The phrase "a needed source" is correct and usable in written English.
It can be used when referring to a source that is essential or required for a particular purpose or context.
Example: "In our research, we identified a needed source that provided crucial data for our analysis."
Alternatives: "an essential source" or "a necessary source".
The Bangladeshi government maintained that the Farakka Barrage deprived southwestern Bangladesh of a needed source of water.
Many local officials have called for its closing, while others, including workers at the plant, maintain that it is safe and a needed source of energy for the area.
A domestic Palestinian gas supply could eventually eliminate spending on electricity and household fuels that are now imported from Israel, and exports would provide a needed source of dollars.
In places where protein is short, for example, insects can provide a needed source of nourishment; they are already abundant, and raising them commercially is environmentally friendlier than raising livestock.
They will also provide a needed source of scalability and liquidity in the market, which can help smooth trading around the world.
He said that Daimler has been for the most part hands off apart from directing him to Santiago, just a needed source of funds to sneak up on ride-hail apps from behind.
But they say firefly tours are a much needed source of extra income.
Yet the Internet is actually injecting new life — and a sorely needed source of revenue — into the Postal Service.
As the largest single private employer on the island and a badly needed source of wealth and investment, he was phenomenally popular with the public there.
Then, as now, the lottery was touted as a critically needed source of funds for our schools, police and fire departments.
In turn, the insane system of the latter provided a desperately needed source of identity.
