The deal is the latest in a string of collaborations with household name engineers.
Doosan is one the largest fuel cells groups in Korea and is likely to play a major part in the desire of the government there to have 15Gw of fuel cell capacity in place by 2040.
Caldwell says this is the first time it has worked with the Korean company but hopes it will be the start of a long-term relationship.
Ceres had been working to seal the deal with Doosan for a year, he added.
In October, Ceres sees the first commercial launch of a product containing its technology through Japanese boiler maker Miura, another of its long-term licensing partners.
Ceres started to work with Miura in 2016, which shows how good we are getting at building long-term partnerships, added Caldwell.