More than 100 vessels now have wind-assisted propulsion systems (WAPS), according to the International Windship Association, giving shipowners a growing pool of operational experience to assess before investing in retrofits. Analysis from Njord Solutions suggests that fuel savings alone do not determine the full commercial or regulatory benefit when FuelEU Maritime, EU ETS, CII and retrofit economics are considered together.
Wind propulsion has moved beyond individual pilot projects, with operational data from fitted vessels giving operators more information on where the technology could make commercial sense.
The key distinction is that a percentage reduction in fuel consumption does not translate directly into the same FuelEU benefit on every vessel.
FuelEU Maritime measures the greenhouse gas intensity of energy used by a vessel on a well-to-wake basis. Wind propulsion is recognised through a wind reward factor, known as fwind, which adjusts the vessel’s calculated GHG intensity according to the contribution from the wind system. The factor ranges from 1, where there is no wind contribution, to a floor of 0.95 for the strongest wind contributions.
This makes the vessel’s operating profile important. The same WAPS installation can produce different results depending on vessel size, propulsion demand, trading routes, service speed and prevailing wind conditions.
The starting compliance position also matters. A vessel entering a retrofit with a FuelEU deficit may see lower energy consumption and an improved GHG-intensity calculation reduce its compliance exposure. A vessel with an existing FuelEU surplus can still benefit from lower fuel consumption and emissions, but its regulatory outcome needs to be assessed against its existing compliance position.
That distinction matters when shipowners build a retrofit business case. A WAPS installation with a given fuel-saving percentage cannot simply be assigned the same financial and regulatory return across a fleet. Fuel mix, trading pattern, operating profile and compliance status can all change the result.
Njord Solutions argues for vessel-specific modelling rather than relying solely on manufacturer projections. WAPS performance can be assessed against actual trading patterns and translated into fuel consumption, fuel costs, emissions, EU ETS exposure, FuelEU balance and CII trajectory.
The fuel-saving figure remains important, but it is only one part of the investment case. The vessel’s operating profile, regulatory position and actual trading conditions determine how much of that technical saving translates into commercial and compliance benefits.
