Is there a way to harness the energy of the tides using buoyancy?

I tried to find it online but I could only find info about conventional tidal energy or energy storage using buoyancy and water pumps. I was thinking of like having a turbine on the ocean floor that worked kind of like a yo-yo where at low tide it is wound up but as the tide increases a buoy would pull up a chain as it tried to float which would turn the turbine creating power. Then as the tide dropped a spring (or similar) mechanism would wind it all back up to recreate the next cycle.

4 Answer(s)

Yes, do more web searching I'm sure you'll find all kinds of way including some that are operational now. Check this out:

"machine for turning tidal energy into electricity humans can use. gravitational pull exerted by one object, such as the sun or moon, that raises tides on another object, such as the Earth. pool of ocean water that is partially cut off from the ocean by a barrier. Often used as a source of hydroelectric power.Jun 14, 2011
tidal energy - National Geographic Society

Browse "energy from ocean tides" you'll get thousands of hits.

No, you are thinking of harvesting wave energy that way. Tidal energy is much too slow to harvest with floats and buoyancy, you need to harvest the flow of energy with anchored turbines that are pushed by the flowing tide. One example is shown below

Yes, there are devices to harness energy from tides. It has limitations due to being in the sea, with rather harsh conditions.
Solar, Hydro, and wind energy are the main sources of green energy.

Yes. For example read about the floating tidal energy platform from Bluewater: