Cross-layer synthesis following the electron from grid interconnect to accelerator die. Vendor concentration, standards state, capex intensity and inflection years per stage. Composes with the AI Power Chain, Investment Layer and Due Diligence frameworks. Anchor for the ongoing series of stage-by-stage deep-dives.

Deep-dive on the OCP Mt. Diablo 400 rack specification (v0.5.0 May 2025 through v0.7.0 March 2026, co-authored by Microsoft + Meta + Google). Four-plane vendor coverage, the August 2026 OCP 800V standardisation with NVIDIA inside the collaboration, and the strategic contest as rack-integration margin migrates above the interface layer. Companion to P4 Hall power at the sidecar/row/facility architecture layer.

Companion deep-dive to Direct-to-Chip Cooling. Six-stage qualified path from sensor contact to electrical and coolant isolation. OCP standardising the sensing element, NVIDIA GB300 pushing detection into the compute platform, Ecolab's $4.75bn CoolIT acquisition consolidating the cooling stack. 100 MW reference topology (~$14.7/kW IT, ~$1.25M campus total) with a companion calculator. Twenty-four named vendors mapped across DETECT / LOCALISE / CLASSIFY / AUTHORISE / ISOLATE / OBSERVE.

Six additive economic roles the same physical battery performs: backup (R1), ride-through (R2), power smoothing (R3), peak management (R4), grid services (R5) and grid-forming (R6). Each migration requires a specific technical, contractual and regulatory gate. Screen for R-stage exposure before chemistry, ownership model or geography. Connective frame across the lithium UPS, hall BESS, EU EED overlay and load-side flexibility companions.

Two simultaneous migrations at the interconnect layer. Boundary 1 is medium migration (copper to optical) at intra-rack scale. Boundary 2 is integration migration (pluggable transceiver to co-packaged optics) at rack-to-rack and switch-fabric scales. Silicon photonics fab ecosystem (GF Fotonix, TSMC, Tower, STMicro, IMEC), pluggable + DSP cohort (Broadcom, Marvell, Coherent, Lumentum) and CPO specialists (Ranovus, Ayar Labs, Lightmatter, Celestial AI). The economic control point may migrate toward whoever owns the electrical-to-optical boundary itself.

An investment framework for the reclassification premium between firm AI capacity and firm-plus-flexible AI capacity. Control models (workload orchestration, storage-mediated facility, BTM dispatchable, DER aggregation, hyperscaler-owned); monetisation channels (market revenue, cost avoidance, time-to-power NPV), and where the reclassification premium routes. FERC RM26-4 validates flexibility as an interconnection attribute, not just a grid-services product. Fourth P4.2 companion to lithium UPS, hall BESS and the EU EED regulatory overlay.

Fifth and final stage of the Grid-to-Chip framework. Every new power architecture destroys one conversion layer and creates another; the investable question is where the value migrates. SiC + GaN wide-bandgap semiconductors, POL/VRM specialists, factorised power (Vicor), on-package IVR (now inside Analog Devices via the July 2026 Empower acquisition). Nvidia 800V direction of travel drives fewer conversion stages and high-ratio late-stage conversion near the accelerator. Two-tier vendor scorecard with architecture-displacement-risk column.

Fourth stage. Low-voltage transformers, UPS, hall BESS, PDUs and the AC-to-DC rectification boundary migration. Four-vintage architecture (V1 legacy AC / V2 hybrid 800V sidecar / V3 row-level 800V / V4 native 800V facility) with per-vintage vendor scorecard. Companion P4.2 investment stack (see hub).

Third stage. HV-to-MV step-down at the site substation, MV distribution across the campus, protection and switchgear. Solid-state transformer vs conventional MV transformer investment contest, driven by Nvidia 800V DC AI factory demand pull and constrained conventional MV transformer supply.

Second stage. The scarce asset is a contract or a queue position. Interconnection agreements, ISO cluster studies, grid-services contracts, load-serving-entity arrangements. Build-versus-extract framework for grid capacity constraints.

First stage. Firm power procurement: nuclear PPAs, SMRs, behind-the-meter gas plus storage, renewables firmed with dispatchable capacity. The economic unit is a contracted energy stream with defined firmness characteristics.

Nine-layer physical stack from GPU die and TIM through cold plate, QDs, manifold and CDU out to the facility loop. CDU as testable control-point proposition. Single-phase vs two-phase reframed as an economic threshold, not a physics deadline. Chilldyne's negative-pressure architecture as the third distinct route. Consolidation race (Ecolab-CoolIT, Schneider-Motivair, Eaton-Boyd, Vertiv-STL/PurgeRite), capex by rack density, three TAM definitions, bull/bear disagreement grid, economic control x growth matrix, six bear cases, five triggers and the sovereign supply-chain overlay. Investor decision map by profile.

Reference underwriting for the Interport multi-port SST architecture. Nvidia MGX qualification chain, single-point-of-failure, customer-adoption trajectory, rent pool, decision tree and the falsification triggers that would break the thesis.

The three US SST pure-plays applied to the 800V DC + MV transformer supply gap. Head-to-head architectures, socket map, adoption scenarios, and the specific milestones that will decide the winner. Standalone tech spotlight ahead of the full Tech Spotlights series.

Canonical reference for on-package delivery (Layer 5 of the AI Power Chain). Four walls of physics, five-way IVR architecture taxonomy (Board VRM to on-die IVR), two-stage PDN, Empower / Ferric magnetics split, the ADI $1.5B acquisition anchor, the Marvell test, seven falsifiers, and the $1.5B reverse-underwrite.

Companion to The IVR Stack. Ferric is an option on the monetisation of merchant IVR scarcity. Value-creation engine, customer economic value (Gate 0), commercialisation ladder (evaluation to platform dependence), evidence-conditioned six-state valuation ladder from $200M to $4B+, three vetoes, tiered acquirer scorecard, reverse-underwrite arithmetic, and the Marvell test.

Interactive scenario model for direct-to-chip cooling. Six architectural inputs drive CDU count, per-rack and campus capex, year-1 opex and 7-year TCO. Anchored to Fig C15 of the parent DTC essay: $14K / $44K / $87K per rack at 40 / 100 / 250 kW. Ships with a capex waterfall, TCO-over-time chart, payback engine on the 45 °C free-cooling and two-phase switches, 3×3 sensitivity matrix on electricity price and utilisation, URL-hash scenario sharing and one-click Markdown export.

Companion interactive topology model to the leak-detection deep-dive. Campus MW and rack density flow through pod / CDU counts, cable metres, sensing endpoints, controllers and unit costs to a $/kW IT figure and campus total. Sensor-mix and coverage-tier controls let the user compare Tier 1 minimum through Tier 3 high-coverage on the same reference 100 MW hall.