PNNL announces big offset potential for biochar

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As much as 12 percent of the greenhouse gas emissions caused by humans could be offset through the use of biochar — a charcoal-like substance made from plants, wood waste and other organic materials.

Pacific Northwest National Laboratory came up with that figure after crunching the numbers for a study that was published Tuesday in the journal Nature Communications.

The scientists behind the study said that the offsets garnered by producing biochar are greater than what could be offset if the same plants and materials were burned to generate energy in a biomass plant.

"These calculations show that biochar can play a significant role in the solution for the planet's climate change challenge," said study co-author Jim Amonette, a soil chemist at the Department of Energy's Pacific Northwest National Laboratory, in a press release. "Biochar offers one of the few ways we can create power while decreasing carbon dioxide levels in the atmosphere. And it improves food production in the world's poorest regions by increasing soil fertility. It's an amazing tool."

PNNL officials said the new study is the most comprehensive analysis of the potential of biochar to date. The carbon-packed substance was first suggested as a way to counteract climate change in 1993 and scientists and policymakers have given it increasing attention in the past few years.

Biochar is made by decomposing biomass like plants, wood and other organic materials at high temperature in a process called slow pyrolysis. Normally, biomass breaks down and releases its carbon into the atmosphere within a decade or two. But biochar is more stable and can hold onto its carbon for hundreds or even thousands of years, keeping greenhouse gases like carbon dioxide out of the air longer.

The substance can also be used to improve soils by increasing their ability to retain water and nutrients, and decreasing nitrous oxide and methane emissions from the soil into which it is tilled.