If the Great Wall of China would be completely built from coal,
the Internet with it's need for 0 billion kWh of electricity
since January 2012 would already have consumed 0% of it.
The Internet consumes a lot of energy. Roughly 1 trillion kWh per year. Emails, webpages, videos and social websites need electrical power. This electrical energy is mostly produced by burning substances like coal, gas, oil or uranium.
In June 2012, the State Administration of Cultural Heritage in Beijing released a new measurement of the Great Wall of China. Their study shows that the monument has a total length of 21,196 km being the largest human-made structure ever built.
Assuming that the Great Wall of China would be completely built from coal, we find out that the complete wall would just be big enough to produce the amount of electrical power sufficient for operating the Internet for the duration of a single year.
That means, that the Internet consumes a Great Wall of China built from coal every year.
The previous measurement by the State Administration of Cultural Heritage from the year 2008 released, that the total length of the Great Wall (then only 8.851 km) was containg 71% of man-made sections (6.259 km), the rest being trenches and natural defensive barriers such as hills and rivers. Assuming, that the current measurement from 2012 contains 75% of man-made sections (15.897 km), an overall wall height of 7.5 m, an overall wall width of 6.5 m at the bottom and an overall wall width of 4 m at the top, we find out, that the Great Wall contains a volume of 634.3 million cubic meters, which is the amount of coal needed to produce the electrical energy to operate the Internet for one single year as described above.
Original photograph by Bill Price III, March 2008.