[jtsiskin]

In a PoW coin, if the cost of electricity < price of coin, more people will start mining, and vice versa. So let’s assume that over time, the price of a coin = cost of electricity to mine it + amortized/opportunity cost of the hardware (and assume that cows are spheres - https://en.m.wikipedia.org/wiki/Spherical_cow).

But electricity costs can be very different in different parts of the world. This leads to miners in areas with high electricity costs shutting down, and mining operations opening up in low electrical cost areas. This can lead to a majority of the network falling under one political jurisdiction. PoS avoids this problem entirely.