Sunday, February 22, 2009

Firewood economics follow-up:

It was October 12th when we were getting ready to burn our first woodstove fire and we contemplated home heating economics with this much commented post. Well, now we are a little over 4 months into winter, hopefully nearing the end of it. We are very nearly out of wood. We have maybe 2-3 weekends worth left, but it is mostly the oddly shaped pieces that won't fit in our stove. An hour with a saw should set them straight.

I came across this article that asks the question that I was asking last year, but now on a national scale: "What if everyone wanted/needed to heat with trees at the same time? Would there be enough trees to go around?" I bet that you already know the answer: No.

There's a lot of math and graphtasticness in the article for the kinda folks that enjoy that sorta thing. Here's the bottom line:

"Of the 532 Trillion BTUs that could be generated annually from forest growth, approximately 55% or 297 Trillion BTUs would end up as ‘actual heat’. Natural Gas and Heating Oils collectively generated 5,074 Trillion BTUs of ‘actual heat’. Thus, this analysis indicates that we could sustainably replace 297 / 5,074 Trillion BTUs or 5.8% of fossil fuel home heating use with home heating from wood. Alternatively, the entire United States forest stock of hardwoods contains 364 billion cubic feet of wood, or 2.84 billion cords which would throw off 24,024 Trillion BTUs (note, this is only 24% of the total annual energy usage of the country). So the good news is if we were really cold and sans fossil fuels, we could chop down trees for at least 4 years before the US would resemble Easter Island (24,024/5,074= 4.74 years)."

1 comment:

  1. This comment was great: "When totally dry, sewage sludge has about 4000-7000 Btu/lb, which is equivalent in heat to lignite coal."

    Hey if the Eskimos can do it...