You cannot convert watts to pounds of CO2, its just not possible, its like converting inches into giant red hot air balloons, there is no conversion rate for it. If all your power comes from wind and hydro then its a 1:0 ratio, if all your power comes from burning coal in a fire pit then its a higher ratio, but without knowning exactly where your power comes from and what percentage comes from where you cant come anywhere close to guessing how many pounds of CO2 come from each kW of power produced.