Pinnacle Renewable Energy created this very informative video to explain the whole process of how wood pellets are made – from beginning to end. Check it out!
Wood pellets begin their journey as tree seedlings. By absorbing nutrients from the soil, and carbon dioxide from the air, along with sunlight and rain, the seedling is eventually nurtured into a full grown tree. Then, it’s harvested for lumber and replaced with a fresh seedling. This renews the process all over again, in a controlled sustainable way.
Turning the harvested trees into something useable involves a long process of de-barking, cutting, chipping, sawing, drying and planing. This creates almost 60 percent scrap. Half of this scrap is wood chips that go into the pulp and paper industry. The rest is what we call saw-milling residuals, which make up nearly 30 percent of the original log. These residuals used to be burned up at the sawmills to save space. Now, they’re bought by the truckload and brought to pellet plants.
The raw material is kiln-dried, then mixed with dry shavings. This mixture is fed through the hammer mills, where it’s ground down into more manageable particles. Hammered material is then squeezed through a high-pressure pellet die, which pushes out pencil-sized tubes of compressed wood. These tubes are then cut into pellets and cooled back down to room temperature – which strengthens their composition in the process.
When fully cooled, the pellets are transferred to a storage silo where any uncompressed dust is screened through and re-used. Quite a process, right?