Key takeaways:
- Up to 16% less energy by 2030: DNV says efficiency measures and speed reductions could cut global shipping energy use by up to 16% versus business as usual.
- Around $23bn in annual fuel savings: The same measures could save roughly 40 million tonnes of fuel a year, worth about $23 billion at an assumed fuel price of $580 per tonne.
- Retrofits can still pay on older ships: In DNV’s example of a 15-year-old 5,000 TEU containership, a $2.35m retrofit delivering 16% fuel savings paid back in roughly 1.4 to 4.2 years, depending on fuel prices.
The classification society estimates that these measures could reduce the global fleet’s energy use by up to 16% in 2030 compared with a business-as-usual scenario. That would correspond to savings of roughly 40 million tonnes of fuel and 120 million tonnes of CO₂-equivalent emissions.
Using an assumed fuel price of $580 per tonne, DNV puts the potential annual fuel-cost saving at around $23 billion. The savings could be greater where operators use more expensive low-GHG fuels, making efficiency improvements increasingly valuable as shipping decarbonises.
DNV says the potential grows further over time. By 2050, energy-efficiency measures and speed reductions could lower energy use by as much as 25% to 28% compared with business as usual.
Even older ships can justify retrofit investment
The report argues that the opportunity is not limited to new vessels.
DNV presents a case study of a 5,000 TEU containership built in 2013, examining what happens if energy-saving equipment is installed when the ship reaches its 15-year dry-docking.
The proposed package combines a bow retrofit, propeller retrofit and installation of a propeller boss cap fin, at a total estimated investment cost of around $2.35 million. DNV estimates that the changes could reduce fuel consumption by around 16%.
The economics vary considerably with fuel prices. At $580 per tonne, the investment would pay back in about 2.9 years. At the high-price assumption of $1,120 per tonne, the payback falls to around 1.4 years, while at $420 per tonne it rises to approximately 4.2 years.
By 2038, DNV estimates the retrofit could generate a net present value of between $2 million and $10 million in fuel savings, depending on fuel prices.
The calculation assumes the work is carried out during scheduled dry-docking at the beginning of 2028, without additional off-hire time. DNV says hydrodynamic retrofit projects of this kind would normally need to begin at least six months before the scheduled dry-docking to allow for design work, optimisation, fabrication, transport and class approval.
Importantly, the business case does not include costs arising from the EU Emissions Trading System, FuelEU Maritime or a future IMO Net-Zero Framework. DNV notes that exposure to such measures would further strengthen the economics of reducing fuel consumption.
Efficiency becomes more valuable as fuel costs rise
DNV describes energy efficiency as one of the most immediate practical options available to shipowners because it reduces fuel consumption and emissions without relying on the future availability of a particular alternative fuel.
Measures available to owners range from hull and propeller optimisation, coatings and machinery improvements to waste-heat recovery, wind-assisted propulsion, weather routing, trim optimisation and speed reduction. The report says more than 50 operational and technical efficiency measures can potentially be applied across the fleet.
The economics also become more attractive as low-GHG fuels enter wider use. Every unit of energy saved reduces not only fossil fuel consumption today, but also the amount of potentially more expensive low-GHG fuel that would need to be purchased in future.
DNV says a large share of shipping’s remaining energy-efficiency potential could already be cost-effective by 2030, with the economic case strengthening further towards 2050 as more costly low-GHG fuels are adopted.
Why aren’t more operators already investing?
The report nevertheless warns that technical potential does not automatically translate into investment.
DNV identifies financial limitations, technical challenges, organisational practices and legal constraints among the barriers holding back efficiency projects.
One particular problem is the split incentive between shipowners and charterers. The party paying for an efficiency upgrade may not be the same party paying the fuel bill and therefore benefiting directly from the savings. Standard charter contracts that prioritise speed can further weaken incentives to invest in fuel-saving measures.
There is also uncertainty over whether savings claimed by technology suppliers will be achieved under real operating conditions, making reliable measurement and verification important for investment decisions.
DNV’s figures nevertheless suggest that efficiency could play a much larger economic role in shipping’s decarbonisation than simply serving as a supporting measure for alternative fuels. At its estimated maximum 2030 potential, the sector would be consuming around 40 million tonnes less fuel each year — translating into roughly $23 billion in annual savings at DNV’s assumed fuel price.
