Technology
What the Fuel Savings Actually Are
The headline figures are conservative. They are based on standard diesel consumption data, published fuel prices, and realistic operating hours -- with a deliberate shadow reduction applied for multi-turbine wake effects. Aerodynamic drag reduction is excluded from the table entirely; it contributes additional savings not captured in these numbers.
Methodology
Three inputs drive the calculation. All three are standard industry figures, not optimistic assumptions.
Operating hours: 6,500 hours per year -- a standard commercial vessel operating profile. Vessels with higher utilisation will save proportionally more.
Diesel consumption rate: 0.295 kg per kWh of electricity generated. This is the standard conversion factor for marine diesel generators at typical load.
Fuel cost: USD 700 to 1,000 per tonne -- the range covering prevailing bunker fuel prices for commercial operators. The table shows both ends of this range.
A 10 to 30% wake and shadow reduction is applied to multi-turbine configurations to account for turbines operating in the partial lee of adjacent units. The precise reduction depends on deck layout; the range used here is conservative for a typical installation.
Savings table
4 × 50 kW -- average output ~60 kW, annual production ~390,000 kWh, diesel saved ~115 t/yr.
4 × 100 kW -- average output ~120 kW, annual production ~780,000 kWh, diesel saved ~230 t/yr.
8 × 100 kW -- average output ~240 kW, annual production ~1,560,000 kWh, diesel saved ~460 t/yr.
The 4 × 100 kW configuration is the reference layout for initial vessel assessments. 8 × 100 kW applies where deck layout permits full deployment.
Beyond generation
The table above covers direct electricity generation only -- the fuel displaced by not running the generator to produce the same kWh. It does not include aerodynamic drag reduction.
As documented in the venturi effect section, turbines mounted at the leading edges of the superstructure disrupt vortex shedding, reducing the aerodynamic resistance the propulsion system must overcome. This effect was observed empirically on the Stena Jutlandica, where 4 kW of installed turbine capacity delivered 80 to 90 tonnes of annual fuel saving -- a figure only explicable through drag reduction rather than direct generation.
H Nordic turbines at 50 to 100 kW are an order of magnitude larger. Their drag reduction contribution scales accordingly. Total fuel savings -- combining both effects -- will exceed the figures in the table for most vessel geometries.
Assumptions
Vessels with utilisation above 6,500 hours per year -- tankers and bulk carriers on continuous trading routes, for example -- will generate proportionally higher savings. The linear relationship is direct: 7,500 hours yields approximately 15% more than the table figures.
The USD 700--1,000 per tonne range used here reflects recent bunker fuel price volatility. Operators with fuel hedging arrangements should use their effective all-in cost. At USD 1,200 per tonne -- within recent historical range -- the 4 × 100 kW configuration saves up to USD 276,000 per year on direct generation alone.
Diesel generator baseline
Marine diesel generators consume approximately 220 grams of fuel per horsepower per hour under typical load. Converting to SI units and applying the 0.295 kg/kWh rate, a vessel running a 500 kW generator set at 60% load consumes roughly 885 kg of fuel per hour purely for electrical generation.
A four-turbine 100 kW installation producing an average of 120 kW offsets approximately 13.5% of that generator load continuously during operation. On a vessel running 6,500 hours per year, that offset adds up to the figures shown in the table.
The turbines do not replace the generator -- they reduce how hard it runs. The fuel saved is real diesel not burned, not a theoretical offset.
EU and Nordic funding
Maritime decarbonisation projects are a priority category for several EU and Nordic innovation funding programmes. Qualifying installations may be eligible for grant support that reduces the net capital outlay and shortens the payback period.
Relevant programmes include the EU Innovation Fund, Horizon Europe's clean maritime calls, and Nordic national schemes for shipping decarbonisation. Eligibility depends on vessel flag, operator domicile, and route geography.
H Nordic can provide documentation to support funding applications. Speak to us early in the process -- funding applications typically need to be submitted before equipment is ordered.
Send us your vessel type, route, and operating hours and we will produce a preliminary savings and payback projection within five working days.
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