Less than a second a day in 100 years is a huge change in earth scale. I'm curious, what kind of tidal plant would even come close? Is it assuming we extract 100% energy from the tidal waves and entirely stop the tides, somehow?
I'm fairly certain stopping the tides would be devastating to the environment since several ecosystems (tidal plains, marshes, riparian zones, etc.) depend upon them.
Doesn't it depend on how much less than a second it is?