Clean Energy? Coal Burned with Oat Hulls Reduces CO2 Emissions

In the work to find cleaner energy, scientists recently determined that burning oat hulls with coal in a coal-burning power plant significantly reduces emissions of carbon dioxide and particulate material, according to a release.

For this, researchers from the University of Iowa looked at the practices at the University of Iowa (UI) Power Plant. For more than 10 years, technicians there have burned a mix of coal and oat hulls, said the release.

The team learned that when compared to burning only coal, a 50-50 mix of oat hulls and coal has a reduction by 40 percent of CO2 and cuts down the emission of heavy metals, hazardous substances and particulate matter, according to a release.

"Our general conclusion is that when optimized, co-firing (burning biomass with coal) presents a good option for energy production, without incurring the negative environmental effects that comes with burning fossil fuels alone, like fossil carbon dioxide emissions and harmful particulate matter," said Betsy Stone, assistant professor of chemistry, in the release.

The researchers also noted that while controlled burning of any biomass (grasses, wood chips, oats) might seem preferable to burning coal, those materials require specialized equipment and may not burn efficiently. Also, supplies may be limited, as the release noted.

With oat hulls, the UI Power Plant has a ready supply from a nearby Quaker Oats facility. The university adjusted its equipment to burn oat hulls more effectively-40,000 tons a year, at this point, as the release confirmed.

To learn the actual effect of the oat hulls, the scientists tested emissions in April through May 2014. They learned that co-firing with the hulls produced 90 percent less filterable particulate matter. It also decreased air pollutants by 41 percent. Heavy metals including copper, nickel, manganese and zinc fell by 51 percent as a result of co-firing with the hulls, too. CO2 emissions were decreased by 40 percent, said the release.

The team published their findings in the journal Fuel, noting there: "Many environmental advantages were observed with co-firing oat hulls as a new potential fuel for energy generation."

The university funded the study.

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