Burning wood/biomass or gas generated from biomass releases the CO2 that has been captured by the plant while growing. Replanting the same plant will capture the same amount again. It’s effectively solar energy using photosynthesis instead of solar cells. So it’s a renewable energy, as long as you replant what you harvest.

The problem correctly pointed out in the article is that often the replanting comes after the harvest, or does not effectively happen at all - at least for wood pellets.

I would imagine it taking out plenty of minerals and nutrients from the soil though, needing constant fertilizer usage which comes with its own set of problems.

The minerals remain in the ashes. Other nutrients may be an issue, but for example when producing biogas, they’re essentially in the leftover parts of the plant. Biogas is mostly methane, so carbon and hydrogen.

Oh I see, thanks!

Isn't that an inaccurate simplification? A lot of harvested wood is not from tree plantations but from old(ish) growth forests. It also takes decades to regrow trees so the carbon capture is taking place over an extremely long time compared to the near instant release from burning the wood. Add to that the emissions from harvesting the trees using heavy equipment, transporting them, and processing them into pellets. Burning wood is also pretty inefficient when it comes to energy or heat production and it releases a lot of particulate matter. Of all the renewable options it's obviously the worst.

There is promising process to burn biomass a low oxygen environments producing biochar(black carbon residue) without releasing CO2. This process is still in testing stages and is not deployed at scale with unclear scaling and costs.

https://www.american.edu/sis/centers/carbon-removal/fact-she...