  Protoplanetary disk are the foundation of planet formation. Lightning can
have a profound impact on the chemistry of planetary atmospheres. The emergence
of lightning in a similar manner in protoplanetary disks, would substantially
alter the chemistry of protoplanetary disks. We aim to study under which
conditions lightning could emerge within protoplanetary disks. We employ the
ProDiMo code to make 2D thermo-chemical models of protoplanetary disks. We
included a new way of how the code handles dust grains, which allows the
consideration of dust grains of different sizes. We investigate the chemical
composition, dust charging behaviour and charge balance of these models, to
determine which regions could be most sufficient for lightning. We identify 6
regions within the disks where the charge balance is dominated by different
radiation processes and find that the emergence of lightning is most probable
in the lower and warmer regions of the midplane. This is due to the low
electron abundance ($n_{\rm e}/n_{\rm\langle H \rangle}<10^{-15}$) in these
regions and dust grains being the most abundant negative charge carriers ($
n_{\rm Z}/n_{\rm\langle H \rangle}> 10^{-13}$). We find that $\rm NH4^+$ is the
most abundant positive charge carrier in those regions at the same abundances
as the dust grains. We then develop a method of inducing electric fields via
turbulence within this mix of dust grains and $\rm NH_4^+$. The electric fields
generated with this mechanism are however several orders of magnitude weaker
than required to overcome the critical electric field.
