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Energy Usage -- Comparisons

There's an annual release of an "energy flow diagram" showing usage of energy within the US. For 2020, that totaled about 93 quadrillion BTUs (British Thermal Units), which ... is frankly kind of hard to envision.

Let's round that up for the sake of simplicity to 100 quad.

A BTU is the energy it takes to raise 1 pound of water by 1 degree Farenheit (about 1/2 litre by about 1/2 degree C for the Rest Of The World).

So a quadrillion BTUs is the energy it would take to raise the temperature of 1 quadrillion pounds of water by 1 degree F.

Or, say, to boil a somewhat smaller quantity of water.

So if the US decided that its singular national goal was to boil water, how much could it boil?

It turns out: 46.7 billion tonnes. or 46.7 km3. A cube 3.6 km on a side.

If you wanted to make the height a bit more reasonable, say, 100m (330 ft), it would measure 21 km * 21 km * 100m. (21 km is about 13 miles)

Or about 18 million olympic swimming pools (2,500 m3 or 660,000 gallons, or 2 acre-feet each) of water.

For each of the 330 million people in the US, there's abut 300 million BTUs. That works out to the energy to boil off 1/20th of an olympic pool's worth of water per person.

Calculations using

The legend since it's all but impossible to read:

Data is based on DOE/EIA MER (2020). … Distributed electricity represents only retail electricity sales and does not include self-generation. … EIA reports consumption of renewable resources (i.e., hydro, wind, geothermal and solar) for electricity in BTU-equivalent values by assumign a typical fossil fuel plant heat rate. End use efficiency is estimated as 65% for the residential sector, 65% for the commercial sector, 21% for the transportation sector and 49% for the industrial sector, which was updated in 2017 to reflect DOE’s analysis of manufacturing.

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@dredmorbius I'm looking at these end use efficiencies and going, I know, I know, Carnot limit, but... duuude.

@feonixrift I actually spent an hour or so trying to find methodology. Turns out the small print on the chart itself is the best there seems to be.

Efficiencies are assumed at specific rates for power generation, industrial, commercial, residential, and transportation usage.

Renewables are actually stated in the pre-conversion fossil-fuel equivalents. This effecitvely both 1) overstates the contribution of solar, wind, hydro, and possibly geothermal, and 2) makes accounting for actual efficiency losses amongst them ... more obscure.

Pretty much everyone focuses first on the "rejected energy" values. That's something of a red herring. The real message is that total energy use fell about 8% from 2019. As of 2018, my 100 quad estimate was pretty much spot on actual usage.

@dredmorbius 1/20th of a swimming pool is about as much hot tea I drink in a year, so the numbers check out. 😅🫖🍵

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