Kingofgrass
Member
I’ve had my slurry tested etc and I’m clueless on working out what’s it worth to a digester does anyone on here know how to work it out roughly if I pm you the results over ? TIA
Thanks for the reply,53m3 it’s come back on the test,transport isn’t an issue as it would be technically going there on return loads.as they deliver digestate free is there a rough figure per m3 of gas =£??Not very much, probably not worth transport off site. Very worthwhile in an on-site digester though. Our design calculations gave 30 m3 biogas from a tonne of slurry and 200 m3 from a tonne of maize silage.
I know a farmer getting £25 a ton for his slurry I was shocked aswelIn this area, the best you could hope for would be a free swap, with the digester hauling it both roads. Slurry isn't worth much, I have never ever heard of money changing hands
At our plant we take it in for free if we are offered, I wouldn't even pay to transport it
Dependent on a lot of factors, but for a rule of thumb a cubic metre of gas could yield 1.5 kWh of electricity and 2 kWh of heat in very round numbers. Out of that there is maintenance of digester and CHP before any profit.Thanks for the reply,53m3 it’s come back on the test,transport isn’t an issue as it would be technically going there on return loads.as they deliver digestate free is there a rough figure per m3 of gas =£??
Sorry 51,not 53 nrm did the test53m3 sounds incredibly high. Who did the test? Slurry is normally thought to be in the region of 20m3 per ton, quite often less (depends on water content).
If you compare that against a good whole crop silage, which is over 200m3 gas and can be bought for say £40 a ton, it leaves the slurry worth at most £4 a ton. It also takes 10x as much slurry to achieve the same gas output, so you have 10x as much digestate to store and handle. Add the high transport costs for road hauling, and you will see that slurry is pretty worthless unless produced and digested on farm.
There’s not much water that goes into our lagoon I’m surprised it was that goodIt's 90% water, how the heck did they get 50 cubes of gas out of that?
Their on about 70% maize,more than normal,I get what your saying about checking the mix and digestibility of the cows but mucks about perfect coming out the cows,milking well,getting in calf well.as for the sample I scraped up into a pile and took to random samples,parlour washings are diverted into a tank no roofs/gutters go into the lagoon.i do struggle with muck to thick in the summer.thanks for the reply hazard a guess to what’s it worth in £££/ton ? And I’ll see what they offer meSlurry on average is about 8% DM of which around 80% is VS (80% of 8% - not the overall total)
The slurry VS will produce around 200 M3/CH4/ton
So, 80% of 8% = 6.4% of the overall total is available to produce Biogas
The next calculation is based on the efficiency of the Biogas Plant and level of biodegrading, at best you could expect around 15m3 CH4/ton which will be around 60% of the total Biogas production.
However, lets not undervalue slurry.
Slurry is the No1 feedstock for any biogas plant as it will liquidize the system, add nutrient to feed the bacteria, and carry the nutrient as a fertilizer. So, it should have a value.
Your sample clearly shows a gas production figure of 51 m3/ton, and a DM of 11.6%, this increases the VS to 9.3%, and CH4 to around 20m3/ton/VS if this represents 56.7% of the total Biogas (as per your sample) then my calculations = around 34m3 Biogas/ton.
You gave them a good sample, and if consistent, I would be checking the feed mix and digestibility of you cows diet
Their on about 70% maize,more than normal,I get what your saying about checking the mix and digestibility of the cows but mucks about perfect coming out the cows,milking well,getting in calf well.as for the sample I scraped up into a pile and took to random samples,parlour washings are diverted into a tank no roofs/gutters go into the lagoon.i do struggle with muck to thick in the summer.thanks for the reply hazard a guess to what’s it worth in £££/ton ? And I’ll see what they offer me
All the man asked for was a value. Poor chap has had a lecture on analysis, granted a good lecture and explanation.
Depending on the plants needs and own feed and assuming they are not too tight on lagoon and digester capacity, between £4 and £7 per tonne delivered. Personally I would say nearer £4.