Over the last ten years shaft-driven shipboard mechanical power transmission has been increasingly replaced by electrical power. For example, both the Royal Navy Type 45 destroyer and the Queen Elizabeth carrier are electrically driven. The prime mover is used solely for generating electricity, which is then distributed to various motors, including those driving the propeller shaft(s), and other consumer loads.
Now, analysts at IDTechEx have issued a new report, Electric Boats and Ships 2017-2027, looking at this fragmented but often highly profitable and growing sector.
There are already over 100 manufacturers of electric boats and ships. The report finds that the market for hybrid and pure electric boats and ships will rise rapidly to over $20 billion worldwide in 2027 for non-military versions. Recreational boats is the largest and fastest growing electric marine market in sales number, followed by underwater leisure and autonomous underwater vehicles. On-water commercial marine category is currently the largest marine EV value market. Leisure craft on inland waterways, notably in the USA and Europe, will become the largest sector as more places from Germany to India ban internal combustion engines or, as with SunMoon Lake in Taiwan, the operators unanimously agree to go clean and quiet.
Huge environmental pressures are making owners of industrial and commercial seagoing craft address the issue of propulsion. According to the report, one large ship can emit the global warming carbon dioxide of 70,000 cars, the acidic nitrogen oxides of two million cars and the carcinogenic particulates of 2.5 million cars.
All-electric systems consist of an electric motor being powered by a battery pack. Hybrid electric systems consist of a fuelled engine and energy storage used to propel the craft sometimes (parallel hybrid) or to charge the battery (series hybrid).
Traditional “electric drive” where there is no substantial battery and therefore no pure electric mode or even downsized engine is mainly suited to large craft: it is seen in diesel-electric and nuclear-electric ships and submarines not covered in the report.
Beyond new electric craft, there is already a substantial and growing business in retrofit of hybrid electric ferries and other ships with pure electric or hybrid electric powertrains.