kiln dryer

[Duffryn]

Yes D is a mine of Knowledge - he has posted before but I can't find the thread.

 

Others have posted their average m3 fuel burnt per batch

As Ashley said there are a number of variables here. The figures below are based on the Glen farrow boiler which is the only batch fed boiler I have a great deal of experience of. The comments are not a criticism of Glen Farrow my understanding is that most large batch fed boilers will deliver similar results.

 

If we take a 200kwh boiler, the rating relates to its peak output. Out of a 200kwh boiler you would realistically on expect to get 120kwh an hour maximum over the course of a day, probably less so let’s work on 100kwh.

Wood at 20% m/c has circa 4.2kwh per kg . Source Energy Cost Comparison | Nottingham Energy Partnership

 

So a tonne of wood at 20% m/c has 4,200kwh of energy in it

The boiler will only be 60% efficient. So out of the 4,200kwh you will only generate 2,520 kwh.

 

Working at 100kwh output from the boiler you will use a tonne of wood every 25 hours.

 

Based on the current medium tariff ( boilers over 200kwh) you would generate 5.18p per kwh. So every 25 hrs you would be paid £130 for a fuel cost of 1 tonne of fuel. I have used the medium tariff because most manufactures now offer a boiler just over 200kwh to ensure you get this.

 

The key to making the figures add up here is to use “free fuel” or getting paid to burn the fuel as I know one entrepreneurial user is doing.

[Duffryn]

I should have related this to drying times. Based on an average of 100kwh then I would expect a 40ft kiln to take roughly 6 days to dry 32m3 of logs. So 5.7 tonne of fuel per drying cycle for an income of £780

[arboriculturist]

As Ashley said there are a number of variables here. The figures below are based on the Glen farrow boiler which is the only batch fed boiler I have a great deal of experience of. The comments are not a criticism of Glen Farrow my understanding is that most large batch fed boilers will deliver similar results.

 

If we take a 200kwh boiler, the rating relates to its peak output. Out of a 200kwh boiler you would realistically on expect to get 120kwh an hour maximum over the course of a day, probably less so let’s work on 100kwh.

Wood at 20% m/c has circa 4.2kwh per kg . Source Energy Cost Comparison | Nottingham Energy Partnership

 

So a tonne of wood at 20% m/c has 4,200kwh of energy in it

The boiler will only be 60% efficient. So out of the 4,200kwh you will only generate 2,520 kwh.

 

Working at 100kwh output from the boiler you will use a tonne of wood every 25 hours.

 

Based on the current medium tariff ( boilers over 200kwh) you would generate 5.18p per kwh. So every 25 hrs you would be paid £130 for a fuel cost of 1 tonne of fuel. I have used the medium tariff because most manufactures now offer a boiler just over 200kwh to ensure you get this.

 

The key to making the figures add up here is to use “free fuel” or getting paid to burn the fuel as I know one entrepreneurial user is doing.

 

*** "The key to making the figures add up here is to use “free fuel” or getting paid to burn the fuel as I know one entrepreneurial user is doing." ***

 

Sorry, I interpret 'getting paid to burn fuel' as recieving the RHI tariff - Is that correct? Thanks.

[openspaceman]

*** "The key to making the figures add up here is to use “free fuel” or getting paid to burn the fuel as I know one entrepreneurial user is doing." ***

 

Sorry, I interpret 'getting paid to burn fuel' as recieving the RHI tariff - Is that correct? Thanks.

 

I'd interpret as meaning burning waste wood that has a gate fee.

 

Typically to avoid the ~£80 landfill tax.

 

In theory using an approved, but exempt incinerator one could burn max 40kg.hour=>960kg/24 hours of certain wastes approved for that incinerator, which might include normall untreated wood from pallets, offcuts from joinery and MGF/fibreboard.plywood.

 

8 years ago as I was laid off, there seemed to be a relaxation on the contraries that were accepted in the "virgin" woodchip arriving at the boilers, one could see bits of chipboard and blue and red stained chip plus occasionally a faint whiff of creosote.

 

At that time the woodchip was worth about £25/tonne so someone supplying 4000/tonne/year to a big boiler and diluting it with 1% non virgin waste which had a £50/tonne gate fee would gain £30k/annum.

[Duffryn]

Sorry been out all day. Yes I meant charging a gate fee on burning waste wood. The GF boiler is perfect for this in that it is accredited to burn "Waste wood with a moisture content of <18% based on both grade A and mixed municipal,

construction/demolition and commercial classification from DEFRA 2008 - Waste Wood as a Biomass Fuel". Plus it has a large fuel chamber that permits loading by forklift.

[County 764]

I should have related this to drying times. Based on an average of 100kwh then I would expect a 40ft kiln to take roughly 6 days to dry 32m3 of logs. So 5.7 tonne of fuel per drying cycle for an income of £780

 

That's an impressive return if your buying roundwood it in at say £30-40 per tonne. Your calculations are probably based on the dry seasoned weight that's being fed into the boiler at but still a good return.

 

I always said I'd get a kiln before it was in fashion but it was the time you have to spend feeding them that put me off plus the initial outlay. Maybe I should of got one.

[arboriculturist]

That's an impressive return if your buying roundwood it in at say £30-40 per tonne. Your calculations are probably based on the dry seasoned weight that's being fed into the boiler at but still a good return.

 

I always said I'd get a kiln before it was in fashion but it was the time you have to spend feeding them that put me off plus the initial outlay. Maybe I should of got one.

 

Don't forget the roundwood has to be handled - processed - handled - dried - handled - fed into boiler = fuel / labour / overheads for everything associated with the above, so there are a lot of hidden costs!

 

The RHI may have been 20K per annum for those who signed up early, however the actual net profit on the RHI scheme is far below that.

 

Many benefits if course even so.

[arboriculturist]

As Ashley said there are a number of variables here. The figures below are based on the Glen farrow boiler which is the only batch fed boiler I have a great deal of experience of. The comments are not a criticism of Glen Farrow my understanding is that most large batch fed boilers will deliver similar results.

 

If we take a 200kwh boiler, the rating relates to its peak output. Out of a 200kwh boiler you would realistically on expect to get 120kwh an hour maximum over the course of a day, probably less so let’s work on 100kwh.

Wood at 20% m/c has circa 4.2kwh per kg . Source Energy Cost Comparison | Nottingham Energy Partnership

 

So a tonne of wood at 20% m/c has 4,200kwh of energy in it

The boiler will only be 60% efficient. So out of the 4,200kwh you will only generate 2,520 kwh.

 

Working at 100kwh output from the boiler you will use a tonne of wood every 25 hours.

 

Based on the current medium tariff ( boilers over 200kwh) you would generate 5.18p per kwh. So every 25 hrs you would be paid £130 for a fuel cost of 1 tonne of fuel. I have used the medium tariff because most manufactures now offer a boiler just over 200kwh to ensure you get this.

 

The key to making the figures add up here is to use “free fuel” or getting paid to burn the fuel as I know one entrepreneurial user is doing.

 

1 tonne split green logs for fuel approx. equates to 4m3 when dried to 20% MC, which is what you burn in 24 hours to heat the 40ft container with 36m3 of logs in. Part of eack batch of 36 you need to be kept for boiler fuel.

 

I am just trying to ascertain the exact return per annum 'at todays' RHI medium tariff rate, one would recieve as 'Net profit' after the fuel costs and associated overheads are factored in.

 

My rough costings show that an annual 'net profit' from the RHI 'at todays' medium tariff rate to be approx. £9,200.

 

Anyone care to say what 'net profit' from the RHI their costings give?

[openspaceman]

At that time the woodchip was worth about £25/tonne so someone supplying 4000/tonne/year to a big boiler and diluting it with 1% non virgin waste which had a £50/tonne gate fee would gain £30k/annum.

 

That should read 10% non virgin waste not 1%

[R5log]

1 tonne split green logs for fuel approx. equates to 4m3 when dried to 20% MC, which is what you burn in 24 hours to heat the 40ft container with 36m3 of logs in. Part of eack batch of 36 you need to be kept for boiler fuel.

 

 

 

I am just trying to ascertain the exact return per annum 'at todays' RHI medium tariff rate, one would recieve as 'Net profit' after the fuel costs and associated overheads are factored in.

 

 

 

My rough costings show that an annual 'net profit' from the RHI 'at todays' medium tariff rate to be approx. £9,200.

 

 

 

Anyone care to say what 'net profit' from the RHI their costings give?

 

 

1 ton = 4m3 logged

Don't think so, more like

1 ton = 2m3 roughly