This paper presents a techno-economic evaluation of potential Greenfi eld projects of integrated fi rst-and second-generation sugarcane biorefi neries, in which ethanol is converted to bio-based propylene through metathesis of ethylene with 2-butene. Two scenarios were tested, considering improvements both in fi rst-and second-generation ethanol production: with and without pentoses fermentation, which increases the amount of ethanol produced. The viability of the proposed propylene production facility was studied through Minimum Bio-Propylene Selling Price (MBSP), and sensitivity and risk analysis were performed. Results show that, compared to the average propylene prices in recent years, the MBSP (based on the average estimates) would be no more than 85-90% higher than the price of the conventional fossil-fuel based product. In addition, three aspects were further assessed: (i) scaling of production plants, (ii) learning effects, and (iii) policies that would result lower capital costs. The results show that the cumulative effect would lead a substantial reduction of the MBSP, leading to a competitive price of 1347 US$/t.
The desired energy transition to guarantee net-zero greenhouse gases (GHGs) emissions needs to take place in every sector of the global economy. The transport sector is responsible for a large share of energy consumption and GHGs emissions while contributing to the increase in air pollution. Although new technologies are available, the use of diesel in road transport is still predominant. These new technologies, nonetheless, still present inconsistencies in their environment, economic performances and do not necessarily provide improvements when considering the entire fuel life cycle used in medium and heavy-duty trucks. This systematic review addresses the uncertainties in life cycle studies regarding the road transport sector fuel consumption, GHGs, and air pollutant emissions economic analyses. Results show that there are higher chances of reducing GHGs emissions through biogas or fuel-cell hydrogen trucks, while PM 2.5 and NOx emissions have higher chances of being reduced with fuel-cell hydrogen or natural gas trucks. There is, however, a reduced interest by the scientific community in the transport literature in dealing with air pollutants, and the focus is mainly on GHGs emissions. When it comes to economic viability, natural gas and hybrid trucks are the best substitutes.
This study analyzes 34 tools through 442 publications on energy systems modeling, aiming to identify the most relevant trends in research and the research gaps in energy planning. For detecting these gaps, the publications analyzed were categorized based on pre-defined criteria regarding geographical coverage, sectoral coverage, time horizon, analytical approach and energy source. The categories were designed to be a broad classification with the appropriate level of information required to differentiate between models. The results show that there is a lack of studies concerned with better understanding the energy systems in Africa and South America. Environmentally-oriented publications account for 50.4% of all the publications studied. Modelers have thus shown a greater interest in studying issues related to climate change mitigation than in other areas of the energy chain.
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