Tuesday, September 30, 2008

Turn out your lights

I was a kid during the last — or some would say the start of the current, energy crisis in America. In the first grade we were thoroughly subject to energy-conservation propaganda. This is a good thing. I brought home from school these stickers with "Make Every Kilowatt Count" printed on their face and stuck them to our lamps and switches. You can be sure my folks loved that!

So I have this deep programming to turn the lights off. No one else in the house does. This is a point of contention and anxiety for me. I regularly get home from work to find that all the bedroom lights are on and have been all day. It makes my skin crawl. So, I was getting after my son who is a young teen to turn off his light and told him I was going to bill him for the wasted power. So I had to figure it out. OK, sixty Watts times nine hours times whatever our cost per kWh is comes out to about nine cents per day. Oops. Needless to say, he wasn't much daunted by the dime looming large over his head. But the incandescent bulb puts out a lot of heat too. We could count that. And amortize the life of the bulb... But really, this was simply the wrong approach. The truth is, it's just a drop in the bucket.

But how big is the bucket? What if every American changed their ways? How about everyone in the world? How big could our impact be?

The latest figures I could find suggest that the US consumes 3,717,000,000,000 kWh annually. There are over 305 million of us. So that divides to over 12,186 kWh that we're each consuming annually or a bit over 1,000 kWh per month. (I'm rounding down at every step to make sure that I don't overstate the issue.) 1,000 kWh is the equivalent of 16,666 60-Watt bulb hours. Now, to be fair, that includes all the electricity we consume at work and shopping and so forth. But still, given how much we have to account for, couldn't we each find a way to save maybe the equivalent of one such bulb for eight hours each day? For my family, that would be just turning off the lights regularly. Maybe for you it means spending an extra $100 on your next appliance to get the more energy-efficient model. After all, that's only 14.4 kWh monthly — less than 1.5% of our electricity budget.

And if each of us did that, we can leverage that massive population and note that as a nation we'd save 4,392,000,000 kWh. Sounds like a lot. But looking to understand what that means in more tangible terms and being concerned about both the global oil shortage and climate change, I decided to convert that number into barrels of oil. I looked around the net for figures and when I found some consensus, I went with it. The following numbers could be wrongish. I suspect they're close enough for back-of-an-envelope calculations and that I'm within an order of magnatude. A barrel of oil contains enough chemical energy to be the equivalent of 1700 kWh. But we have to get it out of the ground and move it to the refinery and/or generation plants and the conversion process itself is lossy — heat leaves the system during generation. If we use 38% as the net efficiency, we're still getting 646 kWh of electricity generated. That's at the generation plant. Some is lost in pushing it down the wire to your house — but we'll ignore that amount. So that 4,392,000,000 kWh that the US could conserve through relatively minor efforts and expenses (it seems to me) amounts to about 6,798,762 barrels of oil. Each year.

It's still just a drop in the bucket. Just like that dime that my son might pay when he leaves the light on. But it's something. It's a start. And it's that much less carbon in the air. That much longer that we have until whatever's going to happen, happens.

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