Who We Are As the largest private-sector power producer in the world and the nation's largest producer of clean and reliable energy, Constellation is focused on our purpose: lighting the way to a brilliant tomorrow for all. We have been the leader in clean energy production for more than a decade, and we are cultivating a workplace where our employees can grow, thrive, and contribute. Now integrated with Calpine, our portfolio includes 55 gigawatts of capacity from nuclear, natural gas, geotherm