Natural Disasters & Selecting Your Generator Fuel Type

We are sometimes asked what precautions to take when selecting a standby generator, given the possibility of an earthquake.

The mid-south area is in close proximity to the New Madrid fault line with an epicenter in northeast Arkansas.  There were two earthquakes in December, 1811 and two more followed  in early 1812, each with a magnitude of 7.0 or greater.  Ground shaking in the Memphis area was ranked IX or, “violent”, on the Modified Mercalli scale.   A quake of similar magnitude could cause moderate to severe damage to substantial buildings, with a possible partial collapse.  Some buildings may be shifted off foundations.  Walls could fall down or collapse.

Below is a USGS mapped probability of an earthquake with magnitude of 5.0 or more within 100 years.  Northeast Arkansas, southeast Missouri, and northwest Tennessee have the greatest potential with probabilities approaching 40%.


Memphis will certainly feel a major quake with results varying based upon the magnitude.

So—if you’re considering a standby generator for your home or business, two questions one might have include, “What services might be impacted?” and “What factors should I consider before purchasing a standby generator?”

What services might be impacted?

A minor earthquake will result in rattled nerves but, most likely, minor damage.  In a moderate to severe quake, expect widespread power outages and disrupted fuel lines.  The fire marshal might order natural gas lines be shut down as a fire preventive measure.  Bringing natural gas lines back on line could vary from a few days to several months, depending upon earthquake severity and whether gas lines were damaged or broken.

Understanding the Different Generator Fuel Types

Most folks purchase a standby generator due to frequent power outages in their neighborhood or in preparation for extended outages due to ice storms, tornadoes and straight-line wind storms.  There are those who are also concerned about the potential of an earthquake with many thinking the odds are increasingly favorable over the next 50-100 years.

Most residential standby generators are fueled with natural gas.  The same generator can operate on liquid propane vapor.  Switching from natural gas to LPV may or may not require additional parts from your generator manufacturer.  Consult your dealer for details.

Two generator manufacturers, Cummins and Kohler, offer dual-fuel generators.  A dual-fuel generator has two fuel regulators, one for natural gas and the other for LPV.  Natural gas is considered primary and LPV is secondary.  If natural gas lines go down, a dual fuel generator will automatically switch to LPV.

Don’t confuse the term “dual-fuel generator” with generators that can be fueled from natural or LPV.  A true dual fuel generator accepts two independent gas lines, one being NG and the other LPV.

Some folks don’t like the idea of having a propane tank sitting out in their yard.  Smaller 130-gallon propane tanks sit upright and look much like a hot water heater.  Larger tanks can be buried in your yard to eliminate the unsightly view.

A diesel generator is another option to consider if you are concerned about the potential of a major earthquake event.  Diesel generators have a built-in subbase fuel tank and there are a few Memphis-area diesel fuel providers that will deliver and fill your tank periodically.  Expect to pay a premium for a diesel engine.

Last, generator manufacturers do offer seismic-certified generator systems, however. most residential generators are not seismic-certified.  You will need to consider an industrial generator for seismic certification.

If you like the idea of having a true “Dual-Fuel Generator” but you’re not quite ready to install a propane tank, consider ordering a generator with dual-fuel capability.  You can always add the second fuel line at a later date.  Cummins liquid-cooled generators are dual-fuel configured while Kohler Generators offers dual-fuel configuration as an option.  If you want a Kohler Generator configured as dual fuel, it is important to order the generator with the option installed at the factory.  Retrofitting an existing unit can become an expensive project.

For more information or questions concerning standby generators or earthquakes, as they relate to standby power, feel free to call us at 901-379-8097.