Keystone Unit 1 CAMD Analysis
Updated: September 24, 2021
The goals of this analysis is to contextualize PA's proposed limits for Keystone Unit 1 with historic data. I evaluated:
 Ozone season data only
 I removed partial hours and substitute data hours

These tables summarize the historic data in a few different ways:
 Each table shows a different value
 The first table shows the best (minimum) value
 The second table shows the average value
 The third table shows the 99[th] percentile value
 Within each table, the selected metric is either:
 The best year drawn from 2003-2020
 The third best year drawn from 2003-2020
 The best year drawn from 2010-2020
 The third best year drawn from 2010-2020

Note: the best or third best year is selected based on the overall ozone season average NOX rate.

There was interest in what the daily average translates to in lb/day, so I have included that value in the Daily Limit tables. (For reference, the proposed 30-day rolling average limit of 800 lb/hr * 24 hrs = 19,200 lb.)

Daily Limit
Compare to: 0.3 lb/mmBtu daily average limit

Metric
Time Period
Year
Best daily average NOX Rate (lb/mmBtu)
Daily NOX Mass (lb/day) on that day
Best year
2003-2020
2003
                                                                          0.035
                                                                          6,258
3[rd] best year
2003-2020
2005
                                                                          0.037
                                                                          6,199
Best year
2010-2020
2010
                                                                          0.045
                                                                          8,333
3[rd] best year
2010-2020
2018
                                                                          0.061
                                                                         11,614

Metric
Time Period
Year
Average daily average NOX Rate (lb/mmBtu)
Average daily NOX Mass (lb/day)
Best year
2003-2020
2003
                                                                          0.043
                                                                          7,604
3[rd] best year
2003-2020
2005
                                                                          0.045
                                                                          7,918
Best year
2010-2020
2010
                                                                          0.052
                                                                          9,567
3[rd] best year
2010-2020
2018
                                                                          0.099
                                                                         17,040

Metric
Time Period
Year
99[th] Percentile daily average NOX Rate (lb/mmBtu)
99[th] Percentile daily NOX Mass (lb/day)
Best year
2003-2020
2003
                                                                          0.111
                                                                         13,862
3[rd] best year
2003-2020
2005
                                                                          0.154
                                                                         13,124
Best year
2010-2020
2010
                                                                          0.083
                                                                         14,366
3[rd] best year
2010-2020
2018
                                                                          0.288
                                                                         29,820

30-Day Rolling Average Mass Limit
Compare to: 800 lb/hr 30-day rolling average limit

Metric
Time Period
Year
Best 30-day rolling average NOX Mass (lb/hr)
Best year
2003-2020
2003
                                                                            309
3[rd] best year
2003-2020
2005
                                                                            314
Best year
2010-2020
2010
                                                                            384
3[rd] best year
2010-2020
2018
                                                                            592

Metric
Time Period
Year
Average 30-day rolling average NOX Mass (lb/hr)
Best year
2003-2020
2003
                                                                            323
3[rd] best year
2003-2020
2005
                                                                            336
Best year
2010-2020
2010
                                                                            414
3[rd] best year
2010-2020
2018
                                                                            719

Metric
Time Period
Year
99[th] Percentile 30-day rolling average NOX Mass (lb/hr)
Best year
2003-2020
2003
                                                                            349
3[rd] best year
2003-2020
2005
                                                                            371
Best year
2010-2020
2010
                                                                            455
3[rd] best year
2010-2020
2018
                                                                            883


