tldr: If global energy usage grows at 2% every year, and we generate 1% of the total demand annually with tidal energy, the Earth's rotation will cease in ~1000

tldr: If global energy usage grows at 2% every year, and we generate 1% of the total demand annually with tidal energy, the Earth's rotation will cease in ~1000 years. While i won't dispute that tidal energy is not truly sustainable, at least not in the way solar appears to be, i think we can agree that in the short team (a few centuries) cargo ships saving fuel would be a net positive with no measurable impact on the rotation of the planet. Edit: after some more napkin math, i have a hard time taking this paper seriously at all. It appears to suggest that the available tidal energy would remain constant throughout this process? Also, 1.02^1000 equates to a roughly 400 million factor increase in the current energy demands of the planet. That's not something i'd expect such an advanced civilization to be trying to generate out of some waves.