  We investigate the solar wind energy flux in the inner heliosphere using
12-day observations around each perihelion of Encounter One (E01), Two (E02),
Four (E04), and Five (E05) of Parker Solar Probe (PSP), respectively, with a
minimum heliocentric distance of 27.8 solar radii ($R_\odot{}$). Energy flux
was calculated based on electron parameters (density $n_e$, core electron
temperature $T_{c}$, and suprathermal electron temperature $T_{h}$) obtained
from the simplified analysis of the plasma quasi-thermal noise (QTN) spectrum
measured by RFS/FIELDS and the bulk proton parameters (bulk speed $V_p$ and
temperature $T_p$) measured by the Faraday Cup onboard PSP, SPC/SWEAP.
Combining observations from E01, E02, E04, and E05, the averaged energy flux
value normalized to 1 $R_\odot{}$ plus the energy necessary to overcome the
solar gravitation ($W_{R_\odot{}}$) is about 70$\pm$14 $W m^{-2}$, which is
similar to the average value (79$\pm$18 $W m^{-2}$) derived by Le Chat et al
from 24-year observations by Helios, Ulysses, and Wind at various distances and
heliolatitudes. It is remarkable that the distributions of $W_{R_\odot{}}$ are
nearly symmetrical and well fitted by Gaussians, much more so than at 1 AU,
which may imply that the small heliocentric distance limits the interactions
with transient plasma structures.
