A heavy block falls. Gravity does work.
The gravity-block concept is the big visual centerpiece of SolarPowerRig.com. The old offshore rig sits above deep water. Heavy blocks are connected to cables, guides, winches, generators, and control systems. When power is available from the solar arrays, the system can lift or reset the blocks. When power is needed, the blocks descend through the water column and gravity becomes part of the energy story.
In the manga version, the drop can be as much as 2,000 feet toward the ocean floor. That enormous vertical distance is what makes the idea dramatic. The rig is not just sitting on top of the ocean. It is using the depth below as part of the machine.
Solarjack explains it like a roughneck: “If the ocean gives us 2,000 feet of down, we might as well ask what down is worth.”