The first project, located in the Kuolavaara-Keulakkopää area in the Kittilä municipality in northern Finland, is intended to feature 17 turbines with an output of approximately 50MW.
The other wind farm should comprise 8-10 turbines, with a planned output of about 25MW, at Joukhaisselkä in the nearby Sodankylä municipality.
The transaction will be implemented in phases, with the sale expected to be completed during the first quarter of 2014.
The sellers will remain responsible for finalising the permitting of the projects, while Impax will raise project financing for construction.
"Given the early stage of the Finnish wind market, we see this portfolio as an excellent foundation asset for our wind investment programme in the region. This is a key market for Impax, and we will target follow-on acquisitions as the market continues to grow," said Daniel von Preyss, managing director of Impax.