According to the Southern Company subsidiary, the utility has also signed agreements with Siemens and Vestas to supply turbines to the projects.
Locations of the sites was not disclosed but the first projects are due online from 2018. RES will act as lead developer and balance of plant constructor for the ten new wind farms.
"The agreement structure with Southern Power is a new approach for RES, which has previously engaged in development partnerships on a very limited basis. However, the rapid growth of wind development across the Americas has presented opportunities to pursue creative operating relationships with strong partners," RES said.
Southern Company said the deals with RES and the turbine manufacturers means it can leverage the US' tax credits for identified projects.
The firm said its owns more than 2.7GW of renewable energy assets or pipeline projects including wind, solar and biomass.
"We now have priority access to a robust, visible development pipeline and a supply chain for turbines from two premier technology providers, reinforcing our focus on wind energy investments over the next several years," said Southern Power CEO Buzz Miller.