TerraForm Power Inc. agreed to acquire a majority stake in a portfolio of wind farms in the U.S. and Canada from Invenergy Wind LLC in transactions valued at a combined $2 billion.

TerraForm, which was formed last year by a spinoff of SunEdison Inc.'s clean-power assets, expects to acquire net ownership of 460 megawatts of wind power plants. An additional 470 megawatts of wind power plants will be acquired by a warehouse facility that will be sponsored by SunEdison and third-party equity investors, with the assets being dropped down to TerraForm later.

TerraForm shares rose 3.5% to $38.86 in recent after-hours trading, while SunEdison rose 3.8% to $30.05.

The assets in the deals, expected to close in the fourth quarter, include seven contracted wind farms and represent roughly one-tenth of Invenergy's total contracted portfolio. Invenergy will retain a 9.9% stake in the U.S. assets and will provide certain operation and maintenance services for those power plants.

Invenergy Chief Financial Officer Jim Murphy stated in a news release Monday that "market interest in these wind projects was strong, reflecting the quality of these renewable energy assets, all of which have long-term power sale contracts."

SunEdison and other renewable-energy developers such as NextEra Energy Inc. and NRG Energy Inc. have spun off groups of power plants, solar farms and wind farms into new companies, such as TerraForm, which sell power to utilities or other companies under long-term contracts and pay regular dividends to shareholders.

TerraForm also raised its 2016 per-share dividend target by 11% to $1.70 from its previous guidance for $1.53.

Write to Tess Stynes at tess.stynes@wsj.com

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