Industries / Colocation

    Tenant power density is changing Your visibility hasn't

    GPU tenants are pushing rack power well beyond the design spec your facility was commissioned against. Verdigris gives you per-tenant-zone visibility into actual electrical capacity. So you can sign tenant SLAs grounded in measured headroom, not assumptions.

    Colocation white space with multi-tenant power infrastructure

    Goldman Sachs projects $250–650 billion in AI infrastructure capital expenditure by 2026. Total data center capex is forecast to reach $3 trillion by 2030, growing at 14% annually. A growing share of that money is going into colocation. And the tenants writing those checks are pushing power density well beyond what most existing white-space designs were sized for.

    A colocation facility commissioned in 2018 for 8 kW racks now hosts tenants deploying 120–140 kW Blackwell racks in the same zones. The original PDU sizing, transformer K-factor, harmonic profiles, and protection coordination were all calibrated for a different load class. Your monitoring still reports averaged 1 Hz data. Which means you're signing tenant SLAs against a capacity model that doesn't match the physics of what's actually running.

    $250B–$650B

    AI infrastructure capex projection through 2026 (Goldman Sachs)

    $3T

    Total data center capex by 2030. 14% CAGR pulled by AI workloads

    20–40%

    White-space capacity stranded by derating without validated headroom

    The capacity-vs-SLA problem

    Most colo operators confront the same compounding bind:

    • Design specs were written for a different load class. A 200 A PDU rated for steady-state server load has different effective capacity under a GPU load with elevated harmonic content. Heating from 5th and 7th harmonic THD reduces real headroom. Your spec sheet doesn't capture that.
    • Mixed-tenant zones share infrastructure. One zone has legacy CPU racks, the next has a GPU tenant pushing 120 kW racks. The transformers, switchgear, and paralleling between them see a load profile no one designed for. Harmonic stress accumulates on equipment rated for clean sinusoidal current.
    • You sign tenant SLAs against an averaged dashboard. Per-zone capacity numbers from your monitoring don't reflect the shared-infrastructure penalty above. When the tenant deploys and a protection event happens, you're explaining a downtime credit to a customer with competitive alternatives a phone call away.

    The conservative answer is to derate harder. Leave 30–40% margin. That strands capacity you've already paid to build. The aggressive answer is to sign SLAs against the dashboard. That occasionally costs you a tenant.

    Shared infrastructure under shifting tenant mixThree tenant zones (legacy 8 kW CPU, mixed, GPU-dense 130 kW) feed a shared paralleling bus and upstream transformer. As the tenant mix shifts, the shared bus sees changing harmonic profile (H1, H5, H7) AND changing RMS current (1× to 15× of legacy baseline). The transformer is stressed differently at each extreme: K-class limit at 100% legacy, amperage limit at 100% GPU.Shared infrastructure sized for one tenant mix, stressed by anotherZone ALegacy 8 kW CPU6-pulse UPS upstreamHigher H5/H7Zone BMixed CPU + GPU~50 kW per rackBursty profileZone CGPU-dense 130 kWActive-PFC PSUsLower harmonics, higher I
    Shared paralleling bus / PDU
    Mixed-tenant zone. GPU tenants ramping in. Fundamental current rising; harmonic profile shifting toward cleaner active-PFC content.
    Upstream transformer
    K-class easing toward K-4, but RMS current rising fast (×5.6 of legacy).
    Per IEEE C57.110 K-class + nameplate amperage
    K-FACTOR (HARMONIC HEATING)K-4Computed: K ≈ 3.27RMS CURRENT vs 2018 DESIGN×5.645 kW per rack avgShared-bus harmonic spectrum (relative to fundamental)H1100%H521.1%H78.6%

    Spectra computed at runtime via weighted superposition of canonical UPS-rectifier and GPU-PSU presets per IEEE 1459. K-class per IEEE C57.110. Per-rack power: 8 kW (typical 2018-era colo design) → 130 kW (Blackwell NVL72 nominal, EVD-110). The transformer is stressed differently at each extreme: K-class limit at 100% legacy (harmonic heating), amperage limit at 100% GPU (fundamental current ×15).

    Per-zone capacity, validated continuously

    Verdigris gives you a measured operating limit per circuit, refreshed continuously as the load mix in each tenant zone shifts.

    8 kHz waveform capture on the circuits feeding each zone resolves harmonic content through the 25th order. The Verdigris Signals layer translates that into the actual safe capacity for each circuit given the load it's currently carrying. Not the nameplate. Not the historical assumption. The validated electrical limit, today.

    That gives you a defensible tenant SLA. When a GPU tenant wants to expand into a zone, you can say "here's the measured headroom on this PDU under your current load profile, and here's how it changes when you double the rack count". Backed by physics, not spreadsheet projections.

    Why incumbent BMS doesn't close the gap

    Schneider, Eaton, Vertiv, and ABB all market predictive maintenance for colocation. Their data sources are still 1 Hz BMS polling and threshold-based alarms. The failure modes that take down GPU-dense tenant zones (sub-cycle transients, harmonic stress on transformers and rectifiers) live below their measurement floor. Adding more sensors at the same sample rate doesn't close the gap.

    What changes for colo operators

    Recover stranded white-space capacity

    Replace conservative derating with per-zone validated limits. Free up the 20–40% margin you're holding back to cover loads you can't measure.

    Defendable tenant SLAs

    Sign capacity commitments grounded in measured headroom. When a tenant pushes up against the limit, you see it well before trip-time, with planning-window lead time instead of an after-the-fact protection event.

    Mixed-tenant zone visibility

    Per-circuit electrical fingerprinting lets you separate signal contributions from each tenant. Investigate degradation without guessing whose load caused it.

    Capacity planning that matches your physics

    When you're sizing a new deployment, base it on measured limits from circuits already running similar load profiles. Not on the design spec from a different decade.

    Read More

    Validate your white-space capacity

    Replace conservative tenant-zone derating with measured operating limits. Sign SLAs you can defend with physics.