Could underwater cleaning robots help ships become more fuel efficient?

Hong Kong-based startup Neptune Robotics says its biofoul cleaning robots can reduce fuel consumption per trip by at least 18%, Bloomberg reported last week. A thin layer of algae, seaweed, and barnacles covering half of a vessel can increase emissions by up to 30% by creating resistance in the water, according to a study (pdf). “It’s like swimming with a thick blanket,” Neptune co-founder Elizabeth Chan said.

How it works:Using AI, the robots first identify the type of biofouling on a ship’s hull and the thickness of the layer before mapping out a plan for cleaning. The cleaning process is similar to cleaning off tarnish from jewelry and involves vibrating the biofoul off the vessel’s hull using high-velocity microdrops of water. The robots cannot reach spots like the ship’s propellers.

The benefit is on several fronts: Neptune’s robots have helped the shipping industry avoid about 1 mn tons of emissions since 2020 by cleaning 700 vessels, with the cost of cleaning falling between USD 12k and USD 40k. The use of robots can also increase safety, since it eliminates the need for divers to clean hulls. Humans are still needed to launch the robots from a boat and to review the cleaning process.

The shipping industry has been in hot water: A majority of countries at the International Maritime Organization’s (IMO) two-week negotiations on climate policy were in favor of mandating a global emissions levy starting next year. The levy — which was backed by 34 countries — will help countries achieve the revised emissions targets approved last year which some experts are already doubting its feasibility. Revenues collected from the tax could be put towards developing low emissions shipping fuels and fund the energy transition of poorer states. Delegates at the IMO are expected to hold talks in the fall to further discuss the different proposals for a carbon levy.