Arizona’s Building Blocks: Redispatch from Coal to Natural Gas (part 2 of 4)

In our last post we started walking through the EPA’s calculation of state goals for CO2 emissions, covering Building Block 1. In this post, we’ll continue the walk-through with Building Block 2: Redispatch from Coal to Natural Gas. Compared to burning coal, burning natural gas emits roughly half the amount of CO2 for each unit of energy generated. (This ignores any upstream methane emissions associated with the extraction and transmission of natural gas. If included, these “fugitive” emissions could exacerbate the global warming potential of natural gas. Many efforts are under way to quantify and reduce fugitive emissions, but that’s outside the scope of this discussion). Thus, switching (or “redispatching”) from coal to natural gas can lower the overall emissions rate from fossil fuel generation sources. Additionally, many states have natural gas power plants that are not fully utilized and in theory could be used to displace coal. In fact, the EPA’s calculations suggest that there is enough natural gas capacity in Arizona to displace nearly all of its coal-fired generation, excluding plants on tribal land, which are initially exempt from the proposed rule. In total, Arizona ranks third among states in terms of energy from coal that EPA anticipates can be replaced with natural gas (behind Texas and Florida). Whether or not this is technically feasible will be a subject for future discussion on this forum.  
State Coal Redispatched to Natural Gas (MWh) Rank
Texas

 72,006,905

1
Florida

 40,406,038

2
Arizona

 24,335,930

3
Arkansas

 18,160,138

4
North Carolina

 16,723,261

5
Oklahoma

 15,067,759

6
Georgia

 13,781,486

7
Illinois

 13,008,442

8
Louisiana

 12,761,626

9
Michigan

 12,119,216

10
Colorado

 11,836,718

11
Minnesota

 11,290,583

12
Alabama

 10,044,069

13
Pennsylvania

 8,723,668

14
Wisconsin

 8,050,599

15
Missouri

 7,926,942

16
Mississippi

 7,503,114

17
Utah

 6,534,930

18
Ohio

 6,480,067

19
Iowa

 6,276,042

20
South Carolina

 6,160,480

21
Virginia

 6,040,987

22
Indiana

 4,178,725

23
Nevada

 4,133,662

24
New York

 4,128,561

25
New Mexico

 3,759,668

26
Washington

 3,735,730

27
Tennessee

 3,297,176

28
Oregon

 2,640,259

29
New Jersey

 2,602,990

30
Nebraska

 2,452,114

31
Massachusetts

 2,268,133

32
South Dakota

 1,965,115

33
New Hampshire

 1,281,341

34
Delaware

 1,221,623

35
Maryland

 933,543

36
California

 933,157

37
Kentucky

 843,264

38
Wyoming

 289,872

39
Alaska

 215,407

40
Connecticut

 99,461

41
Hawaii

 -

42
Idaho

 -

43
Kansas

 -

44
Maine

 -

45
Montana

 -

46
North Dakota

 -

47
Rhode Island

 -

48
West Virginia

 -

49
Block 2Block 2 is perhaps the most controversial for Arizona because it will likely necessitate the retirement of several coal-fired power plants. The coal plants in Arizona potentially affected by the rule include:
  • Apache Generating Station (408 MW, owned by AEPCO),
  • Cholla (1129 MW, owned by APS and PacifiCorp),
  • Coronado (822 MW, owned by SRP),
  • Springerville (1750 MW, owned by TEP, SRP, and Tri-State)
Arizona Power Plants_labeledAdditionally, many of the natural gas plants needed for redispatch in Arizona are located near the Palo Verde Nuclear Generating Station, a trading hub for electricity. Some policymakers have suggested that this could be a problem if the power grid is not robust enough to deliver all the energy from plants clustered in this one location after the coal plants are shut down. However, much more analysis of this issue is needed to draw any firm conclusions.  Written by Eddie Burgess, Energy Policy Innovation Council