Power plants in the WAPA Upper Great Plains West balancing area

The WAPA Upper Great Plains West balancing area takes in 22 power plants with 1,128 MW of nameplate capacity, the 39th-largest of the 40 areas covered here. Its plants sit in three states, with Montana holding 46% of the capacity. Hydroelectric makes up 87% of the mix, and the largest plant is Yellowtail (278 MW). Since 2020, 80 MW has come online here, 100% of it solar.

Hydroelectric977 MW87%
Solar80 MW7.1%
Wind71.4 MW6.3%

Capacity by decade it came online

HydroelectricWindSolar

Above the line: capacity operating in 2025. Below: capacity retired at plants that still run.

The 22 largest plants in the area

Rank	Plant	State	Runs on	Capacity	First unit
1	Yellowtail	Montana	Hydroelectric	278 MW	1966
2	Fort Peck	Montana	Hydroelectric	180 MW	1943
3	Flaming Gorge	Utah	Hydroelectric	152 MW	1963
4	Steel Solar LLC	Utah	Solar	80 MW	2024
5	Fremont Canyon	Wyoming	Hydroelectric	66.8 MW	1960
6	Canyon Ferry	Montana	Hydroelectric	57.6 MW	1953
7	Seminoe	Wyoming	Hydroelectric	51.6 MW	1939
8	Silver Sage Windpower	Wyoming	Wind	42 MW	2009
9	Alcova	Wyoming	Hydroelectric	41.4 MW	1955
10	Glendo	Wyoming	Hydroelectric	38 MW	1958
11	Kortes	Wyoming	Hydroelectric	36 MW	1950
12	Happy Jack Windpower Project	Wyoming	Wind	29.4 MW	2008
13	Buffalo Bill	Wyoming	Hydroelectric	18 MW	1992
14	Boysen	Wyoming	Hydroelectric	15 MW	1952
15	Fontenelle	Wyoming	Hydroelectric	10 MW	1968
16	Tiber Dam Hydroelectric Plant	Montana	Hydroelectric	7.5 MW	2004
17	Guernsey	Wyoming	Hydroelectric	6.4 MW	1927
18	Heart Mountain	Wyoming	Hydroelectric	5 MW	1948
19	Deer Creek (UT)	Utah	Hydroelectric	4.8 MW	1958
20	Spirit Mountain	Wyoming	Hydroelectric	4.5 MW	1994
21	Shoshone (WY)	Wyoming	Hydroelectric	3 MW	1922
22	Pilot Butte	Wyoming	Hydroelectric	1.6 MW	1925

States

State	Plants	Capacity
Montana	4	523 MW
Wyoming	15	369 MW
Utah	3	237 MW

Operators with the most capacity

Operator	Plants	Capacity
U S Bureau of Reclamation	17	790 MW
USACE-Omaha	1	180 MW
Steel Solar, LLC	1	80 MW
Deriva Energy	2	71.4 MW
Tiber Montana LLC	1	7.5 MW