HAX alum Neptune Robotics is creating an army of underwater robots to clean ship hulls—helping save fuel costs and reducing CO2 emissions.

Per Bloomberg, maritime shipping emits roughly 1 billion tons of carbon dioxide each year—more than Germany, France and Ireland combined. The UN shipping regulation body, the International Maritime Organization (IMO), is calling on vessel operators to zero out emissions by 2050.

In response, shipping companies are increasingly exploring climate tech solutions to alternatively power their fleets, looking to batteries, hydrogen, biofuels, and wind. But none of these alternatives can compete at scale just yet. And there’s another problem that slows down ships: biofouling. The slime, algae, seaweed, and barnacles that accumulate on hulls add drag and reduce fuel efficiency. One study co-authored by the IMO found that “a layer of slime as thin as 0.5mm covering up to 50% of a hull surface could trigger an increase of GHG emissions up to 30%.”

Enter Neptune. The company’s underwater robots can identify the type of biofouling on a ship’s hull and its thickness, using an AI-backed operating system to map out a cleaning plan for each ship. The robot then engages in “cavitation cleaning” — vibrating biofouling off the hull with high-velocity microdrops of water. The resulting waste is taken to the shore for proper disposal.

“It is something we can deploy at scale, today,” a spokeswoman for Cargill Inc., which has deployed Neptune’s service for its bulk carriers since 2022, told Bloomberg.

Neptune’s cleaning service is now available at more than 50 ports in Hong Kong and mainland China, with 27 robots in operation and an average of one new robot added every week. new one added every week. The company plans to expand to Singapore later this year.