Liquid hydrogen dredger is the concept that Royal IHC and Rijkswaterstaat developed for a hopper dredger capable of operating on green liquid hydrogen; the H2-Hopper project seeks to reduce emissions generated by the maintenance of channels and coastlines in the Netherlands. Currently, the dredgers employed on the Dutch coast represent nearly 20% of Rijkswaterstaat’s annual carbon dioxide emissions. Their impact is even greater regarding nitrogen oxide emissions and particulate matter linked to maritime operations.
Liquid hydrogen dredger for waterway maintenance
The H2-Hopper was conceived as a trailing suction hopper dredger intended for the maintenance of waterways and coastal areas; this type of vessel extracts sand, silt, and other sediments from the seabed and stores them temporarily in a hopper. Royal IHC completed the basic engineering of the vessel and defined its main systems. The integrated design received class approval from Bureau Veritas, according to technical information published about the project. The vessel would have the capacity to dredge approximately six million cubic meters of sand per year. To meet that level of activity, it would need to refuel about 20 tons of liquid hydrogen once a week.
How the propulsion system would work
The design employs fuel cells to transform hydrogen into electricity; this energy would constantly power a battery bank during navigation and dredging operations. However, a dredger operates with rapid changes in power. Pumps, suction pipes, and discharge systems can increase demand within a few seconds. For this reason, the H2-Hopper incorporates a supercapacitor responsible for responding to load peaks.
This configuration would allow the fuel cells to operate within a more stable range, thereby reducing stress on the batteries and improving the vessel’s energy management. Furthermore, hydrogen propulsion would avoid local emissions of CO₂, nitrogen oxides, and particulate matter during operation. This advantage is significant because many dredgers work near ports, cities, and populated coastal areas.
Cryogenic storage poses challenges
Liquid hydrogen has a higher energy density by volume than compressed hydrogen; even so, it requires insulated tanks and systems capable of maintaining temperatures below −253°C. Liquefaction also requires considerable energy. With current technology, this process can consume more than 30% of the energy contained in the hydrogen itself, in addition to potential evaporation losses known as boil-off.
On the other hand, the Royal IHC design indicates that the volume required to offer one week of autonomy would be acceptable within a dredger of this type; fuel availability and refueling infrastructure remain decisive factors.
Costs and regulation will determine its viability
The greatest obstacle for the H2-Hopper is economic; both the construction of the vessel and the supply of green hydrogen would have a higher cost than a conventional diesel-powered dredger. Nevertheless, Royal IHC maintains that environmental costs can change that comparison. In Dutch public tenders, indicators are used that assign an economic value to emissions and other environmental impacts.
Likewise, investment subsidies and European regulations could narrow the gap; the European Union Emissions Trading System and FuelEU Maritime will progressively increase pressure on fossil fuels used in maritime transport. Dredgers of more than 5,000 gross tonnage will be subject to the European emissions regime starting in 2027. This framework could improve the competitive position of green hydrogen compared to diesel.
A project conditioned by the market
From a technical standpoint, the study shows that a liquid hydrogen dredger can be built and operated with adequate autonomy; the combination of fuel cells, batteries, and supercapacitors responds to the variable demands of dredging. However, the entry into service of a commercial unit will depend on fuel prices, the availability of renewable hydrogen, and port infrastructure. It will also be necessary to secure long-term contracts that offset the initial investment.
The H2-Hopper represents a concrete alternative for decarbonizing workboats; its development demonstrates that the main challenge no longer lies solely in naval design. The central issue will be creating the economic and logistical conditions to take it from the technical blueprint to coastal operations.
Source: Offshore-energy
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