Enter your continuous load and duty to size the genset units at ~75% load (with N+1), the ATS, fuel tank and enclosure — plus daily fuel OPEX and a complete BOM.
Diesel gensets run best at 70–80% load. The calculator picks a standard unit (500–2000 kVA) so the running sets sit at ~75% load, adds an N+1 standby set, and sizes the ATS, fuel storage and 20/40 ft enclosure from your autonomy days.
1200 kW Prime Diesel Station (Containerised, N+1)
Example 1 — 1200 kW Prime Diesel Station (Containerised, N+1) · FOB $6,480
Synchronisation & paralleling:Each genset closes onto the common bus through an auto-synchroniser that matches voltage, frequency and phase angle before the breaker closes (sync check relay ANSI 25). After paralleling, isochronous governors share active load (kW) and AVR droop sharing balances reactive load (kvar).
Load factor:Diesel gensets run most efficiently and with least wet-stacking at 70–80% load. The unit count is sized for ~75% load per running set; N+1 adds a standby set for maintenance rotation and peak redundancy.
Load sharing strategy:Active (kW) load sharing via isochronous governor + load-share lines; reactive (kvar) sharing via cross-current compensation or droop. The PLC/GB cabinet arbitrates start/stop sequencing and sheds non-critical feeders on overload.
Duty class:Prime duty: continuous rated output, unlimited hours. Duty class affects permissible load and service interval.
Pricing basis:Genset priced per unit from the diesel-generators reference (FOB Qingdao); ATS from ats-transfer-switches. Paralleling cabinet, enclosure/container, fuel system, cabling, silencing and civil works are quoted per project (POA).
Fuel estimate:Fuel consumption assumes ~0.25 L/kWh at 75% load (typical 180–220 g/kWh, diesel density 0.84). Fuel price $0.9/L is illustrative; confirm local delivered price.
Noise attenuation:Containerised sets target ≤75 dB(A) at 1 m via acoustic enclosure + inlet/outlet attenuators; residential/urban sites may require ≤65 dB(A) and a critical-grade silencer on the exhaust stack.
Design review:This is a preliminary sizing. A licensed engineer must verify short-circuit rating, synchronising controls, ventilation and exhaust routing, and local emissions/noise regulations.
How it was calculated
Core formulas
Apparent load = kW ÷ 0.8 (pf). Running units = ceil(kVA ÷ (0.75 × unit kVA)). Fuel ≈ 0.25 L/kWh at 75% load; tank = daily fuel × autonomy days.
The calculator keeps each running set at ~75% load (best efficiency, least wet-stacking) and adds one standby set under N+1 for maintenance rotation and peak redundancy.
Containerised or machine-room?
Containerised is a factory-assembled, weatherproof 20/40 ft package that ships and commissions fast. A machine room needs civil works but suits very large or permanently-installed stations.
How is the fuel tank sized?
From ~0.25 L/kWh at 75% load: daily consumption × your autonomy days. The calculator reports both daily consumption and tank volume.
Which items are priced in the BOM?
Gensets (per-unit) and the ATS are priced from the catalogue. The paralleling cabinet, enclosure/container, fuel system, cabling, silencing and civil works are quoted per project.
Embed this calculator
Copy the iframe code below to embed this calculator on any site. The embed page is noindex and fits any width.
Results are engineering estimates for reference. Final design must be confirmed by a licensed local engineer against site conditions and applicable codes. Prices are FOB Qingdao (EXW) and do not include freight, duty or installation.
Send my complete design report
Get the full bill of materials, single-line diagram, calculation steps and FOB pricing as a PDF — free, no sign-up.
Your data stays private. No spam — only a reply to your enquiry.