3 ms·

Numbers are not sourced and, in at least some cases, suspiciously high. Virgin aluminum is more like 14 kWh/kg, not 63. https://www.iea.org/tcep/industry/alumi

• dredmorbius 7y ago
  The stated source is http://web.mit.edu/ebm/www/publications.htm http://web.mit.edu/ebm/www/publications.htm
  • philipkglass 7y ago
    That page does not include any of the numbers in the Low Tech Magazine table. It lists 165 academic and 14 popular publications. The other paper posted by femto shows aluminum at ~16 kWh/kg. The slightly higher value is due to an earlier date cutoff around 2009. See figure 4(b): http://web.mit.edu/ebm/www/Publications/energy_required.pdf http://web.mit.edu/ebm/www/Publications/energy_required.pdf
    • dredmorbius 7y ago
      Fair point, though it's also not untirely unsourced. I'd agree to "poorly".
• 8bitsrule 7y ago
  The OP-linked page points to a source URL at the bottom (An MIT 'Environmentally Benign Manufacturing' bibliography). http://web.mit.edu/ebm/www/publications.htm http://web.mit.edu/ebm/www/publications.htm After that URL it points back to a Low-Tech page called 'The monster footprint of digital technology' https://www.lowtechmagazine.com/2009/06/embodied-energy-of-digital-technology.html' https://www.lowtechmagazine.com/2009/06/embodied-energy-of-d... For a summary graphic, see figure 2 in this cited PDF (Gutowski et.al) http://web.mit.edu/ebm/www/Publications/energy_required.pdf http://web.mit.edu/ebm/www/Publications/energy_required.pdf
  • philipkglass 7y ago
    I did refer to figure 4 in that PDF. It shows aluminum around 16 kWh/kg for smelting. According to the accompanying pie chart, electricity used in smelting accounts for 75% of the energy used in aluminum production while bauxite mining, alumina refining, primary casting, and anode production account for another 25%. Starting from 16 kWh for smelting that would put the full energy intensity at 21 kWh per kg of aluminum.
    • 8bitsrule 7y ago
      Yeah, I misread the Figure numbering in that paper, it should have been '2' (which has a big black '4' next to it). On the whole, and prima facie, that graphic delivers much the same message, and rings true. Can't expect the L-T author to do -all- the work.
• hollerith 7y ago
  Maybe 14 kWh/kg is just the electricity used in the refining process. Maybe to get the 63 kWh/kg figure, you add to the 14 kWh/kg figure the energy needed to collect the cans (if recycled) and to mine the aluminum (if not) and the energy needed to build the refining or recyling plant and the energy used by the workers who mine, collect and operate the refining and recycling plants, including the energy used to feed, clothe, educate, entertain, transport, etc, the workers. In other words, maybe one figure attempts to estimate the second- and third-order energy use, i.e., the "total carbon footprint", and the other does not.
  • benj111 7y ago
    "including the energy used to feed, clothe, educate, entertain, transport" As Sagan might not have Said: If you want to make a kilo of virgin aluminium, you must first invent the global economy.
    • ryan_j_naughton 7y ago
      This made my night and brought back some very dear memories. Thank you. Paying it forward, here is the original clip so others can get a hit of the sweet sweet nostalgia... https://youtu.be/BkHCO8f2TWs https://youtu.be/BkHCO8f2TWs