While the push to wean Duluth’s steam plant off coal continues, the fossil fuel will continue to remain part of the facility’s diet for the foreseeable future, largely because of regulatory delays its operators have encountered as they seek to burn a new biofuel made from wood waste.
“We hoped to be burning renewable fuel oil this year, but that’s not going to happen. And it’s questionable whether or not it will happen in 2020,” said Terry Nanti, general manager of Duluth Energy Systems, a division of Ever-Green Energy, which now runs the district energy system.
Renewable fuel oil is produced from gasified forest residuals, explained Michael Burns, vice president of operations for Ever-Green Energy.
“They put it into a reactor, and they cook off the volatiles. So it makes kind of a wood tar, which then they liquify,” he said.
Burns said this wood-based fuel is expected to qualify as a renewable fuel under the Environmental Protection Agency’s standards, but that designation has been slow in coming.