Well...
In the beggining, Armok created the world, full of many ravenous beasts and bloodthirsty things, and he saw that it was good.
But then, he realized that none but he would be intelligent enough to remark upon the horrors of the world, other then the barely sapient animal people, and so, as the world began to spin and as time moved forward, he created the elves.
He saw how they feared the world, and were killed by the thousands, and Armok saw that it was good.
But Lo and Behold, The elves, fearful of their surrondings and desperate for protection, fled deep into the forests, were they tamed the wildlife and used the magics of the trees to protect them from the world. In addtion, he learned that they could live indefinetly, if not eaten or torn or mutilated or bashed or poisoned or ripped or severed or scared to death. And Armok saw that it was not so good.
Then, he decided to toughen them by infusing them with a desire to fight, and destroy, but it did not go well. The effects of his influence on a already existing creature warped them, splitting them into two tribes. One, Which had escaped much of his influence through their protection from the trees, gained a desire for the blood of sapients but nothing more. This group, thankful of the trees whoch protected them, vowed to do the same to the trees. The second, a group over-exposed to the rays because of being far from the trees, mutated horrifically, becoming shorter, greener, and corrupted beyond recognition into a hideous form. They had a evil nature, but were despised by Armok for their sniveling corrupted ways. The Elves banished these horrifying beings, or "goblins" as they were called, out from the forests, where they settled in other parts of the world. And Armok saw thjat it was a little better, but still not so good.
So then, As the first season of the world came to a end, he created the third race of humanoids. These Humans were taught to kill the trees, and use their lifeless bodies as homes. Insulted by the long-lasting nature of the elves and goblins, he shortened them, making them truly mortal so they would value life even as they took it from others. They settled in the plains of the world, and grew stronger and smarter then any before them. Armok, hopeful, Appeared to them and taught them of the ways of the mountain, of metal and mining. He even gifted to them a race of small inferiors, the kobolds, who might make great practice dummies. But they did not realize the gifts they were given, and shunned the lifestyle they were gifted in favor of their adopted ways. Fulll of rage, he cursed them with inferior "gods": Deities who would continually curse them with horrible puishments, and make them suffer attacks from armies of the dead, led by their own race (Little did he know that some of these deities would appeal to dwarves and goblins, or that Demons would arise from the underworld to impersonate these accursed ones.)
His rage caused the seasons to change once again, as things died after the glare of his rage. Angered ny the failure and subsequent casting from favor of humans, he thought long and hard about his mistakes. The Frail Elves, the cruel wimpy goblins, the blasphemous humans, and the thieving, incapable kobolds. He realized he liked the age limit of the humans, but it needed to be longer, to allow for greater things in their lives. The goblins cruel capabilities and stature appealed to him, but not their stupidity nor their weak bodies, especially their ugliness. The highly intelligent humans appealed to him, but their insolence made him realize they were perhaps too smart, and he realized that leaving them in the plains was a bad idea. Thus, he thought and thought, and, after weaks drawing sketches of humanoids in his own image, and collecting materials and traits from around his world, he spent even longer crafting the epitome of all he had made, until he had his legacy, his magnum opus, the dwarves. The were encircled with band of hair, menaced with spikes of torture and alcholism, and had engraved with intense love of dying horribly. Thye lived in the mountains, worked with the life blood of the mountain, and smelted as they lived. And Armok saw that it was good.
Now all was right in the world, but, after many months of working hard at improving his world, he grew tired, impossibly tired, and could not remain awake. As he fell asleep, and his bloodlust was sated by violence, the world grew cold, the wind grew slow, the plants wilted, the trees grew weak, the water froze, the dwarves retreated into their mountainshome, the humans into their houses, the elves into the trees, the goblins into the towers, and the kobolds into whatever they can find. And, out of respect, all of the dwarves turned off any source of power from any source but the ground.
This is why you cant get power aboveground.