Picture below is of MV Afros, a freighter that is wind power-assisted by virtue of those white towers, called "Flettner Rotors". Because wind power augments normal power, the ships burn less fossil fuel and can keep to schedules that modern society demands. You can read the article here: Sailing Cargo Ships
The MV Afros has four cylindrical rotor sails, like this one, that harness wind power. Credit...Spencer Lowell for The New York Times
Flettner rotors like the ones on the MV Afros are among the first in the water and can be installed in a matter of hours, but their reduction in fuel consumption is limited; they save an average of 3 percent to 15 percent on fuel. Other sails in the works are projected to save as much as 30 percent in fuel use, on average. They will be bigger and more powerful, with more sophisticated automation, maybe even augmented-reality cameras to compensate for sails blocking the view of the horizon.

The MV Afros has four cylindrical rotor sails, like this one, that harness wind power. Credit...Spencer Lowell for The New York Times
Flettner rotors like the ones on the MV Afros are among the first in the water and can be installed in a matter of hours, but their reduction in fuel consumption is limited; they save an average of 3 percent to 15 percent on fuel. Other sails in the works are projected to save as much as 30 percent in fuel use, on average. They will be bigger and more powerful, with more sophisticated automation, maybe even augmented-reality cameras to compensate for sails blocking the view of the horizon.