[Terrapreta] Economics of biochar

[andrew]

On Sunday 30 December 2007 18:56, Rick Davies wrote:
> 1. Your US$1000/ton estimate for a whole sale price for charcoal
> fits well with a reply I received back from Bioregional today, who
> said they could sell for UK£500 a tonne. When asked about charcoal
> fines they quoted UK£300 a tonne

When I worked with them at Croydon the fines were an embarrassment 
(in fact the whole smoky process was too) and just chucked in the 
compost.

IIRC 10 years ago the company received GBP2.71/bag for delivering a 
3kg paper sack to a B&Q outlet, they took GBP0.7 as commmission and 
funded the bags. So the charcoal burner got GBP0.66/kg for cutting 
the wood, running the kilns and then grading, packing and delivering 
the product. It did not make a living wage and the landowner did not 
receive a stumpage payment. There were various levels of subsidy, 
one of these was in using long term unemployed people.

In all the time I was associated with them fines were disposed on 
site, apart from the bags I took home for my own fire.

My point would be that this was a high grade luxury good, selling on 
its green credentials, it enjoyed a premium over imports. I haven't 
seen any evidence that terra preta requires such a product. One of 
the specifications was that a large part (specified % but I don't 
recall what it was) of the product had to be over 50mm. 

The pit method of production I mentioned in another thread produces 
a "burned" looking sample with about 50% over 50mm but all of it 
would be suitable for tera preta or getting credits, however they 
may be policed.

The job I have just come off was leaving about 30tonnes of green, 
woody material per hectare mixed on the soil surface, it actually 
looks viable to pyrolyse this to char fines and leave on site rather 
than rot it back to CO2 and water. I have collected a sample by 
scraping and 3kg wet has reduced to kg air dry, I'll carbonise this 
and then ash it just to see what the energy balances look like with 
inevitable soil contamination. 



AJH