Climate

I'm a woodworker. I have a small hobby shop on the back of my property, looks like a garden shed from the outside, I produce 8 or 10 barrels of sawdust a year. That's probably enough to heat my house through the winter. It all goes to the dump. Here's why:

There's nobody who wants to work with me. There are places that make fuel pellets at industrial scale in my area, they want nothing to do with a guy bringing them 2 or 3 rubbermaid trash cans full of sawdust a few times a year, they want regularly scheduled semi truck delivery. There are farmers that have more modest sized hammer mills and extruders necessary for the job, but they don't want to take the time to run a tool for some guy. I could buy the tools myself, for several times what it cost to heat my house with gas for a year.

So who produces sawdust or other fine wood chips at industrial scale? Sawmills, but they often use their own sawdust to make particle board. Furniture factories maybe? The few remaining that don't mostly use particle board?

Edit to add: There is a source of kinda free wood matter: Branches. The structural or furniture lumber industries don't use limb wood; it's too unstable. Trunks grow roughly parallel to gravity, branches grow more or less perpendicular, so they have a tendency to warp when milled, plus they're smaller and just not worth trying to saw into boards. So they tend to get ground up for wood chips or paper pulp or whatever would be convenient to the business.

The basic answer is that when the power plant is far from the clearcuts, they can pretend it's being fed using waste sawdust. Been a big issue with the UK importing from North America.