Wind-assisted ship propulsion has immense potential for achieving fuel savings and cutting emissions in line with the IMO’s decarbonization strategy for shipping.
Numerous solutions are being commercialized with others undergoing final stages of testing to prove their efficiency. These types of solutions range from rotor sails, rigid or soft sails to ventilated foil systems, and kites.
Wind-assisted propulsion can be implemented on a wide range of ships that have a clear deck area, such as ferries, car carriers, bulk carriers, and tankers, while containerships are more difficult to retrofit for the majority of these solutions.
Khalid Moinuddin Hashim, Managing Director of Thai bulk carrier owner Precious Shipping, believes the potential of wind power cannot be fully harnessed it comes to the dry bulk market.
“We think that dry bulk will not be able to use wind power in any meaningful way as dry bulk ships need their decks to be under a certain height, determined by the various loading installations, where they operate,” Hashim told Offshore Energy-Green Marine in an interview.
” If the wind installations are too high and occupy so much space that they become a hinderance for the safe operation of these ships at loading and discharging ports, then they will not be able to access cargoes easily and this option will not work.”
Rotor sail manufacturer Norsepower is aware of the height concerns of shipowners when it comes to this type of solution, and to that end, it has made its sails tiltable to overcome height restrictions for ships on certain shipping routes.
On the other hand, Japanese shipping company K-Line is betting a great deal on a different type of solution. Namely, the company is about to test an automated power kite aboard one board of one of its Capesize bulkers in 2021.
The demonstration project will pave the way for potential installation up to 50 automated 1000 sqm kites.
The kite, named Seawing, tows the commercial ship forward saving more than 20% fuel and CO2 emissions, according to its developer.
Being a member of the Getting to Zero Coalition, Precious Shipping also aims to place deep-sea zero-emission vessels in operations by 2030.
There is a range of power sources with zero emissions, such as hydrogen, ammonia, as well as electric propulsion being considered by the shipping industry.
Nevertheless, shipowners are still uncertain as to which option will be the most viable one in the future and are taking the ‘wait and see approach’ until a standard design becomes widely accepted and mainstreamed. Meanwhile, the ordering of ships is kept at bay.
When asked which option seems attractive for the dry bulk sector and Precious Shipping, Hashim said:
“As far as the different energy sources are concerned, LNG has a problem with the methane slip, or the inadvertent release of methane from ships that are powered by LNG to run their engines. These methane slips are far more harmful to the environment than CO2 or other GHG. Hence LNG is not going to be a real choice going forward to a decarbonized future.
“That leaves the various hydrogen options. If it is liquid hydrogen that is to be used, you have two issues with it. Firstly, liquid hydrogen can be stored at a temperature very close to absolute zero, and that is an extreme challenge to handle. And, more importantly, liquid hydrogen requires 15 times the volume, as compared to low sulphur fuel oil (LSFO), to give you the same energy equivalent and so storage would become an issue.
“Compared to liquid hydrogen, ammonia seems to be a far easier option in that it stays liquid around -23 degrees Celsius. For the equivalent energy with LSFO you require 5 times the volume of ammonia which is much lower than for liquid hydrogen and therefore becomes more manageable.
However, as explained, liquid ammonia is poisonous for humans and hence safely managing this energy source on board ships will be a challenge.
“Ultimately, the question will come down to commercialization – whichever clean energy source can do the job effectively and cheaply enough, will get the interest from ship owners,” he concluded.
Source: World Maritime News