  We investigate the power of a collisional Penrose process with an unbound
energy extraction from an extreme Reissner-Nordstr\"{o}m black hole. This
process takes infinite time in a time coordinate at a constant radial
coordinate outside of the black hole. For black holes as a power plant, the
power of the process for an observer far away from the black hole can be
useful. We define the power as energy gain from the extreme
Reissner-Nordstr\"{o}m black hole divided by the time interval of the process
in a coordinate time; we estimate the upper bound of the power in a
near-horizon limit, while the efficiency of the process can be arbitrary large
in that limit. Thus, we conclude that there is no trade-off relation between
the efficiency and power in the collisional Penrose process in extreme
Reissner-Nordstr\"{o}m spacetime.
