The Ship Supplier

Amid tightening environmental regulations and emerging carbon costs, the value of selecting the right hull coating has never been higher, writes Yigit Kemal Demirel, Hull Performance Solution Manager, Hempel.

Keeping a clean hull has never been just about good housekeeping. As well as accelerating corrosion and facilitating the movement of harmful invasive species, the buildup of marine organisms on a ship’s hull also increases a ship’s power demand by adding to frictional resistance as the vessel moves through the water. With the emergence of international regulations on energy efficiency and, through the European Union, the arrival of the first direct carbon costs on shipping, selecting biofouling solutions for their impact on fuel consumption has become critical. Hempaguard, developed by Hempel, is a highly innovative and advanced marine coating solution designed as an eco-friendly fouling control coating for underwater hulls. Incorporating cutting-edge technology, it enhances fuel efficiency, reduces maintenance costs, and minimises the environmental impact associated with traditional antifouling coatings.

For vessel owners and operators, investing in a high-performance coating like Hempaguard is a proven way to reduce emissions and, in doing so, improve vessel efficiency ratings. Hempaguard X7 offers scientifically proven ‘Out-of-Dock Power Savings’ of an average of 6% compared to conventional antifouling coatings, and 1.4% speed loss over five years. Combined, these features provide up to 20% fuel savings compared to the market average of conventional antifouling coatings, with remarkably low emissions to water. Hempaguard exemplifies environmentally conscious innovation in the marine industry by merging antifouling and fouling release technologies through the biocidal activation of a hydrogel layer. This results in exceptional fouling control performance while minimising biocide release into the environment. The limited amount of biocide used in Hempaguard efficiently prevents biofouling and significantly improves fuel efficiency even after prolonged operation times. With operators facing several choices of energy efficiency investment, a robust decision-making procedure is paramount.

Hempel has developed a framework that can enable owners and operators to establish the impact of any energy efficiency measure on both vessel performance and cost before they make a purchase decision. The framework considers environmental, sustainability and regulatory requirements against total cost overall and payback, resulting in a ship-specific impact assessment that can support effective investment decisions.

To illustrate: the decision-making framework has been applied to the case study of a typical 40,000 DWT bulk carrier. Four scenarios were tested: three using self-polishing antifouling coatings with varying regimes of hull and propeller cleaning; and one using Hempaguard X7, a silicone-based low friction coating, accompanied by two propeller polishings a year. The scenarios were assessed for their impact on the ship’s required power, fuel consumption, fuel costs, and total CO2 emissions over a five-year docking cycle. The first step - a required power change assessment - traces the power needed to deliver a specific ship speed. Compared to the baseline of a clean hull coated with a self-polishing coating (SPC) Hempaguard X7 scenario implies 8.5% less power initially, i.e. freshly coated and out of dock, with the required power gradually increasing towards the end of the study period, in accordance with the guaranteed speed-loss. But the result is that the Hempaguard X7 option always generates a saving against self-polishing coatings.

This saving is quantified when the vessel’s fuel consumption based on a typical operating profile is considered. The silicone-based coating scenario, i.e. Hempaguard X7, offers far lower fuel consumption across the five-year cycle – a difference of up to 11,000 tonnes, or around US$6.75 million (based on a fuel price of US$572.5/tonne). That is more than enough to outweigh the higher initial cost, delivering a fast payback compared to the SPC option.

"Incorporating cutting-edge technology, it enhances fuel efficiency, reduces maintenance costs, and minimises the environmental impact associated with traditional antifouling coatings."

That fuel saving affects cost as well as compliance. Specifically for this case study, assessing the impact of the measures on the vessel’s IMO Carbon Intensity Indicator (CII) attainable rating – another crucial calculation for any efficiency measures – shows that only the Hempaguard X7 option leaves the shipowner with a CII rating that does not require corrective measures by the end of the study period. CII is not the only measure that demands an impact assessment beyond the cost of purchase and maintenance. The European Union’s Emissions Trading System (EU ETS), for example, imposes an extra cost on greenhouse gas emissions in the form of EU Allowances that need to be purchased to cover emissions on voyages to, from and between European Economic Area ports. Assuming an EUA price of US$90 per tonne of CO2e emitted, over five years the Hempaguard X7 option’s greater fuel savings lead to a total saving of around US$2.45 million in EUA purchases compared to the base self-polishing option. Overall, the silicone-based coating delivers a saving of more than US$6.35 million compared to the baseline self-polishing coating, with a payback period of around 12 months. The saving becomes US$8.8 million when the savings in the EU ETS carbon cost are included, which lowers the effective payback period. It is clear that this calculation will vary dramatically depending on the other energy efficiency measures considered, the vessel operating profile and the resulting exposure to regulatory regimes. However with a rigorous decision-making framework such as the one described above, owners can make effective investments for each vessel in their fleet.

Counting the Costs: A Formula Calculating Coatings Returns