[Thesis]. Manchester, UK: The University of Manchester; 2020.
The development of sustainable bioenergy plays an active role in the decarbonisation
of the energy sector. Unlike other renewables, bioenergy has the potential to expand
its applications beyond climate change mitigation by providing complementary environmental
and socio-economic benefits that support the Sustainable Development Goals. The deployment
of bioenergy could be particularly beneficial in the rural areas of many low and middle-income
countries where traditional uses of biomass still prevail.
Locally available biomass in rural areas, such as agricultural residues, could be
harnessed in more efficient and sustainable manners, and this could be promoted with
bioenergy development. The roll-out of these technologies also arises challenges across
the environmental, economic and social dimensions, especially for emergent technologies.
Tackling these challenges requires a wider understanding of bioenergy technologiesÃ‚
impacts across these dimensions, and this could be achieved through comprehensive
and integrated assessments that investigate these dimensions. This research, therefore,
seeks to gain further knowledge to unfold the following questions; how bioenergy technologies
using agri-residues could be sustainably and feasibly deployed?, and what are the
wider co-benefits, from a sustainable development perspective to rural communities
This study aimed to evaluate the feasibility of small-scale gasification systems to
generate power and heat, using indigenous agricultural residues, to meet the energy
demand of rural areas. Considering also that bioenergy is set within local contexts,
this research was framed in a case study on the coffee sector in Colombia, using coffee
stems as feedstock. The methodology in this research consisted of a combination of
multidisciplinary approaches, comprising process modelling for a technical assessment,
lifecycle assessment (LCA) and techno-economic analysis.
The results of the technical assessment indicate that the gasification of coffee stems
could generate a fuel gas suitable for power generation in engines. In addition, the
heat recovery and integration to supply the demand for coffee processing could enhance
the conversion efficiency of the system. The LCA results show that deploying the coffee
stems gasification-CHP system could impact positively on many environmental issues,
including climate change, when traditional biomass uses and energy production using
fossil fuels are replaced. However, trade-offs should be considered for certain scenarios,
such as those replacing grid electricity with high-hydropower generation.
The evaluation of the economic feasibility indicates that costs of power generation
in the gasification systems could equalise the costs of Diesel-power generation when
the system reaches high capacity factors. Matching the grid-electricity tariffs is
more difficult to attain even at high capacity factors. The integration of the heat
vector in the coffee processing chain contributes to fuel savings and could be translated
into a heat credit that reduces the power generation costs.
The key findings from this research were integrated under a multidimensional framework
that prompted discussions on pivotal drivers, synergies and trade-offs of this bioenergy
system. The synergies relate to the importance of balancing the biomass availability
and the energy demand in context-specific agricultural sectors. It also emphasises
the usefulness of harnessing the biomass conversion by implementing heat recovery
pathways in the system, and of maximising the utilisation of the system (increasing
the capacity factor) to enhance the systems feasibility.
The framework also contributes to understanding how bioenergy from agricultural residues
could contribute achieving the Sustainable Development Goals. The multidimensional
framework highlights potential co-benefits to rural communities, in relation to improving
energy access and health, promoting sustainable agriculture and economic growth, and
reducing inequalities in rural areas.
In conclusion, this research supports the overarching argument that bioenergy technologies
have the potential to deliver energy demands in rural areas while tapping the potential
of agricultural residues. Overcoming barriers to these systems deployment is still
challenging. Yet, the synergies identified across all the dimensions could help to
attain the systemÃƒÃ‚s feasibility and sustainability. Furthermore, wider societal
co-benefits to rural communities could also be realised, as suggests the strong correlation
between bioenergy and the Sustainable Development Goals.