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Two studies conducted in Guadeloupe (West Indies) and Réunion (Indian Ocean) islands were designed to investigate the benefits of producing sugarcane as an energy crop and to assess the influence of agroclimatic factors on energy efficiency, respectively. In this context, it is essential to know the low heating value of the dry above-ground biomass (LHVd, MJ/kg) and its energy yield (EY, MJ/m2) in order to select the best varieties and set up a payment method for growers. Eighteen Poaceae (sugarcane and Erianthus) cultivars were compared under wet tropical environmental conditions in Guadeloupe. Three sugarcane cultivars were studied in four contrasting environments in Réunion. The partition sampling and biomass measurement procedures were identical at both locations. Low heating value (LHV) predictions were achieved using near-infrared reflectance spectroscopy (NIRS) after specific calibration (Guadeloupe), or arithmetically after lignocellulosic compound prediction (Réunion). In both studies, LHV variability was very low and slightly dependent on the site, cultivar and above-ground biomass components (millable stalks and tops, and green and dead leaves). Considering the overall dry above-ground biomass (DAB, kg/m2), the LHVd was calculated by averaging 159 samples (mean 16.65 MJ/kg) in Guadeloupe and 315 samples (mean 16.45 MJ/kg) for Réunion. An excellent linear relationship between the DAB and its EY, regardless of cultivar, age and environment, was found (n = 474 and R² = 0.99). Sugarcane energy content assessment could thus be simplified by measuring the DAB, while enabling development of a faster method of payment for growers based on the DAB measurement and the correlation between DAB and EY. Finally, the findings of this study should allow growers to rapidly determine the commercial value of their sugarcane crops, and also enable purchasers to assess the amount of recoverable energy. (Résumé d'auteur)

The potential for global forest cover The restoration of forested land at a global scale could help capture atmospheric carbon and mitigate climate change. Bastin et al. used direct measurements of forest cover to generate a model of forest restoration potential across the globe (see the Perspective by Chazdon and Brancalion). Their spatially explicit maps show how much additional tree cover could exist outside of existing forests and agricultural and urban land. Ecosystems could support an additional 0.9 billion hectares of continuous forest. This would represent a greater than 25% increase in forested area, including more than 200 gigatonnes of additional carbon at maturity.Such a change has the potential to store an equivalent of 25% of the current atmospheric carbon pool. Science , this issue p. 76 ; see also p. 24

A new two-stage gasifier with fixed-bed has recently been installed on CIRAD facilities in Montpellier. The pyrolysis and the gasifier units are removable. In order to characterise the pyrolysis products before their gasification, experiments were carried out, for the first time onlywith the pyrolysis unit and this paper deals with the results obtained. The biomass used is Pinus pinaster. The parameters investigated are: temperature, residence time and biomass flow rate. It has been found that increasing temperature and residence time improve the cracking of tars, gas production and char quality (fixed carbon rate more than 90%, volatile matter rate less than 4%). The increase of biomass flow rate leads to a bad char quality. The efficiency of tar cracking, the quality and the heating value of the charcoal and the gases, indicate that: temperature between 650 °C and 750 °C, residence time of 30 min, biomass flow rate between 10 and 15 kg/h should be the most convenient experimental conditions to get better results from the experimental device and from the biomass pyrolysis process. The kinetic study of charcoal generation shows that the pyrolysis process, in experimental conditions, is a first-order reaction. The kinetic parameters calculated are comparable with those found by other researchers. (Resume d'auteur)

Abstract Performance of wood gasification genset is sensitive to the moisture content in the feedstock and the electrical load (demand of users). This study investigates the influence of these process parameters on the electrical efficiency of the genset (ηglobal), the electrical engine efficiency (ηengine), the cold gas efficiency (CGE), and the syngas composition. Experimental tests were carried out by varying the moisture content from 11% to 23% and the electrical power from 4.7 kW to 12.8 kW on a commercial gasifier equipped with precise measuring tools. The increase of the performance when the electrical load is increased or when the moisture content in the wood chips is decreased is both quantified and discussed. Such behaviour was mainly explained by differences in engine filling rates and reactor temperatures.

Abstract Charcoal seems one of the most promising bio-reducer because of its high coke replacement ratio in blast furnaces. Nevertheless, biochar materials are subject self-combustion during storage, handling and transport, and need to be studied in order to understand and limit these phenomena. Heat-based methods: were employed to compare and determine the self-ignition parameters of four types of fresh biochar ( Quercus pubescens , Cyclobalanopsis glauca , and Trigonostemon huangmosun , Bambusa vulgar ) that are used as bio-reducers in the silica industry. This study assumed that spontaneous combustion arises from exothermic oxygen chemisorption to fresh biochar surface. Sample mass, heat flow and CO 2 desorption were measured. The weight increased very rapidly as soon as the gas stream was changed from N 2 to air accompanying the heat generation for each material. Desorption isotherms were found to depend on the nature of the feedstock confirming that bamboo biochar was the most reactive one under air exposure.

Abstract Successful conservation of large mammals requires vast areas to maintain viable populations. This often requires to embrace large-scale approaches that extend beyond the borders of formally protected areas. However, the quality of the scientific knowledge about animal movement across large conservation areas vary, and could limit the effectiveness of conservation efforts. Here we used GPS tracking to conduct the first study of large-scale movements of African elephants (Loxodonta africana) in Hwange NP (Zimbabwe), which is an unfenced park part of the Kavango-Zambezi Transfrontier Conservation Area, the world's largest terrestrial conservation area. We show that some, but not all, elephants migrate seasonally, with wet- to dry-season movements linked to the provision of water in Hwange NP. The distance between the most distant locations of individual elephants reaches 260 km. In this partial migration system influenced by management practices, over 20% of the elephants have wet-season ranges established in Botswana, outside of protected areas in private or communal wildlife management areas. Our results call for the urgent drafting of a regional action plan, involving all stakeholders identified by our study and their neighbours, to predict and react to what would happen if water provision in Hwange NP was to suddenly change because of management practices or extreme climate change. Beyond this critical conservation issue for the world's largest elephant meta-population, our results also highlight the relevance of large-scale conservation areas combined with integrative planning involving national wildlife management institutions and the private and communal sector.

Substitution of fossils reducers by charcoal from woody biomass is one of the most suitable option to reduce greenhouse gas emissions of metallurgical industries. The main problem involved in fossils reducers replacement is the lack of mechanical strength of charcoal. Aim of this study is to investigate the impact of pyrolysis parameters, such as temperature and solid residence time, on the mechanical properties of charcoal. Charcoal was produced from two woody biomasses, Eucalyptus globulus and Picea abies (Spruce), in a pilot scale fixed bed rector; with three temperatures (500, 650 and 800 °C) and two solid residence times (0 and 90 min). The particle sizes used were close to those in the industry. Charcoals were characterized by proximate and ultimate analysis, apparent density, friability and compressive strength. Results show an increase in charcoal mechanical strength with increasing pyrolysis temperature. On the other hand solid residence time has a little influence on the mechanical properties. Eucalyptus has a higher density than Spruce, but Eucalyptus charcoal shows a lower mechanical stability than Spruce charcoal independently of the pyrolysis conditions. Proceedings of the 26th European Biomass Conference and Exhibition, 14-17 May 2018, Copenhagen, Denmark, pp. 1240-1243

Abstract In the past 10 years, 90% of cassava starch factories in Thailand have switched from fuel oil to renewable biogas, to cover part of their energy needs. The environmental benefits of switching to biogas have not been assessed quantitatively. To alleviate this, this study assessed 100-year greenhouse gas (GHG) emissions, or carbon footprint (CF), of cassava starch production for four factories in Thailand. Key results demonstrate that biogas reduces the carbon footprint of the Thai cassava starch industry as a whole by 0.9–1.0 million tons CO2eq/year, and highlight methodological precautions to collect LCI data and allocate GHG emissions between co-products with high moisture contents. The system boundaries included farm stage (production of cassava roots), transportation to factory and processing into native starch. The functional unit (FU) was one ton of native cassava starch at 13% water content. Biogas produced from the factory wastewater (95–200 m3/FU) was the main source of thermal energy for starch drying, and for on-site electricity production when excess biogas was available. The total CF of cassava starch was in the range 609–966 kg CO2eq/FU. Agricultural production contributed 60% of the carbon footprint, mainly from the use of nitrogen fertilizers. GHG emissions of root production varied widely due to (1) the diversity of farming practices even within a small radius (50 km), and (2) different agricultural yields in different regions. The contribution of the factory stage to the carbon footprint depended on the use of electricity, biogas and other fuels, ranging from 217 to 342 kg CO2eq/FU. Allocation rules such as wet weight or dry weight basis allocations affected the results markedly.