[GRRN] Energy Savings from Recycling Glass

Tue, 9 Feb 1999 13:21:06 EST

Dear Greenyesers,

We did an energy conserved by recycling vs. energy generated by incineration
analysis a few years back as part of Ontario Hydro's 25-year supply/demand
energy plan , including transportation energy to send the recyclables to
market. The study appeared (after peer review) in slightly abbreviated form in
The Journal Of Hazardous Materials (Elsevier Science, Amsterdam) in a special
issue on incineration, Vol. 47 (1996) pp. 277-293. An earlier version appeared
in Resource Recycling, Nov. 1992.

The energy savings from using recycled glass instead of the batch mix of sand,
sodium carbonate (soda ash) and calcium carbonate (limestaone), is on average
over 3100 kilojoules per kilogram or 260 kilowatt hours per ton. The energy
to collect and process a ton of recyclables (net of energy saved on garbage
collection and transfer) is well under 300 kJ/kg or about 20 kwh/ton.
Shipping a ton of recyclables one mile by truck requires an electrical power
equivalent energy of less than one kilowatt hour (the study was for an
electrical energy analysis, so everything is stated in terms of electrical
energy equivalents, which is different than energy calculations on the basis
of intrinsic energy value, but gives the same conclusions). So you can send
your ton of color-sorted, recycled glass about 240 miles by truck. On the
other hand if you ship by rail you can go 4 to 5 times further, or around 1000

All in all a considerably less pessimistic assessment of glass recycling then
the case presented by Helen Spiegelman.

Jeffrey Morris
Sound Resource Management
Seattle, WA