Evolution of properties of macadamia husk throughout gasification: hints for a zero-waste energy production system

In-depth information about the transformation of biomass during gasification is the key to the sustainable development of this technology. This study elucidated the evolution of physico-chemical properties of macadamia husk throughout relevant industrial gasification conditions. The technical characteristics combined with high kinetics highlighted the suitability of this feedstock for gasification. Non-porous chars with very low surface areas were observed throughout the conversion, which minimizes the potential to use the residues after gasification as adsorbents. Nevertheless, multiple carboxyl and hydroxyl functional groups were present on the char surface. Moreover, an extraordinarily high K content was detected (up to 86 wt% of the char’s total inorganic elements) and evenly distributed on the char surface. Such results consolidated the idea of combining the production of energy and cheap bio-fertilizers using the gasification of macadamia husk. The resulting database offered interesting hints for the development of zero-waste energy production systems with biomass gasification.

Assessing the Grip of Solar Energy Systems on Environmental Sustainability-A Review

: A sustainable energy production system fulfills its goal while being environmentally, socially, and technically sound. The intermittent availability and viability of renewable energy makes this vision a gradual and long-suffering process. In the rapid result-oriented economy, concerns regarding the environment are treated with desperate solutions that may add fuel to the fire. Although substantial research has been going on in the development of emerging technologies and refinement of established systems, we need to be reminded of the larger goal in mind: a benign and sustainable environment. Closing a door on a problem and not opening several new ones is what we must yearn to achieve. Renewable energy systems and their utility may unintentionally harm a different subset of the ecosystem. Solar energy systems are a more recent candidate with a high annual growth rate and thus, are still in the nascent stage to realise the bruised potential of the technology. By 2050, 60 million tons of solar waste will be produced if it is not resolved efficiently. To achieve environmental sustainability, it is imperative to work towards recycling redundant systems, establishing producer responsibility, fulfilling social needs and optimising future technology. By integrating aspects of the research on solar energy systems, their environmental risks, and their potential to create a sustainable ecosystem, this review article attempts to cater to environmental decision making and direct the eventual research and analysis towards their original unified objective.

Energy Recovery from Invasive Species: Creation of Value Chains to Promote Control and Eradication

The use of biomass as an energy source presents itself as a viable alternative, especially at a time when the mitigation of climate change requires that all possibilities of replacing fossil fuels be used and implemented. The use of residual biomass also appears as a way to include in the renewable energy production system products that came out of it, while allowing the resolution of environmental problems, such as large volumes available, which are not used, but also by the elimination of fuel load that only contributes to the increased risk of rural fires occurrence. Invasive species contribute to a significant part of this fuel load, and its control and eradication require strong investments, so the valorization of these materials can allow the sustainability of the control and eradication processes. However, the chemical composition of some of these species, namely Acacia dealbata, Acacia melanoxylon, Eucalyptus globulus, Robinia pseudoacacia and Hakea sericea, presents some problems, mainly due to the nitrogen, chlorine and ash contents found, which preclude exclusive use for the production of certified wood pellets. In the case of Eucalyptus globulus, the values obtained in the characterization allow the use in mixtures with Pinus pinaster, but for the other species, this mixture is not possible. From a perspective of local valorization, the use of materials for domestic applications remains a possibility, creating a circular economy process that guarantees the sustainability of operations to control and eradicate invasive species.

Hyperthermophilic methanogenic archaea act as high-pressure CH4 cell factories

Bioprocesses converting carbon dioxide with molecular hydrogen to methane (CH4) are currently being developed to enable a transition to a renewable energy production system. In this study, we present a comprehensive physiological and biotechnological examination of 80 methanogenic archaea (methanogens) quantifying growth and CH4 production kinetics at hyperbaric pressures up to 50 bar with regard to media, macro-, and micro-nutrient supply, specific genomic features, and cell envelope architecture. Our analysis aimed to systematically prioritize high-pressure and high-performance methanogens. We found that the hyperthermophilic methanococci Methanotorris igneus and Methanocaldococcoccus jannaschii are high-pressure CH4 cell factories. Furthermore, our analysis revealed that high-performance methanogens are covered with an S-layer, and that they harbour the amino acid motif Tyrα444 Glyα445 Tyrα446 in the alpha subunit of the methyl-coenzyme M reductase. Thus, high-pressure biological CH4 production in pure culture could provide a purposeful route for the transition to a carbon-neutral bioenergy sector.

The relationship between hydrogen and its application in wind energy: A systematic review

The aim of this study was to map papers about the use of hydrogen as a fuel and its association with wind energy under siege in two databases (Web of Science and Scopus) to provide insights about this topic and verify its current context. This study was a systematic literature review and content analysis of 87 papers from Web of Science and Scopus database. The papers were analyzed from descriptive, bibliographic, methodologic, results and citation characteristics. The publications about this theme have been mostly developed using mixed research models (quantitative and qualitative), especially due to the need to validate these experimental models for practical application, can be classified into four central clusters: 1) Green hydrogen; 2) Economic Viability and Costs; 3) New Technologies; and 4) Public Policies and Case Studies, with different focuses that converging to the same objective, the use of hydrogen as an ecologically correct and profitable fuel to serve the energy production system from wind plants. From the results obtained, it is observed that the use of hydrogen as a fuel, and wind energy, are themes that have been relatively significant in recent years within the environment of industrial innovation, presenting an eclecticism, where several countries in a pulverized form are increasingly seeking invest in these technologies, which is expressed through the substantial growth in the number of papers published about these themes since 2000s.

EXERGY AND EMERGY: COMPLEMENTARY TOOLS FOR ASSESSING THE ENVIRONMENTAL SUSTAINABILITY USE OF BIOSOLIDS GENERATED IN WASTEWATER-TREATMENT PLANT FOR ENERGYPRODUCTION

Taking advantage of the energy contained in the biosolids generated in a wastewater treatment plant (WWTP) is one of the processes of greatest interest due to the opportunity to obtain an energy resources from a waste. The aim of this research was to analyze the environmental sustainability use of biosolids generated in a wastewater-treatment plant for energy-production by fluidized-bed gasification under exergy analysis. The energy-production system was based on previous studies of sustainable-emergy alternatives using biosolids. Sustainability of the process was evaluated by identifying stages in the energy-production system (from drying application to electricity generation) where it is possible to reduce useful energy losses as well as identifying the value of waste streams within the system through exergy analysis. It was illustrated the destroyed exergy and the efficiency by stage and by product in order to assess the effects of inefficiencies in the process sustainability. The mixture of biosolids with coal was identified as a highly sustainable stage of the process, as it presents the highest index of exergy sustainability (0.99), in contrast to the stages of energytransformation (turbine) and gas-cleaning, which efficiencies are 0.17 and 0.4, respectively. Energy-transformation and gas-cleaning stages are of interest in terms of an improved energy recovery process, making it more efficient by applying new technologies and/or using the waste streams that have high energy potentials.