Friday, September 28, 2012

Going Super-Green: $0.10/kg!

The recycling movement has come so far since its early days, but even so there are still many who do not recycle on a regular basis or to the furthest extent that they can (I admit I may be in this category). Part of the reason for this is that the incentives are not appropriately aligned because to many the costs of recycling (time and effort) out-way the benefits (that fuzzy feeling in your heart or a couple cents per bottle). This is not passing judgement on those that do or do not, but I think everyone can admit that if they got money (and not 5 cents) for recycling they would do it more.

Enter 3D printing, the material that is commonly used in 3D printing is also the same material that is found in many of the objects that people use in their every day life, from milk jugs to water bottles. So if there were a way to turn all of those plastics into filament (3D printer "ink") it would be great! Well I am not the only one who has thought of this, Tyler McNaney's new company Filabot is working on a supplemental device to a 3D printer that can turn your empty bottles into the filament that could become your next mug or who knows even a chair! (For a list of the materials it could produce and what they come from click here)

With this new method of recycling the next question is how much would a Filabot owner pay per bottle to someone who wants to recycle? (how much would that much material be worth after you take away costs?) So...

(A) Filabot power usage: 600 Watts (creator's statement on forum) [= 0.6 kW]
(B) US Average price of Electricity: 10 cents per kW-hr (US Energy Information Administration)

(C) Amount of filament made from 1 milk jug: about 0.07 kg (0.453592 kg./lb.*40 lbs/250 cartons: cartons milk carton boat from WOOF
(D) Time to process 1 milk jug:  = 0.07 hrs (1 hr/kg creator's statement on forum therefore =(C))

(E) Cost of processing 1 milk jug : 0.6 kW * 0.07 hrs * $0.10 per kW-hr= $0.0042

[(D)/(C)] = (F)
(F) Cost per kg of HDPE from Filabot:  $0.0042/0.07 kg=$0.06***

So if it costs less than $0.10 per kg to make filament for a 3D printer then we enter a world where the supply costs become minuscule and profit margins can increase or make up for low wage costs abroad. For some frame of reference filament can cost upwards of $10/kg depending on the material++ (see here and here)
Additionally, the amount of money that could be awarded for recycling milk cartons (and other things) could be increased. This back of the envelope calculation just shows the power that the 3D economy will have once the supply chain and the production process gets linked up. [I understand these are rough calculations, if you would like to submit your own version for HDPE or other materials add it to the comments, please cite sources]

***NOTE: The time is approximate because there is additional time needed to prepare the plastics because currently mixing plastics can result in problems.

++REVISION: After further research the best estimate for the cheapest form of HDPE out there is bulk purchases of pellets for $186 for 55 lbs. Which results in  about $7.50/kg (($186/55lbs)/(0.453592 kg./lb.)) which translates to more than a 98% savings when using the Filabot.