LCA scan of the LEAF (low energy adaptive fuel) trailing suction hopper dredger. Hydrogen-powered dredging)

To make dredging in the Netherlands more sustainable, Royal IHC is studying how to replace the fossil fuels used by their trailing suction hopper dredgers with CO2 neutral fuels. One of these fuels is hydrogen. CE Delft carried out an exploratory LCA study in 2021 to identify how the environmental impact of these sustainable dredging operations compares with common dredging operations on LSMGO (Low-Sulphur Marine Gas Oil). For more information about this project, please contact Royal IHC.

LEAF trailing suction hopper dredgers

Royal IHC has designed two models of the LEAF (Low Energy Adaptive Fuel) trailing suction hopper dredgers using hydrogen as fuel:

  1. A ship with a dual fuel combustion engine running on 30% LSMGO and 70% hydrogen.
  2. A ship with a 100% hydrogen fuel cell.

We evaluated both designs during our exploratory LCA study. In addition, we looked at three different hydrogen production methods:

  1. SMR (Steam Methane Reforming) with CO2
  2. High-pressure alkaline electrolysis with offshore wind power.
  3. Chloralkali electrolysis where hydrogen is released as a co-product.

All models LEAF hydrogen-powered trailing suction hopper dredgers have a lower environmental impact (measured in MKI*, in Euros worth of environmental damage) per m3 of replenished sand) than the benchmark LSMGO trailing suction hopper dredger. Both the type of propulsion and especially the hydrogen production methods affect the ultimate environmental impact of dredging. The trailing suction hopper dredger model with a fuel cell and hydrogen via high-pressure alkaline electrolysis powered by offshore wind energy has the lowest EQI per m3 of replenished sand.

* The MKI in this study was calculated in accordance with the IKZ methodology. Unlike the CML-VLCA calculation method, the IKZ methodology applies a weighting factor of €0.103/kg CO2-eq. for climate change, instead of €0.05/kg CO2-eq.