How many gallons of fossil fuel to make a gallon of each of the following?

synfuel
soy ethanol
cellulosic electricity

To find the amount of fossil fuel required to produce a gallon of each of the mentioned fuels, we need to consider the Energy Return on Investment (EROI) or Energy Efficiency of the production processes. The EROI tells us the ratio of energy output to energy input.

1. Synfuel: The production of synfuel generally involves processes like coal-to-liquids or gas-to-liquids, where coal or natural gas is converted into liquid fuel. The EROI for synfuel production varies depending on the technology used and the specific feedstock, but it is typically around 0.75 to 0.8. This means that for every unit of energy output (1 gallon of synfuel), around 0.75 to 0.8 units of fossil fuel are consumed.

2. Soy Ethanol: Soy ethanol is produced from crops like soybeans through a process called fermentation. The EROI for soy ethanol production is around 1.3 to 1.5, implying that for every unit of energy output (1 gallon of soy ethanol), around 0.67 to 0.77 units of fossil fuel are consumed.

3. Cellulosic Electricity: Generating electricity from cellulosic biomass (e.g., agricultural residues, dedicated energy crops) can be done through different methods such as thermal conversion (e.g., combustion) or biochemical conversion (e.g., anaerobic digestion). The EROI for cellulosic electricity production can vary depending on the specific technology and feedstock. On average, it is estimated to be around 10, which means that for every unit of energy output (1 kWh of electricity), only about 0.1 units of fossil fuel are consumed.

It's important to note that these values represent average estimates and can vary depending on various factors, such as the specific production process, technology advancements, and the efficiency of the operations.