Terry,

Please see below for some questions from ADEQ.

1) 2012 Nuclear Capacity data used to perform step 4a of the Under Construction and At Risk 

Nuclear Generation were obtained from the http://www2.epa.gov/sites/production/files/2014-

06/20140602tsd-egrid-methodology_0.xlsx spreadsheet. These capacity values were verified 

with Nuclear Capacity values reported in EIA 860 Generator Spreadsheet. The calculation 

methodology described in the Goal Computation Technical Support Document pages 14 and 15 

was used to create the following formulas:

&   = (2012   × 5.8% +   )

&  (h) = &   × 8784 × 90%

Application of the above formulas yielded a value of 845,978 MWh, not 842,037 MWh. Are 

there any other factors EPA is considering that we did not identify in the TSDs that could 

account for this discrepancy?

2) Based on the GHG Abatement Technical Support Document, the proposed approach to 

calculating the Renewable Energy target for Arkansas is to apply an 8 % annual growth rate to 

our 2012 RE generation beginning in 2017 because Arkansas is included in the South Central 

region (GHG Abatement TSD pages 4-15 and 4-18). I have verified that the 2012 RE Generation 

Value and Total Generation value listed in the table on page 4 – 6 of the GHG Abatement TSD 

matches the EIA 1990 - 2012 Net Generation by State by Type of Producer by Energy Source 

(EIA-906, EIA-920, and EIA-923) spreadsheet. I then applied the following calculations to 

replicate EPA’s Existing and Incremental Annual RE values for Arkansas:

RE Generation 2017 (MWh) = RE Generation(2012) 

 (h) =   + (  × 0.08)

  

(h) =  ( ) + ( ( ) × 0.08)

Plant Name 

ORIS 

code

Generator 

ID

Fuel 

type

Nameplate 

Capacity

(MW)

Arkansas Nuclear 

One 8055 1 NUC 902.5

Arkansas Nuclear 

One 8055 2 NUC 942.5

2012 Total Capacity 1,845.00

Needs 5.13v3 Under Construction 0.00

At Risk (AR) per 5.8% in proposal 107.01

UC+AR Nuclear Capacity (MW) 107.01

UC +AR Nuclear Generation (MWh) 845,978.26
Where “i” is any year between 2018 and 2029

Should RE Generation reach RE percent generation target (20% from 2012 generation based on 

location in South Central region) during a given year, that generation target is kept at the same 

in subsequent years.

When performing these calculations, I noticed a discrepancy between the numbers I came up 

with and the numbers EPA gives in the Goal Computation spreadsheet TSD. See the table below

Do my formulas seem logical based on EPA’s language in the GHG Abatement TSD pages 4-1 

through 4-36? Are there any assumptions I am missing that might account for the discrepancy?

I realize that the NEEDSv5.13 database has 20 MW capacity of hydro coming online in 2015; 

however, EPA states that it did not include hydro in the proposed approach calculations so I 

think that this would not factor in.

More Questions:

EPA calculates an 827 lbs CO2 per kWh for NGCC in Arkansas, based upon a year in which average NGCC 

ran 32% of the time: 

There is a single large cogen that ran at 72% of the time at a calculated efficiency of 602 lbs 

CO2/kWh. This is the only NGCC unit with emissions below the “average” 827 lbs/mwh. Because the 

other NGCCs were at such a low level, this one cogen skews the average emissions rate significantly 

down during 2012.

The cogen unit will contribute nothing to re-dispatch because it is already above 70%.

All of the remaining NGCC fleet has emissions above the “average” 827 lbs CO2/Mwh. These aboveaverage-emissions units are the ones that would ramp up with re-dispatch.

EPA ADEQ

2012 1,660,370 1,660,370

2017 1,793,200

2018 1,936,656

2019 2,091,588

2020 Existing and Incremental RE 2,288,229 2,258,915

2021 Existing and Incremental RE 2,479,266 2,439,628

2022 Existing and Incremental RE 2,686,252 2,634,799

2023 Existing and Incremental RE 2,910,519 2,845,583

2024 Existing and Incremental RE 3,153,509 3,073,229

2025 Existing and Incremental RE 3,416,786 3,319,087

2026 Existing and Incremental RE 3,702,042 3,584,614

2027 Existing and Incremental RE 4,011,114 3,871,384

2028 Existing and Incremental RE 4,345,990 4,181,094

2029 Existing and Incremental RE 4,708,823 4,515,582
Furthermore, it is the least efficient units (with emissions of over 1000 lbs CO2/Mwh) that ran 11% of 

the time or less in 2012 (despite super-low natural gas prices, and precisely because they were 

inefficient). The efficient units ran close to 50% of the time (but still with emissions above our assigned 

average). 

So the theoretical expansion in Arkansas would be disproportionately among the units with the highest 

emissions rate, well above the EPA-calculated rate.

Because 68% of the Arkansas goal is based upon NGCC re-dispatch, assumptions about the emissions 

rate for re-dispatched NGCC are very significant for the magnitude of the Arkansas goal.

Why does EPA think that our re-dispatched NGCC emissions rate will reasonably be lower than every 

unit that could be re-dispatched to 70%?

The question of whether a state could split its plan between rate-based in one region of the state and 

mass-based in another came up on one of the numerous conference calls this week. It sounded to me 

like EPA would entertain this approach.

So, if it would not be too much further work for Terry, it might be useful to see what mass-based looks 

like for the SWEPCO territory or even SPP region.