Powering a small country with Exit Sign juice

In passing, Luke asked the team, "Do you think that all the power that goes into lighting the exit signs in the US is more than that of a small country?"

I love questions like this. My immediate answer was, "No."

"They don't?" he responded.

"I don't know. You asked, 'Do you think?' and I think it doesn't." A much different answer of "I think" versus "It is."

I also love that instead of immediately googling the answers, we talked about it. The team had done some energy-related calculations at the beginning of the year, and was able to recall some of them. I was quickly wondering, how much does a sign use? How many signs are in an average sized building? How many buildings are there? WHO ELSE HAS ALREADY DONE THIS CALCULATION?

That last one was the right one to ask. The EPA had done the calculation (of course). You can't believe everything you read on the intarwebs, but let's go with this one:

The U.S. Environmental Protection Agency estimates that there are more than 100 million exit signs in use today in the U.S., consuming 30–35 billion kilowatt-hours (kWh) of electricity annually.

That number comes from, according to the Lighting Research Center of Rensselaer Polytechnic Institute:

Many existing exit signs use incandescent lamps. Although the electrical power demand of each sign is small, approximately 24 to 40 watts each, each sign is typically operated 24 hours a day, 365 days a year; so each sign consumes 210 to 350 kilowatt-hours of electricity per year.

And the quoted for the last 10 years value of "EPA says there are 100 million signs in use every year." Good lord, one sign for every 3.5 people in the US? Ugh.

Switching to LED drops the wattage to 4-5 watts each, or 35-ish kilowatt-hours per year. Better, but still sucky. And most signs aren't LED.

So, let's go with 30 billion kWh a year.

1 GWh = 1,000 MWh = 1,000,000 kWh That'll be important in a bit, noting 30,000,000,000 kWh = 30,000 GWh.

Okay, how much does a small country use in a year?

Well, hello Wikipedia (first pass at data) and the US government (authoritative for these purposes).

 Country      GWh/year
 Bangladesh   35,893
 Nigeria      21,110
 DR Congo     6,939
 Ethiopia     3,777

Right. I was way wrong with my "No." The answer is emphatically yes.

But, let's confirm with the US government. Here we have to remember that the US is one of the most retardedly backwards countries when it comes to measurements. Heaven forbid that we should SWITCH TO THE FUCKING METRIC SYSTEM ALREADY. Anyway, note also:

1 kWh = 3412 Btu, and
Quadrillion Btu = 1,055 PJ = 293 billion kWh = 293 TWh
1 gigajoule = 277.777778 kilowatt hours

In particular, 1 Quadrillion Btu = 293 billion kWh. Which means 30 billion kWh a year is roughly 1/10 of a Quadrillion Btu.

Great.

Now, look at the International Energy Statistics. Easy enough to find those small countries using less than one tenth of a quadrillion Btus (the units used by the incredibly MISNAMED "international" energy page): Bermuda, Antigua and Barbuda, Cayman Islands, and more. Heck, if you use the high end of the 35 billion kWh a year, El Salvador fits into the small country category.

So, yeah, I was way wrong, and yes, if you took all the power used for emergency exit signs in the U.S., you could power a small country.