What is a typical life expectancy for a well maintained standby generating set?

The subject of life expectancy must always begin with; ‘It Depends’. A constructive and developed response now follows.

Scene setting Summary.

Following a survey of AMPS member companies, Twenty Five (25) years is considered to be the life expectancy of a generating set professionally installed and maintained at a professionally operated facility for the duty of providing power in the event of a mains failure. With an added proviso; that the total running time does not exceed sixteen thousand (16,000) hours.

Professional technical support expected.

There now follows a series of technical comments aimed at setting the degree of support and service expectations for achieving a 25 year life, followed by useful advice regarding bio-fuel and equipment selection.

The following listed conditions clarify what constitutes a professional service for a generating set package which has been carefully selected, installed, maintained and serviced under a set of specific conditions;

  • Installed within a temperature controlled brick building.
  • Note; Generating sets housed within Containers are often subjected to environmental conditions which expose all the incorporated components to high humidity, dampness and less well controlled residual temperatures, all of which are known to reduce electro-mechanical equipment’s life expectancy. Furthermore, these units are often provided with a lower level of maintenance and service care sometimes due to an administrative oversight, or because of limited access to key components which adversely affects a thorough maintenance regime.
  • The generating set has a service contract, which includes routine inspection and replacement of consumable items.
  • The complete power house and its contents are covered by a maintenance contract.
  • The equipment is routinely tested against a load bank for a duration which raises the engine coolant to the normal-rated operating temperature.
  • There is a battery condition monitoring system and a regular (ideally 3yr) replacement scheme.
  • There will be a programme in place to inspect/replace any component/assembly which is deemed to have a limited service life, examples being:
  • Rolling Element Bearings,
  • Flexible Coupling Rubbers,
  • Component inspection requiring the Engine cylinder head to be removed (not expected if running time is <16,000 hrs.)
  • Exhaust system sections subjected to the local external environment,
  • Switch-gear components wear assessment – counter for the number of closing operations.

Technical comment regarding the need for a regime to be added to all service and maintenance routines brought about by the introduction of biodiesel and ultra-low sulphur fuel (January 2012).

Biodiesel is now the norm. It is often referred to as B7. This indicates it has 7% content of fatty acid methyl ester (FAME). Unfortunately, today’s biodiesel has unwelcome side effects. It is known to attack the fuel system seals and pipes of older diesel engines. It has greater oxidation which over time can work to loosen solids within a fuel system which then rapidly block filters, or collect and block small openings in the fuel delivery system. It promotes a bacterial growth/contamination in fuel tanks, particularly if water/moisture is present in that tank. Worst of all it has an advised life expectancy, which means a fuel turnover policy must be in place every six (6) months at best and definitely before twelve (12) months, has elapsed.

Various companies offer specialist fuel treatment equipment along with additives and a technical advice service.

AMPS Member Companies offered the following advice regarding specifying component content within a power generation package which is expected to achieve a 25 year life. A list of AMPS Members may be found on the AMPS website

This concerns the obsolescence of spares and technical support for major gen-set components. Today the obsolescence is often associated with control systems. Many old control systems operate with a mechanical or electronic topology which has long since been superseded.

Unfortunately, this trend will always continue, but ensuring the generating set has a control system designed and manufactured by an established company based in a country with a stable background for manufacturing technical equipment will hopefully ensure a responsible approach will always be present and available for Customer Support throughout the life of the generating set. This same policy should be applied to the specified acceptable manufacturers for the engine and the ac generator, where major bespoke components as a spares item will be available or an upgrade fix will be a tried and tested route.