Solar Turbines Mars 90

9,450 kWe generator set; many surviving units predate SoLoNOx and need retrofit to permit

Solar Turbines Mars 90 is one of 21 gas turbines tracked in the SecondWatt catalogue, each with specifications, lead times and indicative secondary-market pricing.

Solar Turbines Mars 90 dossier: verified 9,450 kWe generator-set rating, SoLoNOx emissions history, overhaul economics, and pricing for data center buyers.

The Solar Turbines Mars 90 generator set is rated 9,450 kWe ISO at generator terminals, not the 9,860 kW / 13,220 hp mechanical-drive figure Solar's marketing leads with, about 4% higher. What decides siting, before price enters the conversation, is combustion hardware and vintage: SoLoNOx did not exist before 1992, fifteen years after Mars 90's 1977 introduction. Both dated used units found here were built in 1989, three years too early for SoLoNOx, whose original guarantee was only 42 ppmvd NOx / 50 ppmvd CO, above today's 9/15 ppmvd warranty. A pre-SoLoNOx unit is not automatically unusable: regulators permitted three Mars 90 units at a Carson, CA digester-gas plant on water injection plus SCR, tested at 19.3-21.5 ppmvd NOx under a 25 ppmvd limit. Mars 90 and Mars 100 share one twin-shaft architecture, not two machines, under one Solar package specification. Mars 100 (11,350 kWe) is Solar's current new-build PG product; Mars 90 has no current PG page and is now secondary-market/exchange inventory only. A Mars 100 is not a drop-in for a Mars 90 footprint, and a Mars 90 against a Mars 100 requirement undersizes it. Solar's generic Power Uprate program claims up to 20% output gain, which applied to 9,450 kWe reaches roughly 11,340 kWe, near Mars 100's rating — inference, not a named conversion product Solar advertises.

Why it matters

Before price enters the conversation, get the combustion hardware type and vintage in writing: SoLoNOx did not exist before 1992, fifteen years after Mars 90's 1977 introduction, and both dated used units found were built in 1989, three years too early to have it from the factory. Original-vintage SoLoNOx was only guaranteed under 42 ppmvd NOx, not today's 9 ppmvd warranty. That fact, not hours or price, decides whether a used Mars 90 is usable at a site at all.

Who buys it

Data center developers and EPCs assembling multi-unit distributed-power blocks buy Mars 90 generator sets alongside its historical core market of oil and gas producers and industrial cogeneration hosts. Solar's own Pre-Owned Equipment Program lists Mars 90 directly for brokers, resellers, and secondary-market buyers, not only original purchasers. Buyers evaluating a Mars 100 requirement also shop Mars 90 as a lower-output sibling built on the same core architecture.

Role in the data center

Bridge or prime power block in the 7-9.5 MW-per-unit range, sized in multi-unit configurations, gated by combustion-hardware vintage and permit path rather than by output alone.

Key specifications

Technical summary

ISO electrical output (generator set): 9,450 kWe Generator-set heat rate: 11,300 kJ/kWe-hr (10,710 Btu/kWe-hr) Mechanical-drive shaft rating (different product): 9,860 kW / 13,220 hp Exhaust flow / temperature: 144,585 kg/hr / 465 C (870 F) Pressure ratio: 16.3:1, 15-stage axial compressor Gas-producer / power-turbine max speed: 11,170 / 9,500 rpm Generator shaft speed (as fielded, 60 Hz): 1,800 rpm SoLoNOx: optional, introduced 1992; original guarantee below 42 ppmvd NOx Current SoLoNOx warranty (portfolio-wide): 9 ppmvd NOx / 15 ppmvd CO

Configurations and options

Configurations found: generator set (this dossier), gas compressor package, and general mechanical drive, sharing the same core engine. Combustion is Conventional (diffusion-flame) or SoLoNOx (DLE) — not one fixed factory configuration — and which a given used unit carries must be confirmed unit by unit.

Compatibility and dependencies

Verify whether the specific unit is Conventional or SoLoNOx combustion, and if SoLoNOx, which generation and its guaranteed ppm level, before assuming permittability at a given site. A reduction gearbox steps the roughly 9,500 rpm power-turbine speed down to 1,800 rpm at a 60 Hz, 4-pole generator on fielded units; confirm frequency and generator voltage against the specific listing rather than assuming it.

Pricing and availability

Comparable secondary-market band: 74–445 $ per kW. Trend: flat Both dated used units located were built in 1989, consistent with an aging, oil-and-gas-driven secondary-market population rather than an active new-build pipeline, since Mars 90 no longer carries a current power-generation catalog page. Warranty, used: Solar Pre-Owned/exchange program offers warranty reinstatement on secondary-market units; otherwise as-is typical on broker/reseller listings.

Lifecycle and maintenance

Solar's factory Pre-Owned Equipment Program explicitly lists Mars 90 among supported models and offers warranty reinstatement to a second owner, so the overhaul/exchange relationship does transfer. EthosEnergy independently services Mars 90 from a $20-million-plus Houston parts inventory, an alternate channel to Solar factory support.

Common failure points

• Combustor liner / fuel nozzles — coking, hot streaking, or cracked liner panels on borescope
• Hot-section turbine blades (gas producer) — tip curl, coating spallation, or creep beyond OEM limits
• Reduction gearbox — rising vibration or metal in oil analysis between the 9,500 rpm input and 1,800 rpm output
• SoLoNOx / water-injection combustion hardware — pre-1992 units lack SoLoNOx entirely; retrofit water-injection skids show nozzle plugging and corrosion
• Generator windings — falling insulation resistance on megger test versus nameplate class
• Control system (Turbotronic or legacy panel) — obsolete Turbotronic 3 or older analog panels with dwindling parts support
• Package enclosure and base frame — corrosion at the skid base and inlet/exhaust ducting on units built since 1977

Inspection checklist

Fired hours since new, and hours since the last hot-section inspection — request both figures in writing, not a verbal estimate. Starts and starts since the last combustion inspection — request the last 2 inspection reports to see the trend, not just a current count. Combustion system fitted — Conventional versus SoLoNOx (DLE); SoLoNOx only exists on units built or retrofitted after 1992. If SoLoNOx, the combustor generation — original-issue hardware was guaranteed under 42 ppmvd NOx and 50 ppmvd CO, well above the 9 ppmvd/15 ppmvd modern warranty. Borescope of both gas-producer and power-turbine sections — request the last 2 borescope video sets, not a summary memo. Blade and nozzle condition on all rows inspected — flag any single blade with tip curl or coating loss beyond the OEM limit. Combustor liner and fuel nozzle condition on all cans — coking or hot-streaking on even 1 can signals deferred combustion maintenance. Water/steam injection skid condition, if fitted — corrosion and nozzle plugging are common on pre-SoLoNOx NOx-control retrofits. Reduction gearbox inspection — this package steps roughly 9,500 rpm power-turbine speed down to 1,800 rpm at the generator. Generator winding insulation resistance — megger test at 2 or more voltage steps and compare to the original nameplate class. Control system generation — Turbotronic 3, Turbotronic 4, or an older analog panel; parts support differs sharply by generation. Bearing vibration trend across the gas producer, power turbine, and gearbox — 3 or more historical readings outweigh 1 snapshot. Package enclosure, base frame, and fire/gas detection condition — units built since 1977 can carry 40-plus years of skid corrosion. Lube oil analysis history — request the last 4 sample reports, not a single clean result. Idle/storage history and rotor-turning records — a unit stored more than 12 months without preservation needs a fuller inspection.

Procurement channels

Solar's factory Pre-Owned Equipment Program lists Mars 90 directly, with warranty reinstatement to a second owner. EthosEnergy offers independent overhaul and exchange service from a $20-million-plus Houston parts inventory as a non-factory channel.