Technical Support Document (TSD) 

for the Transport Rule 

Docket ID No. EPA-HQ-OAR-2009-0491 

Electric Generation Ownership, Market Concentration 

and Auction Size 

U.S. Environmental Protection Agency 

Office of Air and Radiation 

July 2010 

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Electric Generation Ownership and Market Concentration 

In this Technical Support Document (TSD), we explain in more detail the issues and 

analyses completed for the alternative remedy of State Budgets/Intrastate Trading described in 

the proposed Transport Rule preamble in section V.D.5. In summary, this option would set 

state-specific caps for SO2, NOX annual, and NOX ozone season emissions from electric 

generating units (EGUs) and create separate allowance trading programs within each state in the 

respective regions starting in 2012. Under this option, EPA would allocate allowances to the 

covered sources within each state and the covered sources would only be allowed to use for 

compliance allowances allocated within their state. To address the concentrated nature of 

numerous state power markets through allocations, under this option some allowances would be 

withheld from certain sources in each state that control a large share of fossil-fueled power 

generation, and made available for companies with a small share of generation in the state 

through auctions. 

The first part of this TSD describes the steps EPA took to determine whether the potential 

for market power may exist if only intrastate trading is allowed. It provides a state by state 

analysis of electricity generation ownership and why EPA believes electricity markets are 

sufficiently concentrated to be a concern. Second, this TSD looks at the threshold for auction 

participation that was chosen. The objective was to have both enough potentially disadvantaged 

participants to make the auctions competitive, and to have sufficient sources supplying the 

allowances to each state pool for auctioning. Finally, we discuss the share of allowances that 

would be available for purchase and why it would be adequate to address the market power 

problem and meet the needs of owners with a small market share. 

Market Concentration 

 For the State Budgets/ Intrastate Trading option described in the proposal, EPA analyzed 

power generation ownership by state to determine whether market power would be a potential 

threat in states within the Transport Rule regions. The analysis was conducted by taking the 

following steps: 

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1) EPA ran the Integrated Planning Model (IPM) for the State Budgets/Intrastate 

Trading option in which allowance trading was limited to intrastate (IPM run 

“TR_SB_Intrastate_Trading”). We looked at the detailed output parsed files from 

that IPM model run for 2014 with particular interest in electricity generation (MWh) 

at the unit level. Specific details about the EGU modeling for this proposal are 

available in the RIA and the IPM v3.02EISA Documentation. 

2) Following the overall IPM modeling, two primary data sets were used for this 

analysis of market concentration: the 2014 IPM parsed file containing operating 

projections at the EGU level and holding company information from the Velocity 

Suite Ventyx database.1

 Units were primarily matched to the parent or holding 

company using CAMD_ID or ORIS code. Some units were matched by hand due to 

differences in representing units in each database or multiple ownership of units. In 

the case of multiple owners, the generation was prorated using percentage of 

ownership information. 

3) Once EGUs were matched with their owners, we summed the total amount of 

generation owned by each company in each state. The results were sorted by state 

using pivot tables in Excel and compared to total generation for each state. This 

allowed EPA to analyze how much generation each holding company or parent 

owned in each state and calculate each company’s share as a percentage of total state 

generation. Many companies appear multiple times with their share of generation 

ownership in each state in which they have operations. Any owners with zero 

generation were excluded. Units that could not be matched have also been omitted. 

In three states, Florida, Missouri and Nebraska, the generation from unmatched EGUs 

was over 10 percent of the state’s total generation. However, excluding these units 

from the analysis does not change whether the states are considered concentrated or 

not. In Florida, these additional units would potentially make an already not highly 

concentrated state even less so. In the case of Missouri and Nebraska where two 

 

1

 http://www.ventyx.com/index.asp 

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companies own about 70 percent of the total generation in each state, including these 

units would not change the fact that they are considered highly concentrated markets. 

The excluded EGUs in the remaining states are generally a small percentage—5 

percent or less—of a state’s generation and are not believed to have a significant 

impact on the results that would materially affect EPA’s overall analysis of state 

electricity markets. 

Overall, results for amount of electricity generation, number of parent or holding 

companies, size of parent companies, and market share distribution varied widely from state to 

state. In all states (except Tennessee and the District of Columbia, which have only one owner 

and therefore no market share issues), there was at least one company with only a small share—

less than 10 percent—of total generation. Additionally, in most states, there was at least one 

large company with 25 to 50 percent of generation ownership. In extreme cases, one or two 

entities owned 90 percent or more of the power generation in a state. Another way to look at the 

results is that 38, or around 5 percent, of the largest generation owners region-wide control more 

than 40 percent of the generation in this analysis. Of the total 699 companies identified, 615 

companies own less than 10 percent of the generation in a state in which they operate (46 entities 

own between 10 – 25%). These results indicate that there may be disparities among covered 

sources in the allowance markets and that the capability to exert market power is likely. The 

results are displayed below in Table 1. In this table, small owners are those that are projected to 

own 10 percent or less of the state’s generation in 2014, medium owners own 10 – 25 percent, 

and large owners own more than 25 percent. 

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TABLE 1: PERCENT AND NUMBER OF COMPANIES IN EACH MARKET SHARE 

CATEGORY BY STATE 

Pct of Generation Owned 

(MWh) 

Number of Companies 

State Small Medium Large Small Medium Large Total

Alabama 15% 20% 65% 9 1 1 11 

Arkansas 38% 34% 28% 14 2 1 17 

Connecticut 18% 82% 0% 7 4 - 11 

Delaware 4% 0% 96% 4 - 2 6 

District of 

Columbia 

0% 0% 100% - - 1 1 

Florida 41% 31% 27% 28 2 1 31 

Georgia 16% 12% 72% 18 1 1 20 

Illinois 15% 23% 62% 15 1 2 18 

Indiana 28% 44% 28% 23 3 1 27 

Iowa 19% 0% 81% 56 - 2 58 

Kansas 15% 19% 67% 4 1 1 6 

Kentucky 27% 12% 60% 10 1 2 13 

Louisiana 29% 43% 28% 21 2 1 24 

Maryland 5% 0% 95% 8 - 2 10 

Massachusetts 19% 16% 65% 23 1 2 26 

Michigan 15% 24% 61% 27 1 1 29 

Minnesota 19% 23% 59% 26 1 1 28 

Mississippi 16% 14% 70% 11 1 1 13 

Missouri 10% 33% 57% 11 2 1 14 

Nebraska 10% 0% 90% 10 - 2 12 

New Jersey 31% 14% 55% 23 1 1 25 

New York 52% 48% 0% 50 4 - 54 

North Carolina 6% 0% 94% 8 - 2 10 

Ohio 16% 51% 32% 24 3 1 28 

Oklahoma 34% 26% 39% 20 2 1 23 

Pennsylvania 41% 59% 0% 44 4 - 48 

South Carolina 11% 11% 78% 6 1 2 9 

Tennessee 0% 0% 100% - - 1 1 

Texas 65% 35% 0% 78 2 - 80 

Virginia 31% 15% 54% 14 1 1 16 

West Virginia 1% 12% 87% 4 1 2 7 

Wisconsin 8% 50% 42% 19 3 1 23 

TOTAL 615 46 38 699 

To further examine the market power concentration, we used the Herfindahl-Hirschman 

Index (HHI) for the power sector in each state as a way to measure the size of the firms in 

relation to the industry and as an indicator of the amount of competition. HHI is a commonly 

accepted measure of market concentration that has been used by the U.S. Department of Justice, 

the Federal Trade Commission, and state attorney generals to measure market concentration for 

purposes of antitrust enforcement. The HHI of a market is calculated by summing the squares of 

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the percentage market shares held by the respective firms. A score of 1,800 or more indicates 

that the industry is highly concentrated and that the potential for market power may exist. 

According to our analysis, six states (AR, FL, IN, NY, PA and TX) had HHI scores below 1,800. 

The remaining HHI scores ranged from 1,817 in Louisiana all the way up to 10,000 in Tennessee 

and the District of Columbia. These collectively high HHI scores indicate that the electricity 

markets by state are exceedingly concentrated and that steps may be needed to ensure that 

markets operate as intended. Table 2 shows the HHI scores for each state in the Transport Rule 

region. Scores in some states are slightly inflated due to the exclusion of units that could not be 

matched to owners and were therefore omitted from the HHI calculation. 

TABLE 2: HERFINDAHL-HIRSCHMAN INDEX SCORES 

State HHI Score 

Alabama 4,715 

Arkansas 1,676 

Connecticut 1,869 

Delaware 4,652 

District of Columbia 10,000 

Florida 1,471 

Georgia 5,429 

Illinois 2,557 

Indiana 1,555 

Iowa 3,634 

Kansas 4,898 

Kentucky 2,176 

Louisiana 1,817 

Maryland 4,522 

Massachusetts 2,464 

Michigan 4,356 

Minnesota 4,022 

Mississippi 5,129 

Missouri 3,844 

Nebraska 4,121 

New Jersey 3,361 

New York 758 

North Carolina 4,709 

Ohio 2,040 

Oklahoma 2,090 

Pennsylvania 1,096 

South Carolina 4,068 

Tennessee 10,000 

Texas 956 

Virginia 3,254 

West Virginia 4,059 

Wisconsin 2,644 

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The preliminary analysis of the generation ownership in each state which showed that a 

small number of entities own a large share of generation combined with the HHI scores support 

EPA’s concern that market power problems may arise in states where dominant entities with a 

large share of allowances would be able to control the availability and prices of allowances in the 

market. The detailed spreadsheet results for the market concentration analysis described in this 

TSD, "Detailed Analysis of EGU Ownership by State,” are available in the docket for this 

proposal. 

Criteria for Auction Participation 

 Once EPA determined that the potential for excessive market power in numerous state 

allowance markets was likely, we decided that making a portion of allowances available to 

potentially disadvantaged entities through auctions would reduce that risk. As explained in the 

proposal, only entities projected to own 10 percent or less of the generation in a state would be 

eligible to participate in the state auction. EPA looked at a range of generation ownership 

percentages and determined that 10 percent would ensure sufficient participation and provide 

assistance for entities at a potential disadvantage in the allowance market. EPA believes that 

entities with greater than 10 percent ownership generally own multiple units, receive a 

considerable share of allowances, and would not need access to auctioned allowances. 

 The data show that using a 10 percent threshold would allow more than 85 percent of all 

entities to participate, excluding the very largest owners-- those with the potential to control the 

markets. Looking at the states individually, we project that at least 60 percent of the owners in 

every state in the program (except Tennessee and the District of Columbia which have only one 

EGU owner each) would be eligible and, in some states, up to 90 percent. At the 10 percent 

threshold, there is at least one large owner that would be required to contribute allowances to the 

auction. In addition, there are relatively few entities between 10 and 20 percent ownership share, 

indicating that the majority of entities are either large or small with only a small group in 

between. In some of the less concentrated markets, a threshold greater than 15 or 20 percent 

could possibly make all (or nearly all) entities eligible and leave no entities to supply allowances. 

 Similarly, if a threshold much below 10 percent is applied, then fewer entities will be 

eligible to participate in auctions, and they may actually have to contribute allowances and they 

may still face an unfair market. The 10 percent limit helps those potentially disadvantaged 

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entities and prevents the advantaged ones from controlling the allowance market. The number of 

entities between 5 - 10 percent of ownership region-wide is not large, but ensuring owners in that 

range access to allowances through the auctions keeps them from becoming potentially 

disadvantaged. A lower market share requirement would reduce the number of participants and 

auction competitiveness, whereas a greater number helps to ensure that auctions remain viable 

and that prices reflect their market values. In general, looking at the data available to EPA, the 

10 percent threshold for auction participation strikes the right balance between those who need 

access to allowances and those who have access and makes the field more level for all regulated 

entities. 

Percentage of Allowances in the Auctions 

EPA believes that the allowance distribution methodology including auctions described 

in the preamble would provide entities that own a small share of power generation with access to 

the allowances needed to cover their projected emissions. However, as described in the 

preamble, there is some amount of inherent variability in electricity generation from year to year 

that is not fully addressed through allocations. EPA analyzed the variability on a state by state 

basis for small entities to identify an appropriate size range for the state allowance auctions. The 

variability analysis for entities with a small market share is similar to the approach used for the 

variability analysis that was conducted for the State Budgets/Limited Trading remedy described 

in the proposal. This analysis supports EPA’s recommendation for somewhere in the range of 2 

to 5 percent of the total available allowances in each trading program in each state be auctioned 

to entities with a small share of electric generation in a state. 

1) Two primary data sets were used for this analysis: heat input data for 2002-2008 and 

unit level descriptions from the CAMD database and holding company information 

from the Ventyx database. Units were primarily matched using CAMD_ID or ORIS 

code. Some units were matched by hand due to differences in representing units in 

each database, or multiple ownership of units. In the case of multiple owners, the 

owner of the largest percentage was used. In a handful of cases, since multiple units 

were co-owned by the same parties, the second largest owner may have been listed as 

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Some units were excluded because the two data sets could not be matched. It is not 

expected that these exclusions would impact the analysis, and may in fact make the 

analysis more conservative (meaning find a greater variability) in its outcome. Only 

80 of the roughly 3,750 units included in the variability analysis were excluded 

because they could not be matched to a holding company. 

 

2) Emission rates used to create the state budgets were matched to each unit. Then, the 

heat input for each unit was multiplied by the emissions rate to get emissions for 

annual SO2 and NOx, and ozone season NOx. This provided emission totals that 

reflected only heat input variability and accounted for any controls known to be 

installed by the end of 2009. 

3) The next step involved rolling up data to the holding company level by state. We 

determined each holding company’s ownership by state using a pivot table. 

Companies with share of generation equal to 10 percent or less were considered small 

and identified as such. We then calculated combined annual emissions of small 

holding companies for each state using a pivot table. 

4) Finally, we calculated variability for the companies included for consideration 

because of their small market share. A line was fit to the emission trends for each 

state and pollutant. We found expected values for annual emissions for each state and 

pollutant using the fitted line. Then EPA calculated the differences between the 

expected and actual (calculated) emissions. We found standard deviation of 

differences; for 95 percent confidence interval, we multiplied by 1.65 (note this is 

one-tailed, since only positive deviations are problematic). After that, we divided the 

variability by the total state budget for each pollutant to determine percent of state 

budget represented by variability of small holding companies. Setting a 4 percent 

threshold, we looked at those cases more closely for outlier data and explanations for 

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TABLE 3: VARIABILITY OF ENTITIES WITH SMALL MARKET SHARE IN 

TRANSPORT REGION 

Standard Deviation/State 

Budget (95% confidence 

interval) 

 SO2 NOx OS NOx 

Alabama 0.27% 0.32% 0.58%

Arkansas 0.15%

Connecticut 3.20% 2.82% 3.36%

Delaware 0.91% 1.01% 1.50%

District of 

Columbia 

NA NA NA

Florida 3.22% 2.22% 1.74%

Georgia 0.34% 0.72% 2.16%

Illinois 1.92% 1.06% 1.53%

Indiana 1.31% 1.20% 2.11%

Iowa 1.67% 1.19% NA

Kansas 2.10% 1.85% 2.80%

Kentucky 3.87% 0.65% 3.43%

Louisiana 0.01% 2.51% 2.71%

Maryland 3.64% 1.80% 2.41%

Massachusetts 3.72% 6.42% NA

Michigan 0.47% 1.01% 2.25%

Minnesota 4.00% 3.09%

Mississippi NA NA 3.40%

Missouri 1.74% 0.60% NA

Nebraska 0.80% 0.55% NA

New Jersey 37.72% 6.64% 7.30%

New York 11.90% 5.70% 7.02%

North Carolina 0.34% 2.27% 3.72%

Ohio 2.78% 1.83% 3.79%

Oklahoma NA NA 1.45%

Pennsylvania 4.36% 1.17% 1.58%

South Carolina 5.73% 3.83% 4.00%

Tennessee NA NA NA

Texas NA NA 1.80%

Virginia 3.10% 3.73% 6.07%

West Virginia 1.00% 0.97% 1.52%

Wisconsin 2.39% 1.34% NA

NOTE: In NJ, large variability can be explained by large changes in heat input patterns at two plants. 

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For most states and pollutants, variability for holding company considered to have a 

small market share is less than 4 percent. For states that had variability greater than 4 percent, 

explanations for the high variability were found, including variability from one or two high 

emission units (often being used less over time in preference for lower emission units, reducing 

future impact of these units). Note that all entities will receive allowances through budget 

allocations regardless of their relative size. However, with variability, covered entities may need 

access to additional allowances at times. This analysis shows that the variability tends to be 

within about 4 percent for the smaller owners in most states and that a modest amount of 

additional allowances would help to ensure that they are able to meet their compliance 

obligations even when their budget allocations are insufficient. 

In a handful of states, an allowance pool for auctioning to small owners is less necessary, 

because the markets are not highly concentrated. However, for this option, EPA would 

implement a uniform allowance allocation method and auction format for all included states in 

each program. The detailed spreadsheet results for the variability analysis of small owners of 

power generation described in this TSD, "Detailed Analysis of Variability of Entities with Small 

Market Share," is available in the docket for this proposal.