I started this thread in response to the discussion here http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3834&page=1#Item_18

Posted By: davidMiltwin,
Sheep farming consumes lots of petrochemicals.
Transport, cultivation, fertilisers, veterinary products etc.
Sheep farming damages upland ecology and pollutes rivers and lakes.
Sheeps wool insulation is only a bit green, and as you've discovered it's not as effective as some other insulations which are less expensive.

Posted By: Mike George"Sheeps wool is only a bit green"

When compared to what david?

Posted By: rogerwhitIn defence of sheep farming, it modifies upland ecology, dependent on stocking density. Much of our uplands are only suitable for sheep or conifer growing as economic land use - otherwise, if left they will tend to revert to mixed tree cover up to the tree-line, which will include many non-native trees anyway that seed in, eg sitka spruce, plus rhododendron ponticum .... and it occurs to me that sheep farming consumes no more petrochemicals than commercial veg growing ...

Posted By: davidMick George
"Sheeps wool is only a bit green" When compared to what david?
Rockwool for instance.
If you claim sheepwool is "greener" please quote some evidence.

Rogerwit
"In defence of sheep farming, it modifies upland ecology"
This modification has changed moorland and bogs into grassland, removed hundreds of miles of hedges, created a monoculture of non- native grasses, poisoned watercourses etc. How is this a defence of sheep farming? Our taxes paid for this destruction and now we are paying again to undo some of the damage.
Why does all land have to have an economic use? The uses you cite are both uneconomic. Sheep farming depends on subsidy and upland sheep farming is disappearing. There are very few sheep left in N WScotland, the huge flocks of the 1970's have disappeared and large areas of Sutherland & Caithness conifer forest has been restored to bog and moor.
Forestry has always been subsidised and most of the profits made are in the form of tax breaks.
"Without sheep much upland would be recolonised by scrub and trees".
And why not? R. Ponticum is only a problem in a relatively small area and Sycamores should be tolerated.
I don't understand the point about commecial veg. growing. Are you saying that growing veg. is "green" because the same use of petro chemicals is involved? Or are you saying sheeps' wool is a good insulation because it uses the same quantity of petrochemicals as growing veg. We have to eat vegetables. We don't have to use sheeps' wool to insulate houses.

Fair point.
Perhaps this will help;

CRITIQUE OF THE GREEN GUIDE TO SPECIFICATION
14 November 2008
(amended 5th February 2009)

Page 9
"An example of this problem is sheep’s wool insulation. The summary rating for sheep’s wool insulation in the Green Guide is A, whereas many mineral fibre, and expanded polystyrene products score a summary rating of A+. Scrutiny of the rating for each impact category reveals a possible reason for the relatively poor summary rating. Impacts that stand out are Climate change: B, Ecotoxicity to Land: E and Acidification: E. These poor ratings would appear to indicate that carbon sequestration has not been considered and that the wool is being considered incorrectly as a co-product alongside meat production rather than as a waste product, thereby allowing for the inclusion of farming activity in the analysis.

Page 23
The following example illustrates the importance of carbon sequestration on the climate change rating for insulation products. The principles of this example can be applied to any product that is made wholly or partly from natural plant-based raw materials. This particular example uses data produced on a brand of hemp insulation (Isonat) in an independent LCA study commissioned by DEFRA referenced against data produced on a mineral fibre product (Rockwool) contained in a report commissioned by Rockwool themselves (Schmidt et al.). The carbon required for the production and transportation of Isonat hemp insulation is 1.344 (kg CO2 eq. / kg of insulation produced). The carbon sequestered during plant growth that can be allocated to the insulation product is 0.997 (kg CO2 eq. / kg of insulation produced). Thus, if carbon sequestration is considered the GWP100 figure is 0.347. Alternatively if carbon sequestration is not considered then the GWP100 figure is 1.344. The critical importance of this issue can be seen when it is considered that the GWP100 figure for an equivalent Rockwool product is 1.220 (kg CO2 eq. / kg insulation). "

I don't agree with the claim that the results of BRE tests are skewed because wool is not seen as a waste product
It was never considered to be a waste product until it was used for insulating buildings. It was a valuable part of sheep farming. No mention of methane production but carbon sequestration gets a mention.

Energy consumed in production is not the only or even the most important factor in choosing a product. Environmental damage is critical as is performance and cost.
It seems that, as you say, we have little evidence that sheeps wool is "green" so why do so many assume it is.
I think they are ignorant of the nature of the beast. Sheep farming is not a benign activity and nor is the production of Rockwool. I think we end up splitting hairs.
I think consumers think they are buying into the fluffy white lambs and sheep view of the countryside and I agree that there are products which claim to be green but are not.

<blockquote><cite>Posted By: biffvernon</cite>In the crazy economics of agriculture that exists, wool is an almost valueless waste from meat production. Sometimes it costs more to shear a sheep than the price of a fleece.</blockquote>

Agreed. Wool has been devalued by the march of synthetic fibres.

Let's go back to a basic - we have to produce insulation material from something. This may be animal, plant or mineral. If we are to compare the merits of wool, shouldn't it first be in comparison with other renewable organics, eg flax and hemp?

All land doesn't of course have to have an economic use, however we must derive our needs from the planet somehow.

Not even much of the usually-overlooked one, the 80% petrochemical content of the shepherd's sandwich box!

Dartmoor started to get deforested by what became quite a dense population of humans, from 5000 yrs ago.

David, Do you have a links to the DEFRA and Rockwool reports? I am very interested in reading more. If not links then title and year of publication will do, thanks

Posted By: Chris Wardle It has already been pointed out that the wool is worthless (why is the wool insulation so expensive then?).

Yes, that's what gets my goat

Chris Wardle.
Sheep are indeed farmed for meat but this was not always so.The huge expansion of sheep farming into the Scottish Highlands in the 19th C and the resultant Clearances was not meat driven ,it was for wool for uniforms. Sheep have been selectively bred for wool production for clothing and carpets and Welsh hill sheeps' wool was always a low value product because of the short staple.
There are historic reasons for the huge numbers of sheep and current overproduction is a result of subsidy policy which has preserved an industry whose time passed long ago.
There may be a return to wool when other materials become expensive but that's no excuse for maintaining the countless millions we have now.
Perhaps the cost of the insulation is related to it's true production cost!

David - regardless of any historic reasons or government short-sightedness, we have a surplus of wool, which in terms of the economy that drives it's production is a waste product. It is therefore more 'sustainable' to use this as an insulator (or whatever you want to use it for) than it is to fabricate an artificial material to do a similar job.

I too would love to see some of the facts you have regarding the lack of eco-credentials for wool etc - I have a vested interest as I sell the stuff and don't really want to be a hypocrite. if there is a 'greener' way, point me down it!

Thanks Saint, the aerogel table seems to have done the work for me - except for the wool. Interesting figures

Can anyone fill in the blank [Embodied Energy of Sheeps wool]?

They have this on Green spec

http://www.greenspec.co.uk/html/materials/insulation.html

which basically compares all the different types of insulation and rates them in terms of embodied energy etc - they don't give all their workings but you may be able to request them... (it's a brilliant resource though - I use em all the time)

that was them? bugger.

indeed - I use it for contact details more than anything but a massive pinch of salt shall be supplied from now on.

I'm getting really tired of all this greenwash - you find a well put together coherent site and they go and mess it up with unreliable data and wishful thinking. it really winds me up and makes my job alot more difficult. b*stards!

The fact that sheep farmers are subsidised and still can't make a decent living suggests there should less of em and more trees. The fact that even though there is a surplus of wool and it is essentially worthless yet people still don't seem to be able to make it into a cost effective insulation suggests that it can never be a cost effective solution. I say quit subsidising sheep farmers and the oversupply of wool will go away. What we do produce will be sort after for high value added products like posh jumpers for golfers.

So Chris, would you go for the cheaper rockwool? It's cheaper because the environmental damage is treated as an externality and not included in the price.

(I'm wearing a 'pure new wool' jumper as I type.)

Its probably to do with economies of scale, how much rock wall can a factory churn out per minuit per unit of energy compared to the processing of wool?

Subsidies for farmers are there to pay them enough to earn a living otherwise they would be out of buisness due to competition from other countries which can produce cheaper.

Take China for example and all those EU manufacturing businesses that didnt receive subsidies like the farmers and have no chance against the far east.