Container ships built within the past five years are now good candidates for dual-fuel conversions, according to engine developer MAN Energy Solutions.
Gas-fuelled engine conversions have been considered too costly for many shipowners. But following the contract to retrofit Hapag-Lloyd’s 15,000 TEU vessel Sajir, as well as the order for LPG engines for four gas carriers owned by BW LPG, MAN believes conversions are becoming viable for more vessels.
MAN head of sales, retrofit projects Klaus Rasmussen noted that the company had been able to refine conversion strategies as the number of projects grew. The age range for suitable candidates is not limited by the need for payback time, he said, but by the fact that vessels must have modern ME-C engines. These feature the electronic controls needed to control fuel injection and exhaust valve timings on gas engines.
The company also confirmed further technical details of work to be carried out on the 2013-built Sajir. The vessel’s fuel gas supply system will be delivered by MAN Cryo. It will feature the first installation of MAN’s pump vaporiser unit, which uses pumps driven by the engine’s exhaust valve actuator to compress fuel before vaporising it for injection.
Hapag-Lloyd is considering plans to convert a further 16 vessels designed LNG-ready by previous owner United Arab Shipping Co. Mr Rasmussen acknowledged that Hapag-Lloyd has paid a higher cost for works on Sajir due to it being the first of its kind. Any further retrofits would be cheaper as a result of this work, he said. Hapag-Lloyd has put the cost of LNG conversions at US$25M-30M.
Further conversions would also offer economies of scale on LNG fuel. The 6,700m3 membrane tank, enough for one voyage between Europe and Asia, is the most significant element of the 90-day retrofit. Mr Rasmussen noted that the engine conversion could be completed in around five weeks. The remaining two months will be devoted to installing the tank and the complicated steelwork supporting it.
At 368m in length and weighing 149,400 dwt, Sajir is the biggest ship ever to be converted for dual-fuel operation. The twin main engines on Nakilat’s gas carrier Rasheeda – which became the first vessel ever converted in 2015 – mean that it was arguably a more complicated and costlier project.