Activities implemented jointly and the use of fuel alcohol in Brazil for abating CO 2 emissions

Australia is one of the major producers and exporter of agricultural products. Annually, Australian agriculture produces approximately 151 Tg CO2 equivalent emissions. The use of fossil fuels in crop cultivation, harvesting and transportation are considered as the primary source of these greenhouse gas (GHG) emissions. Moreover, agronomic management and crop residues left in the field also contribute to these GHG emissions. Alternative waste management practices include the use of crop residues and agro-wastes as feedstocks for bioenergy production. Anaerobic digestion is considered as sustainable environmental technology to convert industrial sugarcane residues to carbon dioxide (CO2) - neutral biogas. The biogas thus produced can be used to produce heat, electricity and upgrade to biomethane for vehicle use. The produced biomethane can replace the diesel consumption associated with GHG emission in cane transport. Sugarcane is one among the most cultivated crop in the world. Australia alone produced nearly 33.5 million tonnes of cane in 2018 (FAO 2018). These large production of sugarcane lead to an increase in crop residues and agro-wastes from the sugarcane industry. In this study, an investigation regarding the anaerobic co-digestion of crop residues and agro-wastes from sugarcane industry viz, sugarcane trash (SCT) or sugarcane bagasse (SCB) with chicken manure (CM) was investigated in a batch experiment at 37 °C. In spite of various researches conducted till date about co-digestion of lignocellulosic waste with manure, no research data was available regarding the effect of feed ratio on co-digestion of SCT/SCB with CM. This research gap was investigated in this study. In addition to this, steam explosion pre-treatment of SCT/SCB was included to investigate how the pre-treatment influence methane yield among different feed ratios of SCT/SCB with CM. At first, SCT and SCB were subjected to steam explosion pre-treatment (steam impregnation at 130 °C for 5 minutes followed by steam explosion). Later, two sets of biochemical methane potential (BMP) tests were conducted at an Inoculum to Substrate Ratio (ISR) of 2. Co-digestion of untreated and steam exploded SCT or SCB with CM was investigated at feed ratios of 75:25, 50:50 and 25:75 on volatile solids (VS) basis. Assays with 100% untreated and steam exploded SCT or SCB were also included. Chemical analysis revealed that the steam explosion improved the VS content in pre-treated biomass compared with untreated biomass. The increase in VS was 1.6% and 5.7% in SCT and SCB, respectively. On the other hand, a slight reduction in total solids (TS) of nearly 4% and 1% were observed in the case of SCT and SCB, respectively. BMP results showed that the steam explosion had a profound effect on the methane production rates and yields, especially for SCB than SCT. Methane (CH4) yields of 201.8 and 199 ml CH4/gVSadded were obtained during the mono-digestion of untreated SCT and SCB, respectively. The corresponding values for 100% steam-exploded SCT and SCB were 207.5 and 225.6 ml/gVSadded, respectively. In comparison to mono-digestion, the co-digestion of SCB or SCT with CM did not improve the methane yields. Nevertheless, pre-treatment improved the methane production rates and yields of pre-treated biomass than untreated biomass. Among the studied feed ratios, best methane yields of 206.5 ml/gVSadded were obtained when steam-exploded SCT was co-digested with CM at 75:25 ratio. However, methane yields decreased with an increase in the amount of CM added. SCB also showed a similar trend. The best methane yield of 199.5 ml/gVSadded was obtained when steam-exploded SCB was co-digested with CM at 75:25 ratio. Among the tested feed ratios, all co-digestion mixtures except for 75:25 and 50:50 ratios of untreated SCT to CM showed synergistic effects. The best synergistic effect of 18.57% was observed when untreated SCB was co-digested with CM at 25:75 ratio. Kinetic modelling results confirmed that the steam explosion pre-treatment improved the methane production rates and yields by increasing the hydrolysis rate constant values. However, a higher hydrolysis rate constant was noticed for SCT than SCB. The highest hydrolysis rate constant of 0.16 d-1 was achieved at feed ratios of 50:50 and 25:75 of pre-treated SCT:CM. Interestingly, more than 75% of methane in pre-treated assays was produced by Day 11. The study thus suggests that the steam explosion can improve the methane production rates, yields and productivity of SCT and SCB. However, the use of CM as co-substrate did not improve the methane yields when compared to the mono-digestion of SCT or SCB, but a positive synergism was evident in most of the co-digestion feed ratios.

Mitigating Curtailment and Carbon Emissions through Load Migration between Data Centers

In this paper, we used the life-cycle analysis (LCA) method to evaluate the energy consumption and greenhouse gas (GHG) emissions of natural gas (NG) distributed generation (DG) projects in China. We took the China Resources Snow Breweries (CRSB) NG DG project in Sichuan province of China as a base scenario and compared its life cycle energy consumption and GHG emissions performance against five further scenarios. We found the CRSB DG project (all energy input is NG) can reduce GHG emissions by 22%, but increase energy consumption by 12% relative to the scenario, using coal combined with grid electricity as an energy input. The LCA also indicated that the CRSB project can save 24% of energy and reduce GHG emissions by 48% relative to the all-coal scenario. The studied NG-based DG project presents major GHG emissions reduction advantages over the traditional centralized energy system. Moreover, this reduction of energy consumption and GHG emissions can be expanded if the extra electricity from the DG project can be supplied to the public grid. The action of combining renewable energy into the NG DG system can also strengthen the dual merit of energy conservation and GHG emissions reduction. The marginal CO2 abatement cost of the studied project is about 51 USD/ton CO2 equivalent, which is relatively low. Policymakers are recommended to support NG DG technology development and application in China and globally to boost NG utilization and control GHG emissions.

Quantifying the challenge of reaching a 100% renewable energy power system for the United States

Greenhouse gas emission reduction and cost from the United States biofuels mandate

Effectively addressing today’s energy challenges requires advanced technologies along with policies that influence economic markets while advancing the public good.

Methane emissions along biomethane and biogas supply chains are underestimated

Advanced nonconventional renewable & alternative clean energy technologies which are used for generation of electricity have shown real promise and received renewed interest in recent years due to an increasing concern of environmental issues of greenhouse gas (GHG) emissions, being responsible for global warming & climate change, environmental pollution, and the limitations and conservation of natural energy resources. One of these innovative & emerging technologies is non-conventional, renewable and clean low-temperature geothermal energy (LTGE) technology. The vast low-temperature geothermal resources found widely in most continental regions have not received much attention for electricity generation. Continuous development of innovative drilling and ORC power generation technologies and other factors make this nonconventional and renewable energy source one of the best future viable, alternate and available source to meet the required future electricity demand worldwide, significantly reducing GHG emissions and mitigating global climate change. Section 2.1 of this chapter presents some novel applications of using LTGE resources and section 3.1 presents the fundamental concept of LTGE for power generation using ORC binary technology and discusses its limitations, environmental & economic considerations, and energy-conversion performance aspects. Another innovative alternative clean energy technology is thermoelectric (TE) power generation. Most of the recent research activities on applications of TE power generation have been directed towards utilisation of industrial waste heat (Riffat & Ma, 2003) where the cost of fuel input is cheap or free. In this large-scale application, TE power generators offer a potential alternative of green electricity generation powered by waste-heat energy that would contribute to solving the worldwide energy crisis, and the same time help reduce environmental global warming. The relatively low conversion efficiency of TE generators has been a major cause in restricting their use in electrical power generation. Recently, there has been a renewed research interest in TE technology due to emerging novel TE materials. Section 2.2 of this chapter presents innovative applications of using TE power generation technology and section 3.2 presents TE fundamental concept and discusses its limitations, energy-conversion performance, and material considerations for novel TE power generators. Thermophotovoltaic (TPV) power generation is another promising alternative clean energy source technology. There have been some causes for limiting the applications of TPV power generation technology. The

Both air pollution and greenhouse effect have become important issues with regard to environmental protection both in China and across the world. Consumption of energy derived from coal, oil, and natural gas forms the main source of China’s major air pollutants, SO2 and NOX, as well as the major greenhouse gas CO2. The energy structure adjustment approach provides a sensible way, not only to achieve climate change mitigation and air pollutant reduction, but also to reduce abatement costs. In this paper, a multi-objective optimization method was adopted in order to analyze the collaborative optimization of emissions and abatement costs for both air pollutants and greenhouse gases. As a typical industrial city and economic center with fossil fuels as its main energy source, Tianjin of China is used as the research sample to prove that this method can mitigate air pollutants and greenhouse gas emissions and reduce abatement costs. Through demonstration, the results show that the optimization method proposed can reduce SO2, NOX, and CO2 emissions by 27,000 tons, 33,000 tons, and 29,000 tons, respectively, and the abatement costs will be reduced by 620 million yuan by adjusting the energy structure of Tianjin. The proposed method also suggests that China can achieve reductions of abatement cost and greenhouse gas and air pollutant emissions under the proposed energy structure. The results indicate that collaborative optimization would help China and other countries cope with climate change while improving domestic air quality.

The energy sector was responsible for approximately 84% of carbon dioxide equivalent (CO2e) greenhouse gas (GHG) emissions in the U.S. in 2012 (EPA 2014a). Methane is the second most important GHG, contributing 9% of total U.S. CO2e emissions. A large portion of those methane emissions result from energy production and use; the natural gas, coal, and oil industries produce approximately 39% of anthropogenic methane emissions in the U.S. As a result, fossil-fuel systems have been consistently identified as high priority sectors to contribute to U.S. GHG reduction goals (White House 2015). Only two studies have recently attempted to quantify the abatement potential and cost associated with the breadth of opportunities to reduce GHG emissions within natural gas, oil, and coal supply chains in the United States, namely the U.S. Environmental Protection Agency (EPA) (2013a) and ICF (2014). EPA, in its 2013 analysis, estimated the marginal cost of abatement for non-CO2 GHG emissions from the natural gas, oil, and coal supply chains for multiple regions globally, including the United States. Building on this work, ICF International (ICF) (2014) provided an update and re-analysis of the potential opportunities in U.S. natural gas and oil systems. In this report we synthesize these previously more » published estimates as well as incorporate additional data provided by ICF to provide a comprehensive national analysis of methane abatement opportunities and their associated costs across the natural gas, oil, and coal supply chains. Results are presented as a suite of marginal abatement cost curves (MACCs), which depict the total potential and cost of reducing emissions through different abatement measures. We report results by sector (natural gas, oil, and coal) and by supply chain segment - production, gathering and boosting, processing, transmission and storage, or distribution - to facilitate identification of which sectors and supply chain segments provide the greatest opportunities for low cost abatement. « less

Cellulosic biomass-based sustainable aviation fuels (SAFs) can be produced from various feedstocks. The breakeven price and carbon intensity of these feedstock-to-SAF pathways are likely to differ across feedstocks and across spatial locations due to differences in feedstock attributes, productivity, opportunity costs of land for feedstock production, soil carbon effects, and feedstock composition. We integrate feedstock to fuel supply chain economics and life-cycle carbon accounting using the same system boundary to quantify and compare the spatially varying greenhouse gas (GHG) intensities and costs of GHG abatement with SAFs derived from four feedstocks (switchgrass, miscanthus, energy sorghum, and corn stover) at 4 km resolution across the U.S. rainfed region. We show that the optimal feedstock for each location differs depending on whether the incentive is to lower breakeven price, carbon intensity, or cost of carbon abatement with biomass or to have high biomass production per unit land. The cost of abating GHG emissions with SAF ranges from $181 Mg-1 CO2e to more than $444 Mg-1 CO2e and is lowest with miscanthus in the Midwest, switchgrass in the south, and energy sorghum in a relatively small region in the Great Plains. While corn stover-based SAF has the lowest breakeven price per gallon, it has the highest cost of abatement due to its relatively high GHG intensity. Our findings imply that different types of policies, such as volumetric targets, tax credits, and low carbon fuel standards, will differ in the mix of feedstocks they incentivize and locations where they are produced in the U.S. rainfed region.

Energy crisis and carbon emission are increasingly prominent issues in our society. As one of the clean energy sources, thermoelectric power generation is a promising alternative energy technology to convert heat into electricity. If there is a heat source, thermoelectric generators can provide electricity for watches, sensors, electronics, spacecraft, etc., and can also be used to recover waste heat, such as automobile exhaust heat, industrial waste heat, ship waste heat, etc. This paper begins with the basic principles of thermoelectric generators and an outlook of thermoelectric materials in different application scenarios. Then, the thermoelectric generator systems, which can be classified into different groups according to their different power generation levels, also the corresponding progress, challenges, and future development are presented. In addition to exploring high-performance thermoelectric materials, the system efficiency of thermoelectric generators is much dependent upon advanced structural design and thermodynamic optimizations. In the previous and present works, some new optimization methods are applied to improve the performance of thermoelectric devices and systems, these include such as the asymmetric design, phase change heat transfer, optimization for thermoelectric devices based on temperature distributions, also heat pipe and converging design for thermoelectric generator systems. These works help breakthrough in thermoelectric power generation from low-level power generation to relatively higher-level power generation. The current progress helps provide a comprehensive insight into thermoelectric power generation technology from micro power supplies to kilowatt systems.

BackgroundBioethanol produced from the lignocellulosic fractions of sugar cane (bagasse and leaves), i.e. second generation (2G) bioethanol, has a promising market potential as an automotive fuel; however, the process is still under investigation on pilot/demonstration scale. From a process perspective, improvements in plant design can lower the production cost, providing better profitability and competitiveness if the conversion of the whole sugar cane is considered. Simulations have been performed with AspenPlus to investigate how process integration can affect the minimum ethanol selling price of this 2G process (MESP-2G), as well as improve the plant energy efficiency. This is achieved by integrating the well-established sucrose-to-bioethanol process with the enzymatic process for lignocellulosic materials. Bagasse and leaves were steam pretreated using H3PO4 as catalyst and separately hydrolysed and fermented.ResultsThe addition of a steam dryer, doubling of the enzyme dosage in enzymatic hydrolysis, including leaves as raw material in the 2G process, heat integration and the use of more energy-efficient equipment led to a 37 % reduction in MESP-2G compared to the Base case. Modelling showed that the MESP for 2G ethanol was 0.97 US$/L, while in the future it could be reduced to 0.78 US$/L. In this case the overall production cost of 1G + 2G ethanol would be about 0.40 US$/L with an output of 102 L/ton dry sugar cane including 50 % leaves. Sensitivity analysis of the future scenario showed that a 50 % decrease in the cost of enzymes, electricity or leaves would lower the MESP-2G by about 20%, 10% and 4.5%, respectively.ConclusionsAccording to the simulations, the production of 2G bioethanol from sugar cane bagasse and leaves in Brazil is already competitive (without subsidies) with 1G starch-based bioethanol production in Europe. Moreover 2G bioethanol could be produced at a lower cost if subsidies were used to compensate for the opportunity cost from the sale of excess electricity and if the cost of enzymes continues to fall.

This work presents an assessment of sugar‐energy sector expansion in Brazil, focusing on the growth of the bioelectricity supply and considering two scenarios. The first scenario, called the BASE scenario, was based on the projection made by the Brazilian Energy Research Company (EPE) for the Brazilian commitments at the Paris agreement, presented during the COP 21 (Conference of the parties) conference and ratified in the Nationally Determined Contributions (NDC), assuming that all the electricity from biomass could be produced by the sugarcane sector. The second is a scenario considering a higher share of the sugar‐energy sector in the Brazilian electricity matrix, called the BIO scenario. The investment needed for each scenario was evaluated, using a bottom‐up approach and assuming currently available technologies. The results showed that the BIO scenario could produce 55 TWh of surplus electricity more than the BASE scenario, boosting the share of the sugar‐energy sector in the electricity matrix, reaching a total of almost 130 TWh per year and requiring an additional investment that was 39% higher than in the BASE scenario. As the sugarcane surplus electricity could replace electricity from natural gas power plants, the BIO scenario could reduce emissions by 18.4 MtCO2eq in comparison with the BASE scenario. Through the input–output model used to evaluate the socioeconomic impacts, it was observed that the BIO scenario could add 919 000 job positions and cause a positive impact to the gross domestic product (GDP) of US$ 28.8 billion, which corresponds, in comparison with the BASE scenario, to adding 83 000 more job positions, and provides a 12.5% higher contribution to GDP. The total output was 8.6% higher in the BIO scenario in comparison with the BASE scenario. All of these analyses were carried out for three selected regions in the country: the traditional region, comprising São Paulo and Paraná states; the expansion region, including Goiás, Minas Gerais, Mato Grosso and Mato Grosso do Sul states; and the rest of Brazil region. A spillover effect was observed over the total output in the Rest of Brazil region, showing that the impact of the investment over this region was proportionally higher in comparison to the investment done in other in other regions. The Rest of Brazil Region also presents a higher share of the indireect effects over the GDP, jobs created and total output. The final results of this research show the potential of the sugar‐energy sector to boost electricity generation, which can contribute to the reduction of greenhouse gas (GHG) emissions, and to preserving the share of renewable sources in the Brazilian electricity matrix and increasing energy security and generation closer to the biggest centers of consumption, mitigating challenges for electricity transmission between subsystems in the National Interconnected System (SIN). © 2021 Society of Industrial Chemistry and John Wiley & Sons Ltd.

Assessing the economic efficiency of bioenergy technologies in climate mitigation and fossil fuel replacement in Austria using a techno-economic approach