[mrflora]

I'm just exploring a half-baked idea: powering the U.S. with woodgas. Using the figure of 20 lbs. dry wood = 1 U.S. gallon of petroleum, to replace essentially all U.S. petroleum consumption (21 mmbd) would require 17 billion lbs. or 8.5 million tons of wood. I am thinking of the paulowina or princess tree, which grows very fast and tolerates a wide range of soils and temperatures. They can grow over 20 feet in 3 years. If 1 ton of wood is obtained from each tree, then 8.5 million trees are required. I am not a good enough tree farmer to know how much land each tree requires, but say it is 1000 square feet. Thus 8.5 billion square feet or about 340 square miles must be harvested each day or about 120,000 square miles each year.

[RonMN]

I think this would be a classic display for EROEI.

I'm not trying to flame your thread, but harvesting 340 square miles per day would have to be mechanized (it couldn't possible be done by hand)...And I would have to assume these harvesters are running on oil.

So in the end you'd likely burn more energy from oil that you would recoup from the woodgas.

[EnergyUnlimited]

Mrflora
Read something about Easter Island before cutting down 120 000 sq miles of forest a year.

[WisJim]

The problem that I see with all of the bio-fuel type of proposals is the lack of concern for soil fertility and soil quality down the road. Sure you could get a few good crops of trees from fast growing varieties, but if no organic material is put back on the soil, no matter what the crop, you lose soil tilth and fertility. That is one of the reasons that modern chemical fertilizer based agriculture needs ever increasing amounts of fertilizer to maintain yields. It isn't sustainable without cheap oil to produce fertilizer.

[Madpaddy]

mrflora said,
$this->bbcode_second_pass_quote('', 'I')'m just exploring a half-baked idea