Tidal energy is not renewable
Regarding the "How Are Tides Formed?" section with 
a nice neat diagram and some math"<p>But that is not really correct. it would be but there are large land masses interfering with the process. Ocean tides are better conceptualized as water sloshing in a bathtub.<p><a href="https://www.youtube.com/watch?v=PSJRymZ5bJs">https://www.youtube.com/watch?v=PSJRymZ5bJs</a>