SEGS IX

Solar power plant in California, United States of America. Approximate location 35.033, -117.338.

SolarCaliforniaUnited States of AmericaSteam

SEGS IX is a 92 MW solar power plant in California, United States of America. It is operated by Terra-Gen Operating Co-Solar. Based on reported annual generation of 140 GWh, it can supply roughly 40k homes. It ranks #2958 of 10,938 United States of America power plants by installed capacity. Commissioned in 1990, it is around 36 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, solar supplies about 8.6% of United States of America's electricity; the national grid averages 384 gCO₂/kWh (43.0% low-carbon) (2025).

92Source-backed capacity
140GWh reported / yr
40,085homes powered
1990commissioned (~36 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0010446.

Data status

Known data

FacilitySEGS IX WRI
CountryUnited States of America · California WRI
Coordinates35.033, -117.338 WRI
FuelSolar WRI
MW installed capacity92 MW WRI source record; scope not independently normalised
OwnerTerra-Gen Operating Co-Solar WRI
Commissioned1990 WRI
TechnologySteam WRI
GWh reported / yr140 GWh/yr WRI

Calculated from dataset

Capacity rank in country#2958 of 10938 calculated
Fuel-specific rank in country#86 of 3283 calculated
Capacity vs country/fuel peers30.67× · 3 MW median · 3283 peers calculated
Homes-powered equivalent40,085 calculated from reported generation
Climate17.9°C · HDD 1,272 derived from coordinates
Environmental severityC1 · 43/100 derived from coordinates

Not available

GWh reported / yrNot available not in dataset
CO₂ emissionsnot applicable not applicable

Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.

Data provenance

The capacity and/or fuel fields on this page include a source-backed provenance label from GEM, an official registry, Wikidata, OSM, or a cross-source match.

capacity: Wikidata P2109 nameplate capacity; fuel: WRI source-record fuel

In context: how this plant compares

At 92 MW, SEGS IX is well above the median solar plant in United States of America (3 MW). Technically it is described as Steam. Solar PV converts sunlight directly into electricity with no moving parts or fuel; output varies by time of day and weather, so it pairs with storage or flexible backup.

Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.

Reported generation trend

2013: 169 GWh20132014: 160 GWh20142015: 163 GWh20152016: 158 GWh20162017: 152 GWh20172018: 152 GWh20182019: 140 GWh2019169 GWh

Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).

Owner

Operated by Terra-Gen Operating Co-Solar.

Local climate & thermal context

This solar plant converts sunlight directly into electricity with photovoltaic panels. It sits in a cold desert climate (Köppen BWk) — Northern Hemisphere, latitude 35.0°N — which shapes how much energy it can produce and how its output varies through the year.

17.9°Cannual mean temp
1,272heating degree-days (base 18°C)
1,253cooling degree-days (base 18°C)
702 melevation

Monthly mean temperature

J: 8 °CJF: 10 °CFM: 13 °CMA: 16 °CAM: 21 °CMJ: 26 °CJJ: 30 °CJA: 29 °CAS: 25 °CSO: 18 °CON: 12 °CND: 7 °CD30 °C

Heating degree-days here run 48% below the median power plant in this dataset — a proxy for how much extra energy heated equipment must replace through its surfaces in winter.

Climate heat-demand index: 30/100 — this site sits in the bottom third of the power plants we cover by heating degree-days.

Solar PV loses ~0.35%/°C above 25°C cell temperature — roughly 1.6% at warm-season highs here (estimate).

Climate normals: WorldClim 2.1 (1970–2000 monthly normals, 10 arc-min, CC BY 4.0); zone: Köppen-Geiger world climate classification (Kottek et al. 2006, 0.5° grid). Degree-days & heat-demand index computed by PowerAtlas — a modelled heat-demand proxy, not a measured site figure.

Site climate & environmental severity

For a plant’s outdoor hardware — heat-recovery steam generators (HRSG), expansion joints, valves, flanges and their insulation — the local climate sets how fast unprotected steel and coatings degrade. This site sits in a benign, low-corrosion environment (estimated ISO 9223 class C1 — Very low), with dust abrasion the leading environmental stress.

C1ISO 9223 corrosivity (indicative)
43/100environmental-severity index
22.3°Cseasonal temperature swing
141 kmdistance to coast

Higher environmental severity is exactly where protective removable insulation pays back most: a sheltered micro-climate slows corrosion, UV and thermal-cycling damage and extends outdoor hardware service life. This is an indicative site-climate context — not a condition assessment of any specific plant or operator.

Indicative estimate via the ISO 9223:2012 informative method (atmospheric corrosivity from temperature, time-of-wetness and airborne salinity), using WorldClim climate normals, the Köppen-Geiger class and coast distance. Indicative, not a measured corrosion rate.

How it compares & nearby plants

The #86 largest solar power plant of 3283 in United States of America by capacity.

United States of America has 3283 solar power plants in this dataset, together about 38,093 MW of capacity.

Nearby power plants

Location

Coordinates 35.033, -117.338 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is SEGS IX?

SEGS IX is a 92 MW source-record solar power plant in California, United States of America, commissioned in 1990.

How much electricity does SEGS IX generate?

SEGS IX generates about 140 GWh of electricity per year.

How many homes can SEGS IX power?

Its output is enough to supply roughly 40,085 homes.

Who operates SEGS IX?

SEGS IX is operated by Terra-Gen Operating Co-Solar.

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