Ames-based biofuels company Renewable Energy Group has completed $34.5 million in upgrades at its Danville, Ill., biorefinery. The work included the addition of biodiesel distillation. The plan is to use a wider assortment of feedstocks with lower carbon intensities. The project also included logistical improvements such as an additional truck loadout, new warehouse and office space, and the acquisition and integration of approximately 13 million gallons of biofuel and feedstock storage from the neighboring Bunge facility. REG also bought land nearby, and now has nearly 30 acres, up from 8.