flap up and down producing electricity. 1st Green tunnel!
The main tube made of piezo crystals wrapped in a waterproof membrane and a couple of honking large extension cords at each end!!!
Tide flows in/ out, load changes with the traffic, moon phase...Free electricity!
Norway could sell all their unneeded smart electric meters to California.
Since electricity in Europe is 50 HZ, the tunnel would only need to move at a 50 HZ cycle and not the 60 Hz required for the USA!