Why Does Power Quality (PQ) Matter in Next-Gen Data Centers?
What is Power Quality?
Power quality (PQ) describes how clean and stable electrical power is within a data center, measured against ideal voltage and frequency conditions.
Key PQ metrics include: voltage stability, harmonics, flicker, rapid voltage changes, dips, swells, and interruptions.
Why is PQ Gaining Importance in Data Centers?
Rapid Capacity Growth: APAC data center capacity is projected to grow at a 21% CAGR from 2024 to 2028, driven by cloud services, 5G expansion, and AI adoption.
Source: Powering possibility: Closing the clean energy for asia pacific data centers
Energy Availability Under Pressure: As APAC data center capacity expands, access to reliable energy is becoming an important concern. The high power demands of AI and other compute-intensive workloads are driving operators to prioritize locations with stable, high-capacity electricity and minimal risk of outages or disruptions.
Source: Powering possibility: Closing the clean energy for asia pacific data centers
Power Quality Becomes Critical: Even when sufficient energy is available, its quality becomes critical. Fluctuations, harmonics, and brief interruptions can disrupt AI and high-performance workloads. In fact, power-related issues are the leading cause of unplanned data center outages, highlighting why clean, stable electricity is essential to protect equipment, prevent downtime, and ensure reliable operations.
Souce:
How Power Quality Intelligence Can Drive Data Center Sustainability Efforts | Data Center Frontier
Annual outage analysis 2025 | Uptime Intelligence
The Reality: Poor Power Quality = Wasted Capacity + Higher OPEX
What are the Disadvantages of Poor PQ in Data Centers?
- Harmonics from non‑linear loads are widespread: With over 90% of a data center’s load coming from non-linear equipment, harmonics can build up quickly. Each device – from servers to cooling systems – adds its own “electrical noise,” distorting the overall power supply. This cumulative effect can stress equipment, reduce efficiency, and compromise the data center’s power quality.
Source: The hidden disruptor of data center harmony: Vol 1 - DCD
- Voltage sags and transients are common in data centers and can cause data errors and hardware damage. Voltage sag occurs when the supply voltage drops below 90% of the normal level for a few milliseconds, which can cause flickering lights, data errors, and storage losses, while transients are extremely brief overvoltages of up to several thousand volts that can damage power supplies and IT hardware.
Source: Siemens · Announcement · Power Quality for data centers
- Utility disturbances such as grid voltage and frequency fluctuations, are a key external cause of power quality issues that can disrupt data center operations and force increased use of backup systems.
- Costly downtime and data loss: Power quality issues are responsible for a large share of data center outages and can lead to data corruption and hardware failures that disrupt operations and incur costs.
- Business and reputational impact caused by unreliable service and reduced customer trust: Unplanned outages and performance issues due to poor power quality undermine service reliability and can harm customer confidence in data center providers.
- Reduced energy efficiency, leading to higher PUE and increased CO₂ emissions: Harmonics and voltage distortion increase energy losses and heat, which degrade efficiency and raise PUE, the industry’s key efficiency metric, with corresponding environmental impacts.
- Equipment and infrastructure degradation: Poor power quality increases electrical and thermal stress on both IT equipment (servers, storage, cooling systems) and electrical infrastructure (transformers, cables, switchgear), leading to failures and shortened lifespans.
Souces:
Costly Downtime & Reputational Damage: Annual outage analysis 2023: The causes and impacts of IT and data center outages
Equipment Failure: Behind some of the biggest data center challenges | Flex
How Can Power Factor Correction (PFC)
Reduce Harmonics and Improve Power Quality?
What is Power Factor Correction (PFC)?
- Power Factor (PF) measures how efficiently electrical power is being used.
- PF = Real Power ÷ Apparent Power
- A PF of 1 (or 100%) means all the power drawn from the supply is doing useful work.
- Power Factor Correction is the process of improving PF, so that more of the supplied power is actually used efficiently, and less is “wasted” as reactive power, and overall power quality in the system is enhanced.
Traditional Approaches of PFC
- Internal harmonic filters
- Integrated at the device level
- Reduce harmonics at the source
- Based on passive PFC designs
- Limited improvement to overall power factor
- External harmonic filters
- Installed at the circuit or electrical distribution level
- Reduce harmonics generated by multiple downstream loads
- Commonly based on passive PFC designs
- Can occupy significant physical space
- May add complexity to the electrical distribution layout
- It was recently reported by Schneider Electric that data centers using electronically commutated (EC) motors for their HVAC systems were found to have a very high harmonic signature, with total harmonic distortion of current (THDi) exceeding 40% at maximum load. This is very likely to be from passive PFC correction methods.
Source: Power Quality eGuide for Data Centers | Schneider Electric
In-built Active PFC
- In-built active PFC in EC fan by ebm‑papst
- Integrated directly into the fan’s electronics
- Improve power quality by reshaping current so it aligns with voltage, reducing harmonics at the source and minimizing reactive power draw
- Based on active PFC, enabling continuous correction across operating range
- Achieve power factors close to 1.0 and low THDI (typically ≤5%)
- Eliminate the need for additional external harmonic filters or oversized power supply components, simplifying installation
- Enable smaller and more cost-effective power infrastructure (e.g., transformers, cabling) due to cleaner current draw
Success Story:
In-built Active PFC Enables Energy & Space Savings
Retrofit to active PFC fans
When designing a data center, ebm‑papst 3-phase active PFC fans deliver measurable advantages in power quality and power factor compared to industry-standard solutions.
Standard fans generate higher voltage and current harmonics (THDU and THD(I)), which often require oversized transformers and emergency power generators to stay within permissible power quality limits. In contrast, 3-phase active PFC fans significantly reduce harmonic distortion and improve power factor, enabling a more efficient electrical system design.
As a result, data center operators can downsize transformers and generators while maintaining power quality compliance, leading to substantial overall system cost and efficiency benefits.