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Sunday, August 15, 2010

Grasping Incomprehensibility

It's a geek post. You've been warned.

If you are a regular reader, you have some basic familiarity with how bulk power systems are run. The topic of this post involves generation and load balancing. That is, matching power output to power consumption, adjusted for the expected power flows to other systems based on purchase and sale agreements. If you're meeting your obligations, your instantaneous ACE (Area Control Error) is more or less zero.

So, once in a while, events transpire such as those documented in Of Yardsticks and Manly Measurements, but without the drama. Having a meter go bonkers and sending you out by a few hundred or even a few thousand is just something that happens once in a while, and part of why we're here. Someone has to fix the broken stuff, you know.

But this event was different.

The visual ACE alarm activated, meaning we were at least a few hundred megawatts out of nominal, so we stopped jawing and took a look. But instead of showing us a number that we could comprehend on the big monitor, we saw 1.42838E+15.  (Not that I memorized the number....I took a screen shot.)

What the huh?

I didn't even know that our software knew how to show gigantic numbers in that scientific notation format, let alone what to do with them.

Although I didn't dig deep enough to get the exact value until later, I can tell you now that it was 1,428,382,474,567,680.

That's 1.4 quadrillion plus.

Every application and system that was was paying attention to this number summarily disabled itself, having just had a clear view into infinity and needing to sit down with a cup of tea to think things over.

It wasn't long before we found the source of this particular problem. For typical meter oddities that crop up, the 100 here, 500 there, we sometimes have to poke around to find it, but 1.4 quadrillion is hard to hide in a closet. We quickly tracked it down to a faulty tie line value that represented a remotely-located power plant, and flipped it to its backup data source, problem resolved.

That was cool.

So, how big is 1.4 quadrillion, exactly?  Stay with me through this, because I promise this will get slightly amusing again after we trudge through the technical stuff.

First, let's translate what a megawatt is again, as a refresher.  Megawatts (MW) are a representation of rate, or flow, while a Megawatt Hour (MWh) is a representation of delivered totals.  Think of it in fire pump terms.  A pump flowing 500gpm will deliver 500 gallons every minute.  If allowed to run for only 30 seconds, it will deliver only 250 gallons.  Likewise, a power plant running at 100MW but online for only 15 minutes will deliver only 25MWh.

To allow you to get your hands around what a MW is, exactly, look at your power bill.  1 megawatt is equal to 1,000 kilowatts, and your monthly household electricity consumption will be shown in kilowatt hours (KWh).  A typical home might use roughly 1,000 KWh (or 1 MWh) per month.  So, a 100MW power plant produces, roughly, enough power every hour to supply one hundred homes for a month.

Back to the big number: 1,428,382,474,567,680

It isn't really accurate to call it 1.4 quadrillion megawatts, it's like saying a million billions or something.  Quantity steps of watts use the same system as computer memory storage measurements: kilobyte, megabyte, gigabyte, etc.  1,000 kilowatts is a megawatt, 1,000 megawatts is a gigawatt (already moving into irrationality in power company terms). 1,000 gigawatts is a terawatt, then.... petawatt, exawatt, .... what we have here is 1.4 zettawatts.  Zettawatts?  L O L

How much theoretical power was this, really?

According to Wikipedia (the oracle of truth, I know), global energy usage is approximately 15 terawatts annually.  If this power plant had actually been producing 1.4 zettawatts and kept it up for just a single hour, it would have produced enough energy to power the globe for 95,225,498 years.

That is still beyond comprehension.

OK, it produced enough power every second to serve the Earth's energy needs for 26,452 years. Or to power Doc Brown's DeLorean DMC-12 time machine through nearly 328 million time-travel jumps.

Still hard to grasp, but we'll leave it at that.

For what it was worth, it was still only equivalent to 4 trillionths of 1% of the sun's energy output rate.

In real life it would probably have left a crater at that power plant's location a few thousand miles wide, and vaporized every power line on the continent in one trillisecond of glorious multicolored flame.

Good thing it was just a meter error. Feel free to allow a banking error of that magnitude on my account, as I am sure it will meet my needs for a several thousand years, too.

That was cool.  Thanks for letting me geek out a little bit.  My two jobs make me so serious on the clock, that I have to get a little goofy sometimes.

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