Will future cargo ships be free of exhaust?

The Orcelle, a concept cargo ship, would use various power sources, including the wind from "rigid" sails that also have solar panels. Image source: Environment News Service
My son and I were reading a book Thursday about ships that a cousin had given as a gift. We looked at drawings of engine rooms and sleeping quarters.
But in the back of the book, I spotted a rendition of a sleek, futuristic-looking ship with an intriguing design. It turned out to be the Orcelle, a concept cargo ship of the future.
It might take until 2025 for the ship or a version of it - which could carry 10,000 cars from continent to continent – to make it to the ocean. But it apparently would be an emission-free ship.
I was amazed.