Magnesium can be extracted by electrolysis of salts derived from sea water, or, better, from salt lakes such as the Dead Sea. The electrical energy necessary to electrolytically extract 1 kg of...

Magnesium can be extracted by electrolysis of salts derived from sea water, or, better, from salt lakes such as the Dead Sea. The electrical energy necessary to electrolytically extract 1 kg of magnesium in this way is 40 kWh. The current price of magnesium is approximately $5/kg. What fraction of this price is the cost of the electricity used to make it? If electricity prices rise by a factor of 3 (responding to similar increases in the cost of oil or gas), how much will it increase the cost of making magnesium? Take the price of industrial electricity to be $0.06/kWh.