Techno-economic evaluation of spruce to ethanol biorefinery

Production of ethanol from any lignocellulosic material will also lead to the production of several by-products. The easy conceivable products from a bioethanol biorefinery or bioenergy combine is ethanol, biogas, solid lignin, electricity and heat (for district heating). Depending on the configuration of the production plant, the feedstock and processing parameters the product distribution between the products can be altered to some extent. The process configuration will also to some extent influence the investment and production cost of the processing plant. Also, the location of the processing plant will influence the transportation cost of the raw materials and products as well as the possibility to deliver the products to a grid (applicable for electricity, district heat and biogas).  

In this investigation ethanol production from spruce wood has been evaluated in a Swedish perspective. Aspen plus and Aspen process economical evaluator were used to solve mass and energy balances for the ethanol production plant and to estimate the production cost of the biorefinery. Databases for district heating networks and forestry production in a Sweden were used to evaluate how, and to which extent a production plant could be integrated with the raw material supply and the product distribution.

The results show that the minimum ethanol selling price is greatly influenced not only by the incomes from by products, but also on the possibility to efficiently integrate the production with surrounding society.