Appointed a research associate in 1966, and then a senior research associate (1969–1980), da Rosa became a professor in electrical engineering in 1980. During this time, his interests gradually turned more to the fundamentals of energy processes and renewable energy. His classes on renewable energy were greatly appreciated by the students and he continued teaching these energy classes until 2011, well after his retirement in 1983.
In 1966, da Rosa was appointed as a research associate, later becoming a senior research associate from 1969 to 1980. He transitioned into a professorship in electrical engineering in 1980 and his focus shifted towards the fundamentals of energy processes and renewable energy. His classes on these topics were highly regarded by students, and he continued teaching them until 2011, even after retiring in 1983.