  In this note we investigate outcomes of a symplectic formula for the
gravitational waves charges in the general relativity linearized around the de
Sitter spacetime. We derive their explicit form at {\it scri} in the Bondi
frame, compare with the connected Noether expression and analyze their gauge
dependence which allows us to fix unambiguously boundary terms. We also discuss
minimal requirements needed to impose on initial data to have finite values of
charges. Furthermore, we analyze transformation laws of the energy upon the
action of the de Sitter group and discuss its physical interpretation. Finally,
we calculate its flux through a cosmological horizon instead of {\it scri}. We
show that in the limit $\Lambda \to 0$, one recovers Trautman--Bondi formula
strengthening recent proposal that one should choose a~null surface as a more
natural boundary for the astrophysical systems in the presence of the
cosmological constant.
