Determining Total Cost of Ownership for Data Center and Network Room Infrastructure

Overview

The paper expresses physical-infrastructure TCO per rack so that different facilities and designs can be compared against the IT work they support. The model rests on 100 kW of capacity and a 10-year life, and TCO is split into capex and opex categories. In the example breakdown electricity, service, power equipment, cooling equipment, installation, racks, space and engineering are the main buckets, with electricity the largest single opex item.

A high-availability data center has a lifetime physical-infrastructure TCO of about $120k per rack, roughly half capex and half opex. The key finding concerns utilization: a typical data center runs at about 30% of design capacity, with a range from about 10% to over 90%. The cost of paying for unused capacity is the single largest driver. The paper calls this share unabsorbed cost.

Modular, scalable infrastructure is therefore recommended, with capacity added as load grows. Practical rightsizing is estimated to save about 30% of TCO on average. The paper dates from 2011, so its cost categories and proportions reflect that period's prices, but per-rack normalization and the unabsorbed-cost logic remain a usable comparison method. In a modular build only the capacity needed for the expected load is bought on day one and the rest is added as load grows, which explains why the typical 30% utilization is so costly.

Key points

1. Lifetime physical-infrastructure TCO of a high-availability data center is about $120k per rack, roughly half capex and half opex.
2. Typical utilization is about 30% of design capacity (range about 10% to over 90%).
3. Model basis: 100 kW capacity, 10-year life.
4. Rightsizing with modular scalable infrastructure saves about 30% of TCO on average.
5. Main cost buckets: electricity, service, power equipment, cooling equipment, installation, racks, space, engineering; electricity is the largest opex item.

Using it in design

• Have the TCO engine report cost per rack and per kW over a user-selectable life (default 10 years) and split capex from opex.
• Add a phased build-out mode where capacity modules are deployed as load ramps.
• Show unabsorbed cost for a day-one full build versus a modular build.
• Start the default utilization ramp near 30%.

Who should read it

Designers preparing data center investment budgets and managers deciding whether to grow capacity in stages.

Related standards

• EN 50600-1

Publication details

Authors

Neil Rasmussen

Publisher

Schneider Electric

Year

2011

Document number

WP 6

Document language

English

Source type

Manufacturer

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation