The latest trend for the next generation of bulk carriers is a "hybrid engine".
Just like hybrid cars, they aim to achieve zero CO2 emissions by operating on battery power and being recharged during port operations and port stays.
During the sail, conventional propulsion systems are used.
This new model is said to reduce CO2 emissions by 30%.
The ships are currently being built, and we should be able to see more of the hybrid - battery powered bulks in operation starting from 2022/2023!
Source :
https://shipandbunker.com/news/world/927590-norways-hagland-shipping-orders-two-battery-powered-bulkers