If it were possible to stretch a cable around the world like the blue line in the above animation, it would generate much more DC than what is generated in the core, but the core generates it in a volumous area, and in electronics, that equates to a large current, rather than a large voltage, and it would be a toss up on the Wattage, but it would be substantial. However to the Demographics that would have to be overcome to accomplish this, which is not likely , as some folks around the world would rather die than cooperate with their neighbors, such is life. A more reasonable assumption would be to generate it along a several hundred mile multiple line, though a system of capacitors would have to be employed to bleed off AC currents, which could damage any regulating equipment in line, such as lightning.

The effect is no different than using magnets to induce a current in a wire, as the gravity fields are cutting across the whole of the planet and generates opposing fields at opposite points , because as one point is entering the field in clockwise direction , the other point is entering in counter clockwise direction, making a positive and negative field effect.

Just shows what can be possible with world cooperation, oh well , maybe on Mars before it becomes fragmented over viewpoints, or find a way of doing it on a space station in high orbit.