  Observations and models suggest that the conditions to develop lightning may
be present in cloud-forming extrasolar planetary and brown dwarf atmospheres.
Whether lightning on these objects is similar to or very different from what is
known from the Solar System awaits answering as lightning from extrasolar
objects has not been detected yet. We explore terrestrial lightning
parameterisations to compare the energy radiated and the total radio power
emitted from lightning discharges for Earth, Jupiter, Saturn, extrasolar giant
gas planets and brown dwarfs. We find that lightning on hot, giant gas planets
and brown dwarfs may have energies of the order of $10^{11}-10^{17}$ J, which
is two to eight orders of magnitude larger than the average total energy of
Earth lightning ($10^9$ J), affirming the stark difference between these
atmospheres. Lightning on exoplanets and brown dwarfs may be more energetic and
release more radio power than what has been observed from the Solar System.
Such energies would increase the probability of detecting lightning-related
radio emission from an extrasolar body.
