Polylactic Acid or PLA manufactured by Natureworks LLC has come under fire recently with agriculture reports that show that nitrous oxide or N2O used in cheap fertilizers used in corn growing is contributing to green house gasses that are 310 times more potent than Co2 or fifteen times more potent than CH4. The fertilizer that is used when growing corn crops at Natureworks in Blair Nebraska uses anhydrous ammonium; urea and urine or ammonium nitrate. These cheap fertilizers that are used within the 30 mile radius of the Blair, Nebraska manufacturing plant contribute to large amount of global warming.
Polylactic Acid
Polylactic Acid corn based plastics: According to the American Carbon Registry Per acre nitrous oxide emissions ranged between 0.12 and 1.45 t CO2-e annually and this varied among the fertilizer types. Our analysis resulted in an estimate of total annual N2O emission of 61 million tons of carbon dioxide equivalent for the three crops across the 31 states. Seventy percent of these emissions were from corn fields. Corn fields that are used in manufacturing PLA plastics, 2.2 KG of corn is used to manufacture 1 KG of PLA, this increases the amount of global emissions for usable sources of energy.
The numbers are alarming, 100 bushels of corn are required per 1 metric ton of PLA, 130 bushels of corn are planted per acre in corn fields. Conventionally farmed corn is typically a mono-crop that receives a lot of synthetic fertilizers and pesticides; and organic corn is in high demand for organic food. The only part of the plant that’s used to make PLA is the kernels, which means everything else becomes agricultural waste. Overall, this seems like an inefficient way to make polymer feedstock.
The current facility in Blair, Nebraska has the ability to manufacture 140,000,000 Kilograms of Polylactic Acid a year. Which has the footprint of 107,692 acres of land used in the United States to make Polylactic acid, if the United States used 100% Polylactic Acid we would need around 6,900,000 acres of land. Currently the United States uses around 20 billion pounds of plastic each year.
Currently 203.3 Tg (TerraGrams) of Carbon Dioxide equivalent would be produced if Natureworks was at full capacity, if Natureworks was at full capacity in production it would create 56 Tg of carbon dioxide equivalent more than all of the landfills combined in the United States according to the US Gas and Sinks . This is not only to say that we are only looking at the footprint of the fertilizers involved in growing the highest greenhouse gas crop on the planet, but then turning that product into bioplastics that are thrown into a compost facility which by aerobic breakdown creates more CO2.
Creating Polylactic Acid or corn based plastic is by far the worst environmental decision that a company can make as the contribution to green house gases from just the fertilizers used are mind-blowing.
