Valero Energy was not only named after a mission (the Mission San Antonio de Valero), it is on a mission to be the largest independent refiner in the US. Valero churns out about 3 million barrels per day, refining low-cost residual oil and heavy crude into cleaner-burning, higher-margin products, including low-sulfur diesels. It operates 15 refineries in the US, Canada, the UK, and Aruba. It also has 11 ethanol plants with a combined production capacity of about 1.3 billion gallons per year. Once a more diversified company, Valero has exited the retail business in order to focus on its oil refining and ethanol operations.