"Without the tariff protection we would probably supply 90-plus percent of all (ethanol) import needs they (China) had," Dwyer said while on a panel with Renewable Fuels Association chief economist Scott Richman.

The trade conflict between the two countries escalated just about a year after China said it would target the roll-out of gasoline known as "E10," containing 10 percent ethanol, by 2020. This was expected to bolster the country's demand for U.S. ethanol.

"The reality is that the tariff war has hurt us badly. It was horrible timing."

"If this trade war ended tomorrow you would see margins expand by 10 cents a gallon," Dwyer said.

While domestic measures like the promised expansion of higher ethanol gasoline blends such as E15 help, trade issues need to be resolved for the industry to thrive.

"Exports are the future of our industry - even more so than E15," Dwyer said.

(Reporting by Ayenat Mersie; Editing by Phil Berlowitz)