Major Category:
Metrics, standards, and LCA
I am trying to clarify something I was told recently told. When LCA is completed on plastic materials, it is done considering the raw material being crude oil and the processes employed, drilling, refining, cracking, etc. However, what I was told was that plastics are actually made from the byproducts of gasoline or fuel manufacturing and never really are made straight from crude. Given most of the oil drilled is used for gasoline or fuel, then is it correct to start there when doing LCA, or is it more correct to start somewhere else, or....? Seems then there is something not quite right about starting from crude oil? What am I missing here. Anyone?
To perform a proper LCA analysis, you have to take in account values like CO2 emissions per ton at the packaging material manufacturing stage (that is once the resin is manufactured to produce a packaging material). These values are available from databases published by the EPA (here is an interesting link: www.epa.gov/ord/NRMRL/lcaccess/resources.html [9]) and trade associations. In streamlined LCA software (LCA that are specialized in packaging), material metrics containt these values. If you have an opportunity to use the sustainable packaging scorecard that Walmart uses, you will see how these data are used to come up with sustainable performances of packaging. To summarize, you don't have to add on every single value of CO2 emissions for every processing step (from drilling to manufacturing) unless you really want to do the excersise.
To start with, 90% of crude oil is used for making fuels (energy). The other 10% is used for making all other products (chemicals, solvents, bitumen, plastics etc.). Crude oil processing leads to products that can be used either for energy or for other products. In polymer synthesis, part of these products are used as raw material and another part supplies the required energy. So, in a LCA we take into account both.
One of the most important steps in performing a LCA is establishing the system boundaries. The person performing the LCA (or more likely the person paying for the LCA) must decide where to set the boundaries. In other words, what to leave in and what to exclude. These decisions may be made with a view toward expediency, cost, time or availability of data. When reading a LCA, I am always interested in where the system boundaries were placed in order to put the data and conclusions presented in the proper context.
I hear you Larry, but man, every LCA is going to have different baseline assumptions and answers. Unless there is some rule on the LCA baseline, comparing LCA claims from competing suppliers of a given product would be totally useless. The only use for such a report would be internal company scorecarding. Is there any move to declare how far one has to dig to come up with a bonefied, accurate LCA?