How Microgrids for Data Centers Increase Resilience, Optimize Costs, and Improve Sustainability

Overview

Electricity is roughly 50% of data centre opex excluding IT; an internal study found 40-51% depending on enterprise, colocation or hyperscale type, excluding IT depreciation. Worldwide microgrid capacity is projected to grow more than 20% per year, and installed cost has fallen an estimated 25-30% since 2014. Standby diesel backup is not a microgrid because it does not run continuously; continuously operated distributed energy resources (CHP/CCHP, solar, wind, biomass, fuel cells, battery storage) run under a microgrid controller.

Diesel backup weaknesses: on-site fuel storage typically limits runtime to a few days, emissions rules cap annual run hours, and start-up is not guaranteed (fuel quality, loading, starter batteries). Solar needs about 4-5 acres of land per MW, and cited installed cost fell from $8.50/W in 2009 to $3.05/W in 2019. Energy storage suits peak loads while CCHP or fuel cells are better for base load.

Controller duties are managing grid disconnection and reconnection, balancing DER against load in island mode, maintaining breaker coordination for every DER combination in both modes, and maximizing renewables with export limits in grid-connected mode. Sizing-study inputs are site limits and weather, load profiles, tariffs and demand charges, fuel access and cost, asset and O&M costs, intended buy/generate/store/sell use, export limits or net-zero agreements, and expansion plans. Cybersecurity should align with IEC 62443-4-2 and IEC/ISA 62443-3-3, and ownership options include energy-as-a-service.

Key points

1. Electricity is roughly 50% of opex excluding IT; 40-51% in an internal study.
2. Microgrid capacity projected to grow over 20% per year; installed cost down 25-30% since 2014.
3. Standby diesel is not a microgrid; continuously run DER under a controller is.
4. Diesel limits: fuel storage of a few days, emissions caps on annual hours, no start guarantee.
5. Solar needs 4-5 acres per MW; cost fell from $8.50/W (2009) to $3.05/W (2019).
6. Storage suits peak loads; CCHP or fuel cells suit base load.
7. Controller: islanding and reconnection, island balance, breaker coordination for every combination, export-limited renewables.
8. Cybersecurity aligned with IEC 62443-4-2 and IEC/ISA 62443-3-3.

Using it in design

• Add an on-site energy/DER layer: sources utility, diesel_standby, gas_chp, cchp_absorption, pv, wind, fuel_cell, bess with a continuous vs standby flag.
• Provide a generator fuel autonomy calculator (tank size vs load to hours/days) and warn on multi-day resilience goals.
• Check protection coordination for each source combination including island mode, check PV land at about 4-5 acres/MW, and link CCHP waste heat to absorption-chiller capacity in the cooling plant.
• Give the feasibility module tariff, demand charge, fuel price and export-limit inputs, and an IEC 62443 cyber checklist for the microgrid controller.

Who should read it

Data-centre owners and electrical designers weighing on-site generation against energy cost, grid risk and carbon targets.

Related standards

• IEC 62443-4-2
• IEC 62443-3-3
• Uptime Institute Tier Standard: Topology
• IEEE 2030.7

Publication details

Authors

Carsten Baumann

Publisher

Schneider Electric

Year

2020

Document number

WP 289

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