Comparing Renewable Fuels

California stands to reap the environmental, economic and security benefits of biofuels. Sustainable Conservation is contributing to this effort in several areas: biomethane, biodiesel and new alternatives to gasoline.

Biomethane has a much higher energy yield than ethanol or biodiesel. Energy yield is the ration of the energy output to the energy input (for producing the fuel). A higher ration indicates that the fuel is produced more efficiently. Biomethane yields 9 units of energy for every unit of energy used to process the fuel, compared with 3 for biodiesel and 1 for ethanol.

Renewable Vehicle Fuels
Potential Calif. Feedstocks Displaces Approximate Energy Yield*
Biomethane Livestock manure, landfill gas, food-processing waste, other organic material Diesel, compressed or liquified natural gas 9:1
Biodiesel Sunflower, safflower, canola oils; used cooking oil/grease; crop waste such as walnut shells and orchard prunings Diesel 3:1
Alcohols (ethanol, butanol, etc.) Sorghum, sugar beets; sugar cane; potentially grasses, woody biomass and other plant-based sources Gasoline 1:1
* Energy yield is the ratio of the energy output to the energy input for growing and producing a fuel. A higher ratio indicates a higher energy yield per unit of energy input.