[abhibeckert]

Or... drop an anchor, pull the floating barge against the tide towards the anchor when the sun/wind are optimal. Let the tide pull the barge away from the anchor (with a generator on the winch cable) when you want power while the sun/wind aren't providing power.

Tides have massive potential for power generation. The best part is how predictable they are.

Your idea of weights being raised and lowered makes more sense for land based energy storage (and it is being trialed right now, with promising results).

[angiosperm]

It is very hard to share a motor/generator between multiple weights on land, because you would need multiple adjacent mineshafts, so the economics are difficult. At sea there is plenty of depth anywhere you care to sink something.