Details were scant when CPC Corporation Taiwan (CPC) laid claim to be the first company to operate electric-powered tankers over 500 dwt. According to the press release, the 2,900 dwt Chung Yu No 21 and Chung Yu No 22 were built specifically to deliver bunkers in the port of Kaohsiung and featured three Yanmar 6EY22ALW diesel generators supplying an electric motor.
At the time, Tanker Shipping and Trade asked CPC and Yanmar for comment concerning the layout of the propulsion system, but so far none has been forthcoming.
It seems that some of the details were lost in the translation of the original press release, but the story generated comments on LinkedIn from engineers and other knowledgeable members of the shipping fraternity.
Gennaro Consulting chief executive Giulio Gennaro was the first to question if the propulsion system was electric alone. Caroline Light, a support engineer, also had doubts, having served on diesel/gas dual-fuel LNG tankers in the 1980s. She described the vessel having a layout of two large electric motors on a single gearbox driving a single propeller.
Aurora Marine Consultants managing director Gert Josefsson pointed out that diesel-electric tankers were operated by Swedish companies in the 1990s.
Judging from this feedback, in all probability, the propulsion unit is actually diesel-electric, with the three Yanmar diesels providing electricity to one, or maybe two electric motors connected to the propeller shaft.
If the CPC tankers are not electric, there are other instances of electric commercial vessels. There have been electric ferries for many years (see video above for the latest launch of an electric ferry), and last year, China introduced into service an electric-only ship.
The China News agency reported the 70 m long unnamed coal carrier has a capacity of 2,000 tonnes. The vessel only serves two ports, where it takes two hours to charge up a mixture of lithium cells and super-capacitors, which is also the time required to load and unload the coal. The cells provide 2.4 MWh of energy to power two 160 Kw electric motors.