New willow coppice - ideas?

[Big J]

Friends/customers of mine are very interested in starting a willow coppice. They have a lovely house and a bit of land south of Edinburgh and their aim is energy self sufficiency. This is as much a need and an ideological desire, as they have no mains electricity or water.

 

The wind turbine is going up this week (as far as I'm aware), and they have a good bit of fairly boggy moorland that they can use for coppice.

 

They were very interested in coppicing, and it's something I'm extremely keen to try as it's something I want to do for myself in the future.

 

My questions are:

 

1) What acreage will be required to sustain a reasonably large (older, and presumably not fantastically insulated) house and a smaller (new, presumably well insulated) holiday cottage. Possible total floor area around 200-250 square meters.

 

2) Which variety of willow (or indeed any other tree would be considered if advantages were clear) would be best for exposed, reasonably boggy site? The site is at about 200m above sea level too, with a south west aspect, but receives quite sustained cold weather in winter.

 

3) What would be the best coppicing cycle to use? How often should the willow be harvested?

 

4) What spacings should be used, and would cuttings suffice, or would whips need to be bought?

 

5) Best drying methods and best method for converting the coppiced material into heat?

 

Sorry for the multitude of questions, but I want to make sure that I have the full picture before making any recommendations to them!

 

Thankyou in advance for any advice offered!

 

Jonathan

[renewablejohn]

Seems strange to put a wind turbine up and then plant a forest which will stop the wind.

[Marko]

It depends... A boggy ground may well sound like ideal for willow and it will probably grow fine. Harvesting in the winter would possibly be problematic though. Short Rotation Coppice is harvested every 3 years but this is usually chipped and burnt wet in power stations. I am trialing some SRC willow at 6 years to see wether it will make decent logs which can be stacked to dry to get the most out of them. I will let you know how I get on in 5 years and 364 days (I planted them this morning).

 

Willow cuttings will strike very easily but you will find the growers of most SRC varieties have protected royalties so it would be best to buy whips from an authorised source.

 

It might also be worth considering Alder. You can grow it easily from seed, it would like the ground conditions but would be on a much longer harvest cycle. Ash would be OK also. Spacings would be determined by species.

 

No matter what you plant, it will be a bit grim dragging it out of a bog in winter though.

 

The BCTV guidance would suggest 7.5 - 10 acres would be needed to be self sufficient.

[Big J]

Seems strange to put a wind turbine up and then plant a forest which will stop the wind.

 

It would be a good way from the house and behind the turbine, in terms of prevailing wind.

 

Thanks for the reply Marko. The folk in question are mostly retired but have a teenage son, so no issue regarding labour for harvesting. In my mind they would either let it grow on beyond 3 years and continue to use their Aga, or chip it dry and use it in a wood chip boiler.

 

Would it be as much as 10 acres required? Preliminary research seems to indicate that 8-12 tonnes a year is achievable from 1 hectare (2.7 acres) which seems like a reasonable amount for a household. That's assuming 1kw to 1kg of dry willow (roughly), an 80% burn efficiency creating a total of a minimum of 6400kw a year (27kw a day spread over 8 months). Perhaps I'm off on my calculations though.

 

The estate I live on has a lot of self seeding willow that are a tremendous size for their age. We spent a few days clearing a small glen of trees barely 20 years old that had wide canopies reaching 15-18m in height, and trunks up to 20 inches in diameter. I should try to get a specific identification of the species, but theoretically cuttings from these trees should be suitable?

 

Good luck with your coppice - I'll be very interested to find out how you get on!

 

Jonathan

[detritus21]

Looking at your figures 10 acres would be about right based on 2.7acres a year on a 3-4 year cycle.

[renewablejohn]

If they wanted to be independent from the grid they could consider a small CHP

plant something like this. 20kw output for US$ 26k plus shipping

 

Power Pallets: Integrated Gasifier-Genset Skids Gasifier Experimenters Kit

 

If you managed to get it registered with CHPQA they would be eligible for FIT's on all electric generated and RHI if the government gives the green light to renewable heat incentives.

Edited September 15, 2010 by renewablejohn

[Marko]

Cool. That is one clever way to pack a pallet. Are there any that you know of in the UK where a visit may be allowable?

[renewablejohn]

Cool. That is one clever way to pack a pallet. Are there any that you know of in the UK where a visit may be allowable?

 

If you look on the Gek website it gives you the address of Gek equipment that has been sold in UK but I think it is all equipment prior to the skids being used. I know Ken on the Navitron site has a Gek which he uses to run a Lister and I think he is based in Surrey.