Areas of industrial wind facilities*
facility	capacity/area†	acres/MW
Snowflake, Ariz.	99 MW/7,000 acres	71
Altamont Wind Resource Area, Calif.	580 MW/50,000 acres	86
Montezuma Hills, Calif.	180 MW/6,800 acres	38
Colorado Green, Lamar	162 MW/11,840 acres	73
Prairie Wind, Colo.	69 MW/7,000 acres	101
Twin Buttes, Colo.	75 MW/9,000 acres	120
Winergy offshore, Del.	1,101 MW/67 mi2	40
Cassia County, Idaho	200 MW/4,500 acres	23
Boone County, Ill.	27 MW/800 acres	30
Baileyville Wind Farm, Ogle County, Ill.	80 MW/5,000 acres	62
Big Sky, Ill.	75 MW/10,000 acres	133
Bishop Hill, Ill.	400 MW/25-30,000 acres	62-75
Crescent Ridge, Ill.	54.5 MW/2,200 acres	40
LaSalle Country, Ill.	384.5 MW/25,000 acres	65
Mendota Hills, Ill.	50.4 MW/3,500 acres	69
Twin Groves Wind Farm, McLean County, Ill.	396 MW/21,000 acres	53
Cerro Gordo, Iowa	42 MW/2,110 acres	50
Franklin County, Iowa	200-300 MW/40,000 acres	133-200
Pomeroy Wind Farm, Pocahontas County, Iowa	198 MW/8,200 acres	41
Elk River, Kan.	150 MW/8,000 acres	53
Ford County, Kan.	100.5 MW/5,000 acres	50
Spearville, Kan.	100 MW/10 mi2	64
Cape Wind (off shore), Mass.	420 MW/24 mi2	37
Harvest Wind Farm, Mich.	53 MW/3,200 acres	60
Huron County, Mich.	48 MW/4,700 acres	98
Muskegon, Mich.	31.5 MW/8,000 acres	254
Trimont Area Wind Farm, Minn.	100.5 MW/8,900 acres	89
Bluegrass Ridge, Mo.	56.7 MW/7,000 acres	123
Judith Gap, Mont.	135 MW/8,300 acres	61
Pierce County, Mont.	150 MW/72 mi2	307
Ainsworth, Nev.	59 MW/11,000 acres	185
Colfax County, N.M.	20 MW/800-1,200 acres	20
Cherry Valley, N.Y.	60 MW/1,200 acres	40-60
Fenner, N.Y.	30 MW/1,500 acres	50
Gore Mountain, N.Y.	27.5 MW/1,700 acres	62
Long Island Sound, N.Y.	140 MW/8 mi2	37
Pierce County, N.D.	150 MW/72 mi2	307
Velva, N.D.	12 MW/3 mi2	160
Wilton Wind Energy Center, N.D.	49.5 MW/8,000+ acres	162
Arlington, Ore.	104 MW/14,000 acres	135
Biglow Canyon, Ore.	350-450 MW/25,000 acres	56-71
Elkhorn Valley, Ore.	101 MW/10,000 acres	99
Shepherds Flat, Ore.	750 MW/32,000 acres	43
Forkston Twp., Pa.	75-125 MW/7,400 acres	59-99
Galveston Offshore, Texas	150 MW/11,355 acres	76
Desert Sky, Texas	160.5 MW/15 mi2	60
Horse Hollow, Texas	735 MW/47,000 acres	64
Pampa Wind Project, Texas	4,000 MW/400,000 acres	100
Stanton, Texas	100 MW/12,000 acres	120
Wildorado Wind Ranch, Texas	161 MW/16,000 acres	75
Milford Wind Corridor, Utah	300 MW/40 mi2	85
Sheffield, Vt.	52 MW/3,000 acres	58
Big Horn, Wash.	200 MW/15,000 acres	75
Desert Claim, Wash.	180 MW/5,237 acres	29
Hopkins Ridge, Wash.	150 MW/11,000 acres	73
Kittitas Valley, Wash.	181.5 MW/6,000 acres	34
Klondike II, Sherman County, Wash.	75 MW/6,400 acres	98
Nine Canyon, Kennewick, Wash.	63.7 MW/5,120 acres	80
Wild Horse, Wash.	64 MW/7,500 acres	118
Mountaineer, W.V.	66 MW/4,400 acres	67
Bent Tree, Freeborn County, Wis.	200 MW/32,000 acres	160
Forward Wind Energy Center, Wis.	200 MW/32,400 acres	162
Kewaunee County, Wis.	11 MW/603 acres	54
Monroe County, Wis.	80 MW/10,000 acres	125
Evanston, Wyo.	144 MW/7,800 acres	54
Blue Highlands, Ont.	49.5 MW/4,500 acres	91
Sederglan Wind Farm, Alb.	70.5 MW/3,900 acres	131
Prince I & II Wind Energy Project, Ont.	189 MW/10,000 hectares	55
Thunder Bay, Ont.	100 MW/8,000 acres	80
Codrington, Australia	18.2 MW/240 hectares	33
Anse-a-Valleau, Que.	100.5 MW/4,800 hectares	118
Stanstead Station, Que.	62 MW/920 hectares	37
Dollar Wind Farm, Australia	79.2 MW/2,000 hectares	62
East Otago, Australia	650 MW/300 mi2	295
Macarthur, Australia	334 MW/5,500 hectares	47
Horns Rev (off shore), Denmark	160 MW/20 km2	31
Butendiek (off shore), Germany	240 MW/35 km2	36
Duddon Sands (off shore), U.K.	500 MW/66 km2	33
London Array, Thames Estuary (off shore)	1,000 MW/245 km2	61
Walney (off shore), U.K.	450 MW/74.5 km2	41
E. Ayrshire, Dumfries, Galloway, Scotland	300 MW/8,000 hectares	67
Beinn Ghlas, Scotland	8.4 MW/300 hectares	88
Braes of Doune, Scotland	72 MW/1,000 acres	14
Lewis, Scotland	600 MW/45 mi2	50
Novar, Scotland	17 MW/300 hectares	44
Sutherland, Scotland	50 MW/2,731 hectares	135
Windy Standard, Scotland	21.6 MW/350 hectares	40
Carno, Wales	33.6 MW/600 hectares	44
Makara Hills, New Zealand	210 MW/55 km2	65
Quartz Hill, New Zealand	210 MW/3,000 hectares	35

* The data are gathered mostly from news articles, some from government and company documentation. The list includes proposed (and possibly rejected) as well as operating facilities. Ridgeline facilities described only by length instead of the whole area taken are not included.

According to "Permitting setbacks for wind turbines and the blade throw hazard," by Scott Larwood, presented at the 2004 California Wind Energy Collaborative Forum, University of California, Davis, the distance that turbines should be from each other for minimal wind interference is 3 rotor diameters when aligned perpendicular to the wind and 10 rotor diameters when parallel to the wind. This is also the spacing described by the New York State Energy Research and Development Authority and others. The minimum area required around each turbine in a single line where the wind is generally from one direction would therefore be 13d × 3d (where d is the rotor diameter). The minimum area in an array would be 10d × 10d.

For a stand-alone turbine, the area required would be a 13d × 6d oval at a site where the wind is generally from one direction and up to a 20d-wide circle to use the wind from any direction. Depending on surrounding features, very tall towers may allow reducing that area to some extent.

The GE 1.5-MW turbine, with a 70.5-m rotor span, therefore requires at least 48 acres per tower in a single line perpendicular to the wind (32 acres/MW) or 123 acres per tower in an array (82 acres/MW). Each Vestas V90 1.8-MW turbine, with a 90-m rotor, requires 78-200 acres (43-111 acres/MW). Tom Gray of the American Wind Energy Association has written, "My rule of thumb is 60 acres per megawatt for wind farms on land."

Note that larger turbines are not substantially more efficient than small ones, because they require proportionally more space.

&dagger Remember that capacity is different from actual output. Typical average output is only 25% of capacity, so the area required for a megawatt of actual output is four times the area listed here for a megawatt of capacity. And because two-thirds of the time wind turbines produce power at a rate far below average, even more (3×, perhaps, for a total of 12×) -- dispersed across a wide geographic area -- would be needed for any hope of a steady supply.