Most people think of data centers as highly controlled environments—full of blinking lights, air conditioning, and redundant systems designed to keep everything running no matter what. But there’s one common weak spot that gets overlooked far too often: fuel quality in the backup generators.
In 2025, research indicates that over 90% of medium and large enterprises report losses exceeding $300,000 per hour of downtime. In high-risk environments like data centers, that makes backup power absolutely non-negotiable. And yet, generators still fail frequently. One of the top reasons? Dirty, degraded, or contaminated diesel fuel.
Let’s talk about why it happens, what it costs, and how fuel polishing in a data center can keep your data center out of downtime.
Why Generators Fail?
Diesel generators are critical for data centers. When the grid goes down, they’re expected to kick in within seconds and carry the full load without hesitation. However, diesel fuel isn’t static, it changes over time. And that’s where the problems start.
Water contamination is one of the primary reasons that enters tanks through condensation or poor seals. Once it’s there, it creates the perfect environment for microbial growth—what some technicians call “diesel bug.” The byproduct is sludge. Sludge clogs fuel filters and lines. That alone can stop a generator from running.
Particles and sediment build up over time as well—rust from tank walls, dust from air ingress, and other contaminants that settle and spread. And then there’s oxidation, which happens when diesel ages. It thickens and breaks down, turning gummy and unstable.
All of these issues can lead to something you never want to deal with in a crisis: your generator failing to start, or worse, shutting down mid-run.
The High Cost of a “Small” Problem
This isn’t just about inconvenience. It’s about real business impact. A recent study found that 54% of major data center outages in 2025 resulted in losses exceeding $100,000, with nearly one in five exceeding the $1 million mark.
And many of those were caused not by storms or hardware faults—but by failed generators that hadn’t been properly maintained, or had been running on contaminated fuel. It’s not hard to see the pattern: you can have the best generator money can buy, but if the fuel feeding it is compromised, the whole system is at risk.
How Fuel Filtration Solves the Problem?
Fuel filtration—especially when paired with an efficient fuel polishing system—helps ensure the diesel in your tanks stays clean, dry, and ready to use.
Here’s what a good filtration system actually does:
- Removes water before microbial growth or corrosion happens
- Traps particulates before they reach engine components
- Circulates and filters stored fuel on a regular schedule
- Extends the usable life of diesel so you’re not wasting fuel or risking poor performance
With the right setup, you’re not just fixing problems—you’re preventing them. And in a world where the average cost of a serious outage is so high, prevention becomes more essential.
How to get started in your facility?
If you’re responsible for a data center, here are a few practical steps you can take:
- Test your stored diesel fuel regularly – Contamination often goes unnoticed until the generator fails. Don’t wait that long.
- Invest in a quality fuel filtration or polishing system – It pays for itself the first time your generator starts up flawlessly during a power cut.
- Include filtration into your maintenance routine – It’s not just about equipment; fuel needs the clean-up, too.
- Train your team – Ensure that the facilities staff and operators understand how fuel degradation works and how to identify warning signs.
The bottom line
Even if you’ve got the best backup generator, it can’t help if the fuel running it is unstable or full of sludge. Fuel filtration isn’t just a technical upgrade—it’s a critical part of protecting uptime and avoiding costly outages. If your data center relies on diesel backup power—and most do—it’s worth asking yourself a simple question: Is your fuel as ready as your equipment? If you’re not sure, it’s time to find out.
Contact Njord Filtration today to learn how the best fuel polishing system for data centers can keep your generators running smoothly when it matters most.