  The energy extraction from an electrostatic black hole by the decay or
splitting of electrically charged particles is analyzed. We determine the
energetic conditions that make the extraction process viable and present a
general expression for the efficiency in terms of the parameters of the
electrostatic black hole and the decaying particles. We also examine the
conditions that optimize the efficiency of the extraction process. We analyze
two particular cases, the first one is the extraction process from a Reissner
Nordstr\"om black hole, for charged test particles with nonvanishing angular
momentum; the second one and more interesting corresponds to the energy
extraction from a Reissner Nordstr\"om de Sitter black hole. For the latter
there are two regions where the energy extraction is possible, the generalized
ergosphere and a cosmological ergosphere induced by the cosmological horizon.
Under certain conditions the two ergospheres get connected and cover the whole
region between the event horizon and the cosmological horizon, and therefore
the energy extraction is possible at any point in the vicinity of the black
hole. Moreover, the efficiency of the energy extraction can be the same for
different break up points and also there is the possibility of a different
efficiency for the same break up point. The conditions that maximize the
efficiency are determined as well.
