Hiya, Thank you, Rikki Nitzkin, for initiating this discussion about embodied energy in straw bales. It so happen to be that Canadian FranÃois Gonthier-Gignac and I are in process of developing a tool to promote cleaner ways of building through optimizing Embodied energy, energy efficiency and costs in residential housing. It's part of our Environmental Management/Sustainable enegry studies at Aalborg University, in Denmark. Our case study so far has the following research question: "How to measure/assess the environmental and energy savings of a Big Bale Building when compared to conventional residential passive house construction ?" We are now in the process of gathering data and we'll welcome relevant information and links, if any of you have some good ideas: We'll get back with the results to you in January '08. And here's my 2 cents to the well considered answer by Rob Tom: All your reflections are very relevant. However put to the task of coming up with an amount of kilo joule which goes into 1 single big bale, my approach would be to find out how many big bales an average (European) baling machine make per hectare, and find out the liters of diesel consumed. These figures should give the individual answer. The LCA (Life Cycle Analysis) tool then also need some figures for transport to storage and to site, and we'll have to give some estimates; typically not more than 25 km in Europe.ÂÂ [Following the doctrine of not building an igloo in Sahara, nor a SB in the deep forests]. To me this would give the figures, though I'd at any time support Brians view: That the Bales are simply stored while in the house and will eventually return to soil, and thereby off-setting other building materials...making it carbon negative. Sincerely, Max Vittrup Jensen Natural Builder and Human Ecologist... PS: For the record: I really don't like LCA tools!!!! strawbale-request@amper....muni.cz wrote: Send Strawbale mailing list submissions to strawbale@amper....muni.cz To subscribe or unsubscribe via the World Wide Web, visit http://amper.ped.muni.cz/mailman/listinfo/strawbale or, via email, send a message with subject or body 'help' to strawbale-request@amper....muni.cz You can reach the person managing the list at strawbale-owner@amper....muni.cz When replying, please edit your Subject line so it is more specific than "Re: Contents of Strawbale digest..." Today's Topics: 1. Fw: [Strawbale] RV: [Paja] Datos sobre una bala de paja (Brian Waite) 2. Carbon (Brian Waite) 3. Re: RV: [Paja] Datos sobre una bala de paja (Robert Tom) ---------------------------------------------------------------------- Message: 1 Date: Sat, 3 Nov 2007 12:51:18 -0000 From: "Brian Waite" <brian@brianwaite....uk> Subject: Fw: [Strawbale] RV: [Paja] Datos sobre una bala de paja To: "European strawbale building discussions" <strawbale@amper....muni.cz> Message-ID: <002801c81e18$3a9bda40$0ae12950@bitzspecial> Content-Type: text/plain; charset="iso-8859-1" ----- Original Message ----- From: Brian Waite To: European strawbale building discussions Sent: Saturday, November 03, 2007 9:50 AM Subject: Re: [Strawbale] RV: [Paja] Datos sobre una bala de paja It is argued by some more qualified than myself that because carbon is locked into the straw during its growth, that carbon is effectively "banked" thereby offsetting the carbon in the other building materials so that a strawbale building can have a zero or even negative carbon rating. This line of reasoning seems to me to be more valid than the "offsets" used to cancel out our extravagancies with token gestures. Another plus for SB: Research is now showing that because farmers are not allowed to burn off straw, and have to plough it back into the soil, this is creating a problem with soil fertility inasmuch as straw needs fungal action for it to decompose and there is now an excess of fungi building up in the soil, year by year, seriously depleting its' fertility. Brian www.strawbalehouse.co.uk ----- Original Message ----- From: Laimis Zmuida To: European strawbale building discussions Sent: Friday, November 02, 2007 5:25 PM Subject: Re: [Strawbale] RV: [Paja] Datos sobre una bala de paja Hello, It's hard to make exact calcullations, because it is very complex phenomenon. But there are some approximate figures. It is called embodied energy. Here are the tables: With straw: http://www.canadianarchitect.com/asf/perspectives_sustainibility/measures_of_sustainablity/measures_of_sustainablity_embodied.htm Without straw: http://www.greenhouse.gov.au/yourhome/technical/fs31.htm Laimis Zmuida Straw bale buildings in Lithuania - http://blogas.lt/siaudunamai 2007/11/2, Rikki Nitzkin <rikkinitzkin@earthlink...>: I have gotten a request for exact figures on -how much energy is spent in producing a bale -how much CO2 is produced by it can anyone help? -------------------------------------------------------------------------------- ____________________________________________________ European strawbale building discussion list Send all messages to: Strawbale@amper....muni.cz Archives, subscription options, etc: http://amper.ped.muni.cz/mailman/listinfo/strawbale ____________________________________________________ -------------- next part -------------- An HTML attachment was scrubbed... URL: http://amper.ped.muni.cz/pipermail/strawbale/attachments/20071103/1134a21a/attachment-0001.html ------------------------------ Message: 2 Date: Sat, 3 Nov 2007 18:22:07 -0000 From: "Brian Waite" <brian@brianwaite....uk> Subject: [Strawbale] Carbon To: "European strawbale building discussions" <strawbale@amper....muni.cz> Message-ID: <001801c81e46$72001090$c9c82950@bitzspecial> Content-Type: text/plain; charset="iso-8859-1" ----- Original Message ----- From: Brian Waite To: European strawbale building discussions Sent: Saturday, November 03, 2007 9:50 AM Subject: Re: [Strawbale] RV: [Paja] Datos sobre una bala de paja It is argued by some more qualified than myself that because carbon is locked into the straw during its growth, that carbon is effectively "banked" thereby offsetting the carbon in the other building materials so that a strawbale building can have a zero or even negative carbon rating. This line of reasoning seems to me to be more valid than the "offsets" used to cancel out our extravagancies with token gestures. Another plus for SB: Research is now showing that because farmers are not allowed to burn off straw, and have to plough it back into the soil, this is creating a problem with soil fertility inasmuch as straw needs fungal action for it to decompose and there is now an excess of fungi building up in the soil, year by year, seriously depleting its' fertility. Brian www.strawbalehouse.co.uk -------------- next part -------------- An HTML attachment was scrubbed... URL: http://amper.ped.muni.cz/pipermail/strawbale/attachments/20071103/f360fe66/attachment.html ------------------------------ Message: 3 Date: Sat, 03 Nov 2007 13:24:12 -0400 From: "Robert Tom" <ArchiLogic@yahoo...> Subject: Re: [Strawbale] RV: [Paja] Datos sobre una bala de paja To: "European strawbale building discussions" <strawbale@amper....muni.cz> Message-ID: <op.t077ymci291bzk@edg-2wjjz8rsqjd> Content-Type: text/plain; format=flowed; delsp=yes; charset=iso-8859-15 On Sat, 03 Nov 2007 05:50:38 -0400, Brian Waite <brian@brianwaite....uk> wrote:a strawbale building can have a zero or even negative carbon rating.Another plus for SB: Research is now showing that because farmers are not allowed to burn off straw, and have to plough it back into the soil, this is creating a problem with soil fertility inasmuch as straw needs fungal action for it to decompose and there is now an excess of fungi building up in the soil, year by year, seriously depleting its' fertility.2007/11/2, Rikki Nitzkin <rikkinitzkin@earthlink.net>: I have gotten a request for exact figures on-how much energy is spent in producing a bale -how much CO2 is produced by itI won't provide any figures for the embodied energy of straw bales simply because the variables are too wide-ranging to nail it down to any discrete amount. For instance, in countries where straw is cut and baled by hand and then used in the immediate vicinity, the EE numbers will be substantially different than say, rice straw that is cut and baled in Texas or California where it is likely that huge tractors that are bigger than the homes of many people on this planet were used and then the straw might be trucked a hundred miles or more to the building site. And it could easily be argued that since no one actually grows straw for the purposes of harvesting the straw, and since straw bales are a by-product of cereal grain production, the EE of strawbales could be considered to be negative. But I won't go into that. The problem of soil fertility due to excess fungi (mentioned above) sounds spurious. The initial stages of decomposition of straw and other carbon-rich materials like sawdust, wood chips requires nitrogen. Nitrogen is a nutrient that is essential to plant growth and green leaves. When straw is ploughed back into the soil, the initial stages of decomposition depletes nitrogen from the soil at the expense of any plants growing in it. Nitrogen-starved plants may be weak, growth-stunted and tinged with yellow, all of the signs of poor plant vigour. Once the straw has decomposed, it is beneficial to soil health and structure and subsequently, to any crops growing in it. But that decomposition cycle usually takes longer than a single crop-growing season and land costs being so high, no farmers can really afford to let fields lay fallow so if nitrogen fertiliser is not added to the soil, crop health will suffer. Traditionally, straw was taken off and used for animal bedding so that it would be mixed with nitrogen-rich animal urine and manure before it was returned to the soil, hence no nitrogen depletion. |