Boskalis reduced fuel consumption by 9.8% on a dredger according to IMO E2 test cycle

In 2008, the Dutch dredging company Royal Boskalis Westminster B.V. used to look actively for solutions to reduce greenhouse gas emissions: XBEE Enzyme Fuel Technology was one of the leading projects.

The company selected the M/V Coastway, a dredger then located in Bahrain, to check the capacity of XBEE to reduce the polluting gas emissions. The reference test was carried out on July 19, 2008, and the comparative measurement on December 15, after almost four months of treatment with XBEE.

The trailing suction hopper dredger is equipped with two Wärtsilä engines, model W6L32B, and the test has been made on the starboard engine developing a power of 2,760 kW.

The results analyzed by Boskalis personnel demonstrate how significant is the impact of XBEE Enzyme Fuel Technology on gas emissions and specific fuel consumption in ships working regularly on low loads such as dredgers, tugs, and cable layers.

Without XBEE
% reduction according to E2 test cycle
Fuel consumption

It is interesting to observe that although the fuel consumption of this dredger has been reduced by 9.84% according to the E2 test cycle, such ships mostly work on loads ranging from 25 to 50%. Taking this into account, the specific fuel consumption is reduced by an average of 13.81%.

  • Although the accuracy and repeatability of the performed tests is not fully satisfactory, the measurements indicate that the fuel additive XBEE affects the engine performance in a positive manner.
  • The measured reduction of NOx is significant […]
  • The observed reduction in specific fuel consumption is questionable due to the accuracy of the measured power, fuel rack and fuel pump characteristics. However, the measurements also show that more CO2 per MT fuel and less CO is produced, which can indicate that the fuel combusts more efficiently.
MM. Smits and MeijerProject Managers at Boskalis

Interestingly, the authors of the report chose to minimize the results by basing their calculation of the break-even point fuel price on the lowest reduction of fuel consumption, i.e. 1.4% at 75% load. Even so, such break-even point is set to about $665 per ton of fuel considering prices in 2023.

If we take into account the actual reduction of fuel consumption by -9.84%, XBEE Enzyme Fuel Technology is completely paid when you treat fuel that cost more than $91.4 per ton!