According to clean tech group Evac, the ever-growing shipping industry is the most sustainable form of transportation, but due to the size of the sector, it currently contributes to roughly 3% of global greenhouse gas (GHG) emissions every year.
Evac company Cathelco considers marine growth prevention to be a crucial, but sometimes underestimated, part of the puzzle when considering the industry’s energy-efficiency improvement opportunities. Maintaining a smooth and clean hull free from biofouling is paramount to optimising the energy efficiency of ships. The impact can be even up to 25%. Cathelco is are currently investigating new, interesting opportunities for advanced marine growth prevention.
Current and future technologies need to be harnessed to reduce fuel consumption and harmful CO2 emissions. The initial IMO GHG Strategy has an ambitious target to reduce the carbon intensity of international shipping by 40% by 2030, compared to 2008 levels. Some industry players are already determined to do more and reach carbon neutral shipping by 2050 at the latest.
When biofouling species, barnacles, and mussels colonise the underwater parts of a ship’s hull, the increased roughness will increase a ship’s hydrodynamic drag. The immediate effect is a loss in ship speed at a constant power – or a power increase to maintain a constant speed. Both have negative economic and environmental impacts through increased fuel consumption and atmospheric emissions, including GHG.
Chris Hewitt, Cathelco Product and Technical Manager said: “Using the best marine growth prevention systems with regular maintenance significantly impacts on fuel consumption and CO2 emissions of the vessels. It is good to acknowledge that if neglecting the prevention, a slime layer can trigger up to 25% increase in GHG emissions.”
The significant 25% reduction in GHG emissions means up to 22% savings in the vessel’s fuel consumption.
The transfer of invasive aquatic species to new environments by ships has been identified as a major threat to the world’s oceans and to the conservation of marine biodiversity and, therefore, to the planet´s ecological and economic well-being. These species are causing enormous damage to biodiversity. Direct and indirect health effects are becoming increasingly severe and environmental damage is often irreversible. Moreover, significant economic impact occurs on industries that depend on the coastal and marine environment, such as tourism, aquaculture, and fisheries.
Hewitt continued: “Well-maintained marine growth prevention system has a big impact in reducing the risk of transferring of invasive aquatic species. The system eliminates the settlement of macro biofouling organisms on the ship’s interior piping systems while enhancing energy efficiency and reducing air emissions from ships. The technology also significantly lengthens the lifecycle of the pipes.”
The Cathelco marine growth prevention systems, also known as antifouling systems, usually consist of pairs of copper and aluminium anodes, mounted in sea chests or strainers and connected to a control panel. In operation, the copper anode produces ions which are carried by the flow of seawater, creating an environment where barnacles and mussels will not settle or multiply.
New technologies are under development to prevent the marine growth. The most common technologies currently in use for biofouling mitigation are ultrasonics and hull and propeller cleaning.
Hewitt concluded: “We are also following the development and investigating new, interesting opportunities for advanced marine growth prevention. It is exciting to work closely with our long-term customers and academia to see what the future holds for us.”
