In its 2015 financial year results, Mainstream reported increased post-tax profits of €96 million – up from a €47 million loss in 2014.
The firm said it is looking to raise €100 million "from one or more investors" to help fund projects in South America, Africa and south-east Asia.
Mainstream CEO Eddie O'Connor said there had been "indication of a significant level of appetite ... from third-party institutional and strategic investors" to invest in its projects.
The increase in profits are in part down to its joint venture with Actis in South Africa, where the transfer of three under-construction projects to their Lekela Power partnership meant Mainstream received €28 million.
Mainstream's turnaround was also helped by the sale of the Hornsea Project One site in early 2015 to Dong Energy. Mainstream developed the project as part of the Smart Wind consortium with Siemens Financial Services.
Mainstream said the sale was part of its offshore wind exit strategy.
"I am delighted to attribute the robust financial turnaround made in 2015 to the diligent implementation of our new business plan, which reflects the value realised from the recent sale of certain offshore assets, payments received following delivery of projects to the Lekela platform and reductions to our cost base," O'Connor said.