Page 9 - Biofuels for a More Sustainable Future

2 Biofuels for a More Sustainable Future

(describing pilot projects or potential future developments) (compare: Lane,
2017). Due to a high feedstock variability accessible to be utilized for bio-
fuels generation the existing biofuels technologies and processes have
expanded over time thus creating a wide net of production opportunities
and innovation potential in this field.
Generally, biofuels technologies can be divided into “conventional” and
“advanced” biofuels (Fig. 1.1). Conventional biofuels (also called “first gen-
eration biofuels”) designate ethanol and biodiesel generated from eatable
crops. Advanced biofuels (encompassing the “second, third and fourth gen-
eration biofuels”) are defined as liquid fuels from nonfood/nonfeed sustain-
ably grown feedstocks and agricultural (municipal) wastes. The need for
advanced biofuels originated from a concern about the competition for nat-
ural resources (e.g., water, energy, land) between fuel and food production
(Rathmann et al., 2010; Harvey and Pilgrim, 2011, Ajanovic, 2011).
Accordingly, advanced biofuels cannot create any competition with food
crop production, while they need to meet higher sustainability require-
ments, that is, contribute to greenhouse gas (GHG) emission reduction
by a larger percentage than conventional biofuels.
The designation of biofuels “generations” is directly linked and subject
to the specific technology and feedstock used for biofuels production. It also
relates to the temporal development trends over years and the complexity of

Fig. 1.1 Biofuels technologies with corresponding development stages. (Authors’
presentation modified from Ziolkowska, J.R., 2014. Prospective technologies, feedstocks
and market innovations for ethanol and biodiesel production in the US. Biotechnol.
Rep. 4, 94–98; Ziolkowska, J.R., 2018. Introduction to biofuels and potentials of
nanotechnology. In: Srivastava, N., Srivastava, M., Pandey, H., Mishra, P.K.,
Ramteke, P.W. (Eds.), Green Nanotechnology for Biofuel Production. Biofuel and
Biorefinery Technologies. Springer, Basel, pp. 1–15.)