Page 49 - Advances in Eco-Fuels for a Sustainable Environment

26 Advances in Eco-Fuels for a Sustainable Environment

and the latest feedstocks and technologies for different ecofuels will be analyzed,
focusing on yields and perspectives.

2.3.2.1 Biodiesel and bioethanol
Biodiesel and bioethanol produced in the EU are almost completely used in blends
with fossil fuels (gasoline and diesel), hence their development perspectives are
closely bound to the mixing quotas allowed by the member states. In Germany,
the overall incorporation rate (for biodiesel and bioethanol) has been 6.25% since
2009. Italy and the UK are still far from their 2010 targets (4.5% and 3.9%, respec-
tively) while France is the most progressive of all, with 7.57% compared to 5.15% (EU
average target).
The reasons for Europe favoring biodiesel production are both historical and eco-
nomic. The most-used motor fuel in the EU is still diesel. Moreover, the continent is
currently a net importer of mineral diesel and a gasoline exporter, therefore the pri-
ority of EU policy has always been to search for a valid substitute for mineral diesel. In
recent years, a worldwide scandal exploded wherein several EU and non-EU car man-
ufacturers were found “cheating” on antipollution measures, specifically concerning
diesel engine standards. EU political representatives, as a consequence, went so far as
imagining an imminent full repeal of diesel engines on the continent, which would,
however, also hamper the market for the fuel’s ecological version.
From the economic point of view, EU bioethanol production traditionally relied on
crops unsuitable or uncompetitive respective to, for example, the Brazilian market,
based on sugarcane with an energy productivity 4–7 times higher than EU’s wheat,
corn, and sugar beet while biodiesel feedstocks are reasonably productive
(Table 2.7). While the composition of biodiesel depends on the composition of the
parent feedstock, its physical and chemical properties are similar to those of conven-
tional diesel. Biodiesel is considered safe for the environment, showing insignificant
contribution of carbon dioxide and particulate emissions.
Chemically, biodiesel is a mixture of fatty acid methyl-esters derived from either
edible or nonedible oils. The main challenge in biodiesel production is to minimize its
production cost, in which the selection of feedstocks and catalysts may affect costs up
to 75%. The use of edible oils sparks the issue of food security while nonedible oils
require additional pretreatment steps, due to due to their high fatty acid and moisture
content. Nevertheless, the use of spent oils has gained attention, due to its effective
elimination of disposable oils. Oil wastes are in fact inexpensive to procure and harm-
less to the environment if properly disposed of [27]. Sources such as algal oil, micro-
algae, jatropha, and grease were initially reported to have the potential to reduce
production costs by 60%–90% [28]. New third-generation biodiesel from high oil-
content microalgae could possibly provide sustainability of this type of fuel in the
future. Algae in fact seem to be the most promising feedstock, with potential oil con-
tent that could be a hundred times more than other available sources. The main advan-
tage of algal biomass is its high photosynthetic efficiency and high productivity,
where the main difficulty lies in the extraction of oil.