A View From the Cheap Seats

April 8, 2009

Earth Hour? Or, Power Hour?

Filed under: Environment,Global Warming — trzupek @ 8:58 pm


By Rich Trzupek

As you peruse this column, dear reader, you have a decided advantage over the guy writing it: you know how the local elections turned out. For you, it’s Wednesday and the decisions have been made, but for me, it’s Sunday and I haven’t a clue. This fine publication has been a topic of discussion among some of the candidates of course, and has even been employed as a projectile weapon by at least one of them, but – however it all turned out – it’s time to bid a fond farewell to this election season and begin to review what we have missed.

So congratulations to the winners and condolences to the losers, whomever they may be, and let us hope that, whatever the outcome was, the elected put the interests of the electorate ahead of their own. That said, let’s move on.

We had something called “Earth Hour” a couple of weeks back, which was a matter of much excitement, or so I am told. The idea seems to have been that the beleaguered planet would “get a break” for sixty minutes by virtue of people turning off their lights. This, in turn, would reduce energy consumption and that (we finally get to the “earth” part of “Earth Hour”) would reduce emissions of that scourge of humanity, carbon dioxide, from power plants.

Regular readers of this rant know that this particular scientist doesn’t put a lot of stock in the theory that human activities affect the climate, so it will come as no surprise that Casa Trzupek was fully and proudly illuminated during “Earth Hour”. A little post-game analysis, however, suggests that people like me actually gave the planet more of a break – if one were actually needed – than the folks who were fumbling around in the dark on March 28.

To understand why, you have to understand a little bit about the way the power is generated and produced. It is you and I who decide how much electricity is generated. Demand drives the system, and perhaps the best way to look at it is that electricity is “pulled” through the grid from our homes, rather than “pushed” to us by power plants.

Demand changes, of course, so the system has to be ready to adjust to those changes. Most times, those shifts in demand are gradual and predictable, thus the generation side (that is, the power plants) can adjust to shifts in demand in a pretty smooth fashion.

However, when everybody does something all at once, like – say – turning their lights off for an hour, the shift in demand is not smooth at all. It is rather chaotic, as a matter of fact. You can’t decelerate a big, coal-fired boiler in an instant, any more than you can bring a speeding freight train to a halt in anything less than miles.

So, when the lights began to go off, there was a drop in energy usage, but no drop in energy production, which is the part that matters. The boilers kept roaring along, producing as much power as they had been a minute before. The excess energy had to be dumped off of the grid, which it was.

Then, the power plant operators had a tough choice to make. Should they power down for a while? Doing so was, after the point of “Earth Hour”. But there’s a practical problem with this strategy. First, very shortly after you power down, you’re going to have to start ramping up because demand is going to jump up radically once the hour is over, and if you’re not ready for it, you could very well take down a portion of the grid.

And, even if you do drop the load on your boiler and swing it back up again, those kind of radical shifts in load increase emissions of carbon dioxide and emissions of non-pretend air pollutants as well. So maybe that’s not the best strategy.

Either way, whether operators chose to keep running at full load and dump the excess power, or whether they chose to power down for a bit, I would be very surprised to find there was any net decrease in carbon dioxide emissions at all during “Earth Hour”.

And, if there was a slight decrease, it would have been more than offset by what happened when “Earth Hour” ended. A sudden surge in demand places a strain on the electric generators in the system. (The boilers make steam, which is ultimately used to spin the generators). This kind of rapid “acceleration”, which isn’t exactly the right term, but it gives you the idea, takes a lot more energy than the gradual, smooth shifts in load that occur when things are normal.

Consider your car as the analogy. When you make a big change in acceleration, like going from a standing stop to forty miles per hour, your gas mileage goes to crap, because you’re using a lot of energy to overcome inertia. However, when you’re tooling along at fifty-five already, it is not nearly so wasteful to smoothly accelerate to sixty.

So, at the end of “Earth Hour”, when those lights came back on, it used a lot more energy to produce the same amount of electricity as the power plants were producing just before “Earth Hour” commenced. More energy means more emissions, and there you have it.

It’s yet another example of the law of unintended consequences. “Earth Hour” may have changed things, but not in the way that Al Gore would have liked.


1 Comment »

  1. Hey – I loved this column. I’m searching for your column on the truth about the landfill situation – that there is plenty earth left and we are not any where using up our landfill space. Where can I find it? jacell@sbcglobal.net

    Comment by J. Ellers — April 23, 2009 @ 6:49 pm | Reply

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