Economics of a 650 m3 Biogas plant

[Foregoneconclusion]

This would be largely slurry/ animal waste fired.

Plan to use heat and leccy all year round on farm and district system.

What sort of running time could i expect/ should i be targeting, what sort of capital/ running costs could be expected?

Practically speaking what is the most efficient way of managing the slurry/feedstock "flow" in and out of the plant?

 

[sjt01]

It all depends!
1. How well the plant is designed and maintained - vital
2. Quality and energy density of feedstock
3. Quality of initial seed - startup culture
4. How well it is managed
We have been running 10 years now, on dairy slurry, maize silage (keeping best quality for cows), a bit of energy beet and whey from our cheesemaking. Here are our running statistics.
If you are in Norfolkl sometime you are welcome to visit. Note that our export is limited to 131 kVA by the cable. Our digester is 800 m3 capacity single tank, 720m3 working volume of slurry.

 

[Foregoneconclusion]

Thankyou for that information.. i shall digest! How often do tlyou have to de grit or shut down for engine change?

 

[teslacoils]

Are the economics the same as normal farming then, IE generous subsidy needed to make it pay?

 

[Exfarmer]

These figures will look very different with no FIT income.
They are very interesting

 

[sjt01]

Thankyou for that information.. i shall digest! How often do tlyou have to de grit or shut down for engine change?

Our digester tank is designed with a hopper bottom with a degrit pipe. The degrit operation takes about 2 minutes once a month. The engine oil changes are every 1200 hours or 50 days off for about an hour. Tappets and plugs alternate oil changes. We were down for 2 weeks a couple of years ago when the engine had its 56,000 hour service, return to workshop. It has now done just over 74,000 and runs really smoothly.
When the engine is down we have a biogas boiler for our heat load, and to avoid wasting gas.

 

[sjt01]

These figures will look very different with no FIT income.
They are very interesting

Our plant has been much modified over the years! To build it again we could cut out a lot of the cost.

However if I was doing it again I would not grow crops for it, just put in a small amount of top and sides of silage clamp. PV harvests energy from land much more cheaply (was very much dearer when we costed the project 12 years ago). I would use PV during the day for the majority of the load, with the CHP turned right down, store gas for main generation at night.

 

[kmo]

@sjt01
Seems like you've boosted output from 2010 to 2018 by cutting the waste products used (slurry), and by increasing the amount of animal feed ( maize and beet )going in.

 

[sjt01]

@sjt01
Seems like you've boosted output from 2010 to 2018 by cutting the waste products used (slurry), and by increasing the amount of animal feed ( maize and beet )going in.

We upped the output from 2010 by getting a CHP that worked! We put in all the slurry we have - when the cows are at grass there is much less and we have gone more extensive grazing.

 

[Exfarmer]

Our plant has been much modified over the years! To build it again we could cut out a lot of the cost.

However if I was doing it again I would not grow crops for it, just put in a small amount of top and sides of silage clamp. PV harvests energy from land much more cheaply (was very much dearer when we costed the project 12 years ago). I would use PV during the day for the majority of the load, with the CHP turned right down, store gas for main generation at night.

please don't think I am critical of you, my solar company also depends heavily on FITs for its returns

 

[sjt01]

please don't think I am critical of you, my solar company also depends heavily on FITs for its returns

Times and incentives change, we must change with them. I will be at Saxham tonight, resurrection of the Institution of Agricultural Engineers East Anglia Branch

 

[Exfarmer]

Times and incentives change, we must change with them. I will be at Saxham tonight, resurrection of the Institution of Agricultural Engineers East Anglia Branch

sounds like a very interesting evening