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Renewable cooling via absorption chillers being supplied by various green heat technologies such as solar collectors has been widely studied in the literature, but it is still challenging to get positive economic outcomes from such systems due to the large expenses of solar thermal systems. This study offers the use of a new generation of solar collectors, so-called eccentric reflective solar collectors, for driving single-effect absorption chillers and thereby reducing the levelized cost of cooling. This article develops the most optimal design of this system (based on several different scenarios) using multi-objective optimization techniques and employs them for a case study in Brazil to assess its proficiency compared to conventional solar-driven cooling methods. For making the benchmarking analyses fair, the conventional system is also rigorously optimized in terms of design and operation features. The results show that the eccentric solar collector would enhance the cost-effectiveness by 29%. In addition, using optimally sized storage units would be necessary to get acceptable economic performance from the system, no matter which collector type is used. For the case study, at the optimal sizing and operating conditions, the levelized cost of cooling will be 124 USD/MWh and an emission level of 18.97 kgCO2/MWh. [ABSTRACT FROM AUTHOR]

Supercritical water gasification is a promising technology for renewable hydrogen production from high moisture content biomass. This work produces a machine learning surrogate model to predict the Levelised Cost of Hydrogen over a range of biomass compositions, processing capacities, and geographic locations. The model is published to facilitate early-stage economic analysis (doi.org/10.6084/m9.figshare.22811066). A process simulation using the Gibbs reactor provided the training data using 40 biomass compositions, five processing capacities (10–200 m3/h), and three geographic locations (China, Brazil, UK). The levelised costs ranged between 3.81 and 18.72 $/kg H2 across the considered parameter combinations. Heat and electricity integration resulted in low process emissions averaging 0.46 kgCO 2 eq/GJ H2 (China and Brazil), and 0.37 kgCO 2 eq/GJ H2 (UK). Artificial neural networks were most accurate when compared to random forests and support vector regression for the surrogate model during cross-validation, achieving an accuracy of MAPE: <4.6%, RMSE: <0.39, and R2: >0.99 on the test set. [Display omitted] • A techno-economic surrogate model for supercritical water gasification is created. • Model predicts the LCOH for different biomass compositions, scales, and locations. • RF, SVR, and ANN algorithms were compared for the surrogate model. • ANNs achieved the highest prediction accuracy during cross-validation. • Final model is published to facilitate early-stage feedstock evaluation. [ABSTRACT FROM AUTHOR]

Future projections indicate an expansion for both food and energy demands, which can increase pressure on land use, while there is an urgent global need for climate change mitigation. Bioenergy is foreseen as key option to meet future energy demands and reduce greenhouse gas (GHG) emissions, however its sustainability depends on locations and regional characteristics. Simultaneously, agricultural production models that co-produce food, feed, and energy offer sustainability synergies and co-benefits, but site-specific sustainability assessments of their large-scale implementation are missing. This study presents a bottom-up approach to assess spatially explicit sustainability aspects of bioenergy-livestock integrated systems (BLI) in Brazil and shed light on their contribution to future energy demands, to climate change mitigation targets, and their impacts on selected ecosystem services, including bioenergy production, climate change mitigation, reduction of food competition, biodiversity conservation, and avoided deforestation. The proposed integration considers livestock intensification and use of biofuels by-products as animal feed supplement, taking advantage of synergies between these two value chains. The expansion of the BLI system in the Center-South region of Brazil produce up to 89 billion liters of ethanol, enough to meet future domestic ethanol demands from multiple shared socioeconomic pathways and generating surpluses for export. This production takes place on 16 million hectares of pastureland within the Sugarcane Agroecological Zoning, excluding the Amazon and Pantanal biomes, and biodiversity hotspots. BLI expansion mitigate up to 250 million tonnes of CO 2 eq and generate 15 billion dollars of profits. The best locations to maximize the selected ecosystem services are west of São Paulo, east of Mato Grosso do Sul, and the south-central region of the states of Goiás. This study may encourage the formulation of enhanced public policies for the integration of bioenergy and livestock value chains and guide a sustainable large-scale deployment of BLI systems. • Bioenergy and livestock integration (BLI): co-production of food, feed and energy. • BLI systems: 89 billion liters of ethanol and 250 million tonnes of CO 2 eq mitigated. • Enough ethanol to meet future Brazilian demands and surplus to be exported. • Biomass expansion only on pastureland inside Sugarcane Agroecological Zoning. • Without land displacement and deforestation of native vegetation. [ABSTRACT FROM AUTHOR]

The key objective of this paper is to analyze the techno-economic feasibility of this alternative for the Brazilian municipalities, classified according to population subgroups, using this parameter as a basis for the calculation of the municipal solid waste generated, the project costs and revenues. Different expenses were taken into consideration, like equipments and installation costs, operation and maintenance costs and the interest rate of the investment. In relation to revenues, they come from of the sale of electricity, the incomes of the recyclable materials, the fees paid by the Brazilian municipalities for the disposal of municipal solid waste in sanitary landfills and incomes by the carbon credits. An analysis of each population subgroup, combining three different economical scenarios was done, with an annual rate of interests of 10.58% for Scenario 1, 7.5% for Scenario 2 and 15% for Scenario 3. The economic feasibility was evaluated using as economic indicators the net present value and the internal rate of return. The net present value was positive for the municipalities with more than 60,714 inhabitants for the Scenario 1, 34,203 for Scenario 2 and 259,845 for Scenario 3. A hypothetic gasification plant is capable to generate 905 kW/ton municipal solid waste for a population of 60,714 inhabitants (Scenario 1), 794 kW/ton municipal solid waste for a population of 34,203 inhabitants (Scenario 2) and 1065 kW/ton municipal solid waste for a population of 259,845 inhabitants (Scenario 3). It is concluded that the economic feasibility increases with the installation of bigger units, showing a positive scale up gains, therefore as higher the capacity of the installation lower the specific costs and higher are the benefits. [ABSTRACT FROM AUTHOR]

Highlights: [•] Different scenarios for energy recovery of MSW in Brazilian cities have been calculated and evaluated. [•] Two alternatives were analyzed to carry out the energy recovery from MSW: landfill biogas and Waste-to-Energy plant. [•] This study was based on urban centres using the MSW characteristics of the metropolitan region of Belo Horizonte. [•] This study also have been assessed the environmental impacts of the energy recovery from MSW using the LCA methodology. [•] Landfill as the worst MSW management option and the most promising option is the combustion of MSW for energy generation. [ABSTRACT FROM AUTHOR]

• Existing sugarcane biorefineries in Brazil are the main advantage to implement BtL route; • High costs of equipment and technologies are the main challenges to economic viability; • Bioethanol commercialization helps to make the integrated BtL plant feasible; • Base case presents IRR close to the minimum rate accepted by the sector (10–12%); • Lower equipment costs and higher ethanol prices combined to improve the process viability. Brazil is one of the major players in the biofuels market worldwide, and its existing biorefining infrastructure can be used as the basis to support the implementation of new advanced biofuel production routes at a large scale. This paper demonstrates the benefits of the integration of both biochemical and thermochemical processes and how this configuration has the potential to overcome the main barriers that the Biomass-to-Liquids (BtL) route currently faces. Important bottlenecks such as the high equipment costs, low industrial process efficiency, and high feedstock prices were studied in detail by assessing a series of production scenarios that take into account the Brazilian context for building new biorefinery plants. By carrying out a techno-economic analysis aided by a simulation framework (the Virtual Sugarcane Biorefinery), we evaluated the potential technological synergies of a BtL plant processing sugarcane bagasse and straw integrated into a first-generation sugarcane ethanol distillery. Results in this paper indicate that it is possible to achieve economic feasibility with the implementation of the BtL route in the country. Under a base scenario, a greenfield plant would be very close to the range of economic viability (IRR from 10 to 12% per year), whereas more optimistic economic conditions (e.g., lower CAPEX and higher fuel prices) would induce even better results (IRR greater than 16% per year). Doubling the milling capacity also favors the BtL process, with IRR reaching 20% per year if the best economic conditions are achieved in the Brazilian context. [ABSTRACT FROM AUTHOR]

Bioethanol as fuel oxygenator is currently being introduced in Mexico with an estimated yearly demand of 3 billion liters expected to be produced mainly from sugarcane. This paper studies how to employ some of the expertise acquired by Brazil during its transition from typical mills into advanced biorefineries to retrofit the Mexican sucroalcohol industry. A typical Mexican sugarcane factory design is retrofitted to three biorefinery designs commonly found in Brazil, which are an autonomous distillery, a biorefinery with 50:50 feedstock ratio for ethanol and sugar production and a molasses distillery. The results of a techno-economic analysis considering these four designs under Mexican conditions are presented, followed by an economic comparison of the autonomous distillery design operating under Mexican and Brazilian conditions. Sustainability analysis is then carried out to identify the advantages and drawbacks of each design. The analysis compares an environment-driven scenario promoting bioethanol production and use for phasing out fossil fuels, against a commercially focused framework considering only environmental and economic issues affecting stakeholders' profit. Results show in monetary terms the impact of each indicator of a retrofitting path from currently profitable biorefineries coproducing sugar and alcohol to sustainable distilleries using molasses and juice as feedstock to produce bioethanol. • Retrofitting the Mexican sugar industry with Brazilian expertise for ethanol production. • Techno-economic and sustainability analyses of all designs. • Calculation with same tools and bases, thus highlighting differences between countries. • Comparison of environment-driven sustainability versus current commercial practice. [ABSTRACT FROM AUTHOR]

Comminution is an essential step in processing itabirite ores, given the need to liberate silica and other contaminants from the iron minerals for downstream concentration and then pellet feed production. In general, these ores in Brazil are not particularly hard to crush and grind, but both capital (CAPEx) and operating (OPEx) expenditures in this stage of preparation can be critical for the project, in particular due to uncertainties in iron ore prices. Several circuits have been designed and are in operation for this type of ore in Brazil; however, it is not yet clear which technologies are more cost-effective and in which configuration they should be applied. This work critically analyzes four comminution circuits for an undisclosed case study. For these circuits, CAPEx, OPEx, and some environmental sustainability indices, as well as qualitative technical criteria, were used in the comparisons. This work concludes that two of these process routes, especially those based on more energy-efficient technologies (and one of these still rarely explored even at bench-scale), have demonstrated to be very attractive from multiple standpoints. [ABSTRACT FROM AUTHOR]

Several economies around the world are using second-generation (2G) ethanol produced from agricultural residues, like sugarcane straw and bagasse, as a sustainable solution to replace petroleum products. Since first-generation (1G) ethanol uses the sugars of sugarcane, an integrated 1G⁻2G production would enable the production of more ethanol from the same amount of sugarcane without leading to increased use of arable land. The ethanol production process is complex, involving different high-energy consumption operations such as evaporation and distillation. The economic competitiveness of this process depends heavily on the amount of thermal and electrical energy produced using sugarcane straw and bagasse as input. Thus, the objective of this study was to use the mean-variance methodology to determine the optimal allocation of residual sugarcane biomass between 2G ethanol and bioelectricity productions, with simultaneous objectives of maximizing the return and minimizing the risk for investors of this sector. In this paper, four scenarios are analyzed. The first one is the base scenario that represents the current state of production costs and investments. scenarios 2, 3, and 4 considered four cuts of 10%, 20%, and 40% in the production cost of ethanol 2G, respectively. The results show the optimum biomass allocations and the growth rates of returns as a function of risk growth. It can be concluded that from scenario 4, the production of 2G ethanol becomes financially advantageous for the investor, presenting greater returns with smaller risks.