Burying biomass produces methane as it anaerobically decomposes. I'd imagine that capturing that is fairly challenging compared to (essentially) burning the bio

Burying biomass produces methane as it anaerobically decomposes. I'd imagine that capturing that is fairly challenging compared to (essentially) burning the biomass and separating out the carbon. Biomass can be pyrolized to produce flammable gas, charcoal/biochar, "wood vinegar", and a few other byproducts in a process that produces surplus energy. As long as you have biomass feedstock coming in, you can produce highly concentrated solid or liquid carbon on the far side and get energy out as power.