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matt

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energy equivalence [Mar. 14th, 2007|07:47 am]
matt
Let's say I have a tree that dies in my backyard- I decide to have a small bonfire. The wood has dried out, and it's about 50kg. Let's say, also , that it is about 40% carbon, which burns nearly completely, releasing 20kg of carbon. To convert carbon to carbon dioxide, multiply by 3.7 (44/12). That's 74kg of CO2.

If I drive to work (which I don't about 95% of the time now), let's say I went about 20 miles round trip. My vehicle burns about 0.3kg CO2 per mile. That's about 6kg CO2. That bonfire cost an equivalent of over 12 trips back and forth, or 250 miles in my car- about two thirds of a tank of gasoline.

Most people see their actions as a set of balanced choices, whereby the fact that I commute to work rather than directly consume CO2 in my personal vehicle for 12 days "offsets" the choice to celebrate clearing a tree with a bonfire. That's OK, but the choice to commute is not carbon-free either. Between the bus and shuttle, what would be about 15-20 minutes of driving each way turns into a 50-90 minute commute on a shuttle and a bus or train. The bus costs $1.50 each way, the train $2.45. The shuttle is used either way. These options burn carbon too- but I have absolutely no way of computing exactly how much. I know the shuttle can't be good, since there's only about 10 people on the shuttle bus maximum when I commute, which is "early". Economically, it's probably cheaper to drive, especially if I use the train. But my concern lately is that commuting, for me, is emitting more carbon than the drive back and forth, and I wish I could actually compute the emission.

Another thing that's been bothering me lately is the tendency for (particularly rich environmentalists) to "buy" carbon credits. Not since the sale of indulgences has there been a more egregious method of expiating guilt, IMO. In principle, it's a good idea: it's like a voluntary tax on carbon emission. But waht's the point of rich coffers of environmental groups if they can't actually reduce carbon dioxide production? It seems like a modified Pascal's wager- the alternative, a dead planet, is too "horrible" to consider, so doing anything even though it might not actually be helping is better than nothing.
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Comments:
[User Picture]From: nightspore
2007-03-14 08:02 pm (UTC)
Right now the money is used to decrease methane emissions, which are much worse than CO2. So the offsets do offset greenhouse gases.
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[User Picture]From: hbergeronx
2007-03-14 08:16 pm (UTC)
How do they do this? I mean, to offset CO2 you can plant a tree. To offset methane, you have to reduce output, which means they're taking industrial capacity offline. Do you have a website?
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[User Picture]From: hbergeronx
2007-03-15 12:50 am (UTC)
Ok, I did some web searching. Some sites say that methane is 21x more potent a greenhouse gas than CO2, so if you burn 1 ton of methane you get a credit for 21 tons of CO2. This ignores the fact that burning 1 ton of methane produces 2.75 tons of CO2, so the figure should be more like 18.25 tons, which is the figure used on some websites.

Since 1990, landfills have cut their methane production in half, half of that from use in energy generation and the other half from flaring (burning). It seems, though, that in order to incentivise the remainder they are beginning to create certification programs wherby people "pay" to have the landfills burn this gas. This is not something that should be voluntary, it should be mandatory, and no credit should be offered. Many larger landfills have to do this by law (for safety reasons! In NJ, they've done this for ages, which is why I'm shocked it's such an "innovation") and where it is mandated by law, they don't get to package up and sell their obligation.

Part of the problem I've had with personal composting piles is that it's often ignored that in a big landfill, the emission can be trapped and burned. In a compost pile, it just gets released ito the air. All those people with personal composters don't realize that they're polluting, too- they have no way of measuring and monitoring the methane (and sulfur) outputs of their piles.

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[User Picture]From: hbergeronx
2007-03-14 08:19 pm (UTC)
I could have said, "let's say I take some dead wood down to the beach and make a bonfire."
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