Bias in the CMB B-mode power spectrum reconstruction for SWIPE+Planck dataset. The ratio between the bias (see Eq. A.3) and the input CMB power spectrum . All angular power spectra were computed as the average among 200 different simulated NILC CMB reconstructions and adopting the masks employed in Sect. 5. The shaded regions display the relative uncertainty computed as , where N_sims is the number of simulations. Top: Results of the application of rit-NILC (blue) and rin-NILC (red). Bottom: Bias from ZB (blue) and hybrid ZB-NILC (red). The Galactic emission was simulated with the d0s0 (left) and the d1s1 (right) sky models.