How to Keep Your Backup Generators Fuelled and Ready

A backup generator is only as reliable as the fuel sitting behind it. You can invest in the best standby power on the market, but if the diesel in the tank has run low, degraded, or grown contaminated while the generator sat idle, that investment fails you at the exact moment you need it most. For any operation where downtime is not an option, fuel readiness is not a detail. It is the whole game.

The challenge with backup power is that it spends most of its life doing nothing. Fuel can sit for months between run cycles, and stored diesel does not stay in perfect condition on its own. Getting it right means storing enough fuel for a real outage, keeping that fuel clean and usable, and doing it all safely and compliantly. Durotank builds the storage that makes this possible, from compact units through to large self bunded fuel tanks built for permanent standby installations.

Here is how to make sure your generators are ready to run the moment the grid goes down.

What Does It Take to Keep a Backup Generator Ready?

Keeping a backup generator ready comes down to four things. You need enough stored fuel to cover your required runtime, fuel that stays clean and stable during long idle periods, safe and compliant storage that protects your site, and a way to monitor levels so you are never caught short. Get those four right and your standby power will start and keep running when it matters.

Let us break each one down.

1.  Store Enough Fuel for a Real Outage

The first question is simple. How long does your generator need to run without a refill, and does your tank actually hold that much?

Size Your Fuel to Your Required Runtime

Work out your generator’s fuel consumption per hour at load, then multiply it by the number of hours you need to stay powered through a worst-case outage. A short grid interruption is one thing, but a major event can leave a site without mains power for far longer than expected. Your storage should cover that scenario with room to spare, not just an average day.

Factor in Delivery Time

During a widespread outage or natural disaster, fuel deliveries slow down and demand spikes. The whole point of on-site storage is that you are not relying on a tanker arriving quickly. Size your tank so you can ride out the outage and still have a buffer while you arrange a resupply.

Match the Tank to the Install

For a permanent standby installation, a fixed self bunded fuel tank gives you high capacity with built-in spill protection. For smaller or distributed setups, more compact storage may suit better. The right choice depends on your generator size, your runtime target, and your site.

2.  Keep the Fuel Clean and Usable

This is the part that catches operations out. Fuel that has sat unused for months is not the same fuel you put in the tank. Diesel degrades over time, and a neglected tank can quietly turn your fuel into a problem.

Understand How Stored Diesel Deteriorates

Left unmanaged, stored diesel slowly changes. Water works its way in through condensation, sludge forms, and microbial growth known as diesel bug can take hold and clog filters and injectors. When the generator finally starts, contaminated fuel can choke it right when you are depending on it. The guide on what diesel bug is and how to stop it explains the problem and how to prevent it.

Turn Your Fuel Over and Keep It Dry

The best defence is good storage and a bit of routine. A well-sealed tank limits water ingress, and using and refreshing your fuel rather than letting it sit indefinitely keeps it in condition. For longer-term standby fuel, periodic fuel testing and polishing keeps it ready to burn. These habits sit alongside the wider best practices for long-term fuel storage efficiency.

Choose Storage That Protects Fuel Quality

A quality tank is part of the answer. Durable, well-designed storage keeps contaminants out and makes inspection and maintenance straightforward, so your backup fuel is always in a state you can trust.

3.  Store It Safely and Stay Compliant

A permanent fuel installation for backup power carries the same safety and environmental obligations as any other bulk storage, and often more scrutiny because these sites are frequently in built-up or sensitive locations.

Contain Any Leak With Self Bunded Design

A self bunded tank has a double-wall design that captures any leak in an outer containment layer before it can reach the ground. For a generator tank sitting permanently on site, often near buildings, drains, or the public, that built-in protection is exactly what you want. It also makes approvals and inspections far simpler.

Meet Australian Standards

Aboveground fuel storage in Australia is governed by standards such as AS1940 and by state environmental rules. Durotank tanks are built to comply with and exceed these standards, so the storage itself is not where your compliance risk sits. If you want the detail, the article on staying compliant with Australian fuel storage regulations covers what applies.

4.  Monitor Levels So You Are Never Caught Short

The final piece is visibility. A backup fuel system you cannot see into is a risk you cannot manage.

Know Your Fuel Level at All Times

Because standby fuel is used irregularly, it is easy to lose track of exactly how much is in the tank until you need it. A fuel management system gives you accurate level monitoring and records, so you always know your readiness and can trigger a top-up well before you run low.

Build Refuelling Into Your Routine

Treat your backup fuel like any other piece of critical infrastructure. Regular checks of level and condition, tied to your generator maintenance schedule, mean there are no surprises when the power drops.

Who Relies on Backup Fuel Readiness Most

Standby power matters to many operations, but for some it is mission critical.

• Data centres. Continuous uptime is the product. Backup fuel readiness protects against outages that could take services offline.
• Hospitals and healthcare. Standby power keeps life-critical systems running, so fuel that starts and sustains the generator is non-negotiable.
• Network and tower sites, often remote, depend on reliable standby fuel to stay connected during outages.
• Water and utilities. Pumping and treatment cannot simply stop, making dependable backup fuel essential.
• Agriculture and cold storage. Farms and facilities protecting perishable stock rely on generators to prevent costly losses during a blackout.
• Remote and off-grid sites. Where mains power is limited or absent, stored fuel keeps generators, and the whole operation, running.

Make Sure Your Standby Power Is Ready With Durotank

Backup power is an insurance policy, and fuel readiness is what keeps that policy valid. Store enough fuel for a genuine outage, keep it clean and stable, protect your site with compliant self bunded storage, and monitor your levels, and your generators will be ready every time the grid is not.

Durotank has been designing and manufacturing Australian-made fuel storage for 20 years, and the team can help you match a tank to your generator, your runtime, and your site. Explore the full range of self bunded fuel tanks or see the options built for reliable generator fuel storage.

Do not leave your standby power to chance. Get a quote today or call the Durotank team on 1300 829 802 for expert advice on fuel storage for your generators.

Fast turnarounds. Australian Made. Built tough, Proven tough.

FAQs

How much fuel should I store for a backup generator?

Base it on your generator’s fuel consumption per hour at load, multiplied by the longest runtime you need to cover during an outage, then add a buffer for delivery delays. On-site storage should let you ride out a worst-case event without waiting on a tanker. The Durotank team can help you size a tank to your runtime target.

Does diesel go bad in a backup generator tank?

Yes. Diesel that sits unused for months can degrade as water enters through condensation, sludge forms, and diesel bug takes hold. This contamination can stop a generator from running when you need it. Good sealed storage, fuel turnover, and periodic testing keep standby fuel usable.

Do I need a self bunded tank for a generator installation?

For most permanent standby installations, yes. A self bunded tank provides built-in secondary containment that captures leaks before they reach the ground, which is important for tanks sited near buildings, drains, or the public. It also simplifies approvals and inspections.

How do I know when my backup fuel is running low?

The reliable way is level monitoring. A fuel management system gives you accurate, ongoing visibility of your tank level and records, so you can arrange a top-up well before your standby fuel runs short rather than discovering a problem during an outage.

Which industries depend most on backup generator fuel?

Data centres, hospitals and healthcare, telecommunications, water and utilities, cold storage, agriculture, and remote or off-grid sites all rely heavily on standby power, and therefore on fuel that is ready to run at a moment’s notice.