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November 24, 2009 / or4green

GreenBuild 2009, part II

One of the most effective presentations I saw at GreenBuild 2009 was about Life Cycle Assessment by Adam Cone. LCA measures the energy and environmental impacts of a product from cradle to grave. After recounting some interesting history of LCA (which he traced back to Coke in 1969), Cone gave an overview of the methodology. Then he used two different LCA tools (EcoCalculator and BEES) to measure expected CO2 emissions from the concrete used in a very simple toy model of a building. Not only were the results different, they were vastly different. The discrepancies were caused by the differing assumptions each made (things like spacing of the beams). The point was quite compelling – using these tools without carefully considering their assumptions can lead to misleading results. True LCA requires a great deal of work.

LCA programs consist of databases and models. For instance, a given material will have a value for how much CO2 is emitted in its production. And given some basic information for something like a building, such as material and dimensions, a simple model will predict how much of the material is required. Again, the models make implicit assumptions that often can only be determined by reading the documentation, if then. LCA and Carbon Footprint software would seem to have considerable overlap. LCA can focus on a specific material and all of its energy and environmental impacts. Carbon footprinting can measure across an entire system, such as a supply chain, but will focus on CO2 emissions. A little searching turned up this related post on lamarguerite about carbon calculator inconsistencies.

I have not looked at these tools closely yet myself, but I would not be surprised to hear that they are already being coupled to O.R.-type decision tools. Sticking with Cone’s simple building example, CO2 emissions can be an objective to minimize, or a constraint level to stay beneath, while the decision variables can be the type of concrete to use, aspects of the building design, the size, etc. So decision-problem-solving capability could be linked to LCA models and data, and in fairly complex ways. This would seem to be a huge growth area.

Another GreenBuild 09 session on LEED applied to restaurants was probably the most puzzling of the ones I attended. It featured speakers from McDonald’s, Dunkin’ Brands (Dunkin’ Donuts), and Chipotle. Having been in the restaurants of all three, I had a rough idea on where each stood with respect to sustainability. Of the three, sustainability seemed to be a core value for Chipotle, which has a slogan “food with integrity” that impacts health, environment, energy, and animal welfare. The Dunkin’ speaker admitted that they “lag behind” in their sustainability efforts. (See this Greenopia review of Dunkin’.) McDonald’s case is perhaps more complex. The company has an extensive corporate social responsibility (CSR) site detailing their achievements. Inhabitant reviewed some of their efforts and challenges here, while the Humane Society of the U.S. (HSUS) has recently called on McDonald’s to improve animal welfare standards.

The session was mostly about each company’s experiences at building LEED certified restaurants. If I recall correctly, Dunkin’ builit one, McDonald’s two, and Chipotle two. Chipotle’s speaker said they hope to incorporate sustainability ideas from the LEED buildings in all of their restaurants. The representative from McDonald’s stated that they must figure out how to lower the costs if they are to expand the scope.

This was a conference about sustainable building, yet sustainability has to be about an integrated approach that transcends buildings. In the fast-food restaurant model, it touches anything from packaging to coffee sourcing to animal welfare to the drive-through restaurant model, and more. This theme was barely mentioned during these restaurant presentations, and surprisingly not at all in the Q&A. Hopefully it will become more pervasive in the restaurant business and others over time.

coming up in Part III of this post: Dark skies, Coastie gathering, and more…


  1. Stefan Goessling-Reisemann / Nov 27 2009 3:12 pm

    Hi Ian, a small note regarding LCA and Product Carbon Footprinting (PCF): these tools can only be applied appropriately, if the WHOLE product life cycle is known. In contrast to tools that analyse material properties, LCA and PCF are dependent on the precise history of the product (from resource extraction to waste disposal). This is due to the fact that LCA and PCF measure the ecological performance of the PROCESSES of production, use and disposal of the product, and does not measure properties of the product itself. You could say that LCA and PCF results are thus path dependent.

    Having said this, it should be clear that two different LCA/PCF models will almost all the time give different results IF the assumptions on the actual processes differ. So if you simply plug generic process data into your models, and not actual data from the real processes to be analysed, the results have to be somewhat random. This circumstance makes (accurate) LCA/PCF so darn time consuming.

    Greetings, Stefan

  2. or4green / Nov 30 2009 8:20 pm

    Thank you for the insight Stefan. I think you bring an important point to light, and I like the way you describe LCA/PCF results as “path dependent”.

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