Southwestern Energy, a locally based energy company, signed a 101,000-square-foot office lease in Houston. The firm will occupy DHL's former space on the first through fourth floors of 515 W. Greens Road. Occupancy will begin this month with the entire space occupied by September. The building, known as One Commerce Green, is a 12-story stricture with 340,956 square feet within the North Belt/Greenspoint submarket. It was built in 1983 and was fully renovated in 1996.