Technical and economic modelling of processes for liquid fuel production in Europe

The project which is described had the objective of examining the full range of technologies for liquid fuel production from renewable feedstocks in a technical and economic evaluation in order to identify the most promising technologies. The technologies considered are indirect thermochemical liquefaction (i.e. via gasification) to produce methanol, fuel alcohol or hydrocarbon fuels, direct thermochemical liquefaction or pyrolysis to produce hydrocarbon fuels and fermentation to produce ethanol. Feedstocks considered were wood, refuse derived fuel, straw, wheat and sugar beet. In order to carry out the evaluation, a computer model was developed, based on a unit process approach. Each unit operation is modelled as a process step, the model calculating the mass balance, energy balance and operating cost of the unit process. The results from the process step models are then combined to generate the mass balance, energy balance, capital cost and operating cost for the total process. The results show that the lowest production cost (L7/GJ) is obtained for methanol generated from a straw feedstock, but there is a moderate level of technical uncertainty associated with this result. The lowest production cost for hydrocarbon fuel (L8.6/GJ) is given by the pyrolysis process using a wood feedstock. This process has a high level of uncertainty. Fermentation processes showed the highest production costs, ranging from L14.4/GJ for a simple wood feedstock process to L25.2/GJ for a process based on sugar beet. The important conclusions are as follows: - In every case, the product cost is above current liquid fuel prices; - In most cases the feedstock cost dominates the production cost; -The most attractive products are thermochemically produced alcohol fuels