North Korea on September 3rd, 2017 conducted its sixth nuclear test and as per them, it was their first test of a thermonuclear weapon (hydrogen bomb) of 100-kiloton capacity.
They also warned that it could be used for a “super-powerful” high-altitude electromagnetic pulse (HEMP) attack. North Korea’s state owned news agency published a press release after the test and warned that the weapon ‘is a multifunctional thermonuclear having great destructive power and when detonated even at very high altitudes super powerful EMP attacks and could wipe out electrical grids across the US. This has put the United States electricity sector on a high alert.
Actually, this kind of threats to electricity grid by a thermonuclear weapon are not new. In 1962, when the United States had exploded nuclear devices above the Pacific Ocean, the electrical damage was found in Hawaii. This weapon is not like the atomic bombs exploded by the U.S. over Hiroshima and Nagasaki in 1945, it does not destroy buildings or kill people directly. But, electromagnetic waves coming out from the explosion generate pulses which affected the electric grid and electronic devices similar to the lightning surge.
When a weapon of this magnitude (100-kiloton) detonated high in the atmosphere can knock out the power grid across a huge area of the United States. The outages can last for months, indirectly will cost many lives, as hospitals will be without power, emergency services will not be able to function normally, and people may run short of food and water.
The political experts are saying, though North Korea has the technical capability to deliver a damaging electromagnetic pulse, the chances of that country using it against the U.S. are minimal. North Korea is well aware of the reciprocative action from the US by using a powerful destructive nuclear weapon. The power grid experts in the United States are already in the process of taking technical measures to save the electric grid from such threats.