Drax aiming for 50% biomass in next few years

[Chris Hogg]

I understand all that. It is why hydrocarbons have nearly twice the calorific value of coal, weight for weight. If Drax was going to burn a hydrocarbon, then I can see why they could claim that the CO2 emitted would be less than simply proportional to the reduction in the amount of coal burnt. But cellulose is a carbohydrate, not a hydrocarbon, more specifically it's a polysaccharide, (C6H10O5)n

and contains a significant amount of oxygen, which will reduce it's calorific value compared with a true hydrocarbon. To put it another way, it's already partially oxidised. In fact the calorific value of pelletised wood chips is roughly half that of anthracite which means that they would have to burn about twice as much, by weight, as the coal it's replacing. So I still don't see where the claimed savings in CO2 are going to come from, over and above the 50% brought about by the reduction in coal use.

Drax claim it's still viable, even including processing and transport costs.

They'd need some pretty massive storage. Mind you, the 'domes' that they're constructing were rather large.

Elsewhere in this thread, DL suggested that the Drax biomass project returned to potential profitability because the cheap price of shale gas in the US had undermined the wood chip market, presumably dramatically reducing its price. I wonder if the Drax planners have considered the possibility of the same thing happening here!

[whisky-dave]

I was wondering why they had those special buildings for containing the wooden chips is that really necessary, or what was specail, othrer than the shape about them.

[The Natural Philosopher]

and contains a significant

the only relevant factor here is the ratio of carbon to hydrogen

C6H10

That's a LOT of hydrogen to be burnt.

the actual weight of the wood is only relevant in terms of calculating the energy per molecule of CO2 released, as typically wood will have an energy value per tonne, quoted.

Viability at a small scale is not the same as being able to run the whole planet.

They can always go back to coal..

:-)