Energy Demand#

Implementation status: Two layers. Production roll-up Simplified (aggregate; CASCADE computes per-route — a documented fidelity gap, not a defect; module added 2026-07-18). All 29 governing equations of CASCADE’s Energy Demand page are additionally implemented standalone in src/engine/energy-demand-full.ts (DL-136, Stage-1 shadow under the DL-138 integration registry — the production default is unchanged). Source: src/engine/energyDemand.ts:energyDemandAt, energyDemandSeries; src/engine/energy-demand-full.ts (full page) Test evidence: tests/energy-demand.spec.ts; tests/suite-j-energy-demand-full.spec.ts

The roll-up converts the engine’s BAU emissions series into per-carrier energy demand in EJ: fossil Jet-A1, SAF (incl. PtL), methane, liquid hydrogen (produced vs delivered), gaseous hydrogen for PtL, and the electricity roll-up.

Baseline energy pool#

The time-series gross is BAU emissions of an all-Jet-A1 fleet at CI = 89 gCO₂e/MJ. Back-conversion (identity stated explicitly in the module header):

\[E_{BAU}\,[\mathrm{EJ}] = G_{gross}\,[\mathrm{GtCO_2}] \times \frac{1000}{89} \approx 11.236\ \mathrm{EJ/GtCO_2}\]

(1 Gt = 10¹⁵ g; 1 EJ = 10¹² MJ). The module imports computeLCA and reads the engine’s own slice and blend functions, so the roll-up can never drift from the engine.

Carrier split#

The pool is partitioned exactly:

\[X_{SAF} + X_{CH_4} + X_{LH_2} + X_{JetA} = 1\]

  • \(X_{SAF}(y)\), \(X_{CH_4}(y)\) — the engine’s own safBlend / methaneBlend total shares (never re-derived here). If their sum exceeds 1 both are scaled pro-rata back to 100 %.

  • \(X_{LH_2}(y) = s_{LH_2}(y) \times (1 - X_{SAF} - X_{CH_4})\) — the LH₂ fleet adoption (half-S logistic from eis to min(2050, eis + h2\_offset), ceiling h2_ceiling, default 80 %) applied to the post-drop-in residual pool: SAF and CH₄ blend into the kerosene fleet first, hydrogen aircraft capture a share of what remains. This guarantees the partition even when raw ceilings would exceed 100 %.

  • \(X_{JetA}\) — the remainder (≥ 0 by construction).

LH₂ produced vs delivered#

Vapor losses mean more hydrogen must be produced than is delivered to aircraft tanks (cf. CASCADE Energy Demand, eq. total-hydrogen-loss; Hydrogen, eq. hydrogen_vapor_loss_boiloff_recovery):

\[\frac{E_{LH_2,prod}}{E_{LH_2,del}} = \frac{1}{1 - f_{loss}\,(1 - f_{BOR})}\]

with \(f_{loss} = vap/100\) (default 2 %), \(f_{BOR} = bor/100\) (default 50 %). The denominator is clamped at \(10^{-6}\): at vap = 100 % and bor = 0 the physical model diverges (all H₂ vented), and the module returns a large-but-finite ratio instead of ∞ so downstream roll-ups stay finite (documented guard).

GH₂ for PtL vs LH₂ fuel#

Gaseous hydrogen feedstock for PtL SAF is kept strictly separate from the LH₂ aircraft-fuel terms (no conflation — the DL-024 distinction):

\[E_{GH_2} = E_{SAF,PtL} \times \varepsilon_{PtL,H_2}, \qquad \varepsilon_{PtL,H_2} = 1.4\ \mathrm{MJ_{H_2}/MJ_{SAF}}\]

(FT stoichiometry, CASCADE-stable range 1.36–1.42). Simplification: CASCADE divides by the PtL product-slate fraction \(P_{PtL}\) for unallocated accounting; HyFlux has no such parameter, so \(P_{PtL} = 1\) (allocated, jet-fuel-only basis). Recorded.

Electricity roll-up#

\[E_{elec,H_2} = (E_{GH_2} + E_{LH_2,prod}) \times \frac{1}{\eta_{elys}}, \qquad E_{elec,PtL} = E_{SAF,PtL} \times 0.61\ \mathrm{MJ_e/MJ_{SAF}}\]
\[E_{elec,total} = E_{elec,direct} + E_{elec,H_2} + E_{elec,PtL}, \qquad E_{elec,direct} \equiv 0\]

Direct-electric aircraft demand is zero: the el_* parameters have no consumer in the aggregate engine at this layer, so the term is reserved but identically zero (documented).

Years outside the engine’s 2019–2050 sweep return an all-zero demand — no slice exists and nothing is extrapolated.

Known deviations / limitations#

These apply to the production roll-up (energyDemand.ts). Each of the last four is closed in the standalone full module (energy-demand-full.ts, DL-136, shadow — htype decomposition, liquefaction/PtG/removals electricity, methane vapour gross-up, product slate \(P_{PtL}\) and the α_eFuel allocated-primary-energy formulas, all test-asserted in tests/suite-j-energy-demand-full.spec.ts); the production default remains bit-identical until the DL-138 stage gates pass.

  • No route resolution. CASCADE resolves demand per route from fleet composition and aircraft assignment; HyFlux partitions a global pool by aggregate shares. Totals are consistent with the CASCADE equations; per-route, per-class or range-dependent resolution is not possible.

  • All hydrogen is treated as electrolysed — smr_share is ignored in the production roll-up (SMR needs no electricity, so this is a conservative upper bound on electricity demand).

  • Liquefaction electricity (liq kWh/kg) is not added to the production electricity roll-up — the liquefaction term is kept CI-side only.

  • PtG e-methane H₂/electricity and removals electricity (CASCADE’s E_elec,CH4 / E_elec,removals terms) are not in the production roll-up.

  • Methane vapor losses are not in the production roll-up; methane demand is the delivered pool share only.

  • Source defect carried, not reproduced by default: the page’s eq. 15/16 applies the LH₂ loss gross-up twice; CURRENT_EVIDENCE applies it once and CASCADE_PARITY reproduces the printed form (src/engine/basis.ts; regression-locked in tests/suite-d-divergence.spec.ts).

  • Λ(t) (total land use) is declared as an output variable with no defining equation anywhere in the source file — not implemented, not guessed (LAMBDA_NOT_DEFINED_NOTE).