Hydrogen fuel cells are future, says WWM boss

Typography
USING fuel cells powered by hydrogen will help the next generation of harbour tugs to cut emissions, according to Michiel Wijsmuller, managing director of WorldWise Marine Engineering (WWM). Part of the Offshore Ship Designers group, WWM is working with tug operators Ijmuiden-based Iskes and Rotterdam-based Smit to develop a 50 tonne bollard pull harbour tug that will have zero emissions when on standby and very low emissions in service.

USING fuel cells powered by hydrogen will help the next generation of harbour tugs to cut emissions, according to Michiel Wijsmuller, managing director of WorldWise Marine Engineering (WWM).

Part of the Offshore Ship Designers group, WWM is working with tug operators Ijmuiden-based Iskes and Rotterdam-based Smit to develop a 50 tonne bollard pull harbour tug that will have zero emissions when on standby and very low emissions in service.

!ADVERTISEMENT!

"Our clients want harbour tugs that can safely and cleanly operate in densely populated areas, so we have gone as far as we can with today's technology to achieve zero emission conditions by designing an electric propulsion system, powered by fuel cells running on hydrogen and also battery back-up during standby and mobilisation periods and only firing up diesel generators when substantial bollard pull is required," said Mr Wijsmuller. "We will also incorporate power regenerating features by way of the towing winch when paying out the towline and by one of the propeller units when the tug acts in the dynamic braking or steering mode."

WWM's fully electric tug will be powered by 200 kW fuel cells during waiting time and mobilisation/demobilisation periods. During berthing and assist operations, diesel generators can be brought on line to provide more power but with a generator bank of 2-4 units, the engine load can be closely matched to the electrical demand ensuring the diesels operate at maximum efficiency and optimum load.

A retractable Voith in-line azimuthal thruster in the bow for mobilisation and demobilisation purposes is a major energy saver. "The tug can move around safely on hydrogen power," he said. "Then when we are using the main generator sets and electric motors in a ship-handling operation the thruster is tucked away, cutting drag. The main propulsion motors are mounted directly on top of the stern azimuthal propellers. The result: the hull provides ample space and flexibility for installing tanks to store hydrogen under a pressure of 700 bar."

"Our studies show this tug will reduce the emission of NOx, SOx and particulate matter by 95%, while oil fuel consumption, and so CO2 emission, is reduced by 50% compared to a conventional harbour tug," he added. "The concept is bringing together a number of technologies not common in marine applications and we are working with NedStack Fuel Cell Technology BV and Bakker Sliedrecht Electro Industrie BV on electrical details.

"Much of the concept is simply the sensible application of conventional naval architecture to emissions reduction. For example, we have optimised the hull form to make resistance as low as possible while free running and have used propellers with a maximum bollard pull to power ratio. Then we are designing in heat recovery systems to minimise the auxiliary power needed to run other systems. We will use computer simulation to ensure we match the power required for particular services to the optimum load of the gensets we fit. Running the diesels at maximum efficiency is important for reducing fuel consumption and particulate emission."