if I want to update the Non methane VOC that is 600 kg/TeraJoue to 26.8 kg/Mg. do I also have to change the Method from Per Unit energy consumed to Total annual loading?

Demand\Residential\Cooking\Traditional Stove Wood\Non Methane Volatile Organic Compounds

Since the units imply that NMVOC emissions are dependent on the amount of fuel consumed, the method should still be "Per Unit Energy consumed". Even though the denominator is in units of mass, the Net Energy Content stored in the Fuels Database is used by LEAP to make the necessary conversions from mass to energy.

For your information, the "Total Annual Loading" is used if the total annual emissions is known. For example, this method could be used when the total energy consumption for a demand sector is specified in a "Technology with Total Energy" branch and the emissions for the sector are known.

Hope this helps,

Emily