Ah, but the principle is that the lagoon is filled by the moon (spinning those turbines as it floods in) and then they put down gates to keep the water in, releasing it when the tide has turned. The tides are every 6 hours, so you get a lot of generation during that time - it may not be continuous 24/7 but you get it between 4pm and 10pm, so we would get a lot during the evening when the sun has set and solar is no longer producing. They say generation will be 14 hours a day,
Sure, we still need storage though - efficient storage would fix all our energy problems! I think if we could pump water uphill during peak generation times, it would store a lot of energy. I vote to re-use all the old gas meters we have kicking around for the task!