Many years ago I had the chance to visit the National Maritime Museum in London. It is a fantastic museum and if you’re ever in London, try to take a day to visit.  The Royal Greenwich Observatory is nearby as well, so you can see the prime meridian and the transit telescope. I seem to recall that Christopher Wren was the architect of the Observatory. Anyway, I remember a visit to the cafeteria there and an observation that I made while buying lunch. 

As an American in Europe, your presence is obvious to everyone. Well, to everyone but a few who may suspect you’re a Canadian.  And a more awkward bunch of preening land lubbers you’ll never find than American tourists abroad. So, standing there at the food counter with fish & chips and waiting for my aliquot of Coca Cola, the matron behind the counter noted that I was an American and asked if I required ice. Yes indeed, says I. She nods and hobbles over to a small ice bucket, not unlike the kind you see in a motel room. She brings the bucket and using a pair of tongs, reaches in and fetches a single ice cube for my 300 mL portion of the blessed nectar. 

At first I was struck with their miserly approach to dispensing ice. They didn’t invest in a commercial high output ice machine like even the most modest American mom & pop cafe had. But sitting there munching on my deep fried cod, I started to think about the vast resources Americans consume in order to have a ready supply of ice.

Just think of it. How many restaurants are there in the USA? According to Datanetwork there are 516,326 restaurants in their database for the USA. If you assume that each restaurant has 1 ice machine, and the ice machine draws, say, 12 amps at 120 VAC, and using the rms value for AC voltage (0.707 * 120 V = 84.84 Vrms) we can use Ohms law to calculate the wattage: power = EI = (84.84 Vrms * 12 Amps) = 1018 watts while in operation. Obviously, there are wide variations in parameters out there in the field. This is just a SWAG- Scientific Wild Assed Guess.

So, multiplying the number of restaurants times the wattage: 516,326 * 1018 watts = 525,619,868 watts, or ~ 526 megawatts of demand.  Assuming that the power distribution losses  in the grid are ~20 % (just a guess!), that means that the utilities have to generate 657 megawatts at the plant so that 526 megawatts get to the consumers.  But it gets better.

The thermodynamic efficiency of a power plant is approximately 33 %, so 657 megawatts/0.33 = 1991 megawatts thermal have to be consumed to to generate the 657 megawatts electrical.  Let’s assume a typical ice maching runs 25 % 0f the time, or 6 hrs per day: Energy consumption for one day is 1991 megawatts * 6 hours = 11,946 megawatt hrs thermal per day. So, lets get down to coal and oil consumption-

(11,946 MWHr * 3,412,000 BTU/MWHr) = 40.76 E9 BTU ==> (40.76E9 BTU/13,000 BTU per lb bituminous coal) = 3,135,000 lbs of bituminous coal per day, or 1568 tons per day, or 572,000 tons per year. The metric conversion is 1.1025 tons per metric ton. So, 572,000 tons/1.1025 = 518,821 metric tons per year.  For conversion to equivalent barrels of crude oil, use 4.879 barrels equivalent crude oil per metric ton of coal.  Thus, 518,821 MT coal * 4.879 bbl crude oil/MT of coal = 2.53 million barrels of oil per year to energize ice machines for our cokes and Slurpies. 

So, 2.53 million barrels of oil * 60$/barrel= $151.8 million. A drop in the bucket in a $10 trillion economy. But it is just a tiny sliver of the whole spectrum of profligate uses of energy.  What we need is to summon some sensibility and reduce our individual consumption of energy.  Think of all of the devices the typical home now has that are always on- anything with a clock, DVD  players and televisions that can be activated by remote, plug in cell phone chargers, etc.- all consume a trickle current.

So forgive me for asking the following question. If we are more than happy to commit the brightest minds in our country to find new energy souces, develop more potent weaponry, teach urban combat in our war colleges, invade savage and squalid middle eastern “countries”, resurrect the nuclear power industry, invent hybrid automobiles, etc., then why can’t we commit a small portion of that effort to reducing demand for resources whose scarcity can trigger a war?

Oh yea, reducing consumption means buying fewer goods and services. How do you reduce consumption while maintaining growth? There is the fly in the ointment.

[Note: this posting makes a lot of assumptions. It is meant to be an order of magnitude estimate of the consequences of our fetish for ice cold drinks.  I value and welcome corrections, comments, and dialog. Th’ Gaussling]