The US energy grid is a network that delivers energy to homes across America. It generates $400 billion of electricity a year, consists of 3,200 utilites and uses 450,000 miles of high –voltage transmission lines to carry electricity from power stations to homes. Currently there are 4 existing lines 245-499 kV, 500-699 kV, 700-799 kV and 1000 kV (DC) and the grid is divided into three major sections which are Eastern, Western and Texas (ERCOT).
Today, hackers are a major challenges faced by the energy grid. In 2014, there were 79 separate attacks alone. Although the hackers rarely damage or disrupt the machines, the fact that their malware has been found in software is worrying because it gives hackers the ability to enter in destructive code that could be damaging in the future.
Sources:
http://www.bloomberg.com/bw/articles/2013-08-22/homegrown-green-energy-is-making-power-utilities-irrelevant
http://www.eia.gov/energy_in_brief/article/power_grid.cfm
https://en.wikipedia.org/wiki/Electrical_grid