The basic idea behind C12 Negative is that there’s certain valuable materials that can be used as a carbon sink. To see if this idea works, you need to do a product lifecycle global warming potential calculation. My best estimate of the impact of consuming 1 kg of C12 Negative PLA filament is that 2.47 kg (3.27 kg if you’re dirty) CO2 equivalent emissions are released to the atmosphere. Here’s the breakdown:
- CO2 sequestered by PLA: -1.83 kg (1 kg of PLA has 0.5 kg of carbon, which means 1.83 kg in CO2)
- NatureWorks Ingeo PLA when leaving factory gates: =0.62 kg (because of +2.45 kg worth of emissions mainly from non-renewable energy used in production)
- Transport (rails, shipping & trucking) of plastic from US to China: +0.19 kg
- Filament production in China: +1.06 kg of which 70% is from non-renewable energy use and 30% from reel and packaging
- Shipping of filaments to Finland: +0.29 kg
- Trucking them from Finland to end user in UK: +0.31 kg (you would save most of this by living in Finland)
- The end user actually printing the filament into an object: +0.0 kg to +0.8 kg, depending on the energy you use
- The above gives a total of =2.47 kg to =3.27 kg CO2 equivalent emissions into the atmosphere
As all things must die, also your creations will at some point end up in a landfill etc and release the +1.83 kg of CO2 sequestered by the PLA back to atmosphere. However, even if PLA is marketed as biodegradable, it degrades well only in commercial composting facilities (6 months for 60% release). If not incinerated for energy, it’s more likely that the carbon gets stored for hundreds of years. Maybe at the end to be collected as methane to be burned for energy.
As is evident, the “negative” in C12 Negative is still an unreached goal rather than reality.
The easy savings should be done first, e.g. shipping the filaments directly to UK and not via Finland would save around 0.3 kg emissions, helping the Chinese factory to install solar power would save around 0.5 kg. Producing the filament in UK while using renewable energy from own sources, would save around 1.1 kg in emissions.
The key, for the filament to start being on the negative emission side, is the use of renewable energy while producing the PLA. E.g. if NatureWorks or some other PLA manufacturer would start using only renewables, then with 1.1 kg savings from above, the negative CO2 emission goal would be met with -1.08 kg CO2 equivalent emissions.
Does anyone know of such a supplier?
Some carbon nanofiber tests were done recently, you can read more here!