Bioenergy resources from waste, energy crops and forest in Los Ríos Region (southern Chile) - A systemic approach based on sustainability on designing a bioenergy area
by Alfredo Nicolas Erlwein-Vicuna
Date of Examination:2016-06-29
Date of issue:2016-07-01
Advisor:Prof. Dr. Hans Ruppert
Referee:Prof. Dr. Hans Ruppert
Referee:Prof. Dr. Martin Kappas
Referee:Prof. Dr. Renate Bürger-Arndt
Referee:Prof. Dr. Christoph Dittrich
Referee:Dr. Christian Ahl
Referee:Prof. Dr. Peter Schmuck
Persistent Address:
http://dx.doi.org/10.53846/goediss-5722
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Abstract
English
As many countries today, Chile is facing the taking off of renewable energies. Los Ríos Region in south-central Chile shows one of the highest biomass productivity. Therefore, in the quest for a scientific analysis of sustainable solutions a research question was set, to look for the best, most sustainable bioenergy production concept that could be developed in Los Ríos Region. To answer the research question, systemic multiscale quantitative/qualitative multi- and inter-disciplinary processes of selection and elimination of alternatives are carried out. This process follows a classical discarding method to obtain the best bioenergy alternatives. Every step corresponds to a chapter in the text as follows: Total possibilities: The limitations of strictly quantitative approaches are explored. In order to get solutions, these approaches have to be complemented with qualitative and transdisciplinary methods General quantitative level: The results of the international research on sustainability and techno-economic performances of different biofuels are compiled. As particular methodologies result in different formats, the information is gathered and processed by a synthesis method. Relevant differences among different biofuels are found, but also differences among results of different authors regarding the same biofuels. The ranking of the studied biofuel according to their environmental performances give the following order from best to worst: biofuels from residues (liquids and gaseous, including all biofuels from lignocellulosic biomass), biogas, biodiesel and bioethanol. Specific crops and geographic conditions may change the ranking in specific cases. Correlations are found between greenhouse gas (GHG) reduction and cultivation systems, as well as GHG reduction and the output/input energy ratio. Prioritized qualitative level: Components of a bioenergy system are selected according to local specifications. With such a set of selected components, a network analysis using Ucinet-Netdraw software is carried out (Borgatti, S.P., Everett, M.G. and Freeman, 2002), from which an index of network connectivity is developed for every energy carrier analysed. Among biofuels, biomethane has the best score, followed by syngas and alcohol in second place. Regional quantitative level: The biomass and bioenergy potential of the Los Rios Region is estimated for energy crops, urban and industrial organic waste and slurry from cattle production. The program BioStar is successfully validated for the Region and then used for modelling the productivity of energy crops. The results suggest that about 332,400 hectares, equivalent to 18.1% of the region’s surface area, currently covered dominantly by grasslands, could potentially be used to grow energy crops. This area could provide 2,96 million m3 of biogas from wheat or 4,98 million m3 from maize. In a region that consumes 553 GWh and produces 771 GWh of electricity, the potential production of electricity from cogeneration of biogas could be 6,809 GWh from wheat or 11,449 GWh from maize respectively. Therefore, the electricity that could be produced from maize in this region would account for over 20 times the consumption of the region, equivalent to 19% of the national electric production. Maximum yields of 22.1 t DM/ha for wheat and 33.9 t DM/ha for maize are calculated, which is similar to the empirical data in the region. Regarding cogeneration of other sources, the regional potentials are: Industrial and urban organic residues 71.5 GWh, slurry (theoretical maximum) 560 GWh. Local qualitative level: The German bioenergy village concept is tested for Los Ríos Region. The heat from biogas of a heat and power cogeneration unit can be sold in Germany for a considerably higher price than in Chile. After a qualitative analysis, three alternatives for bioenergy village concepts are proposed: a) BEV1, a rural village with a (non-electric) biogas network, b) BEV2, an urban area with a heat network, and c) BEV3, an urban community with cogeneration of power and heat from organic municipal solid waste (OMSW). BEV1 would allow each family to reduce their firewood demand by 62% by changing the type of stove and using green biomass (grass or crops silage) from 140 to 1,200 m2 for completely energy self-sufficient cooking and drastically reducing air pollution at the same time. BEV2 would provide more energy efficiency and comfort, but needs urban settlements. BEV3 is presented in detail in the next level. Local quantitative level: A quantitative study of the biogas potential from the organic fraction of Valdivia’s waste is performed with the goal to make the Isla Teja campus of the Universidad Austral de Chile in Valdivia (UACh) independent of external power sources. The sustainability performance of such a system is compared for three situations: S0) the current situation, S1) an energy crop based system, and S2) an OMSW based system. As was expected, the sustainability performance of the energy supplied by biogas from crops was positive in relation to the current situation, but the energy production from OMSW was much more sustainable concerning land use, noxious gases, transportation, water and soil pollution, as well as nutrient recycling. The greenhouse gas (GHG) reduction of the energy crop-fed campus is positive or negative depending on whether or not indirect land use changes are considered in the calculations. However, an outstanding GHG reduction of 940% is reached when using OMSW, since the release of methane gas from the landfill is avoided. Finally, an energy crop-fed campus would reduce its energy costs by 30%, whereas an OMSW-fed campus would increase them by 59%. Epistemological considerations: This chapter explores the limitations of quantitative and disciplinary approaches in complex, inter or transdisciplinary problems, and suggests ways to overcome such limitation. Among the findings can be mentioned that the level of complexity of the problem analysed do not allow a strict scientific demonstration of the “best” performances obtained. In part that is so because of the multidisciplinary nature of the problem, in which disciplinary demonstrations are incomplete. Demonstration is commonly restricted to a final stage of the research exercise, whereas the problem definition and election of the research method are not subjected to demonstration, being simply defined from consensual criteria. As the main problem involves applied sciences, design is involved in the process. By definition, the design of a solution give always the “best” solution, as is at the core of the solving process. However, as a cognition is also a historical/evolutionary process, every design process give the “best” solution in relation to its context regarding cultural, economic, scientific, etc. Under this perspective, the use of a model of network analysis allowed to process qualitative and transdisciplinary, as well as quantitative and disciplinary information, resulting in a useful tool for dealing with such complex topic.
Keywords: Bioenergy; Bioenergy Village; Sustainability Science; Energy crops; modelling biomass potentials; Sustainable campus; Biogas CHP; Organic Municipal Solid Waste OMSW