It's in the Tank: Strategies for Maintaining Standby Generators Powered by Biodiesel:

by Eric Plebuch

Introduction:

In a contemporary marketplace where a continuous source of electricity is less a convenience than a necessity, most businesses recognize the value of investing in an emergency generator set. Not only do these standby power systems allow companies to minimize costly instances of downtime by supplying electricity to critical loads when the grid goes down, they also power systems vital to employee and customer safety during an outage, such as lighting and HVAC units.

Due to the risks inherent in storing large quantities of natural gas, most companies with large critical and emergency loads opt for diesel standby generators over gas units. While a diesel generator can be instrumental in protecting a business from the staggering costs of a grid outage, any generator can fail if it is not properly maintained. Invariably, facilities managers are aware of this hazard, and they perform routine maintenance on their generators to minimize the risk of failure. Unfortunately,
many overlook the fact that generator fuel, like a generator itself, must be properly maintained.

While fuel maintenance is critical regardless of what type of diesel is being used, the introduction of biodiesel into the marketplace has made fuel maintenance particularly important. Not only is the shelf life of biodiesel significantly shorter than that of standard diesel, its innate properties can cause problems that lead to generator damage if precautions are not taken. But the most startling aspect of biodiesel that eludes the knowledge of many operators of standby generators is the simple fact
that biodiesel is already in their generator’s fuel tank.

Many states have begun mandating biodiesel use, requiring that all diesel fuel sold within the state contain a minimum percentage of biofuel. Diesel sold in the state of Oregon has contained no less than 2% biodiesel since the implementation of House Bill 3463 in 2009. Because the bill originally required a 2% biodiesel minimum but did not require dispenser labeling for mixtures containing less than 5 % biodiesel, many operators of standby generators were unaware of the fact that they were filling their fuel tanks with biofuel. While House Bill 3463 was recently amended to increase the biodiesel minimum to 5%, requiring dispenser labeling for all biodiesel sold within the state, many consumers are still unaware of the risks of using biodiesel in standby applications.

While biodiesel can cause problems with generator sets that are far less likely with the use of standard diesel, there are precautions that generator operators can take to protect their standby units.