Living Building Challenge 4.0

Calculations

SURPLUS RENEWABLE ENERGY CALCULATIONS

Note:

  • PP kWh = Excess kWh during performance period. 


  • EPA Grid Factor = EPA factor (tCO₂e/kWh), taken from EPA eGRID Summary Table for project 
subregion (total output emission rate).
 Note: The values taken from the eGRID table need to be 
converted from lb/MWh to ton/kWh by dividing by 2×10⁶ 

  • PP tCO₂e =
tCO₂e avoided due to excess generation during performance period.

Step 1 – 
Convert eGRID factor from lb/MWh to ton/kWh by dividing by a factor of 2×10⁶.


Step 2 – Multiply excess kWh fed back into the grid during the performance period by the EPA grid factor 
for project subregion.

  • (PP kWh) x (EPA grid factor) = (PP tCO₂e)

Step 3 – Multiply the tCO₂e avoided due to excess generation by 10 years.

  • (PP tCO₂e) x 10 years = Total tCO₂e credit toward carbon offset

EXAMPLE CALCULATION

Assume a project in the Pacific Northwest producing 1000 kWh of surplus during its 12-month performance period.

Step 1 – 
Convert eGRID factor from lb/MWh to ton/kWh by dividing by a factor of 2×10⁶.

  • 635.5 lb CO₂e / (2×10⁶) = 0.0003177 tCO₂e/kWh

Step 2 – Multiply excess kWh fed back into the grid during the performance period by the EPA grid factor for project subregion.

  • (1,000 kWh) x (0.0003177 tCO₂e/kWh) = 0.3177 tCO₂e 
 



Step 3 – Multiply the tCO₂e avoided due to excess generation by 10 years.

  • (0.3177 tCO₂e) x 10 years = 3.177 tCO₂e credit toward carbon offset