Amsterdam receives over 20 million tourist visitors per year, and with hundreds of thousands taking to the canals to enjoy the city by water, sightseeing ferries contribute considerably to the collective emissions output in the Dutch capital.
In 2005 Amsterdam’s local governing body laid down an ultimatum for operators of the city’s famous glass sightseeing water ferries — as of January 1 2015, all boats of this kind had to either be fitted with a repowered engine and aftertreatment system, or replaced by an electric alternative.
Terlouw Rotterdam, the Volvo Penta Center in the Netherlands, worked with Slot Jachtbouw, an Amsterdam shipyard, between 2012 and 2014 to systematically swap out many of the old engines and replace them with repowered new ones that are fitted with STT Emtec’s marine DNOx® after-treatment system.
Since repowering ended at the beginning of this year, a total of 50 out of 150 canal boats operating on Amsterdam’s waterways are powered by Volvo Penta D5A TA marine diesel engines. Ferry companies now enjoying the benefits of a Volvo Penta engine include Canal Company, Blue Boat, Rederij Kooij and Rederij Lovers.
“Amsterdam is one of the most popular urban tourist destinations in Europe — thousands come every year to experience the magic of this city,” explains Jeroen van Liefland, sales manager for Terlouw Rotterdam. “The canal boat operators needed to find an engine and aftertreatment combination that met the requirements of the local authorities and didn’t result in a long repowering process that would cause costly downtime. Volvo Penta and STT Emtec proved to be a winning combination.”
Cleaning up Amsterdam
The Volvo Penta D5A TA engine is a highly reliable, type-approved marine diesel engine that boasts low exhaust emissions and excellent fuel efficiency. Because of the high level of tourist trade in the Dutch capital, canal boat operators required an engine that they could trust — and Volvo Penta offered just that.
“Volvo Penta is well known in the Netherlands for its dependability — the boats’ operators can’t afford to take their sightseeing ferries out of the water for lengthy repairs or maintenance, especially during peak times,” says Jeroen. “Maximizing uptime is paramount to our customers; they chose Volvo Penta because it’s a partner they know they can rely on.”
Prior to the repowering operation — which fitted the ferries with 4-cylinder engines — the ferries ran on 6-cylinder engines. This additional power was less of a help and more of a hindrance; because the speed limit on the Amsterdam canals is only 6 kph, the sightseeing vessels had a very low specific load profile.
But, thanks to Volvo Penta’s engines, which are smaller with a lower maximum output, the ferries can now run at a higher load at low speed limits, resulting in higher exhaust temperatures. These high exhaust temperatures allowed for the use of the DNOx® aftertreatment system, developed by STT Emtec.
The aftertreatment system
The D5 engines were fitted with a marine DNOx® system, which reduces NOx by diluting the charge air with recirculated exhaust gas. The amount of NOx being produced since the repowering project has significantly declined — thanks to Volvo Penta and fellow Swedish company STT Emtec.
Example of weighted emissions from diesel engine, cycle E3.
The exhaust gas recirculation (EGR) system operates with a patented EGR value, which precisely controls the exhaust and inlet air mixture. In addition, the CCT active uses the on-board fuel as a reacting agent to help control the soot loading in the diesel particulate filter (DPF). Soot can be burned automatically when exhaust temperatures are high enough but, given the low speed limit in the city, which prevent the exhausts from consistently reaching high temperatures, the CCT active controls soot buildup at lower temperatures. Using the system, the engine’s carbon monoxide, hydro carbon and carbon particle emissions are all reduced by up to 90%, and NOx emissions are reduced by up to 45%.
Together, Volvo Penta and STT Emtec tested the D5 engine with and without the DNOx® system, and found the results to be exceptional. The D5 engine’s lower fuel consumption and cleaner performance, coupled with STT Emtec’s advanced system, are helping Amsterdam work towards its goal of becoming a zero emission city by 2025.