NuStar Energy L.P. engages in the transportation, terminalling, and storage of petroleum products and renewable fuels, and transportation of anhydrous ammonia in the United States and internationally. It operates through three segments: Pipeline, Storage, and Fuels Marketing. The Pipeline segment engages in the transportation of refined products, crude oil, and anhydrous ammonia. The Storage segment offers storage, handling, and other services for refined products, crude oil, specialty chemicals, renewable fuels, and other liquids. The Fuels Marketing segment provides bunkering operations in the Gulf Coast; and blending operations with Central East System primarily for ship owners, marketers, and traders. The company was incorporated in 1999 and is headquartered in San Antonio, Texas. As of May 3, 2024, NuStar Energy L.P. operates as a subsidiary of Sunoco LP.