I can't wait for the day when all our power is generated by clean, renewable sources. So I get excited when I see projects like the proposed tidal lagoon power station.
It's an artificial lagoon made by sea walls that contain turbines. At high tide water flows into the lagoon, spinning the turbines to generate power. At low tide the water leaves the lagoon and again spins the turbines to generate power.
I think it's pretty clever - and the sea walls could be used for cultural and sports activities too.