[dragonwriter]

> Growing biomass is carbon neutral,

No, growing biomass sequesters carbon.

> burning fuel derived from it never is.

Burning fuel derived from biomass releases the carbon sequestered in growing it. So, the whole process is carbon neutral.

(Yes, that means fossil fuels are carbon neutral viewed over the entire time window from when the biomass from which they were derived was grown. They aren't carbon neutral over the timescales we care about, but anything derived from recent and sustainable biomass production is.)