The documentation for this package and related projects (home assistant integration) should have a note that the smartplugs (like HS110) need access to internet NTP servers (most likely obtained from *.pool.ntp.org) in order for today_energy_kwh accumulation to be accurate.

While I haven't tested it myself, another user reported on the Home Assistant forum that blocking the smartplugs from internet access will prevent timers defined by kasa that get programmed into the smartplug from functioning correctly.

Note: The problems won't start until the smartplug is rebooted after internet access has been blocked.

See #128 - There doesn't seem to be a way to force the use of local NTP servers (barring some sort of DNS and/or network redirection at the gateway)

Additionally there doesn't seem to be functionality to be able to explicitly set the clock in either this repo or softScheck/tplink-smartplug.