Conventional ammonia production uses fossil-based hydrogen, resulting in high greenhouse gas emissions. Given the growing demand for sustainable solutions, it is essential to replace fossil hydrogen with renewable alternatives. This study assessed the technical, economic, and environmental viability of renewable ammonia production in Minas Gerais. To this end, an optimization model based on mixed integer linear programming (MILP) was developed and implemented in LINGO 20^® software. The model incorporated investment costs; raw materials; transportation; emissions; and indicators such as NPV, payback, and minimum sale price. Hydrogen production routes integrated into the Haber–Bosch process were analyzed: biomass gasification (GS_WGS), anaerobic digestion of vinasse (Vinasse_BD_SMR), ethanol reforming (Ethanol_ESR), and electrolysis (PEM_electrolysis). Vinasse_BD_SMR showed the lowest costs and the greatest economic viability, with a payback of just 2 years, due to the use of vinasse waste as a raw material. In contrast, the electrolysis-based route had the longest payback time (8 years), mainly due to the high cost of the electrolyzers. The substitution of conventional hydrogen made it possible to avoid 580,000 t CO₂ eq/year for a plant capacity of 200,000 t NH₃/year, which represents 13% of the Brazilian emissions from the nitrogenated fertilizer sector. It can be concluded that the viability of renewable ammonia depends on the choice of hydrogen source and logistical optimization and is essential for reducing emissions at large scale.

The development of new technologies for the production of renewable energy is fundamental to reducing greenhouse gas emissions. Therefore, the search for new energy generation methods that are environmentally responsible, socially rational, and economically viable is gaining momentum in order to mitigate carbon footprint. The aviation sector is responsible for a significant fraction of greenhouse gas emissions; for this reason, the decarbonisation of this sector must be investigated using biorefinery models. This study presents a mixed-integer linear programming (MILP) model for optimising the design and configuration of the supply chain in different states of Brazil for the production of sustainable aviation fuel (SAF) and green diesel and gasoline, using microalgae cultivated in sugarcane vinasse as the raw material. The technology of hydrothermal liquefaction was assessed in terms of its capacity to convert microalgae without need for the energy-intensive drying step. The MILP model was developed in the LINGO v.20 software using a library of physical and economic process models. We consider the selection of processes based on the object of total minimum cost, with optimal production plant scaling and regional supply chain design, including an assessment of resources and final product distribution. A case study was implemented in Brazil, considering different regions of the country and its local demands for fuels. São Paulo is the most profitable state, with a cash flow of 1071.09 and an IRR of 36.19%, far outperforming the rest. Transport emissions alone represent between 0.6 and 8.6% of emissions generated by the model. The costs of raw materials, mainly hydrogen (57%) and electricity (27%) represent the main costs evaluated in the model. The production cost (MUS$/TJ biofuel) is in the range of 0.009–0.011. Finally, changes in the cost of electricity have the greatest impact on the model.

Biofuels are considered an alternative to sustainable energy production due to their potential to reduce greenhouse gas emissions. This paper presents a mixed integer linear programming (MILP) model to evaluate the optimal configuration of a supply chain for the production of bioethanol, electricity and bagasse pellets from sugarcane potential in Colombia. The results show that gasoline demand in Colombia is met through bioethanol production, and the demand for coal used in thermoelectric plants can be met through the production of bagasse pellets from 17 biorefineries located in 13 study regions. The avoided emissions represent 25.17% of the target proposed by the Colombian government, and transport emissions represent only 2.62% of the emissions generated by the model. Despite the promising results obtained in the optimization of the supply chain for bioethanol and bagasse pellet production in Colombia, there are challenges and limitations that must be considered. One of the main challenges lies in the uncertainty associated with the variability in biomass, bioethanol, and carbon credit prices, which can affect the long-term economic viability of the project. The sustainability of land use for sugarcane production must be assessed with a more detailed approach to avoid conflicts with food production and ecosystem conservation. These aspects represent key opportunities for future research and improvements in strategic planning for the bioenergy sector. Finally, the sensitivity analysis shows that the ±20% variation in the price of sugarcane and the price of bioethanol have a high impact on the payback period with respect to the base case.

The worldwide transition to renewable energy systems is motivated by diminishing fossil fuel availability and the intensifying consequences of climate change. This study presents a Mixed-Integer Linear Programming (MILP) model for designing and optimising the bio-fuel and electricity supply chain in Colombia, using sugarcane as the main feedstock and integrating microalgae cultivation in vinasse. Six alternative biorefinery configurations and four microalgae conversion pathways were evaluated to inform strategic planning. The optimisation results indicate that microalgae achieve higher energy yields per unit of land than sugarcane. Ethanol production from sugarcane could meet all of Colombia’s gasoline demand, while diesel and sustainable aviation fuel derived from microalgae could supply around 9% and 16%, respectively, of the country’s consumption. Further-more, pelletised bagasse emerges as a viable alternative to replace part of the coal used in thermoelectric plants. From an economic perspective, all scenarios achieve a positive net present value, confirming their profitability. Sensitivity analysis highlights the critical factors influencing the deployment of distilleries as ethanol price, algae productivity, and sugarcane cost. Furthermore, transportation costs play a decisive role in the geographic location of microalgae-based facilities and the distribution of their products.

Introduction: The consumption of bioenergy has increased in recent years, contributing to the reduction of greenhouse gas (GHG) emissions. In particular, sugarcane waste has been evaluated in several studies as a potential source of renewable energy. The sugar industry primarily produces sugar and ethanol, and for each liter of ethanol produced, between 10 and 15 liters of vinasse are generated. This residue is highly polluting and, although it is traditionally used for fertigation or disposed of, it holds significant potential for biogas production.Objectives:The main objective of this study was to assess the electricity generation potential from vinasse produced in ethanol plants in Colombia and calculate the CO2 emissions avoided by substituting local electricity use with this renewable energy source.Materials and Methods: Four different scenarios were evaluated based on the percentage of sugarcane juice used for ethanol production. For each scenario, the electricity generation potential from biogas produced by vinasse biodigestion was calculated. Additionally, the CO2 emissions avoided were estimated by comparing the use of vinasse-based electricity with local conventional electricity sources.Results: The results from the different scenarios show that the electricity generation potential ranges between 249,840.36 MWh/year and 437,156.37 MWh/year, depending on the percentage of sugarcane juice used for ethanol production. CO2 emissions avoided ranged from 31,475.26 to 55,081.70 tons of CO2/year. These results indicate that electricity generation from vinasse has a significant impact on reducing greenhouse gas emissions compared to local conventional electricity.Conclusions: The valorization of sugarcane vinasse for electricity generation represents a significant step forward in the production of clean electricity in the sugar sector. The results show that this approach not only has high potential for renewable energy generation but also contributes significantly to reducing CO2 emissions, enhancing the sustainability of the sector.