With regard to the environmental costs, specifically in terms of greenhouse gases, 15 kwh per day in electricity in New Jersey will set you back 6.5 kg of CO2,

With regard to the environmental costs, specifically in terms of greenhouse gases, 15 kwh per day in electricity in New Jersey will set you back 6.5 kg of CO2, while your 4 gallons of gas per day will emanate 36 kg, so almost 6 times more.