The trees are drought-resistant and soil/salt tolerant. Some hummock species include Carolina wolfberry, lime prickly ash, sugarberry, coral bean and prickly pear cactus. Download NRG Energy's Sustainability Report here. Learn more about NRG Energy's sustainability initiatives here. About NRG NRG is the leading integrated power company in the U.S., built on the strength of the nation's largest and most diverse competitive electric generation portfolio and leading retail electricity platform. A Fortune 200 company, NRG creates value through best in class operations, reliable and efficient electric generation, and a retail platform serving residential and commercial businesses. Working with electricity customers, large and small, we continually innovate, embrace and implement sustainable solutions for producing and managing energy.