Selecting Diesel Generator

A diesel generator is an electro mechanical machine that produces electricity. It comprises of a diesel engine coupled to an alternator. Its primary purpose is to provide power when the electrical grid is not available due to several factors (remote areas, grid stability, fault). Developing nations have grids that are not stable and as a result have a large requirement of diesel generators. Developed nations grid supply is generally stable and hence the applications are confined to areas such as critical power (hospitals, data centers, airports), commercial basis where loss of power will incur significant costs and remote areas (mines, communities) where grid supply is non-existent. Other applications include military, marine and telecom.

The following factors need to be considered when selecting diesel generator:

  • Application
  • Prime or Standby Power
  • Operating Conditions
  • Commercial impactThe ideal diesel generator would have the following features:
  • Reliability
  • High performance
  • Support
  • Efficiency
  • Durability
  • Competitive pricing
  • User friendly
  • Functionality

Today there is a large range of generator manufacturers in the market place producing high quality product to simpler low end product. For the purpose of this discussion we will define the range by the following categories:

  • Tier 1 – high spec custom build generators for severe environments and for prime power applications. Eg. mine site no grid, dust, high temperatures, continuous operation where loss of power will cause large financial costs.
  • Tier 2 – quality mass produced generators that can be used for prime power applications and critical standby. Eg. emergency power for high traffic airport.
  • Tier 3 – low end mass produced product for minimal operation in standby application. Price sensitive. Eg. Standby power to a local restaurant that operates under a reliable grid.

Tier 1 generators are manufactured by companies who are based locally. They will either modify tier 2 product or custom build a generator. Components used will be specific to the application reliable and have high levels of support. The end product will be able to meet the demands of the application. Pricing can be up to 5 times tier 2 product however provides the best return on investment.

Tier 2 generators are manufactured by large engine companies based in the US and companies operating in large markets such as China and Europe. The large engine companies are conglomerates with several divisions. Their generators come under their power generation division. Due to their structure they are limited on their ability to produce tier 1 product. Typical constraints are:

  • Company manufactured components must be used
  • Approved suppliers only
  • Mass produced
  • Design variations limited

Large manufacturers based in Europe and China are not tied to any particular brand of component given them scope to assemble diesel generators that meet the requirements of the majority of the market. Due to their large plants they have scalability and can acquire componentry at competitive pricing. Labor costs are lower than that of developed nations. The limitations of their resources restricts them from producing tier 1 product. Any variation from their typical designs increases faults being reported. Their pricing is generally 30% lower than US engine conglomerates.

Tier 3 generators are produced by companies based in China. They use replicated components of well-known brands. They are not build to any particular standard. Reliability is low and support out of China is non-existent. Procurers can be attracted by the low pricing these generators are on offer for. Pricing in general can be up to 40% lower than top tier 2 counterparts.In conclusion when selecting diesel generator it is important to understand the application and environment that it will be operating in. This will provide guidance on which manufactures should be consulted providing the best return on investment.


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