Giga-Pee (17-11-14)

Here's a somewhat funny and completely useless piece of thinking. One of these days, my older son asked me whether at any second, somebody is going to the loo. I answered yes, and certainly a lot more than only one person. Then it got me thinking.

If we assume there are 7.6 billion (7.6E9) people on earth, everybody has to pee 3 times a day, and peeing takes 10 seconds, then on average there are 7.6E6 * 3 * 10 sec / 86400 sec = 2.6E9 or more than 2 million people peeing each moment in time.

Further assuming during those 10 seconds, each person is peeing 0.2 L, the resulting stream is 2.6E6 * 0.02 L/sec = 5.2E4 L/sec or approximately 52 cubicmetres per second.

With Earth's mean temperature of about 15 degC, and the temperature of the human body at about 37 degC, resulting in a difference of about 20 K, and assuming pee has the same density of 1000 kg/m3 and specific heat of 4.2 kJ/kg/K as water, this represents a thermodynamic power of 52 m3/sec * 20 K * 4.2 kJ/kg/K * 1000 kg/m3 = 4.4E6 kJ/sec = 4.4E9 J/sec i.e over 4 Gigawatt — about twice the installed power of the Aswan hydroelectric power plant in Egypt.