Fuel-market system-model rules

Consequential fuel markets

Consequential markets use marginal production mixes calculated in premise/marginal_mixes.py. Technologies registered as constrained suppliers, including pathways dependent on residual or waste feedstocks, are set to zero before the remaining marginal shares are normalized.

The constrained fuel pathways are maintained in premise/data/consequential/constrained_suppliers.yaml. They currently include:

  • bioethanol, from residues;

  • biodiesel, from used cooking oil, with CCS;

  • methane, from biomass;

  • biomass - residual;

  • liquefied petroleum gas, synthetic, from coal; and

  • liquefied petroleum gas, synthetic, from coal, with CCS.

The used-cooking-oil biodiesel pathway was previously labelled biodiesel, from oil crops, with CCS even though its ecoinvent mapping selected used-cooking-oil inventories. Its IAM variable, lead time, lifetime, and constrained supplier entry now use the same explicit used-cooking-oil label.

Cutoff fuel markets

Cutoff markets may legitimately use a waste-treatment activity as a fuel supplier. Such activities are identified by an activity name beginning with treatment. After positive fuel shares have been normalized, the technosphere exchange to the treatment supplier is written as a negative amount. This follows the ecoinvent waste exchange convention and prevents the treatment activity from producing an unintended negative fuel burden.

The sign rule is enabled for generated liquid-fuel, gas, and hydrogen markets. It is not applied to consequential markets or to non-treatment suppliers.

LCIA regression baselines

The deterministic GWP regression scores are refreshed when either rule intentionally changes generated supply chains. In particular, excluding used-cooking-oil biodiesel raises the consequential diesel scores because the remaining marginal suppliers are renormalized, while treatment-exchange sign changes affect cutoff results in versions where those suppliers are selected. Changes also propagate to tested electricity, heat, cement, and steel activities that consume the affected fuels upstream.