First thing: biomass is about 200-250g of CO²eq per kWh. Burning biomass is polluting, and thus is not a viable alternative to nuclear, hydro, solar, wind, and the other low-carbon power sources we should aiming for.

I think "biomass" CO2 emission depends on whether it's renewable biomass (which i meant here) or non-renewable biomass (a.k.a fossil fuels). If you consider it over a 10-year average.