Blue Star Power Systems · Diesel Product Line (Mitsubishi)
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Blue Star MD1250-01
1250 kW standby · Diesel · Liquid-cooled
1,250 kW EPA Tier 2 diesel standby generator from Blue Star Power Systems. Mitsubishi S12R-Y2PTAW-1 49L V12 engine with medium-voltage 4160V output for large industrial and data center loads.
The Blue Star MD1250-01 is a 1,250-kilowatt EPA Tier 2 diesel standby generator and one of the larger units in Blue Star's catalog. It is built around the Mitsubishi S12R-Y2PTAW-1 — a 49-liter V12 turbocharged-aftercooled diesel rated approximately 1,881 HP at 1800 RPM. This is a serious industrial-scale machine, intended for large data centers, hospital main-backup at major medical centers, manufacturing plants with critical process loads, and paralleling arrays where multiple 1,250 kW units are tied together to provide multi-megawatt backup.
The "-01" suffix marks this as the Tier 2 unit, appropriate for stationary emergency standby in jurisdictions where Tier 2 is still permitted. Tier 4 Final variants exist in adjacent sizes for prime / non-emergency duty.
Mitsubishi's S-series industrial diesels — particularly the S12R, S16R, and the larger S20-series — anchor the megawatt-class genset market alongside Caterpillar 3500-series and Cummins QSK engines. Reasons the S12R is widely chosen at this kW class:
Proven heavy-duty design — long stroke, modest mean piston speed, conservative thermal loading
Single-engine 1.25 MW rating — simpler than paralleling two 600 kW units, lower installed cost for kW
Mature service literature and global parts availability through Mitsubishi's industrial channel
Marine and locomotive heritage — duty cycle margin well beyond stationary emergency standby requirements
1,250 kWe single unit is appropriate for a hospital main backup at a 200+ bed facility, a 1-2 MW data center hall, or a large industrial process load
Paralleling-ready when configured with the Basler DGC-2020HD and switchgear — Blue Star uses this engine in N+1 / N+2 architectures at multi-MW critical sites
Fuel storage scales with runtime requirements; 24-hour to NFPA 110 Class 96 (96-hour) sub-base tanks are routinely specified
We have less direct field experience with Blue Star's largest units in our Northern California territory than with Cat or Cummins at this kW class — the dealer footprint differs. That said, the Mitsubishi S12R is a platform we know from MTU and other integrators, and parts and service procedures are essentially identical regardless of who packaged the genset. The main consideration is logistics: a 1,250 kW unit is a 30,000+ pound rigging operation, so install planning and access matter more than serviceability differences between OEM packages.
Engineering specifications
Physical
Length
220 in
Width
95 in
Height
112 in
Dry weight
27,375 lb
Acoustic
Sound @ 7m, full load
91 dBA
Enclosure
Open
Fuel system & runtime
Fuel use @ full load
103 GPH
Fuel use @ 75% load
75.1 GPH
Fuel use @ 50% load
51 GPH
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Get pricing & lead time on the Blue Star MD1250-01
Tell us about the application — kW, voltage, application, install timeline — and we'll respond within one business day with budgetary pricing, lead time, and any sizing notes.
Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.
Estimate runtime on this tank
Estimated runtime
2.5 hours(0.1 days)
Fuel consumption ≈ 79.46 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.
Frequently Asked Questions
What engine is in the MD1250-01?
The Mitsubishi S12R-Y2PTAW-1 — a 49.0-liter (2,992 cu in) V12 turbocharged-aftercooled diesel rated approximately 1,881 HP (1,403 kWm) at 1800 RPM. The S12R series is one of Mitsubishi's flagship industrial diesel platforms and is used by multiple genset OEMs in the 1.0-1.5 MW range. The PTAW suffix denotes the prime / standby tuning with water-to-air aftercooling.
Why a Mitsubishi engine instead of Cat or Cummins at 1,250 kW?
Mitsubishi's industrial engines compete on price-per-kW and reliability in the megawatt class. Caterpillar 3500-series and Cummins QSK60 are alternatives in this size range, with Cat carrying the dealer-network advantage in North America. Mitsubishi's value proposition: comparable build quality at a more competitive price point, with a track record in marine and industrial duty going back decades.
What is the typical fuel-tank sizing for an MD1250-01?
Blue Star packages this unit with sub-base tanks scaled to runtime requirements — 24-hour to 96-hour configurations are standard. At full-load fuel consumption of 103 gph (per the OEM spec sheet), a 24-hour tank is approximately 2,500 gallons; a 96-hour NFPA 110 Class 96 tank is approximately 10,000 gallons. The 75% load figure is 75.1 gph, which is the more typical sizing basis for real-world load profiles.
Does the MD1250-01 support medium-voltage output?
Yes — 4160V output is available on this unit. At 1,250 kWe, the full-load amperage at 480V is around 1,880 A, which drives heavy conductor and breaker requirements. Stepping the alternator output to 4160V reduces the conductor size dramatically and is standard practice for large industrial and data center installations on a medium-voltage distribution bus.