Majestic monarch butterflies have captivated people’s imaginations for generations. Yet all is not well with monarchs. 

Researchers estimate that only a fraction of the monarch population remains, due to habitat loss and other factors. That’s why companies like the Western Iowa Energy biodiesel plant near Wall Lake are joining the Monarch Fueling Station Project.

“Biodiesel production is all about turning the seemingly useless into something useful,” said Kevin Bieret, operations manager for Western...