Powered by Volcanoes
With the rate at which Iceland is mining Bitcoin, one of the contributing factors to its growth is that the island nation is filled with volcanoes and waterfalls. The energy generated from these two sources makes it easier and cheaper for miners to mine a lot of Bitcoin.
Mellerud noted this in his tweet by saying, "Iceland is powered by volcanoes and waterfalls. The mountainous geography, wet climate, and volcanic geology provide excellent conditions both for hydro and geothermal energy."
Because of the natural energy sources around Iceland, they have the highest electricity produced per capita. With less than 400,000 people, citizens have more than enough energy for many things, including mining Bitcoin.