Combined, Windy Rig and Twentyshilling, in Dumfries & Galloway, will produce 81 megawatts of power.
The former is expected to come online in the second quarter of 2021 while the latter should be up and running by the third quarter of the same year.
Greeencoat is buying the assets from developer Statkraft UK, which will provide route-to-market and operational management services for the wind farms once operational.
Chairman Tim Ingram said the transaction followed the template of the Glen Kyllachy acquisition, which will cost £57.5mln once the deal is concluded in October 20201.
“We are delighted to partner with Statkraft on this transaction, demonstrating that UKW [Greencoat] is the continuing partner of choice for utilities, who are well placed to retain and manage the risks associated with wind farm construction," he added.