MARY LOUISE KELLY, HOST:
Time now for All Tech Considered. And today we are considering how technology could make shipping cleaner. The vast majority of the things we buy in the U.S. come here on ships, often from countries oceans away. These ships run on a particularly dirty kind of fuel called heavy fuel oil, or bunker fuel. As NPR's Rebecca Hersher reports, that may be changing.
REBECCA HERSHER, BYLINE: The inside of a modern ship smells like oil, and everything is enormous.
ALEKSEI BUZLOV: So let's go down.
HERSHER: Aleksei Buzlov (ph) is the chief engineer on a coal-carrying ship that I visited when it stopped in Baltimore earlier this year. Its engine room was a cavern four or five stories tall.
There were layers of catwalks around an engine with pistons as long as station wagons. And built into the walls were rows and rows of bulbous storage tanks.
BUZLOV: Fuel tanks - this one, 60 tons; another one, 80 tons - small tanks.
HERSHER: Small because, in all, the ship carries about 300 tons of heavy fuel. The fuel is darker and thicker than diesel or gasoline. It looks kind of like the engine oil for a car. Aleksei spends a lot of his time down here cleaning gunk out of engine parts.
BUZLOV: This is slop.
HERSHER: Slop, the dark grease that heavy fuel leaves behind on basically everything it touches.
Oh, it's like frosting - or poop.
BUZLOV: Don't touch.
HERSHER: Keeping the ship's engine clean enough to run efficiently is a never-ending job. This ship burns an average of 50 tons of heavy fuel every day when it's on the ocean. And in addition to the slop, as it burns fuel, the engine emits CO2, carbon dioxide, and soot into the atmosphere. Add that up across all the thousands of ships crisscrossing the Earth every day, and it's a lot of pollution.
NERIJUS POSKUS: If shipping was a country, it would be the sixth-largest polluter in the world. About 3% of global emissions are released by ocean freight shipping today.
HERSHER: Nerijus Poskus is an analyst at the company Flexport. He says the shipping industry is growing so fast, it's projected to emit more than 15% of greenhouse gases by midcentury if ships keep burning heavy fuel oil, which is untenable if humans hope to avoid the worst effects of climate change. And the shipping industry appears to know that.
POSKUS: Things are changing, and they are changing actually quite fast, finally.
HERSHER: International regulators have tightened emissions standards for when ships are in port. And one big company, Maersk, has said they intend to make their entire fleet zero emission by 2050 - no greenhouse gases, which will require a new type of fuel.
POSKUS: My personal opinion, hydrogen looks like the most promising way to power ships.
HERSHER: Poskus thinks it will take at least a decade, partly because ships are designed to last about 30 years. But the first hydrogen-powered prototypes are being built now in just a few places on Earth. Norway is one of them. The other is Oakland, Calif.
JOE PRATT: OK. So down here where he's working, you have the two holes. Right?
HERSHER: Joe Pratt looks down at the shiny aluminum skeleton of a ship. It's on its way to being a passenger ferry, so you can see the outlines of what will be two catamaran hulls.
PRATT: This is the floor.
HERSHER: His company, Golden Gate Zero Emission Marine, is building it with money from the state of California. When it's finished in the fall, it will be the first hydrogen-powered vessel to operate in the U.S. Pratt says the technology is not particularly new. They're just proving that it can be used to power a boat.
PRATT: Yeah, everything is off the shelf.
HERSHER: One issue his team has had to figure out was how to make sure there was enough room for the hydrogen tanks and for the fuel cells. As big as internal combustion engines are, hydrogen fuel cells and their fuel will require even more space. One thing they don't have to worry about anymore, though - smelly exhaust.
PRATT: It has an exhaust duct, which will have warm, humid air coming out.
HERSHER: The moisture from the exhaust will be collected and used as drinking water onboard. Pratt says his company is already fielding questions from boat tour companies and others who are interested in either building new hydrogen-powered vessels or retrofitting their current ships. There is one more challenge, though, to achieve the goal of zero emissions. The hydrogen fuel that powers a vessel like this isn't necessarily clean. Lennie Klebanoff studies hydrogen fuel cells at Sandia National Lab.
LENNIE KLEBANOFF: In the U.S., about 90% of our hydrogen is made from methane.
HERSHER: When you make hydrogen from methane, the process emits some CO2. So even though the hydrogen itself is clean burning, it's not really zero emissions. There are other ways to make hydrogen, though - from biomass, for example, or - cleanest of all - from water.
KLEBANOFF: So water is H2O. You get the H's off of the H2O, and you're left with O, which is oxygen.
HERSHER: The hope is if even a few companies start buying hydrogen-powered ships in the coming decade, the demand for clean hydrogen will go up, and fossil fuels will stop being the go-to for global shipping.
Rebecca Hersher, NPR News.
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