Blueprint: Farm-Scale Electrochemical Ammonia Unit (Lithium-Mediated) — Build Specification, with Its Failed Economics Printed at Full Size

Build specification for a farm-scale electrochemical ammonia unit (lithium-mediated stack, 1.15 m2, 3.5 V, 50 percent Faradaic efficiency, 2.0 kg of nitrogen per day), drawn from the source paper (DOI 10.5281/zenodo.24108471). SIMULATED, NOT MEASURED — NOT BUILT. This is a clean published failure, deposited so the licence record shows the design as specified and its failed economics at full size, and so nobody builds it blind: the unit requires 40.2 kWh per kg N, costs USD 45,865 to build, and produces nitrogen at USD 16.30 per kg N even with free electricity — 8.8 times the delivered remote fertiliser value of USD 1.85 per kg N. Its break-even electricity price is negative (minus USD 0.36 per kWh). An optimistic future case still costs USD 8.99 per kg N with free electricity. The blueprint carries the full specification (itemised bill of materials, process flow, assembly procedure, sizing rules, commissioning and acceptance tests, operating limits and failure modes) and the source recommendation: do not build at farm scale; capital is better spent on fertiliser logistics and storage.