How to measure fuel efficiency, energy costs, and carbon .
· Oil benefits from having higher energy efficiency than propane giving oil 30% lower CO2 emissions pound for pound. Figure 3 Pounds of CO2 by Fuel Type. Natural gas, because of its low carbon content and high fuel efficiency, achieves lower CO2 emissions than oil, propane, or coal. Natural gas produces 46% less CO2 than coal and 10% less than ...