Concept
Revenue and credits are the money flowing into a process: the main product sold at market price, plus offsetting credits from selling physical byproducts and from policy. Set against the cost of production, these inflows give the margin on the product, or the net cost of making it.
The inflows. Three kinds of money come in:
Price is set by the market, not by cost. Product revenue rests on the price the product clears at — independent of what it cost to make. For a commodity the producer is a price-taker: levelized cost is the floor it must beat, the price is what it receives, the gap is margin. Comparing the two — not assuming price equals cost — is how a TEA reads competitiveness.
Byproduct credits depend on the boundary and a real market. Whether a stream is a salable byproduct or an internal flow is a system-boundary question, and a credit is worth its market price only if a market can absorb it. Each crossing must be booked once.
Gross vs. net. Costs can be reported gross, or net of credits — a modeling choice that must be stated. Netting credits against gross cost yields a net cost of production; the same credits can instead be shown as revenue lines — the same economics two ways, not to be mixed.
Reading green ammonia from the revenue side. The plant sells ~330,000 t/yr of NH₃ at the ammonia market price; against the ~$800/t gross levelized cost, the gap is margin — and as a commodity, the plant takes the price rather than setting it. On the credit side, electrolysis also produces oxygen — ~1.4 t O₂/t NH₃ (from ~8 kg O₂/kg H₂ and ~0.18 t H₂/t NH₃) — which could be sold as a byproduct credit, alongside any policy credit on the hydrogen.
Edge case: crediting that whole ~1.4 t/t oxygen stream at merchant price would overstate revenue badly — a single world-scale plant’s oxygen output far exceeds regional merchant-O₂ demand, so most is vented at zero credit, and only the fraction a local buyer can take is worth market price.