Thanks for the link, Rob. I guess what I'm wondering about isn't so much the specifics of emissions as it is the assumptions, statistical and otherwise, that go into an accepted, objective, independent, industry-wide metrics for determining how lifecycle emissions will be measured and compared. Without such a standard in place--akin to the European RoHS, for example--it's just he said she said.
Good question, Ann. Turns out the Steel Market Development Institute commissioned a study, which we covered. The study compared the cost of making steel against the cost of making alternative materials. They also factored in the savings in alternatives during the lifetime of the vehicle and factored in recycling. Steel of course came out the winner.
I haven’t seen an independent study on this. But it would be a worthy effort.
I'm all for the lifecycle analysis approach. I think it's the best way, perhaps the only way, to determine where systainability goals are not being met. It's also a great wya to find out where cost and other efficiencies could be improved.
But what I wonder about is who's doing, or going to do, all the analysis? This is a ton of work. And what will the metrics be against which performance is measured? I know there have been some consortia and other groups working on, for example, analyzing data center energy use and coming up with various standards and metrics. Rob, do you know if there's anything like this in place for materials?
Yes, Dave, the Steel Market Development Institute has a point -- to look at the full life cycle of materials in order to determine the full emissions impact. Even if the Institute has an inherent bias in favor of steel, the concept it valid. Let the analysis from raw materials through use to recycling determine the cleanest materials.
It's true that the resulting materials lose out a lot on strength. For that reason, recycled composites that were previously used for structural components will only be used for non-structural components. Using whatever results in scrap as filler in other materials sounds like an interesting idea.
I certainly would not want to depend on anything that used fibers recovered by pyrolysis, since they would probably have an unknown reduction in strength. But the scrap material could possibly serve as filler in other materials, such as concrete, or large bulk plastic items. If the epoxy or whatever material remained on the fibers, then they would be protected from damage. The big question would be how far to take the reclamation part of the operation. Grind the scrap into small chunks and use it as filler, or attempt to recover the strands and it may not be cost effective. It certainly will need some serious study.
As Beth and Ann both point out, Boeing has an incentive to fund composites recyclability research simply from a cost savings standpoint. But given that recyclability is a big part of the argument for steel and/or light metals being greener than composites, it makes sense that composites recycling would be a Holy Grail in the composites vs. metals debate. A recent article in Design News mentioned a study by the Steel Market Development Institute which claimed to show that in a full life cycle analysis, steel produces far fewer emissions than other materials.
Obviously, the Steel Market Development Institute is not exactly an impartial observer, but they are not the only ones looking at end-of-life. Life cycle analysis tools are increasingly available, and (hopefully) will increasingly be a part of the materials selection process.
Since the cost of the recycled carbon fiber materials is about 1/10th of the same stuff new, this looks like it's probably worth the effort from that cost standpoint alone. It would be interesting to find out if the cost of the research has been figured into that estimate.
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