Neptune Lines to optimise four newbuild PCTCs for slow steaming

The service is branded as engine part-load optimisation (EPLO), which is described in brief as ensuring the appropriate turbocharging unit is used given a prescribed set of load requirements for the engine while adjusting fuel injection levels, timing and the fuel-to-air mixture ratio. 

The service from HD Hyundai is offered through a partnership with turbocharger specialists Accelleron, and Neptune Lines’ order marks the second contract after HD Hyundai notched a one-ship order in October 2023. 

According to Accelleron, the so-called ’optimisation’ of the engine at part-load "can improve fuel efficiency by as much as 6 grams per kWh, with an equivalent reduction in carbon emissions".

Fuel costs can account for 40% to 50% of the ship’s operating cost, and aside from commercial considerations, consuming less fuel produces fewer CO2 emissions. This is not only an undisputed necessity in terms of fighting the climate crisis, but also a requirement under multiple regional and international regulations, that will only become more stringent. Notably, the International Maritime Organization’s Energy Efficiency Design Index for Existing Ships (EEXI) is making engine power limitation a key ingredient in reducing greenhouse gas emissions.

Hyundai and Accelleron formed a partnership in late 2021 for the EPLO service, and the EEXI regulations came into force on 1 January 2023. 

Slow steaming may seem like a simple and effective solution, but there can be complications. Any ship’s main engine is optimised to perform best within very specific parameters – including the speed at which it operates, often between 75% and 85% of its maximum power. Operating the engine outside these parameters will reduce its efficiency, minimising the positive benefits of slow steaming. Also, operating at lower speeds can increase wear and tear, the risk of failures and increase maintenance costs.

To reap the full benefits of slow steaming, temporary or permanent adjustments to the engine, such as those in the latest EPLO contract, may well be required. Notably, a reduction in engine power settings might mean that fewer turbochargers need to be operational during slow steaming – and this will actually increase fuel efficiency. By installing a turbocharger cut-out system, the engine operator can disable one of its turbochargers during low-load operations. This, in turn, increases the efficiency of the remaining turbocharger(s), by returning their operating levels to within their normal parameters for optimum performance. Like engine derating, turbocharger cut-outs improve fuel efficiency during slow steaming – by 6-10 g/kWh – and also improve the reliability of the turbocharger by restoring its intended operating conditions, reducing incidences of smoke and deposits, as well as wear and tear.