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Calculate Size of Diesel Generator (MS Excel Spreadsheet)
Calculate Size of Diesel Generator (MS Excel Spreadsheet)

Size of Diesel GenSet

This spreadsheet intend to calculate size of needed diesel generator according to the following input parameters:

  1. System Voltage ( P-P ) in Volts
  2. System Voltage ( P-N ) in Volts
  3. Future Load Expansion in %
  4. Average Intermittent Use of Equipment (0.7 To 1.0)

You are about to enter following information for each consumer you have in your consumption calculation:

  1. Equipment (name)
  2. Load Type (linear, non-linear or motor)
  3. Supply (1ph or 3ph)
  4. Qty (num.)
  5. Load (in kW)
  6. Starting P.F
  7. Running P.F
  8. Diversity Factor
  9. Motor Starter (Dol, Y-D, auto-transformer, soft starter or frequency converter)

Calculated results consist of:

  1. Size of Diesel GenSet for linear, Non-linear Load
  2. Size of Diesel GenSet for motor load
  3. Diesel GenSet Efficiency
  4. UPL (unit per liter) of Diesel GenSet
  5. Unit power cost of Diesel GenSet
  6. Approximate fuel consumption
Software:Calculate Size of Diesel Generator (MS Excel Spreadsheet)
Version:22.08.2012 New
Developer:Jignesh Parmar
Size:138 Kb
Download:Right here | Video Courses | Membership | Download Updates
Calculate Size of Diesel Generator (MS Excel Spreadsheet)
Calculate Size of Diesel Generator (MS Excel Spreadsheet)

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More Information


  1. John Galuak Koat
    Mar 05, 2023

    It is helpful to me as an electrical engineer

  2. suram2524
    Nov 30, 2022

    Cannot be downloaded.

  3. Joseph Mwapinga
    May 05, 2022

    I’m happy to have professional discussion related to Power

  4. Swapnil Linge
    May 22, 2021

    Want to know the standard / reference used for DG sizing calculation and criteria to be followed.

  5. Fermin
    May 11, 2018

    Hi guys.
    I am thinking to star a 3 phase motor 75 kw, 460 VAC with a Diesel generator (144 HP rated ), 460 VAC using a soft starter.
    Sombody can help me if this is posible?

  6. mina
    Apr 08, 2018

    hey guys

    how can i calculate the Diversity Factor in a utility with 3 3ph motors that are working simultaneously?

    • Mansour Essaïh
      Oct 24, 2020

      Better late than never.
      The 3 mortors are working simultaneously, so the diversity factor Kd = 1 (*)

      If ypu want to estimate the energy consumption per day, you have to use loading factor or utilization factor generaly = 0.80. But if you know the power absorbed by the machine driven by the electric motor, then, the utilization factor Ku = Machine power/Nominal motor power.

      The global factor Kg = KdxKu.

      If Ku = 0.8, then Kg = 1×0.8 = 0.8.

      If the unit nominal power of your motors is Pn = 22 kW, the total power absorbed is : 3×0.8x 22 = 52.8 kW.

      If your 3 motors work 8 hours per day, then the energy consumed per day is : E = NxKgxPnxt = 3×0.80x22x8 = 422.4 kWh.

  7. vijay
    Feb 08, 2018

    Calculations shown for DG sizing is having minor errors, starting KVA is multiplied twice.

  8. ahmed emara
    Nov 10, 2016

    Hey guys

    now I have 1200 ekw generator with fuel consumption 333 l/hr and I need to calculate the efficiency of that generator set

    is the efficiency subjected to the following equation ?:
    Qin =Wout+Qrej

    Then ᶮ ( efficiency ) = Wout/ Qin .. Wout = 1200 Kw
    Where Qin = m°f *Cvf
    Cvf ( for diesel) = 46000000 j/kg
    ρ= 850 Kg/m³
    But the result was not good
    ᶮ = about 33.17 %

    kindly advise me


  9. John Alias
    Mar 10, 2016

    can anyone please send the detailed calculations and formulas used in this spreadsheet?…it would be really helpful
    Thank you

    Oct 19, 2015

    What is the difference between Average Intermittent Use and Diversity Factor ??

  11. Faihan
    Aug 24, 2015

    Good Job
    How do I add the Air Conditioning units? Are they linear or non? I only know the ton value of each.
    And, What is the correct connection for single phase ACs and lights? Is it Y-D?
    I also have a three phase 60 HP submersible pump that sucks 150 Amps on each phase to start and then goes to 90 Amps to run. Your sheet says that the full load Amps is 38 while I see on the DG display 90 Amps on each of the three phases.

  12. abel
    Jul 29, 2015

    What about considering non linear loads in %age of total load in sizing? The limits of such loads govern sizing if exceeded. Any international standards talks about this in sizing the Genset? How it will be applied in the calculation?

    Apr 27, 2015

    Consider a case where EDG is to be started on to a distribution transformer.How to size the DG set then?

  14. sriram
    Apr 12, 2015

    we have total load in kw .how do we arrive at genset capacity??/

  15. devadath.g
    Jul 21, 2014

    How can we conduct the load test of DG set at site?

  16. Ahmed
    Dec 18, 2013

    Engine overload is 10% only not 130 to 150%.

    It is depend for Standby application or Prime or base load .
    It is better to check and alternator efficiency is about 93 to 96

  17. eleng2007
    Oct 09, 2013

    how to calculate the required daily / monthly fuel tank of generator?

    • Edvard
      Oct 09, 2013

      Hooh, sounds very interesting, but I wouldn’t know really. I guess that eash manufacturer has its own manual or guide you should follow.

      Anyway, your question’s answer depends on how many hours generator will work.

      • Adrian
        Nov 23, 2014

        Edvard, Can I get a password to unprotect the spreadsheet?

  18. srikanth.shanky
    Aug 13, 2013

    Wonder that the starting power factor of the motor assumed to be as 0.8 is correct.Normally the value may be 0.2-0.3.The pf at 80% of speed during starting may be 0.6.Moreover the highest rated motor starting with base load and as well as voltage drop need to be considered for DG sizing.
    Your feedback please.

  19. partoshal
    Mar 25, 2013

    I’m not able to download this item. Please guide me.
    Thanks a lot

    • Edvard
      Mar 25, 2013

      Link works quite well, I double checked. Maybe you’re having problems with on your side?

  20. Mahesh
    Feb 26, 2013

    I’m not able to download this. I also tried to download other sheets some time back but faced the same problem.
    Please suggest.

  21. JaymzSchmerzen
    Jan 23, 2013

    Real useful.. Double checked my calcs =)

    Thanks a lot

  22. Jerome
    Jan 14, 2013


    How accurate the spreed sheet is? this have been tested on site?


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