Fuel Polishing for Diesel Standby Generators: The Real Story Behind Dirty Diesel Fuel

Claire Webb •

You may have had a backup generator in service for many years, but did you know that half of all generators will fail to start at some point during their lifetime because of fuel contamination.

Over the years working for Vertiv, I, unfortunately, have witnessed the catastrophic impact that companies face when they experience a power failure and their generators have failed to start. 

As discussed in the recent Critical Industries Report, a power failure can mean much more than a slight inconvenience or loss of trade, it can mean a loss of aircraft communication or literally a matter of life or death for those on the operating table or in critical care.

Fuel starts to degrade pretty much as soon as it’s delivered. It can become contaminated with water or rust particles from the storage tank.  It can also suffer from microbial infestation, especially if there is any water present as it provides a good medium for the microbes to flourish.  Contamination of fuel can lead to generator malfunction due to blocked engine filters, and worst cases, your generator will not start thereby leaving you without backup power.

Fuel polishing removes water and sediment in a backup generator without having to start it up.  This not only keeps fuel in optimum condition but could prevent a minor emergency becoming a major one.

The benefits of fuel polishing

  • Reduces the risk of losing power during a crisis by improving continuity, efficiency and resilience of your generator.
  • According to Allianz, even a 30-minute power cut results in an average loss of £12,000 for a medium-sized company. They also estimate that blackouts in the US add up to £124 billion as an annual estimated economic loss.
  • Avoids the cost of fuel replacement and disposal which on an average size fuel tank you could save up to 75% just by polishing.
  • Maintain your company’s reputation and avoid loss of trade.  78% of customers do not follow through with purchases because of poor service, and 59% of consumers would try an alternative supplier for better service (HelpScout)
  • Helps reduce your carbon footprint by lowering harmful emissions.


Fuel polishing is critical to prevent loss of power from poorly maintained fuel. Fuel polishing should be carried out in conjunction with regular preventative maintenance visits to ensure the optimal condition of your standby generator. If you want to learn more about our generator maintenance service, take a look at our e-guide and complete our contact form so we can help you today.

Don’t wait until the lights go out! 


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