Environmentally friendly propulsion for Rygerprinsessen

The Norwegian company Rødne Fjord Cruise AS has upgraded the fast passenger ferry ‘Rygerprinsessen’ with SCR after-treatment systems. The SCR system is an environmentally friendly technology which reduces NOx emissions by up to 80% and contributes to a significant reduction in harmful emissions.

Eirik Nesse


Norwegian domestic marine traffic represent 34 % of all NOx emissions in Norway. Reduction of the environmental footprint of passenger vessels are important actions to improve the reputation of an important transportation service in our society. Public fast passenger ferries are performing critical infrastructure services in many local societies in our coastal and fjord regions.   

The SCR systems were supplied by Bertel O. Steen Power Solutions Norway AS in Bergen in connection with the installation of two new engines of type MTU 8V2000M72 with an output of 720 kW each. The engines, together with the SCR systems from STT Emtec AB, reduce emissions in accordance with the IMO Tier III maritime emission standard. The IMO Tier III emission limit standard will enter into force in the North Sea and Baltic ECA (Emission Control Area) from January 2021, but will apply only for new build vessels with keel laying after January 2021.

Retrofit solutions, where SCR systems is installed in existing vessels, often combined with repowering of the vessel, is therefore offering an excellent opportunity to reduce the emissions from this sector faster than solely by the renewal of the fleet. The North Sea ECA also only extend up to 62°N, so vessels build for operation north of this line are not bound to meet the regulatory emission requirements. Implementation by operator initiative are consequently important contributions in the effort to reduce the emission from the marine sector.  

Ragnhild Opsahl Steigen‘We want to run our business with sustainable technology in the sightseeing and tourism segment. We cannot allow ourselves to be an environmentally laggard, and are therefore well satisfied with the installed SCR systems together with the new engines from BOS Power’

– says Ragnhild Opsahl Steigen, technical manager at Rødne Fjord Cruise.




The engine supplier chose STT Emtec SCRmarine based on requirements on space, reliability and documented emission reduction.

John Asle Marhaug at Bertel O. Steen Power Solutions Norway AS says that – ‘STT Emtec SCR is the best marine solution to the challenges of confined engine rooms and space for components and equipment. SCR system from STT Emtec satisfied the requirements for installation and low weight.’

The system is modular solution that is easy to fit in the hull and can also be installed both horizontally and vertically on the exhaust line. SCRmarine systems from STT Emtec utilize compressed air-assisted supply of urea to achieve high dissolution of the ammonia, thus ensuring maximum effect in the catalytic converters. The converters are controlled and monitored by a proprietary ECU system which in turn provides log data for the operator.

Retrofit of an SCR after-treatment system can also offer economic benefits to the operator. The Norwegian ‘NOx Fund’ offers financial support calculated based on the amount of NOx reductions in the operations. Contact BOS Power to discuss options and possible assistance in applying for financial incentives.

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John Asle Marhaug