A Hopkinsville energy plant has helped a Tennessee sustainable feedstock producer reach an important milestone. Memphis-based Delta BioRenewables delivered a commercial-sized batch of sweet sorghum juice this month to the Commonwealth Agri-Energy plant. The plant’s machines that turn corn into ethanol are now using sweet sorghum for the same process. Commonwealth Agri-Energy manager Mick Henderson says sweet sorghum could be used for about 5 percent of the company’s annual ethanol production. Sorghum is drought tolerant and could be a good rotation crop.