Page 239 - Biofuels for a More Sustainable Future

214 Biofuels for a More Sustainable Future

Within the renewable energy sources, bio-energy arising from biomass
represents the largest one, accounting for roughly 10% of the world’s total
primary energy supply (IEA—International Energy Agency, 2012).
It provides an alternative to fossil-based energy (Iakovou et al., 2010) and
can contribute to the bio-economy and the circular economy (European
Commission, 2015).
The use of biomass is expected to increase in the next decades, also due
to the population growth (Cellura et al., 2014). In detail, the technical
potential for biomass is estimated to be possibly as high as 1500EJ/year
by 2050, although most biomass supply scenarios that take into account
sustainability constraints indicate a potential of between 200 and 500
EJ/year (excluding aquatic biomass). Forestry and agricultural residues
and other organic wastes would provide between 50 and 150EJ/year,
while the remainder would come from energy crops, surplus forest
growth, and increased agricultural productivity (WEC—World Energy
Council, 2013). The quantification and characterization of organic waste
(including food waste and residuals from livestock) along the food supply
chainhavebeenprovedtobecrucial forthe identificationofpotential
applications for waste valorization, reducing the overall impacts in a life
cycle perspective and encouraging the production of useful coproducts
(Corrado et al., 2016).
Non-OECD countries are the main users of biomass. In these countries,
traditional biomass (including wood, charcoal, agricultural residues, and ani-
mal dung) is still the main source of energy used for cooking, water and space
heating. However, often the biomass comes from unsustainable sources,
leading to deforestation and soil degradation, and it is burned in very low
efficient stoves. Thus the use of biomass can potentially create environmen-
tal and health problems unless more efficient stoves and fuels (biogas, etha-
nol) are deployed.
Thus the creation of a sustainable energy supply chain from biomass, and
in particular from biomass wastes, is important to manage the potential envi-
ronmental issues related to its use, especially in those countries where it is
one of the main sources of energy.
Tunisia is one of the few developing countries that developed a proactive
policy for the promotion of renewable energy and energy efficiency already
in 1985 (GIZ—Deutsche Gesellschaft f€ur Internationale Zusammenarbeit,
2012). However, renewable energy plays a minor role in the energy supply:
in 2014 the percentage of renewable energy in the Tunisian electricity mix
was evaluated at less than 2% of annual national electricity production