The phrase "a profitable source" is grammatically correct and can be used in written English.
You can use it to describe something that is a reliable and beneficial source of something, such as information, income, or resources. Example: "The stock market has proven to be a profitable source of income for many investors."
They have turned to natural gas as a profitable source of growth.
In an era of tight budgets and reduced payments from insurers, fast food is a profitable source of nonpatient care revenue for hospitals.
It's leading a 15-nation program to cut down emissions of methane, a powerful greenhouse gas, by turning it into a profitable source of energy.
But they fail to specifically ban broader trading strategies, like the high-frequency trading that was implicated in the infamous flash crash of 2010 and that has become a profitable source of banks' proprietary trading.
Still, the ex-slaves and their new Union overseers helped turn Port Royal into a profitable source of cotton, though it was nowhere near as productive as in the antebellum era.
Illegal imports have been a profitable source of revenue for many within the current ruling structure, and many observers sense that a gradual unravelling of the sanctions regime benefits power brokers anxious to maintain control of the the economy as well as the political situation.
In this way, LPBs could be economically turned into a highly profitable source rather than a traditional pollution and costing source.
Because guinea pigs require much less room than traditional livestock and reproduce extremely quickly, they are a more profitable source of food and income than many traditional stock animals, such as pigs and cattle; moreover, they can be raised in an urban environment.
AdMob, which some say is approaching a $100 million business within the next three years, could be an extremely profitable source, especially when the platform is plugged into AdWords and DoubleClick.
These remained an easy and profitable source of income to Beethoven for many years.
Rose saw her mother as a literary apprentice, not as an artist, even though she had always encouraged Wilder's writing — first the journalism, then the juveniles; they were a less strenuous and more profitable source of income for an elderly woman than chicken farming.
