text: In general , if that emission level is exceeded in 2018 or later , the trading program , which reflects the back-stop trading program already developed by the WRAP and is modeled after the new nationwide sulfur dioxide trading program , will require a separate set of allowances for affected EGUs in the WRAP State to be held covering emissions starting the third year after the level is exceeded .
  
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  If that emission level is exceeded in 2023 or later , it will require a separate set of allowances .