future fuels, he believes the options that will be taken up will be ones that have short lead times. “For the marine industry, 2023 is tomorrow!”

Tirelli cites the example of what was the shipping industry’s first hybrid installation for a bulk carrier. In operation since 2019 on the Paolo Topic, Wärtsilä’s hybrid power module, the Wärtsilä HY, ensures seamless integration of a solar array and battery system into the ship’s existing power production systems. This benefits the EEXI and also the CII, something he recommends shipowners consider when looking for solutions. Tirelli points to another bulk carrier hybridisation that meets EEXI requirements and lifts the vessel’s CII rating from C to B. Vessels that only have power limited run the risk of being passed over by charterers looking for both speed and efficiency, he says.

Filippos Nikolatsopoulos, Manager of Business Development at ABS, estimates that 7,000 tankers will likely have to take action on EEXI requirements. In some cases, it could be that scrapping is the cost-effective option. “An issue for tanker operators could be that even relatively young vessels will have to compete with newer, more efficient vessels able to operate at higher speeds.”

Maintenance costs will be another issue. “From a decade of slow steaming, the industry is well aware of the very detrimental effect on engines and components that can be caused by operating an engine at lower than its designed power level.”

Jonathan Strachan, New Build and Vessel Conversion Director at design and engineering consultancy Houlder, estimates that 68% of the bulk carrier fleet will have to take action to comply with EEXI requirements. The average operational speed of the fleet is around 20% lower than design speed. Assuming that a 50% engine power reduction corresponds to approximately a 20% reduction in speed, the majority of vessels will not be adversely affected by fitting a power limiting device. A further 6% of bulk carriers may need further modifications, and the picture is much the same for tankers and container ships. He says that just going for power limitation devices is a missed opportunity to address, for example, the bulbous bow and propeller which were designed for a different speed.

Mitsubishi Heavy Industries Marine Machinery and Equipment (MHI-MME) offers a range of EEXI solutions. Retrofitting redesigned optimal propellers for slow steaming by engine low-load operation can yield fuel efficiency improvements of 3-10% for container ships equipped with high-output engines and 3-5% for other ship types.

MHI-MME is also promoting the development of MET turbochargers to match the needs of propulsion engines and variable turbine inlet (VTI) turbochargers, which are suitable for ultra-low-load operation and enable the improvement of EEXI with ease, says the company. For VTI turbochargers, the turbine inlet can be easily modified to optimise turbocharger efficiency for partial-load operation, giving about a 3% improvement in fuel efficiency. Installation of an exhaust gas bypass line on a standard MET turbocharger allows the exhaust gas to be bypassed during high load and the retrofit of an integrated EGB turbocharger, giving about a 2.5% improvement in fuel efficiency.

EEXI requirements have led to increased interest in MOL Techno-Trade’s propeller boss cap fins (PBCF). With more than 3,500 units sold, the company has introduced a new design with taller, more rounded and twisted fins that provides up to 5% fuel savings as thrust and torque reduction is improved. Combined with other energy saving devices such as a duct, 8% fuel savings can be obtained. The PBCFs also generate energy savings for fins and rudder bulbs.

The company is also developing an energy-saving high lift rudder with bulb fins in partnership with Akishima Laboratories and a rudder manufacturer. The rudder saves energy and provides good manoeuvrability. Its rudder’s twisted horn is shaped to enhance negative pressure on the front edge of the rudder, increasing thrust. The end plate under the rudder is reduced in size to reduce resistance, and a large central bulb with a flat front surface reduces propeller inflow speed and improves propeller efficiency. The first ship fitted with the rudder is expected to be delivered in early 2022.

Class societies are keen to help shipowners, and in April, Korean Register (KR) launched its online EEXI/CII calculation program. KR has established a decarbonization taskforce to help shipping companies to stay compliant with the relevant regulations. The taskforce is also exploring technology for carbon neutral, alternative marine fuels such as hydrogen, methanol and ammonia.