 Polylactide (PLA) was estimated to have a fossil fuel energy cost of 54-56.7 from two sources, but recent developments in the commercial production of PLA by NatureWorks has eliminated some dependence of fossil fuel-based energy by supplanting it with wind power and biomass-driven strategies.They report making a kilogram of PLA with only 27.2 MJ of fossil fuel-based energy and anticipate that this number will drop to 16.6 MJ/kg in their next generation plants.In contrast, polypropylene and high-density polyethylene require 85.9 and 73.7 MJ/kg, respectively, but these values include the embedded energy of the feedstock because it is based on fossil fuel.