The Continuing Decline of Coal in Western US

When assessing the status of coal, we consider two key factors: the amount of electricity generated from coal and the remaining capacity of coal power plants. Generation at current coal plants declines as new sources of Western electricity—solar, wind, geothermal, natural gas, and nuclear—come online. It also declines as plants are retired.

Generation

Coal generation has experienced a dramatic decline in the Western US since 2010 and will drop even further over the next decade. We expect coal generation to drop below 50 TWh in the Western US by 2030 and there is a possibility that all “major” coal plants will close by 2035.

Note: the estimated generation total for 2024 is based on data seen through August.

Capacity

At the end of 2013, the Western US had about 32,200 MW of coal capacity. Since then, approximately one-third—or 10,000 MW—of coal plants have retired.

This leaves a total remaining coal capacity for the Western United States at the start of 2024 at 21,991 MW—spread across nine states, with Idaho and Oregon being coal-free.

In the first half of 2024, two units at the Jim Bridger plant in Wyoming—the 531 MW Unit 1 and the 539 MW Unit 2—were converted to gas. Subtracting these two units leaves the October 2024 Western coal capacity at 20,921 MW.

Here is a breakdown of the remaining capacity per state:

State	Coal Capacity
WY	6,069
UT	4,581
CO	3,804
AZ	2,943
MT	1,630
NM	1,540
NV	740
WA	670
CA	57
ID	0
OR	0

Looking forward we can see how planned retirements will affect the remaining amount of coal capacity.

Year	Start Cap (MW)	Capacity Retired	End Cap (MW)	Units Retiring
2024	21,991	1,070	20,921	WY - Jim Bridger 1,2 - convert to NG
2025	20,921	4,716	16,205	AZ-Cholla 1,2 CO-Comanche 2 CO-Craig 1 NV-Valmy 1,2 NV-TS Power 1 UT-InterMountain 1,2 WA-Centralia 2 WY-Naughton 1,2
2026	16,205	562	15,643	CA- Argus 1 CO Pawnee convert to NG
2027	15,643	1,027	14,616	CO-Hayden 2, WY-Dave Johnston 1,2,3,4
2028	14,616	970	13,646	AZ Springerville1 CO-Hayden 1 CO-Craig 2
2029	13,646	936	12,710	CO-Craig 3 CO-Nixon 1 CO-Rawhide 1
2030	12,710	0	12,710
2031	12,710	2,290	10,420	NM-FourCorners 1,2 Comanche 3
2032	10,420	1,168	9,252	AZ- Coronado 1,2 Springerville 2
2033	9,252	0	9,252

Over the next nine years, an additional 12,700 MW of coal capacity will retire. This represents about 58% of the 2024 capacity. It's worth noting that this figure doesn't include any unannounced retirements, which will undoubtedly occur during this period.

Conclusion

New sources of generation like solar, natural gas, wind, gothermal and nuclear will continue to eat into coal’s share of Western generation. This will happen even if demand increases as expected due to electricification and buiulding of more data centers. By 2030, coal generation could drop below 50 TWh.

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Mission City Research

This article is part of the Mission City Research series on the Western Grid in the United States. Mission City Research is a non-profit based in Monterey, Ca and one of its goals is to help build a cleaner Western Grid.