The US-based investment firm has taken a non-controlling stake in the portfolio, which is also owned by GE Financial Services, operator Atlantic Power Corporation and service provider Ruby Renewable Resources.
The portfolio consists of 11 projects near Twin Falls, southern Idaho. It uses 122 of GE's 1.5MW and was commissioned in 2010.
The cluster of projects will fall within MIC's Contracted Power and Energy portfolio, which, with this investment, stands at approximately 96MW and is made up of two wind projects and some solar developments.
Last month, MIC's parent group, the Australian-based Macquarie Group, was in talks to acquire a 112MW portfolio of Italian wind projects.