Table 1 Calculation example of emission gases by Alnus nepalensis biomass combustion.

Calculation of CO₂ emission

CO₂ emission factor: 112 kg dry matter TJ^-1 (typical for wood combustion)

Higher Heating Value = 17,932,000 J kg^-1

CO₂ emission factor = 112 kg TJ^-1,

we can follow these steps:

Convert HHV to TJ kg^-1:

Since 1 TJ = 10¹² J, we need to convert the HHV from J kg^-1 to TJ kg^-1:

HHV in TJ kg^-1 = 17,932,000 J kg^-1 / 10¹² = 1.7932 × 10^–3 TJ kg^-1

CO₂ emission (kg) = Mass of fuel (kg) × CO₂ emission factor (kg TJ^-1) × HHV (TJ kg^-1)

CO₂ emission (kg) = 1 kg × 112 kg TJ^-1 × 0.017932 TJ kg^-1

Therefore, the CO₂ emission from stationary fuel combustion with an HHV of 17,932,000 J kg^-1 and using the default CO₂ emission factor of 112 kg TJ^-1 would be approximately 2.0083 × 10^–3 kg of CO₂ per kg of fuel

Calculation of CH₄ emission

CH₄ emission factor: 30 kg dry matter TJ^-1

Hight Heating Value = 17,932,000 J kg^-1

CH₄ emission factor = 30 kg TJ^-1

Convert HHV unit to TJ kg^-1

1 TJ = 10¹² J

HHV from J kg^-1 to TJ kg^-1:

HHV in TJ kg^-1 = 17,932,000 J kg^-1 / 10¹² = 1,7932 × 10^–5 TJ kg^-1

CH₄ emission (kg) = Mass of Fuel (kg) × CH₄ emission factor (kg TJ^-1) × HHV (TJ kg^-1)

CH₄ emission (kg) = 1 kg × 30 kg TJ^-1 × 1,7932 × 10^–5 TJ kg^-1

CH₄ emission (kg) = 5.3796 × 10^–4 kg of CH₄ per kg of fuel

Calculation of N₂O emission

N₂O emission factor 4 kg dry matter/TJ

Hight Heating Value = 17,932,000 J kg^-1

N₂O emission factor = 4 kg TJ^-1

Convert HHV unit to TJ kg^-1

1 TJ = 10¹² J

HHV from J kg^-1 to TJ kg^-1:

HHV in TJ kg^-1 = 17,932,000 J kg^-1 / 10¹² = 1.7932 × 10^–5 TJ kg^-1

N₂O emission (kg) = Mass of Fuel (kg) × N₂O emission factor (kg TJ^-1) × HHV (TJ kg^-1)

N₂O emission (kg) = 1 kg × 4 kgTJ^-1 × 1.7932 × 10^–5 TJ kg^-1

N₂O emission (kg) = 7.1728 × 10^–5 kg of N₂O per kg offuel

The concept of global warming potential (GWP) was introduced in IPCC –AR1 (Shine et al. 1990) to compare the greenhouse effects of different greenhouse gases relative to a reference gas, normally taken as carbon dioxide, under this definition, CO₂ would have a GWP value of 1

Alnus nepalensis

Total GWP = (GWP of CO₂ × CO₂ emissions) + (GWP of CH₄ × CH₄ emissions) + (GWP of N₂O × N₂O emissions)

Total GWP = 1 × 2.0083 × 10^–3 + 29.8 × 5.379 × 10^–4 + 273 × 7.1728 × 10^–5

Total GWP = 0.0376 kg CO₂e

This calculation is by 100 years based GWP of emission gases followed AR6 ⁷