Fig. 6: Identification of environmentally and economically feasible product distributions in the Plastic-to-X analysis for hydrogenolysis.
a Examples of randomly generated product distributions based on lognormal (top) and Gaussian (bottom) distributions with indication of their average chain lengths (Supplementary Table 28 for all distributions). Evaluation of hydrogenolysis of plastic caps using hydrogen with either (b) fossil, c wind, or (d) solar origin, showing the gain in GWP compared to the equivalent BAU process (squares) and the margin for profit (circles) per kilogram of total C1–C45 products versus the average chain length of the randomly generated product distributions (see details in the Methods section). The primary y-axis (left-hand side) quantifies the GWP gains obtained by switching from BAU operation to the hydrogenolysis process that generates the same product portfolio. A positive gain indicates that we reduce the GWP of end-products relative to their BAU respective. The secondary y-axis (right-hand side) indicates the margin for profit obtained with the respective process. This unit quantifies the difference between the revenues obtained by selling the different products at market price and the cost of production. Negative values indicate that the cost of production is higher than the achievable revenues, while a positive margin translates to the potential profit obtained through the corresponding process. Minimum average chain lengths to achieve positive GWP gains and profit are indicated. For example, in the case of solar hydrogen, both environmental and economic feasibilities are achieved for chains longer than C11. Breakdowns are available in Supplementary Tables 29–31.
