Mexico City, located in a highland area, 2250 m above sea level and approximately 250 km from the ocean, suffers from water shortages because its population exceeds its environmental capacity. The WEA scheme is applied to Mexico City, and the amount of LCCO2 reduction is examined. 0.45 kg-CO2/kWh was used as the LCCO2 emission factor for fuel-based electricity in Mexico. Figure indicates when the supply of electricity as electricity is 0%, the LCCO2 emissions increases unless more than 90% of the PV electricity is allocated to ammonia synthesis.