  A time-dependent Synchrotron Self Compton model (SSC) which is able to
motivate the used electron spectra of many SSC models as a balance of
acceleration and radiative losses is introduced. Using stochastic acceleration
as well as Fermi-I processes even electron spectra with a rising part can be
explained, which are mandatory to fit the lowstate spectral energy distribution
(SED) of PKS 2155-304 as constrained from Fermi LAT observations. Due to the
time resolution the outburst of PKS 2155-304 observed by H.E.S.S. in 2006 can
be modelled selfconsistently as fluctuations along the jet axis without
introducing new sets of parameters. The model makes the time evolution of the
SED also accessible. Hence giving new insights into the flaring behavior of
blazars.
