Source Review: Thunder Said Energy — Cryogenic Air Separation Economics

Verdict: Consistent Confidence: medium-high

Provides the primary tier-C anchor on ASU capex (~$200/(t/yr) capacity) and energy intensity (150-800 kWh/t O₂). Both numbers are within the literature consensus range and match the Air Liquide Baytown empirical capex of $258/(t/yr) (calculated from $850M / 3.29 Mt/yr). q1's calc uses 300 kWh/t O₂ for ASU electricity (mid-low end of TSE's range); Codex audit accepted this as dimensionally correct. The single methodological caveat: TSE's normalised "60 kWh/ton input air" basis is presented alongside "$100/ton oxygen" — these two figures use different normalisation bases (input-air vs product-O₂), which is a presentation-clarity issue but not an arithmetic error. For q1 the relevant input is the per-tonne-O₂ figure (150-800 kWh/t), which is reliable.

Abstract

Thunder Said Energy's air-separation-unit economics summary establishes baseline economics for cryogenic ASUs used in industrial-scale oxygen production. Capital cost is benchmarked at approximately $200/(tonne O2 per annum) of capacity, with modern plant scale ranging from 200 to 40,000 Nm³/h of O2. Energy consumption per tonne of O2 ranges 150-800 kWh/t depending on plant size, integration, and product purity; electricity is the dominant cost component. The base-case economics quoted are $100/t oxygen and $20/t nitrogen at 60 kWh/t input air. Useful as a tier-C anchor on the capex / energy intensity of building dedicated rocket-grade LOX capacity at scale.

Key claims

• asu-capex-rule: "around $200/Tpa of oxygen capacity" represents typical modern ASU capex.
• asu-energy-range: "150-800 kWh/ton of oxygen" depending on configuration.
• modern-asu-capacity: "200-40,000 Nm³/h of oxygen and 1,000-150,000 Nm³/h of nitrogen" through cryogenic distillation.
• electricity-dominant-opex: "A large share of costs comes from electricity" — primary variable cost.
• asu-base-economics: "$100/ton oxygen, $20/ton nitrogen, and 60 kWh/ton electricity consumption (normalized to input air basis)".

Reviewer notes

For the q1 calc this is the primary tier-C anchor on (a) how much electricity supply is needed to scale ASU capacity to 10⁴-10⁵ launches/yr; (b) the marginal capex of new LOX capacity. Note: 60 kWh/t input air ≈ 280 kWh/t O2 (~4.66× concentration), so the per-tonne-O2 numbers depend on whether the basis is air or product. The 150-800 kWh/t range cited spans approximately the range of literature numbers including the 200-500 kWh/t commonly quoted for modern large ASUs.