Landfill Gas (LFG) Emission Adjustments about open-grid-emissions HOT 2 OPEN

Regarding the NOx adjustement for LFG

According to AP-42,

Converting 39 lbNO2 / million scf to lb / MMBtu using a factor of 500 BTU/scf results in a value of 0.078 lb/MMBtu.

As a side note, the existing value of 0.02 tons / MMBtu appears to be incorrect. Converting 39 lb/million scf to tons/MMbtu results in a value of 0.000039 tons / MMBTu. For 0.02 tons/MMBtu to be correct, the lb/million scf value would have to be approximately (0.02 x 500 x 2000=) 20,000 lb / million scf.

The methodology then involves subtracting the baseline NOx emissions from flaring from the unadjusted NOx emissions

from open-grid-emissions.

For now, we are implementing this fix using the value of 0.078 lbNOx/MMBtu.

To prevent negative emissions, we use the formula
adjusted emissions = MAX(0, unadjusted_emissions - (fuel_consumed_mmbtu * 0.078))

from open-grid-emissions.