The consideration for the transaction is $2.30 per share.
Mercury has also secured an option to acquire the remaining 6.8 per cent of Tilt shares held by TECT.
The company says Tilt is an established business operating power plants in a growing renewables market, with a portfolio of wind farms in Australia and New Zealand.
Shares in Mercury (ASX:MCY) closed down 3.32 per cent to $2.91 on Friday.