How to Maximize Revenues from Your Data Center Energy Storage System with Grid Interactive UPS

Overview

The paper treats two service families: grid balancing (fast frequency response, static and dynamic frequency regulation) and demand management (peak shaving, Triad avoidance), using European and UK market examples. The operating modes of a grid-interactive double-conversion UPS are listed as normal, full or partial disconnection, recharge and export, all commanded by an external controller. The emphasis is on earning extra revenue from the same asset without giving up the priority of protecting the critical load, rather than holding the battery purely as backup.

Technical requirements are given concretely. UK response classes: fast frequency response within 0.5 s sustained up to 10 s, primary within 1-2 s up to 30 s, secondary within 30 s up to 30 min, high response within 1-2 s up to 30 min. The most lucrative fast services need active power adjustment within 500 ms-1 s, with batteries discharged or recharged for about 5 minutes on average. An external controller detects the frequency excursion (example thresholds 49.8 Hz and 50.2 Hz) and total response time to the UPS power set point is below 500 ms.

Recharge limits and state-of-charge partitioning shape the design: available recharge power is typically 20-25% of maximum UPS capacity (example: 1000 kW drawn for an 800 kW load plus 200 kW charging). The adjustable SOC window example is maximum 100%, real-time 65% and grid-services floor 50%, with energy below the floor reserved for the critical load. Static regulation uses a dry-contact fixed-power response, dynamic regulation is commanded over Modbus TCP proportionally to frequency deviation. Minimum asset size for frequency response is typically 1-50 MW, and the paper compares direct, indirect and hybrid business models.

Key points

1. UK response classes: fast frequency within 0.5 s up to 10 s; primary within 1-2 s up to 30 s; secondary within 30 s up to 30 min; high response within 1-2 s up to 30 min.
2. The most lucrative fast frequency services need active power adjustment within 500 ms-1 s, with batteries discharged/recharged for about 5 minutes on average.
3. An external controller detects frequency excursions (example thresholds 49.8 Hz / 50.2 Hz); total response time to the UPS power set point is below 500 ms.
4. Available recharge power is typically 20-25% of maximum UPS capacity, limited by battery recharge capacity and maximum input current (1000 kW drawn for 800 kW load + 200 kW charging).
5. Static regulation uses dry-contact fixed-power response; dynamic regulation is commanded via Modbus TCP proportionally to frequency deviation.
6. Adjustable SOC window example: maximum 100%, real-time 65%, grid-services floor 50%; energy below the floor is reserved for the critical load.
7. Minimum asset size for frequency response services is typically 1-50 MW.

Using it in design

• Model UPS battery state of charge as partitioned: reserved backup energy used for autonomy checks plus an optional grid-service band.
• Give UPS catalogue entries a gridInteractive flag, response time, export capability and supported battery chemistries.
• When grid services are enabled, use only the reserved band in autonomy calculations, and warn when Li-ion is not used for frequent cycling services.
• Show recharge power headroom (input rating minus load) as a check against utility connection capacity.

Who should read it

Data-centre operators and electrical designers considering grid-service revenue from UPS batteries.

Related standards

• IEC 62040-3
• EN 50549-1

Publication details

Authors

Arturo Di Filippi; Luca Valentini

Publisher

Vertiv

Year

2023

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