Radical Derating: A new frontier in maritime engine efficiency

Radical derating of two-stroke engines emerges as a game-changing solution for ship owners facing stringent environmental regulations. This innovative approach promises extended vessel lifespans and dramatically improved efficiency, helping to reduce emissions of in-service vessels.

Andreas Wiesmann, General Manager of Global Sales for 2-stroke Engine Services at Wärtsilä Marine, delves into the technology’s potential, drawing on recent pilot projects and extensive industry experience to illustrate its transformative impact on the shipping sector.

In the face of tightening emissions regulations, the maritime industry is seeking innovative solutions to extend vessel lifespans and improve environmental performance. One such approach gaining traction is ‘radical derating’ – a process that promises to breathe new life into ageing two-stroke engines which are permanently operating at engine loads below 50-60 per cent of the original operating profile.

At its core, radical derating involves a substantial modification of existing engines. By reducing the bore size and reconfiguring the top section, engineers can significantly decrease an engine’s footprint while boosting its efficiency. The potential gains are impressive, with improvements of up to 15 per cent in engine efficiency, or even up to 20 per cent when combined with propulsion upgrades.

“At Wärtsilä, we have been pioneering this approach with our Fit4Power solution. Our research paints a stark picture of the industry’s future: without intervention, over 80 per cent of the global merchant fleet could find themselves in the lowest Carbon Intensity Indicator (CII) rating by 2030. This would necessitate mandatory
corrective action, a daunting prospect for many operators,” Wiesmann said. “To put theory into practice, we embarked on an ambitious pilot project. The task at hand was the conversion of a 12RT-flex96C-B engine to a 12RT-flex72R – no small feat. The scale of the operation was considerable, requiring 26 engineers, over 11,500 engineering hours, and 15 containers worth of parts.”

The results speak for themselves. The retrofitted engine delivers annual fuel savings of up to 2,000 tons and a reduction in CO2 emissions of 6,400 tons. In financial terms, this translates to potential yearly savings of €2.18 million in operational expenses, based on current fuel costs and carbon levies. Add to this the €0.14 million annual savings in parts, and the economic case for radical derating becomes compelling.

Swift implementation

One of the key buying points of this approach is its relatively swift implementation. While still a complex undertaking, a radical derating retrofit can typically be completed in less than four weeks. This compares favourably to the three months often required for a full engine replacement, according to Wärtsilä’s estimates.

The environmental benefits extend beyond improved emissions performance. By upgrading existing engines rather than replacing them wholesale, the process significantly reduces the need for new materials and parts. This aligns neatly with broader sustainability goals and minimises the carbon footprint of the retrofitting process itself.

Comprehensive operation in regulatory middle ground

A radical derating retrofit is a comprehensive operation, involving the replacement or modification of numerous engine components. These include the cylinder liner, cover, and exhaust valve, as well as fuel injectors, pistons, and various control systems. However, the base and lower sections of the engine remain largely untouched, making this a more sustainable option than a complete replacement.

From a regulatory standpoint, radical derating occupies an interesting middle ground. While it represents a significant change to an engine, it is not classified as a major conversion. This means retrofitted engines can retain their original IMO NOx Tier rating, with Wärtsilä’s experts able to update the necessary technical files through a “shop-test-at-sea” method.

An option for the future

Looking to the future, radical derating could form part of a broader strategy for ship owners to meet increasingly stringent emissions targets. “Our roadmap suggests that vessels might transition to alternative fuels like methanol, LNG or Ammonia with our fuel-flexible Fit4Fuels retrofit technology platform following (or combining with) a radical derating retrofit, with the possibility of incorporating bio-fuel blends further down the line,” Wiesmann said.

As the shipping industry charts a course towards decarbonisation, solutions like radical derating offer a practical and immediate step towards improved efficiency and reduced emissions. By providing a means to extend the life of existing vessels and enhance their environmental credentials, this approach can play a crucial role in the industry’s sustainability journey.

“With its potential to deliver significant fuel savings, slash emissions, and prolong vessel lifespans, radical derating presents an intriguing option for ship owners looking to future-proof their fleets. As the maritime sector navigates the choppy waters of environmental regulation, innovations like our Fit4Power solution may well prove to be a vital stepping stone in the transition to cleaner shipping,” Wiesmann concluded.