This chapter provides a brief overview of the contents of the book.
The transportation industry is still largely reliant on fossil fuels, whose use and extraction pose significant environmental costs. Biofuels produced from renewable resources like biomass offer a more sustainable alternative and their production currently amounts to 143 billion litres on a yearly basis. However, it is important that production methods should be energy efficient and that feedstocks should not compete with food sources. Biofuels that meet these criteria are referred to as second-generation biofuels.
Since approximately 2012, the EU Commission has introduced new policies aimed at starting the transition from conventional (crop/food-based) biofuels to biofuels from non-food feedstock that deliver greater climate benefits. In 2015, the EU parliament also set a 6% limit for the maximum contribution of first-generation biofuels and bio liquids to energy consumption in transport for the year 2020.
During the last decade, financial stress in the European transportation biofuels industry has been seen. There are huge differences between EU installed production capacity and actual EU production in both the fuel ethanol and the biodiesel industries (see also Section 2.1 and 4.1).
However, a positive side effect of this current financial situation is that innovation in industrial processes has been stimulated and transitions towards second generation biofuel production, along with improved efficiency and better financial results, may succeed more easily.
According to the authors, both the prospect of (future) declining oil production and unattractive profit margins for current production processes have resulted in the urgent need for new and more energy efficient production pathways for transportation biofuels.
With this book, we intend to provide insights into promising new and innovative pathways for the biological production of the current main transportation biofuels: biodiesel, ethanol and methane. The pathways we intend to describe are non-conventional and should provide higher product yields, less stringent feedstock specifications, lower chemical additive demands, lower waste production and much better energy balances when compared to the more traditional production methods for biodiesel and ethanol.
The two pathways described in Chapters 2 and 3 are both based on the biological conversion of syngas into either ethanol or methane. These two pathways are intended to have amongst other characteristics higher product yields, high energy production efficiencies, less complicated syngas cleaning and they can be produced from various kinds of lignocellulosic biomass. For these two pathways, a lot of attention is given to technological and engineering aspects like gasifier selection, syngas cleaning, process design, reactor configuration and product upgrading (be it either ethanol distilling and dehydration or biogas purification).
Enzymes can be used as catalysts in order to produce biodiesel that consists of 100 wt-% methyl- or ethylesters. The pathway described in Chapter 4 involves the use of enzymes in the production of biodiesel, which has the advantage of being more efficient, producing less glycerol waste and obtaining a 10% higher product yield. In addition to this, the biorefinery concept is also introduced in this book, where a biodiesel is produced in combination with valuable chemicals, which improves the economic benefits of the process, making it more feasible and efficient.
Chapter 5 focusses on biomass availability and biofuel sustainability, and additionally describes novel production pathways and transportation fuels that look promising for replacing existing processes and/or fuels in the future. Hydrogen produced via either electrolysis or water splitting is combined with CO2 to form either conventional fuels or new promising fuels like formic acid. Lastly, the use of metals like iron is also discussed for application as future fuels for heavy trucks.
The content of this book provides not only a reflection of extended desk research but also shows practical experimental results from an engineering perspective. For each of the pathways, there is a comparison made to competing production methods (research and patents), bacteria/enzymes (types, metabolism, reactions, inhibition, and cultivation), process designs, and pilot or laboratory experiment results (when available), a discussion of fuel specifications and demands, and a balanced discussion of the general financial and technical feasibility.
Therefore, it is the authors’ intention to create a book that is appealing to scientists and students for educational purposes as well as professionals within the current biofuels industry with a special interest in innovation and novel pathways.