Tennessee’s coal power plants are 53 years old on average, but in Texas they are 24 years younger

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Over at Vox, Brad Plumer has a good explainer of Obama’s Clean Power Plan. Roughly speaking each state will have to cut carbon dioxide emissions from power plants by a certain percentage.

The state goals worked out by the EPA obviously result from a combination of the existing electricity mix in each state, current economics and political lobbying.

One factor that plays into it (or probably did) is the age of coal power plants. Young coal power plants are more difficult to retire than old ones. This is relatively indisputable. On the international stage this is best seen by comparing Britain with China. Britain has not built a new coal power plant in the last three decades. The vast majority of China’s were built this century. Britain will effectively phase out its existing fleet within a decade. China will be lumbered with its for the next 50 years or so.

If we want to find out the average of coal power plants in each US state we will have to calculate it ourselves using EIA data. EIA’s Form 860 lists the capacity and operating year of more or less all US power plants. The main fuel used in power plants is given, along with the capacity and state. This is enough to give us fairly accurate estimates of the average of coal power plants in each state.

So here they are, ranked from top to bottom.

State Coal capacity (GW) Mean age State Coal capacity (GW) Mean age
Tennessee 9.61 52.75 Kansas 5.47 39.21
New Hampshire 0.56 51.04 Virginia 5.92 38.77
Massachusetts 1.43 49.92 Delaware 0.62 37.84
New York 2.63 49.89 North Dakota 4.24 37.30
Connecticut 0.40 47.00 Wyoming 6.91 35.71
Alaska 0.11 46.38 Oregon 0.64 35.00
Alabama 12.30 45.87 Utah 5.04 34.91
Michigan 12.25 45.83 Mississippi 2.89 34.57
Idaho 0.02 45.51 Wisconsin 8.77 34.17
Ohio 20.27 44.79 Florida 11.34 34.04
New Jersey 2.14 43.57 Oklahoma 5.84 33.92
Pennsylvania 16.25 42.63 Iowa 7.08 33.71
Washington 1.46 42.50 Colorado 5.75 33.63
Minnesota 5.26 42.45 Montana 2.66 33.22
West Virginia 14.97 42.22 Arizona 6.71 32.88
Maryland 5.14 42.06 Louisiana 3.80 32.25
Illinois 17.29 40.88 Nebraska 4.27 31.46
South Dakota 0.48 40.78 South Carolina 6.28 31.23
Kentucky 17.82 40.42 Nevada 1.45 30.95
Missouri 13.13 40.41 California 0.28 29.37
Georgia 13.49 40.31 Texas 25.42 28.88
New Mexico 3.74 40.25 Arkansas 5.49 26.40
Indiana 20.91 39.88 Maine 0.10 25.00
North Carolina 10.97 39.86 Hawaii 0.20 23.00

Tennessee has the oldest coal power plants in America. On average they were built half a century ago. Texas and Arkansas both have relatively significant and relatively young coal power plants. They are just under 30 years old, 20 years younger than those in Tennessee.

It would be interesting to compare the numbers in this table with the state goals set by EIA. If I have the time this weekend I might do a simple analysis of this. Obviously states with older power plants will be able to close them earlier, and thus reduce their emissions faster. It’s also true that older power plants tend to be less efficient. So it should, all things being equal, be much easier for Tennessee to reduce its emissions from coal power plants than it is for Texas. Of course, not all things are equal.

Note on data

State by state data used is available here.

Mean age is weighted by the capacity of each plant.

I processed the data in R and produced the html table using xtable. I have had to manually adjust the EIA files to make them readable in R, so I’m not in a position to post easily reproducible code here. If anyone wants the R code and simplified EIA files used for this they can email me.