Publications (FIS)

Bringing to light a new energy path

biomass residues as a contribution to a sustainable and inclusive energy source in Brazil

authored by
Ana Pimenta Ribeiro
supervised by
Michael Rode

In 2015, the United Nations released a set of 17 goals as part of a new sustainable development agenda. The agenda focused on ending poverty, protecting the environment, and ensuring prosperity for all by 2030. The objective was to reinforce the urgency of acting in order to change the status quo. The topic of renewable energy is mentioned in goal 7, which aims to ensure access to affordable, reliable, sustainable, and modern energy for all. The opportunity for renewable energy production in developing countries is a highly relevant topic. In Brazil, more than 60% of the energy comes from hydroelectricity, making the system highly vulnerable in the context of global climate change, with precipitation and temperature shifts over the years. Hydroelectricity also dominates the energetic sector expansions, although great dams do not bring in a return proportional to their costs, and those that have been planned most recently present disastrous social, economic, and environmental consequences. Previous studies on biomass as a renewable source for energy production in Brazil have shown promising results. Biomass is characterized as plant material generated through photosynthesis and all its by-products: forest-wood, cultivated crops, animal droppings, organic matter. Characterized by its diverse possibilities of sources and conversion technologies for energy products, biomass has a high potential for renewable energy supply. Sustainable power generation through biomass should guarantee the soil health, water, and biodiversity cycle. This research is dedicated to exploring alternative future pathways for the electricity sector in Brazil that unite the respect for people and the environment, advance nature conservation as well as the lives of the people and communities involved, and thereby contribute to more sustainable development. The use of residual biomass as a source for decentralized and clean energy production that does not affect food security is the most promising option. It comes without the enormous impact of the large-scale hydroelectric dams, can be applied virtually anywhere and does not rely on a connection to the central grid, and does not compete with food supply. The aim of this thesis is to investigate the role that biomass can play in the Brazilian electricity matrix. The hypothesis is that residual biomass as an energy source could play a significant role in transforming the Brazilian energy matrix towards a sustainable path. To attain the overall goal, four general steps were defined: (1) to explore the potential areas for sustainable biomass energy production; (2) to evaluate the perspectives for biomass energy production in peripheral areas; (3) to identify the potential of biomass energy production in one entire state and (4) to evaluate the costs and social acceptance for biomass enterprises. On the First Step, the potentials areas for energy production were identified, in which the use of biomass for a sustainable power production can have a particularly high significance for the energy supply of the population: 1. areas with higher energy demand, 2. areas that were more remote of an installed transmission line, 3. areas far from already installed hydroelectric and thermoelectric power plants, 4. areas with an anthropic land use, and 5. areas of relevance for environment preservation. The main findings of this step were that there is an area of approximately seven million hectares with the potential to produce energy through biomass meeting local demand, favoring areas with fewer power connections, avoiding changes in land use, and maintaining priority areas for environmental conservation. On this basis, a new concept for energy supply could be built. The Second Step had the objective to assess potential areas where the energy could have a positive social impact in an example region. The region chosen for the study is a supplier of eucalyptus charcoal for the iron industries in the west of the state of Minas Gerais. By combining the Human Development Index, the yearly permanent crop production, the yearly silviculture production, and the yearly temporary crop production in a GIS system, it was possible to select three municipalities to study. The results indicate a potential for each of the three investigated small municipalities to be self-sustainable in energy production by using silviculture and agricultural waste, and also that the success of biomass energy generation through agriculture residue enterprises depends on more than energy efficiency. The Third Step focuses on the investigation of the possibilities to sustainably attend the demand on a larger scale. Opportunities for power generation from biomass residues in the whole Minas Gerais State were assessed, considering the silviculture and crop yield and applying a conservative index that considerers the portion of residues that should be used maintaining the soil health. The chosen crops were coffee, corn, beans, manioc, and sugarcane. The assessment of production data is vital to estimate the amount of residue generated in the production process. For all the crops, literature indicates a percentage of rests remaining from harvesting or primary processing. For the estimation of residues from forestry, data were selected on the production of eucalyptus charcoal, firewood, and wood in 2016. To ensure the sustainability of the process, data regarding wood products from native vegetation was not considered in this study. Data were generated per municipality to them be joined at the state level. The primary outcomes were that in a state with the tradition of agriculture, 78% of the municipalities could have their basic energy needs attended. This would relieve pressures placed on the construction of new hydroelectric plants, which have negative impacts on the environment. In addition, a cooperative production system among farmers can reduce costs and may allow the partial improvement of their agricultural raw material. Finally, on the fourth Step, the implementation costs were investigated. In a region were many initiatives have been carried out in order to create new opportunities for people affected by a dam rupture with very negative consequences for land use, it was pursued innovative initiatives for agriculture in the municipalities surrounding the Doce River State Park. There was an interest from the communities to increase the cultivation of certain crops and one possibility proposed to the locals was to use agricultural waste for electricity production. Ensuring the sustainability and development of clean technologies, this step sought to evaluate the potential of energy production through agricultural waste, the ideal allocation of the energy production unit, and the costs involved in the enterprise. The demand of the municipalities was considered as the monthly average consumption per resident (150 kW.h/month) and the market prices of October 2018 were applied for the calculation of the implementation costs, which was conducted by a company that works on the area and applied the potentials and the transportation distances to estimate the costs and the allocation of the power plants accordingly. The calculations of the costs involve collection logistics, transport of materials, purchase, installation, and operation of a power generating unit and team training. From a total of 16, 13 municipalities presented a production capable of meeting about 20% of local demand. Based on the residual potential, transportation costs and current market prices, the most efficient arrangement found would be to build two power plants. This step shows that a significant investment is required. But, the enterprise could be viable and pay itself in a short amount of time. This statement is even more applicable in a scenario where the agricultural area is increased, growing the power generation capacity of the power plant. Further studies should explore the spatial limitations for the agricultural expansion, modeling scenarios where the environmental constraints are respected. Over all, the input of the population on the matter is also fundamental for the continuity of such a project, but working together, municipalities can generate energy and create better power availability, jobs, income, and more opportunities for energy decentralization. The overall outcomes of this thesis show that residual biomass presented the potential to be integrated in the Brazilian energy matrix more intensively. The availability of residues was spatially assessed on different scales and could positively impact populations away from large centers and outside of development initiatives. Conservation of native vegetation areas and soil health were considered as critical points in the analyses so that a part of the agricultural residues could be left in the soil to ensure agricultural sustainability and still have a significant energy production. This work is the first of its kind and is a crucial step in the direction of a cleaner and safer energy matrix, also the first to put together a public set of data with this objective. Even adopting less efficient technologies, the availability of agricultural and silvicultural residues for energy generation was enough to be relevant to the local energy mix. The focus on improving life for populations in marginal areas, isolated from large centers, also showed that there is a lack of studies on the use of biomass residues as a contribution to a decentralized, sustainable, and socially acceptable power supply in Brazil. For developing countries, the adoption of cleaner technologies at an early stage has the potential to save a lot of effort, money, and natural resources. The effectiveness of these initiatives still relies on the engagement of rural producers, which could not be ascertained during the development of this study. The acceptance from the communities involved in bioenergy projects is essential for the implementation of successful residual biomass initiatives. The results also generated the recommendation that a more in-depth evaluation of people’s knowledge of bioenergy unveils exciting insights into the development of public policies aimed at achieving different energy sources in Brazil. They can be used as a basis for further studies observing the local characteristics and be a relevant tool for municipalities to know their potentials and seeking investments. These methods could lead to local arrangements, depending on their potentials and affinities, in order to promote biomass energy or be used by public or private initiative, as a basis for projects aimed at sustainable energy development, as basis for planning of energy generation from biomass, reducing dependence of hydro energy. The methods also could provide a basis for promoting decentralizing generation of energy, creating better conditions of social and economic development. In a large and disparate country such as Brazil, with a population quota of 54.8 million people (26.5% of the population) living below the poverty line, such efforts are even more urgent. Following the current trends of global warming, the most impoverished strata of society will be the first to suffer its adverse effects: droughts, diseases, lack of potable water and food. A cooperative energy production system from agricultural and forestry residues among rural producers can offer an alternative here. It may allow to reduce production costs and the partial improvement of agricultural raw material, adding value to the final product. In this sense, the study method can be used as a tool to organize the information on possibilities of generation of energy.

Institute of Environmental Planning
Doctoral thesis
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Sustainable Development Goals
SDG 2 - Zero Hunger, SDG 3 - Good Health and Well-being, SDG 7 - Affordable and Clean Energy, SDG 11 - Sustainable Cities and Communities, SDG 13 - Climate Action, SDG 15 - Life on Land
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