DIESEL & GAS ENGINE LIFE: Air Cooled generators have an engine life that is measured in 100’s of hours. With normal maintenance, Liquid Cooled Natural Gas and Propane units could last five to ten thousand hours. Our Industrial Quality Diesel generators will usually last a minimum of ten thousand hours with the Lister-Petter units routinely running thirty thousand hours before their first major service. Maintenance: Diesel fuel can store up to seven without breakdown by adding preservative additives on an annual basis. Diesel engines do not have a “spark” system and are more durable – yielding substantially lower maintenance and much higher reliability. Operating costs: diesel generators use about half as much fuel as the equivalent natural gas or propane powered generators. Diesel fuel can usually be purchased as “off highway” diesel without road taxes. Availability of Fuel: In the event of a major disaster such as an earth quake, the natural gas supplies are normally disrupted leaving your generator without a fuel supply! Diesel supplies are readily available even in the worst of conditions.