Who'd have thought that the government-mandated exit signs that decorate so many of our buildings - there are over 100 million of them today - could cost so much? Individually, they don't eat much energy, but collectively:
That’s the output of five or six 1,000 MW power plants, and it costs us $2-3 billion per year.
And that's just using coal-plant energy to power them. Ah, the power of numbers.
