Consumers in many other countries are finding out what Iowans and all Americans have known for a while — ethanol is good for the pocketbook as well as being good for the environment. And those, market observers say, are the big reasons that U.S. ethanol exports continue to grow.

U.S. ethanol plants shipped 1.379 billion gallons of ethanol overseas last year with strong sales to Brazil, Canada, China and a range of other destinations. The 2017 ethanol...