Swanmill Windfarm I — United States of America

Swanmill Windfarm I is a 18.7 MW wind power plant in California, United States of America. It is operated by Mark Technologies Corp. Based on its capacity (estimated), it can supply roughly 16k homes (estimated). It ranks #4899 of 10,884 United States of America power plants by installed capacity. Commissioned in 1989, it is around 37 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, wind supplies about 10.3% of United States of America's electricity; the national grid averages 384 gCO₂/kWh (43.0% low-carbon) (2025).

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0054650.

Data provenance

Capacity and fuel are the upstream open-dataset record, not yet matched to a 2026 registry or GEM entry.

capacity: WRI GPPD; fuel: WRI GPPD

In context: how this plant compares

At 18.7 MW, Swanmill Windfarm I is below the median wind plant in United States of America (67.7 MW). Wind turbines convert moving air into electricity; output is variable and site-dependent, and modern turbines deliver some of the lowest-cost new generation on many grids.

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

Key facts

Generation trend

22 GWh in 2013 and 15 GWh in 2018 (−31%)

Highest and lowest year

2015: 29 GWh; 2017: 4 GWh

Share of United States of America wind capacity

less than 0.1% of 104,873 MW across 1,139 plants in this dataset

Age among peers

25 of 1,139 dated wind plants in United States of America are older

Calculated from the capacity and generation records in this dataset (WRI Global Power Plant Database (CC BY 4.0)).

Reported generation trend

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

Owner

Operated by Mark Technologies Corp.

Local climate & thermal context

This wind plant converts the kinetic energy of wind into electricity through turbine rotors. It sits in a hot-summer Mediterranean climate (Köppen Csa) — Northern Hemisphere, latitude 33.9°N — which shapes how much energy it can produce and how its output varies through the year.

Monthly mean temperature

Heating degree-days here run 72% 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: 23/100 — this site sits in the bottom third of the power plants we cover by heating degree-days.

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

This site sits in a moderately corrosive environment (estimated ISO 9223 class C3 — Medium), with humidity / wetness the leading environmental stress.

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 #800 largest wind power plant of 1139 in United States of America by capacity.

United States of America has 1139 wind power plants in this dataset, together about 104,873 MW of capacity.

Nearby power plants

• Mesa Wind Power Corp · Wind · 30 MW · California
• Whitewater Hydro Plant · Hydro · 1.3 MW · California
• Whitewater Hill Wind Partners · Wind · 61.5 MW · California
• San Gorgonio Farms Wind Farm · Wind · 31 MW · California
• GPS Cabazon Wind LLC · Wind · 38.9 MW · California
• Mountain View III · Wind · 22.4 MW · California

Location

Coordinates 33.942, -116.661 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions