Ten percent non-condensable gas in the steam stream can cut net turbine output by up to 25% compared to clean steam — and it doesn't show up as an alarm. It shows up weeks later as a generation curve that's quietly bending the wrong way. Geothermal is the one power generation asset class where the fuel itself is corrosive, gas-laden, and constantly changing composition underground, which is exactly why a maintenance program built for solar or wind leaves the failure modes that actually matter here unmonitored. Sign up to track NCG trends, scaling, and production well records against every wellhead and turbine in one CMMS.
Why It Matters
Unmanaged scaling can strip 15 to 20% of plant capacity over twelve months, and a single unplanned turbine failure from brine carryover can cost a mid-scale facility millions in remediation. Neither failure mode announces itself with a sudden trip — both build silently in pipework and turbine internals until a performance test finally confirms what was already happening. That's the core difference in geothermal O&M: the fluid driving the turbine is also the thing degrading it, so monitoring the resource itself is as much a maintenance task as monitoring the equipment.
Three Failure Modes Unique To Geothermal
Solar panels degrade from sunlight and wind turbines from fatigue, but geothermal plants degrade from the resource that powers them — and that requires its own set of tracked indicators.
NCG Buildup
Every 1% rise in non-condensable gas content reduces available turbine work by roughly 0.86%, making trend deviation the real early-warning signal.
Scaling
Mineral deposition inside pipework and separators that narrows flow paths and fouls heat transfer surfaces if left unmanaged.
Brine Carryover
Liquid droplets reaching the turbine causing blade erosion, a risk that varies by whether the plant runs flash, ORC, or dry steam.
NCG tracking protects turbine output, scaling management protects flow capacity across the whole fluid path, and carryover control protects the turbine blades themselves — three separate monitoring disciplines running at once, all feeding the same maintenance schedule.
Flash, ORC, And Dry Steam Each Wear Differently
| Plant Type |
Resource |
Primary Wear Mechanism |
| Flash Steam |
High-enthalpy resources |
Blade erosion and scaling from brine carryover |
| Binary ORC |
Lower-temperature resources |
Working fluid degradation and heat exchanger fouling |
| Dry Steam |
Vapor-dominated resources |
Particle impingement and NCG-driven corrosion |
Catch The Curve Before It Bends
Oxmaint tracks NCG trend deviation, scaling indicators, and production well data against a rolling baseline, so a field change shows up as a flagged task, not a mystery in next quarter's generation report. Sign up for a free trial to run it on your own field, or book a demo to see it configured for your plant.
Where Geothermal O&M Programs Fall Short
NCG Tracked As A Single Number
Absolute level checked but the trend deviation that actually signals a field change goes unnoticed
Scaling Left Unmanaged
Twelve months pass before mineral buildup is even scheduled for inspection
Generic CMMS Configuration
A template built for solar or wind assets that has no field for wellhead or separator data
H2S Events Undocumented
Alarms logged as incidents somewhere, but not tied to a full auditable safety record
Flash And ORC Assets Merged
One PM schedule applied across turbine types that actually degrade in different ways
Performance Loss Found Too Late
Output decline only confirmed by the next scheduled performance test, not caught earlier
Frequently Asked Questions
Q
Why is a fixed NCG threshold the wrong way to monitor it?
NCG content in geothermal steam varies naturally by field, from near zero up to 25% by weight, so a single absolute alarm level either fires constantly or misses real change. A shift of more than 0.5% from the rolling three-month average is a far more reliable signal that the field itself has changed.
Q
Can one CMMS handle both flash and ORC geothermal assets?
Yes, but it needs separate asset profiles and PM schedules for each — flash plant components like separators and wellheads face different degradation than binary ORC components like heat exchangers and expanders, and merging them into one generic schedule misses failure modes specific to each.
Q
Why does H2S monitoring need to be a formal CMMS record, not just an alarm log?
Hydrogen sulfide is present anywhere geothermal fluid is handled, and compliance audits require a full trail of exposure events, sensor checks, and corrective actions — something that's effectively impossible to reconstruct from paper logs weeks after the fact.
Built For The Resource, Not Just The Equipment
Oxmaint keeps production well records, scaling history, NCG trends, and H2S safety events tied to their evidence in one auditable log, so proving your geothermal field is under control doesn't mean piecing together lab reports and paper checklists. Sign up for a free trial to run it on your own field, or book a demo to see it configured for your plant.
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