The high frequency of global shipping means shipping emissions represent 11% of total transport emissions. A number of low-carbon shipping technologies are already being developed, including battery and hydrogen-based ferries and ammonia retrofits. As these innovations become cheaper and more attainable, the shipping industry will be able to meet the International Maritime Organization’s new emissions regulations, which is consistent with the Paris Agreement.
SWIFTH2 is a project for the Scottish Western Isles Ferry Transport that will use Hydrogen and wind power generation to produce hydrogen through electrolysis for zero carbon ferry transport.
Mitsubishi Heavy Industries is trialing the first carbon capture at sea technologies. According to a study, this could reduce emissions from shipping by up to 85% and with technological advances 90%.
Silverstream technologies uses Air lubrication technology to produce net energy savings on maritime transport of 10-20%
Pathways to Net Zero Maritime Travel
- Hard to replace. While some trading routes could be switched to zero-emission railways, many shipping routes are essential to global trade and can only be carried out by sea. Therefore, solutions for emissions reductions on ships are essential for net zero shipping.
- Difficult to organize and incentivize. Fragmented nature of the shipping industry with complex contracting structure reduces the incentives to drive efficiency to maximum.
- Battery and hydrogen-based solutions may not work over longer distances. The density of batteries and volume of hydrogen cells may affect long distance trips and take up valuable cargo space. Other alternative fuels, such as biodiesel, are unlikely to be able to meet the energy needs of global shipping due to the scarcity of sustainable biomass.
An image of shipping containers.
Net Zero Solutions for Maritime
Improve energy efficiency aboard
There is a 30-55% energy efficiency potential in maritime shipping from an improved hull shape, hotel-load savings, better engines and propulsors with minor logistics and routing improvements. As well as those improvements, wind sail assistance technologies could also significantly reduce fuel use.
Optimisation of voyage plans and optimal approaches to ship speed could also deliver significant reductions.
Retrofit engines to run on a wide range of fuels.
Ship engines (unlike aero-engines) can use a wide range of alternative fuels with only minor adaption required. There are a choice of which new fuels to use: biodiesel which can be slowly introduced into current fuel systems and ammonia, based on zero-carbon hydrogen, (which is preferred to direct hydrogen due to lower volume and greater ease of storage)
Replace short-distance trips with BEVs and FCEVs (Fuel-cell EVs)
On short range trips, smaller ships using either battery or hydrogen-based fuel cells are likely to be the best option. These can play a significant role in riverine, coastal, RoPax, and short-distance cruising markets.
Net Zero Policy for Maritime
The international nature of the maritime industry makes national level policy harder to control and manage. The most emitting flights are those that span large distances and therefore require an international approach to solve them. Unfortunately, although the IMO does have a net zero plan it needs to be much more ambitious in order to reach that goal, a new strategy that will be adapted in 2023 and will need to be much stronger. On an international scale large efficiency improvements, zero carbon retrofitting, and new technologies are needed in order to reach the net zero goal. As well as this, due to the hard-to-abate nature of the industry a robust strong offsetting scheme is needed to be able to facilitate this.
With that said, on a national scale policies can be made such as the UK’s Clean Maritime Plan that will help to kickstart a net zero transition with infrastructure investments, and technological development.