Data Center & Power Glossary

The essential data-center, power-grid & DC Hub terms — defined.

B

Behind-the-Meter (BTM)
Generating power on-site (gas, solar, storage) so a facility runs independent of — or alongside — the utility grid, sidestepping the interconnection queue.
BUILD / CAUTION / AVOID
DC Hub's plain-English market verdict derived from the DCPI score: BUILD = grid-ready, CAUTION = constrained, AVOID = scarce power / long delays.

C

Colocation (Colo)
Renting space, power, and cooling in a third-party data center for your equipment.
Carrier Hotel
Data center with extremely high network carrier density, serving as major interconnection point.
Cross-Connect
Physical cable connecting two customers or a customer to a carrier within a facility.

D

DCPI — DC Hub Power Index
DC Hub's 0–100 score ranking a market's data-center build-readiness from grid headroom, time-to-power, and constraint. Higher = more build-ready; surfaced as a BUILD / CAUTION / AVOID verdict across 300+ markets.
DCGI — DC Hub Gas Index
Withdrawn 2026-08-08, restored 2026-08-30. DC Hub's 0–100 per-state score for natural-gas suitability for data-center siting (gas access + delivered cost), the gas analog to DCPI. An internal audit found the 20-point interstate-share term scored ~0 for all 53 published states (a case mismatch against EIA's capitalised TYPEPIPE values) and the 40%-weighted cost term was a hardcoded constant for nine states including Texas. All three terms were repaired and the index was restored 2026-08-30 — but a figure published before 2026-08-08 came from a different index and must not be compared with one published now (see /api/v1/dcgi/methodology, corrections). The gas-fired $/MWh remains withdrawn: that is a separate, unfixed defect.

E

Excess Power / Stranded Power
Available generation or grid capacity in a location with low current demand — attractive headroom for new data-center load.

F

Fuel Mix
The share of electricity generation by source (gas, nuclear, coal, wind, solar, hydro) on a grid at a point in time.

G

Grid Headroom
Spare capacity on the local grid available for new large loads before transmission upgrades are required.

H

HIFLD (Homeland Infrastructure Foundation-Level Data)
The public US federal dataset of infrastructure — substations, transmission lines, pipelines — DC Hub overlays on its Land & Power map.
Hyperscale
Massive data centers (100MW+) built by cloud giants with custom infrastructure.
Hot Aisle / Cold Aisle
Configuration separating hot exhaust and cold intake air for efficient cooling.

I

Internet Exchange Point (IXP)
Physical location where networks connect to exchange traffic directly.
Interconnection
Direct private connections between networks, carriers, or clouds within a data center.
Interconnection Queue
The waitlist of generation and large-load projects seeking grid connection; its depth is the main driver of time-to-power.
ISO / RTO (Independent System Operator / Regional Transmission Organization)
The operators that run regional US power grids — PJM, ERCOT, MISO, CAISO, SPP, NYISO, ISO-NE — and clear their wholesale electricity markets.

K

kW (Kilowatt)
Unit of power (1,000 watts). Colocation is typically priced per kW.
kWh (Kilowatt-hour)
Unit of energy (1 kW for 1 hour). Used for utility billing.

L

Latency
Time delay for data to travel between points, measured in milliseconds (ms).
Liquid Cooling
Cooling method bringing coolant directly to servers/chips for high-density AI workloads.
LMP (Locational Marginal Price)
The wholesale price of electricity at a specific grid node, reflecting generation cost plus local transmission congestion.

M

MW (Megawatt)
Unit of power (1,000 kW). Large data centers measured in MW capacity.
Meet-Me Room (MMR)
Room where carriers and customers interconnect their networks.
MW-day ($/MW-day)
Wholesale capacity pricing unit for data-center / colocation power.

N

N+1 Redundancy
Having one more component than required so one can fail without impact.
2N Redundancy
Fully duplicating all critical components for fault tolerance.

P

PUE (Power Usage Effectiveness)
Ratio of total facility power to IT power. 1.0 is perfect; 1.2 excellent; 1.6 average.
PDU (Power Distribution Unit)
Device distributing power to servers in a rack, often with monitoring.
PPA (Power Purchase Agreement)
A long-term contract to buy power (often renewable) at a set price; common for hyperscale data centers.
Powered Shell
A completed data-center building delivered with power and cooling infrastructure but no IT fit-out.
Powered Land
A site with secured utility power / substation access, ready for data-center development.

R

RTO (Regional Transmission Organization)
A grid operator that manages transmission and the wholesale market across a multi-state region — see ISO / RTO.

S

Substation
Facility that steps transmission voltage down for distribution; proximity to one is a key driver of time-to-power.

T

Tier Classification
Uptime Institute's 4-tier system: Tier 1 (basic) to Tier 4 (fault-tolerant).
Time-to-Power (TTP)
Estimated months from breaking ground to energized grid service in a market — a core DCPI input.

U

UPS (Uninterruptible Power Supply)
Battery system providing instant backup power during outages until generators start.

W

Wholesale Colocation
Large-scale (1MW+) colo with dedicated space, lower rates, longer terms.
WUE (Water Usage Effectiveness)
Liters of water used per kWh of IT energy. Lower is better.