Electric Bandsawmill and Electric Processor Generator feasibility

[arboriculturist]

I have been offered a quality 38Kw Enclosed silenced diesel 3 phase Generator for 2K.

So I am now crunching the numbers to assess wether it may be a worthwhile investment to make the transition to Electric, as I plan to purchase a Logosol B1001 Bandsawmill in the future and 1 of our processors is due to be replaced and it could be an electric model.

Also we are installing a 16Kw solar array within 2 years and most of it's energy wont be utilised from April to September. We use a lot of diesel at present and fuel prices are rising steadily. Any views on this subject would be most welcome.

 

[Justme]

Just remember your total electrical motor load cant be much over half the genny capacity or the motors wont start properly.

Cost wise the genny will use as much or more than running the processor directly.

 

[Johnsond]

2 hours ago, arboriculturist said:

I have been offered a quality 38Kw Enclosed silenced diesel 3 phase Generator for 2K.

So I am now crunching the numbers to assess wether it may be a worthwhile investment to make the transition to Electric, as I plan to purchase a Logosol B1001 Bandsawmill in the future and 1 of our processors is due to be replaced and it could be an electric model.

Also we are installing a 16Kw solar array within 2 years and most of it's energy wont be utilised from April to September. We use a lot of diesel at present and fuel prices are rising steadily. Any views on this subject would be most welcome.

 

I looked at the 3 phase option from Trakmet and tried to justify it or come up with a solution to transporting a generator around with the mill. I guess a lot depends on wether or not the mill is gonna be static or mobile and what vehicles you already have etc. Cost of fuel is brutal right now and the whole red diesel saga is never far away. The price for the generator is good mind as long as it’s a decent make and not huge hrs. 

[Big J]

We ran our quite large Trakmet TTS800 off a 50kva generator. If memory serves, the main motor was 30kw. The sawmill had a star/delta start on it, and would very occasionally stall the generator on start up when cold, but it'd only ever do it once in a day.

 

I highly recommend it. It makes for quieter and more efficient operation. Maintenance of the generator is easier than a motor on the sawmill as it won't be subject to the same volume of dust. Our 50kva generator used 3 litres of fuel per machine hour.

[arboriculturist]

6 minutes ago, Big J said:

We ran our quite large Trakmet TTS800 off a 50kva generator. If memory serves, the main motor was 30kw. The sawmill had a star/delta start on it, and would very occasionally stall the generator on start up when cold, but it'd only ever do it once in a day.

 

I highly recommend it. It makes for quieter and more efficient operation. Maintenance of the generator is easier than a motor on the sawmill as it won't be subject to the same volume of dust. Our 50kva generator used 3 litres of fuel per machine hour.

Sound advice, especially as the Solar will kick in during several months of the year.

I will be checking those hours and condition for sure.

[openspaceman]

1 hour ago, Justme said:

Just remember your total electrical motor load cant be much over half the genny capacity or the motors wont start properly.

Cost wise the genny will use as much or more than running the processor directly.

 

That makes sense and if you look at the specific fuel consumption at various power outputs you will see the sweet spot will be around 70% of the rated power, so to start the motors you need a larger generator but once running the engine is under loaded and less economical.

 

With our 10kVA genset we found the fuel cost was about the same as the kWh cost from the grid ( over 20 years ago) plus we had capital and operating and management costs on top. The interesting thing was getting some heat out of the engine as about a third goes up the exhaust and  a third into the coolant.

[Justme]

1 hour ago, openspaceman said:

With our 10kVA genset we found the fuel cost was about the same as the kWh cost from the grid ( over 20 years ago) plus we had capital and operating and management costs on top. The interesting thing was getting some heat out of the engine as about a third goes up the exhaust and  a third into the coolant.

I am shocked  you found the costs similar to grid elec.

 

Most gennys use about 0.6l per kWh produced.

At current red diesel rates thats 43p's worth.

 

If you can capture the wet & dry heat lost & use it then it can be a better option.

 

 

[openspaceman]

54 minutes ago, Justme said:

Most gennys use about 0.6l per kWh produced.

At current red diesel rates thats 43p's worth.

Actually it was 30 years ago when I think back and electricity was about 7p/kWh, gas oil was 8p/litre. So IIRC  gasoil is about 10kWh /kg 8kWh/ litre. I don't know how to check back but I do remember working out we did no better than 20% conversion when we should have got double that running most efficiently.

 

Anyway will it be permissible to run rebated gas oil for a commercial purpose even if stationary?

 

as a post script the genset ran 40 hours a week in winter and the service interval came up frequently. Changing the lubrication oil that frequently was a big expense. To offset a little of this I advocated filtering it and adding it to the diesel tank but I was overruled and the oil was disposed of by the mechanic. I worked out the oil represented 2% of the fuel used.

Edited December 14, 2021 by openspaceman
PS

[arboriculturist]

Mm - maybe a generator isn't the answer then.

[Big J]

2 hours ago, arboriculturist said:

Mm - maybe a generator isn't the answer then.

I wouldn't worry about the fuel cost. At todays timber prices, a modest hydraulic mill will cut 3 cubic metres of dimensioned timber. If that's cladding, you're looking at £1500 plus, if not a bit more. That'd be about £10 in diesel.