As solar gets to be less of a experimental entrant and more of a mainstream power source, successful solar companies are increasingly being swallowed up by established energy companies.

This occurred again today. This morning AES Corporation (NYSE: AES), a global energy company with $14 billion in annual revenues, announced a deal to acquire emergent U.S. utility-scale solar project developer and independent power producer (IPP) sPower from Fir Tree Partners and minority owners.

AES has partnered with Alberta Investment Management (AIMCo) for the $1.58 billion deal. After paying out an estimated $853 million in cash and assuming $724 million in non-recourse debt, AES and AIM will each own slightly less than 50% equity interests in sPower, including its 1.18 GW of wind and solar assets. The transaction is expected to close by the third quarter of 2017, subject to standard regulatory reviews and closing conditions.

With the acquisition, AES and AIMCo will get a developer and IPP which has grown with the fast-moving utility-scale solar market in the United States. In January sPower announced that it had put online over 1 GW of solar projects, only 34 months after being capitalized by Fir Tree Partners.

As of today’s announcement sPower has 1.8 GW of operational wind and solar assets, the vast majority of which is utility-scale solar in California and North Carolina. The company has another 91 MW of utility-scale solar under construction in California, and all of these assets hold with long-term power purchase agreements with an average remaining life of 21 years. The company also claims a pipeline of more than 10 GW of projects.

While owning and operating a range of assets and businesses, AES is no stranger to clean energy. The acquisition of sPower will bring AES to over 9.5 GW of combined hydro, wind, solar and energy storage projects, among the 36 GW of generation that the company owns and operates.

Among its clean energy holdings AES has been particularly invested in energy storage. AES’ Energy Storage subsidiary produces the Advancion energy storage solution, and in January installed and commissioned the largest battery storage project in the world for San Diego Gas & Electric Company. AES Energy Storage claims 432 MW of energy storage either in operation, construction or late-stage development in seven nations.