Independent analysis of data centre power architecture, autonomous operations, and the infrastructure behind AI. By Adi Kumar.

The DC-DC Transition: the 800V DC AI power stack

The DC-DC Transition · a nineteen-piece series

The 800V DC AI power stack. A practitioner's field guide

Thirteen main essays laying out the six-layer AI power stack + how the 800V DC transition reshapes each layer. Six supplements addressing specific layer-level questions in depth. Transition tax, hybrid architectures, voltage ceiling, SST supplier dynamics, sidecar rack ecosystem, connector engineering. Written for PE sponsors evaluating power/thermal/DC assets, hyperscaler strategy teams working through architecture decisions, and industrial operators building through the transition.

19pieces total
6power stack layers
Aug 2026 → Feb 2027publishing runway
Consulting-gradevisuals throughout

01The reference framework

Every essay in the series maps to one or more of the six layers of the AI power stack. The framework is a single-page orientation for anyone thinking about power infrastructure design, vendor selection, or procurement across an AI facility.

Figure 0.1
The six-layer AI power stack. Reference framework across the series
Layer 1Layer 1. Utility interfaceMV AC 13.8-33 kVGrid-facingPrimary vendors: Utility + interconnectionLayer 2Layer 2. Perimeter conversionMV to 800V DCTHE consequential layerPrimary vendors: SST vendorsLayer 3Layer 3. Building distribution800V DC busDistributionPrimary vendors: Busway + switchgearLayer 4Layer 4. Rack conversion800V to 48V DCOCP Mt. DiabloPrimary vendors: Sidecar rack OEMsLayer 5Layer 5. In-rack distribution48V busbarStandard-frozenPrimary vendors: Rack OEMsLayer 6Layer 6. Point-of-load48V to sub-1V @ dieSilicon-integratedPrimary vendors: Vicor + Infineon + TIPower flow
Every essay in the series maps to one or more of these six layers. Understanding which layer any specific technology, vendor, or decision touches is the primary orientation tool.
Where to start: if you're new to the framework, read The Architecture Map first. It establishes the six-layer structure that the rest of the series builds on. Then Two Architectures Wearing the Same Name for distributed vs centralised trade-offs, and The Real Reason Data Centres Are Going DC for why the transition is happening now.

02The thirteen main essays

All thirteen essays are live. Parts I-III shipped as the foundational trio; parts IV-XIII follow the six-layer framework across specific layer-level questions.

  1. I
    The Architecture Map
    /architecture/ · layer framework
  2. II
    Two Architectures Wearing the Same Name
    distributed vs centralised
  3. III
    The Real Reason Data Centres Are Going DC. And It Isn't Capacity Alone
    efficiency + reliability
  4. IV
    Arc Behaviour + Insurance Regime
    Layer 3 protection
  5. V
    Grounding + Ground-Fault Detection
    Layer 3 safety
  6. VI
    Battery Integration
    Layer 1 BESS
  7. VII
    Retrofit vs Greenfield Economics
    deployment economics
  8. VIII
    Cooling Co-Emergence
    Layer 5 thermal
  9. IX
    Power Quality + Grid Interaction
    Layer 1 grid-facing
  10. X
    Standards Evolution
    OCP + IEC + UL + NEC
  11. XI
    Vendor Economics
    supplier dynamics
  12. XII
    Commissioning + Skills Gap
    workforce constraint
  13. XIII
    The Ten-Year View (series close)
    2026-2035 outlook

03The six supplements

Each supplement addresses one specific layer-level question that the main series flagged but did not fully develop. Consulting-grade visuals throughout. Six-layer stack decompositions, vendor concentration matrices, procurement flow diagrams, comparison card frameworks. All six supplements live.

  1. Supplement A
    The Transition Tax
    layer-by-layer capex decomposition
    Wed 2026-12-16
  2. Supplement B
    Hybrid Forever
    why most facilities will run mixed AC/DC through 2035+
    Wed 2027-01-06
  3. Supplement C
    The Voltage Ceiling
    1500V DC and the MVDC question
    Wed 2027-01-13
  4. Supplement D
    The Solid-State Transformer
    Layer 2 supplier dynamics. Western vs Chinese
    Wed 2027-01-20
  5. Supplement E
    The Sidecar Power Rack
    Layer 4 architecture. OCP Mt. Diablo ecosystem
    Wed 2027-01-27
  6. Supplement F
    The Connector Wars
    Layer 4/5 interface engineering
    Wed 2027-02-03

04Method & provenance

All essays are practitioner-authored based on primary market research, public information review, and specific operator + vendor engagement. Chart data is cited to primary sources at essay level. Vendor mentions are illustrative. Not investment advice, not comprehensive vendor selection. Retrospective scorecards on every long-form essay explicitly track what changed vs the initial thesis, so readers can judge the analytical track record.

Working on an AI infrastructure decision?

I advise PE sponsors evaluating power/thermal/DC assets, hyperscaler strategy teams working through the 800V DC transition and nuclear PPAs, and industrial acquirers thinking about consolidation.

How I work →

Companion series and hubs. This series is one of the flagship publications on adikumar.coAdjacent series include The Investment Layer (8 essays on financing the AI buildout), Due Diligence for the AI Buildout (14 essays + 3 supplements on M&A + technical DD), and Financing the AI Buildout (10 essays on capital structures). Topic hubs: 800V DC, Power semiconductors, CoolingFull series index also at /tag/dc-transition/.