Technical and economical feasibility study on reducing CO2 emissions of Dutch beam trawlers

Abstract

International and local legislation on emission reduction urge the Dutch beam trawler fleet to reduce the use of fossil fuels. In 2015 the United Nations Paris Agreement was signed and as a result IMO and EU set the objective to reduce the GHG or CO2 emissions of the shipping industry. The Dutch beam trawler
has been confronted with many developments within the last decade that reduced the profitability. Two developments that stand out are: (1) Brexit: the Brexit resulted in a significant reduction in available fishing grounds, (2) Ban on pulse fishing: this method of fishing reduced the operational expenses with
30% to 40%, but is banned by the EU. Al a result to these developments in combination with upcoming (inter)national legislation, the Dutch government introduced a plan ”Noordzee visie” to help vessel owners to reduce their environmental impact. To continue fishing a Dutch beam trawler therefor has to take measurements to comply with these regulations. It will be inevitable to implement the use of sustainable fuels together with energy saving technologies. Vessel owners want to implement these, but without sacrificing operational effectiveness. Therefor it is required to find how different propulsion configuration which are able to reduce CO2 will influence the technical and economical performance of a Dutch trawler.

This research consists of two parts: (1) Literature study and (2) Result processing. Within the literature study the current state of a Dutch beam trawler is defined. Secondly potential converters, energy carriers and energy reduction methods are identified which show potential. At last an assessment model is build to find the influence of available propulsion configurations. The technical feasibility is determined by the configuration being able to comply with: operational effectiveness requirements, maximum added draught, maximum added length, and being able to reduce the CO2 emission with at least 40%. The economical performance of the configurations is assessed by three performance
indicators: (1) yearly operational requirements, (2) Capital expenses of configuration and at last (3) Total cost of ownership.

The operational profile of the vessel is divided into two parts: The long cycle is the time from sailing out from port, the fishing and the return into port. The short cycle is the fishing cycle it the repetition of setting, fishing and hauling the nets. Two types of long cycles exist a 100hr and a 160 hour per week. The short cycle on average takes 2.5 hours. Based on reliability, price and safety aspects multiple converter, energy carriers and energy reduction methods are found for this research. To store the required energy carrier volume including tank arrangement this system examines potential of combining original fuel tank volume together with: net store, fish hold or hull extension.

With the literature study finished the assessment model produces the following outputs.

Technical feasibility: The findings indicate that mono battery configurations are not feasible due to exceeding weight and volume limitations. Fuels like HVO and FAME are technically viable if recognized as zero-emission fuels by the IMO. Hybrid propulsion configurations using MGO-H2(l) and DF-H2(l) are
feasible for all propeller types due to their higher energy density compared to liquid H2. Implementing waste heat recovery or regenerative braking systems, or a combination of both, does not solely determine achieving the 40% CO2 emission reduction target.

Economical feasibility: Depending on the amount of available financial resources in year 2023, available subsidy and to what extent one is willing to take risks, the following conclusions can be made for different categories of initial capital expenses. Lower capital expenditure options opt for HVO and FAME, due to their MGO similarity, which result in low capital investments. Since the TTW emission of bio fuels is sensitive to regulations the dual fuel methanol configuration with a 4.0m diameter propeller is an option which requires more initial investment, but is less sensitive to regulations and therefor more future ready. With initial investments above €2.0M the combination of 4.0m propeller, together with
Orcan WHR and regenerative winch braking, the 100hr cycle performance best for MGO-Hydrogen configuration and the Continuous cycles performance best for a new build beam trawler. Taking into account the remaining value in the TCO a new build beam trawler outperforms all retrofit options, only in the long term 15+ year due to low maintenance and operational expenses.