CGEI is jointly owned by Good Energies and Champlin Windpower. Under the terms the deal, CGEI CEO Mike Cutbirth will join Western's board.
Western has around 165MW of solar and wind projects in California and Arizona. CGEI's pipeline is primarily in US markets, including Utah, California and Hawaii.
Speaking about the deal, Western CEO Jeff Ciachurski said: "With a 4,000 MW pipeline and near term projects in Hawaii and Utah, this complements the consistent Western Wind strategy of executing and completing projects in niche markets with high-level renewable-energy policies and aggressive pricing.
"Mike is a well-respected leader in the US wind business and complements the aggressive vision at Western Wind."
Cutbirth said: "Our portfolio will help continue to fuel the growth plans of Western. Our portfolio is complementary to Western Wind's holdings with projects in key niche markets and there should be significant synergies to the acquisition and merger of our holdings into Western."