4.5.5. Associated Impacts
There is concern over short- and long-term environmental and socioeconomic
effects of large-scale biofuel production. These concerns relate to the energy
balance of biofuel production, conversion, and use; soil and water quality effects;
poor resilience of monocultural plantations; and the implications of biofuels
for biodiversity, sustainability, and amenity (Cook et al., 1991; National
Audubon Society, 1991; Brown, 1998; Christian et al., 1998).
Large-scale bioenergy plantations that generate high yields with production
systems that resemble intensive agriculture would have adverse impacts in place
of natural forest. With the development of conversion technologies that are
efficient at small scales, however (Bowman and Lane; 1999; Larson and Jin, 1999;
Prabhu and Tiangco, 1999), transportation costs are reduced and large monocultures
are unnecessary (see Fact Sheet 4.21). Small-scale plantations
on degraded land or abandoned agricultural sites would have environmental benefits.
The key is to consider site-specific circumstances rather than make generalizations.
Significant amounts of fossil fuels are used in the production, harvest, and
transport of biofuels; the net carbon benefit of biofuels must account for this
fossil fuel use. Energy input-output ratios in biofuel production are 1:10 to
1:15 and improve to 1:30 (Turhollow and Perlack, 1991). As with fossil fuels,
overall system efficiency is lower because of the characteristics of conversion
processes (e.g., Graham et al., 1992; Matthews et al., 1994; Boman,
1996; Mann and Spath, 1997).
Biodiversity concerns relate to plantation species and plantation habitat conditions.
Plantations with only a small number of species achieve the highest yields and
the greatest efficiency in management and harvest, but good plantation design
now includes set-asides for native flora and fauna and blocks with different
clones and/or species. The variety of species in biofuel plantations falls between
that for natural forests and annual row crops. Research on multi-species plantations
and management strategies and thoughtful land-use planning to protect reserves,
natural forest patches, and migration corridors can help address these issues.
Concerns regarding food supply and access to land for host communities are
addressed through community-scaled plantations that feed small-scale conversion
technologies, meet local fuel and timber needs, provide employment with biofuel-powered
rural electrification, and export liquid fuel products (Read, 1999; Fact
Sheet 4.21). Higher incomes may enable communities to invest in modern food
production and replace traditional agriculture, which appears unsustainable
with predicted population and climate change. A barrier to community-scaled
biofuel systems is a lack of institutional and human capital to ensure biofuel
projects that meet local needs rather than foreign investors' carbon credit