Wesley Clark, the retired Army general and former supreme allied commander of NATO, has joined the Blackstone Group as a deal adviser in the energy sector.

Clark, who led the Kosovo campaign in 1999 and briefly ran for the Democratic presidential nomination in 2004, will also serve as director with Fisterra Energy, a company that focuses on power projects in Latin America, Europe and the Middle East, and is led by a former executive chairman of Element Power, Pedro Barriuso.

“Helping countries overcome their energy challenges and develop energy security is critical to economic growth and sustainable development,” Clark said in a Blackstone statement. “I am pleased to join Fisterra’s board of directors and look forward to supporting the team as they work to accomplish their goals.”

Joining Clark at Blackstone will be Lars Thunell, former executive vice chairman and CEO of the World Bank.

Clark, a graduate of Oxford University, retired from the Army in 2000 and has served as the co-chairman of Growth Energy and BNK Petroleum.