Wood could be the new 'clean coal'

A process known as torrefaction could turn wood waste into a lightweight fuel source that burns like coal without coal’s massive greenhouse gas emissions, according to researchers at North Carolina State University.

Torrefaction removes moisture from wood waste and “toasts” the material, converting it into chips that retain 80 percent of the wood’s original energy in just one-third the weight. Those chips could be burned in electricity-producing plants that currently rely on coal, a major source of atmospheric carbon dioxide.

Unlike coal, wood biomass is carbon neutral. It’s also widely abundant in North Carolina, a state that currently imports all its coal from other areas.

While torrefaction isn’t new, North Carolina State’s torrefier machine is. Dubbed the Autothermic Transportable Torrefaction Machine, or ATTM, it’s easily transported to the field, unlike other machines. Creating torrefied wood chips on site could greatly the cost of transporting tons of woody biomass to power plants, the researchers say.