U.S. Secretary of Agriculture Tom Vilsack announced millions of dollars in grants to help retailers offer higher biofuel blends and touted other opportunities to grow the use of renewable fuels last week at the Iowa Renewable Fuels Summit.

Vilsack highlighted $19 million in grants to increase the availability of biofuels in 22 states, including a $5 million grant to Iowa-based Casey’s convenience stores to install more than 450 E15 fuel pumps at 111 stations in...