BENGALURU, Aug 18 (Reuters) - Abu Dhabi National Energy Company PJSC, known as TAQA, is evaluating an investment of up to $2.5 billion in the power businesses of Indian billionaire Gautam Adani, newspaper Economic Times reported on Friday, citing sources.

The investment, anywhere between $1.5 billion to $2.5 billion, could be made in single or multiple group businesses, including picking up a near-20% stake in Adani Energy Solutions the report said.

Adani's power and energy businesses include entities like Adani Energy Solutions, formerly known as Adani Transmission, Adani Power and Adani Green Energy , but both sides believe there is maximum synergy between TAQA and Adani Energy Solutions, the report added.

TAQA may acquire a stake through a combination of primary infusion and secondary purchase of shares from promoter family entities.

The company's founding shareholders, or promoters, hold a 62.52% stake in the company, which includes Gautam Adani's family trust's ownership of 53.93%.

A likely 20% stake in Adani Energy Solutions will amount to 183.43 billion rupees ($2.21 billion), according to Thursday's closing levels at 822.20 rupees.

The Adani Group and TAQA did not immediately respond to Reuters request for comment.

($1 = 83.0750 Indian rupees) (Reporting by Hritam Mukherjee in Bengaluru; Editing by Sohini Goswami)