Search

This paper shows a practice to raise the reliability of an electric power system by the installation of distributed generation, taking gasified biomass as fuel. To calculate the reliability index, a probabilistic load flow was used. This index is determined as the fault probability of the system. The resolution of this probabilistic load flow combines the method of cumulants and Gram–Charlier expansion. To achieve the reliability index, simulating a number of contingencies is required; the greater the number of simulated contingencies, the higher the accuracy of the index obtained. This probabilistic technique uses the random variables as starting information, so the two generators and loads are simulated as random variables. The generators of this distributed generation are biomass-fueled gas engines, commonly found in Spain. The simulations carried out on the IEEE 14-bus Test System, including three biomass generators, show that the inclusion of this type of generation improves the overall reliability indices of the electrical system. [ABSTRACT FROM AUTHOR]

In this paper, the aerial biomass of citrus plantations in Spain was evaluated using destructive methods. Before cutting down the trees, their geometric variables were measured: trunk diameter at 10 cm from the ground (Dt), trunk perimeter at 10 cm from the ground (Pm), mean crown diameter (Dc), canopy height (Hc), and maximum crown height (Hmax). After geometric characterization of the tree, it was felled. This was performed with a chainsaw about 10 cm above the ground. After cutting down, trees with and without leaves were weighed, and biomass variables such as moisture, calorific value, elemental composition, and proximate analysis were measured. The predictive models obtained showed an r2 of 0.78. According to our analysis, in plantations in Spain, where the average plantation pattern is 4 × 4 m, the amount of carbon stored in a plot is 15 t of C per hectare. If leaves and wood are counted, the energy density in citrus plots can be estimated at 900 MJ/tree. However, if only wood is included in the calculation, the accumulated energy per tree is 750.3 MJ/tree, which represents 5.6 × 105 MJ/ha. [ABSTRACT FROM AUTHOR]

Biomass is a renewable energy source that, due to its strong seasonality, needs to be stored, handled, and managed under suitable conditions for its optimal use. Storage is therefore a key process in which biomass can lose many of its qualities as a fuel, but which can also serve to improve the condition of the resource. This paper presents results from a study to assess the effect of large‐scale storage on a range of different biomass resources that was carried out at an electricity generation plant located in southern Spain. It included a series of field tests carried out with different types of biomass resources, to observe the behavior of these products during storage and the changes in their main characteristics. Based on these results, recommendations have been proposed for the optimal storage management of each of the products. The testing program confirms that the initial moisture content of the biomass, particle size, and the leafy content are critical aspects to consider to avoid self‐ignition and dry matter losses. Biomass with high moisture content should therefore be stored in small stockpiles and should be consumed immediately. This is especially important in the case of olive leaves and pine prunings when they have a high initial moisture content. Stockpiles of drier biomass, such as dried olive pomace, fruit tree pruning or dried olive pruning can reach up to 1200 t and be stored for up to 6 months, under adequately controlled conditions. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

In-forest drying of roundwood and biomass (residues) can result in more efficient transport operations from an economical and environmental perspective. On the negative side, in-forest drying may result in dry matter losses (DML), impacting the quantity and quality of residues delivered to energy plants. This paper investigated the impact of roundwood and residues in-forest drying and DML on supply chain costs and Greenhouse Gas (GHG) emissions. For the assessment, a short-term optimization planning tool was applied to a supply chain located in Asturias, Spain, consisting of fourteen supply points and two demand points: A pulp mill (demanding roundwood) and a power plant (demanding residues). Four scenarios were included in the analysis comprising different combinations of DML for roundwood and residues resulting from in-forest drying. Our results indicate that in scenarios that include in-forest drying and DML, the negative economic effects are offset by the substantial reductions in transport costs and GHG emissions. In-forest drying of roundwood and residues without DML can result in a 6.5% reduction in supply chain costs, 14.9% fewer truckloads to destination points, and 18.1% less fuel consumption and GHG emissions. [ABSTRACT FROM AUTHOR]

The Taguchi method of designing experiments is based on a system of tabulated designs (arrays) that enables the maximum number of variables to be estimated in a neutral (orthogonal) balanced manner with a minimum number of experimental sets. Heavy metals remediation of aqueous streams is of special concern due to its highly toxic and persistent nature. Taguchi approach was used for enhanced bioadsorptive removal of Pb(II), Cu(II) and Cd(II) from aqueous solutions using agroindustrial waste biomass from globe artichoke as inexpensive sorbent. Sorbent biomass was characterized as to its chemical composition by infrared spectroscopy (FTIR), revealing the presence of hydroxyl, carboxyl, sulphonic and amine functional groups. Ranks of four factors (pH, temperature, sorbent dosage and initial metal concentration) at three levels each, in a L9 array were conducted, in batch sorption tests, for the individual metal ions of concern. The sorption capacity (q e ) values were transformed into an accurate signal-to-noise (S/N) ratio for a "higher is better" response. The best conditions for individual heavy metal sorption were determined reaching up to 86.2 mg·g -1 for Pb, 35.8 mg·g -1 for Cd and 24.4 mg·g -1 for Cu. This paper also discusses the equilibria and kinetic aspects of the sorption process. Sorption isotherms were successfully described by the Sips model. In addition, the experimental data showed that the uptake kinetic profiles of the three metal ions closely fitted the pseudo-second order model. Conclusively, the agroindustrial waste biomass from globe artichoke represents a potentially viable sorbent for the bioremoval of Pb(II), Cu(II) and Cd(II) ions from aqueous systems., (Copyright © 2018. Published by Elsevier B.V.)

Copyright of Actualidad Jurídica Ambiental is the property of CIEMAT, through its Centro Internacional de Estudios de Derecho Ambiental (CIEDA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• This work estimates water and light use efficiency in garlic based on ground data. • The model integrates series of satellite vegetation indices in crop growth models. • The normalization of these efficiencies for the atmospheric conditions is analyzed. • Additional analysis are the use of cold temperature stress on the noted models. • The results are promising for the operative estimation of garlic biomass production. The objective of this paper was to determine the water use efficiency (WUE) and light use efficiency (LUE) values of garlic (Allium sativum L.) and to analyze the normalization of these efficiencies for the atmospheric conditions. We analyzed the use of daily reference evapotranspiration (ETo) and the vapor pressure deficit (VPD) for these purposes. WUE and LUE were valued based on the experimental measurements of dry biomass production and the estimation of transpiration and radiation interception based on time series of Remote Sensing satellite images. The experimental data were obtained in two commercial fields each planted with a different variety of garlic (var. morado and var. spring) growing in different weather conditions in the province of Albacete (in the south-east of Spain). The correlation between the accumulated values of biomass and the estimated values of crop transpiration and radiation absorption resulted in strong linear relationships. The slope of these correlations resulted in values of WUE and LUE, WUE = 5.51 g m−2 mm−1 and LUE = 2.26 g·MJ−1 for both analyzed varieties. The results demonstrated that the inclusion of temperature stress coefficient is required when the WUE and LUE parameters are normalized using the ETo and the VPD variables. However, atmospheric normalization did not conclusively improve results in this study. Results obtained in this paper provided empirical evidence regarding the feasibility of estimating biomass production in garlic based on the same physiological principles used for other crops. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper analyses the radiometric properties of aerosol column over Western Spain. It is based on 7-year data series of aerosol parameters at the AERONET Cáceres station (Spain) as measured by CIMEL sun-photometers. The study period extends along almost 7 years: from July 2005 to June 2012. The paper aims at analysing the temporal evolution, mean values and spectral dependence of some fundamental aerosol parameters such as aerosol optical depth ( τ), Ångström parameter ( α), single scattering albedo (ω), asymmetry parameter ( g) and volume size distribution ( dV dlogr−1); and their relationship with the most frequent air masses that arrive at Western Spain. Mean values correspond to aerosols of small size and low concentration (mean τ500 = 0.11; mean α = 1.38). In fact, 50% of days correspond to 'continental-clean' type. However, there is a certain variability of conditions, with more than 25% of medium and high turbidity cases with τ500 higher than 0.20. These episodes of high turbidity occur more frequently in August and September and are usually due to the influence of desert-dust aerosol, biomass burning, continental aerosol, or a mixture of them. The analysis of the all basic and derived aerosol parameters is explained by the main influences: continental location, exposed to maritime aerosols coming from the Atlantic Ocean, and affected by Saharan dust intrusions. [ABSTRACT FROM AUTHOR]

• We present a novel integration for reducing CO 2 emissions in blast furnaces. • It combines top gas recycling, oxy-fuel regime, power to gas and biomass pyrolysis. • The integration was modelled using the extended operating line methodology. • The best performance was found for pyrolysis at 700 °C. • The CO 2 emissions were reduced by 58% (9.8 MJ/kg CO2 energy consumption) The paper introduces a novel approach for mitigating CO 2 emissions in blast furnaces by integrating top gas recycling, an oxy-fuel regime, power to gas, and biomass pyrolysis. Various case studies were conducted, involving the adjustment of pyrolysis temperatures (300 °C, 500 °C, 700 °C, and 900 °C) and varying the quantity of blast furnace gas directed to methanation for carbon recycling. Pinus radiata, abundant and cost-effective in Chile and Spain, was chosen as the biomass source. The integration was modeled using the extended operating line methodology and evaluated through 12 key performance indicators, such as flame temperature, coke consumption, CO 2 emissions, and specific primary energy consumption per unit of CO 2 avoided. Optimal performance was observed with pyrolysis at 700 °C and no blast furnace gas recycled through methanation. This configuration achieved a 58 % reduction in CO 2 emissions, with an energy consumption of 9.8 MJ/kg CO2 , and obviated the need for geological storage. Comparing this innovative proposal with other oxygen blast furnace approaches from the literature revealed a 13 percentage point improvement in CO 2 reduction over the second-best alternative. Additionally, the required electrolysis capacity, influencing capital expenditure, was 57 % lower, and energy consumption was reduced by 44 %. [ABSTRACT FROM AUTHOR]

Nowadays, great emphasis is rightly given in the scientific community to hydrogen production from electrolysis. However, to achieve the politically stated target ambitions, all low-carbon sources for hydrogen production must be considered. The present work proposes a local production system of negative carbon hydrogen from lignocellulosic residual biomass using gasification and gas separation through H2-selective membranes as enabling technologies. The feedstock is pruning. In addition, the system produces heat and power for a Renewable Energy Community (REC) to increase the economic feasibility of hydrogen production via their sale. A modular basic plant is sized, based on a simplified system envisaged for RECs under the current regulatory framework in Spain (electrical renewable output of 100 kW). A network of these modular basic plants in the province of Huesca (Aragón) is simulated to create a system of hydrogen refueling stations for mobility in that area. A Levelized Cost of Hydrogen (LCOH) is proposed, comprehending the whole production chain from "field to tank", which is significant in areas where there is no infrastructure for the production and distribution of hydrogen for automotive purposes. The resulting LCOH for the whole system is 8.90 EUR/kg. Sensitivity analysis potentially values a lower LCOH, which unveils that hydrogen mobility can be largely competitive with diesel one. [ABSTRACT FROM AUTHOR]

In this study, we used Spanish National Forest Inventory (SNFI) data, Sentinel-2 imagery and ancillary data to develop models that estimate forest variables for major commercial timber plantations in northern Spain. We carried out the analysis in two stages. In the first stage, we considered plots with and without sub-meter geolocation, three pre-processing levels for the Sentinel-2 images and two machine learning algorithms. In most cases, geometrically, radiometrically, atmospherically and topographically (L2A-ATC) corrected images and the random forest algorithm provided the best results, with topographic correction producing a greater gain in model accuracy as the average slope of the plots increased. Our results did not show any clear impact of the geolocation accuracy of SNFI plots on results, suggesting that the usual geolocation accuracy of SNFI plots is adequate for developing forest models with data obtained from passive sensors. In the second stage, we used all plots together with L2A-ATC-corrected images to select five different groups of predictor variables in a cumulative process to determine the influence of each group of variables in the final RF model predictions. Yield variables produced the best fits, with R2 ranging from 0.39 to 0.46 (RMSE% ranged from 44.6% to 61.9%). Although the Sentinel-2-based estimates obtained in this research are less precise than those previously obtained with Airborne Laser Scanning (ALS) data for the same species and region, they are unbiased (Bias% was always below 1%). Therefore, accurate estimates for one hectare are expected, as they are obtained by averaging the values of 100 pixels (model resolution of 10 m pixel−1) with an expected error compensation. Moreover, the use of these models will overcome the temporal resolution problem associated with the previous ALS-based models and will enable annual updates of forest timber resource estimates to be obtained. [ABSTRACT FROM AUTHOR]

BACKGROUND The olive oil extraction process currently used in Spain and other Mediterranean countries generates large amounts of a semi-solid by-product known as 'alpeorujo' or 'two-phase olive mill waste' ( TPOMW). Although TPOMW can be a source of valuable compounds, it is mostly dried and burnt to produce energy. This paper, and for the first time, reports the use of TPOMW as the main carbon source for the production of surfactin, a high added value biosurfactant, by Bacillus subtilis DSM 3256. RESULTS Bacillus subtilis DSM 3256 was able to grow on TPOMW, the surface tension of the culture medium being reduced to 30.1 ± 0.9 mN m−1. FTIR and mass spectrometry determinations confirmed that the biosurfactant produced was surfactin. The highest surfactin concentration was obtained after 36 h fermentation, and the product yield from biomass ( YP/X) was 0.068 g g −1. Part of the phenolic compounds of TPOMW was extracted with the biosurfactant. CONCLUSION Two-phase olive mill waste can be used as the main carbon source for the production of surfactin. Surfactin yield from biomass was similar to that achieved with other bacterial strains and carbon sources. The biosurfactant was successfully applied to the remediation of sandy soils contaminated with engine oil. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Widespread generalist predators may affect declining keystone prey populations. However, this phenomenon is not well understood. In this paper, we assessed whether the abundance and population growth of European rabbits Oryctolagus cuniculus, a keystone prey species in Mediterranean Iberia, was related to the abundance and diet of red foxes, Vulpes vulpes, a widespread generalist predator. In a locality in central Spain, where rabbit population abundance declined, we estimated rabbit abundance during almost 3 years and determined fox abundance and diet during two concurrent years. We calculated a fox predation index (percentage of consumed rabbit biomass × fox abundance) to assess the importance of rabbits to foxes. We employed a multi-model approach to explain rabbit abundance and population growth. Foxes consumed between 60 and 99 % rabbit biomass in their diets, and this was independent of rabbit abundance. Periods of higher fox predation index coincided with lower rabbit density and vice versa. Two models best explained rabbit abundance and four rabbit population growth. They included the fox predation index and its interaction with rabbit abundance during the previous month. Altogether, fox predation, intraspecific density dependence, and their interaction partly explained rabbit population dynamics. We conclude that in order to propel the recovery of the rabbit in Iberia, it is essential to better understand the role of these factors in driving the abundance of the species. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A real case of study of biomass to apply a gasification process. • Almond shells showed the optimal technological properties. • Greenhouses vegetables residues have not aceptable properties. • Multivariable analysis allows to select olive tree prunings as the optimal ones from economic, technical and logistic point of view. The great potential for bioenergy in Spain is undeniable given our country´s enormous biomass supply. This fact contrasts with the limited evolution in the biomass sector for thermal and electricity generation over recent years. In this paper, we consider the utilization of fluidized bed gasification (FBG) as a biomass utilization technology incorporated into a thermal electric system to improve power plant production both thermally and electrically. Firstly, we studied the biomass resources available within a 100 km radius of the plant's location in Almería province (Spain). This biomass included almond shells, olive tree prunings, holm oak prunings and vegetable residues from greenhouse tomato and pepper plants. Technical criteria were applied to determine the most appropriate biomass to use in the gasification process; this included the physical-chemical characterization, the cost and the logistic-agronomic profile. The physical-chemical characterization included humidity, ash, calorific value, an elemental analysis, sulfur and chlorine, etc. On the basis of this characterization, almond shells were found to be the optimal biomass (M ar = 12.9%, A r = 1.1%, V d = 82.2%, Q p,net,d =18,470 kJ/kg and Cl = 60 mg/kg), and depending on certain parameters, could be classified as A1 or A2. Both the olive tree prunings (M ar = 6.2%, A r = 5.5%, Vd = 83.4%, Q p,net,d =18,193 kJ/kg and Cl =15 mg/kg) and the holm oak prunings (M ar = 9.2%, A r = 4.1%, V d = 80.3%, Q p,net,d =16,335 kJ/kg and Cl =12 mg/kg) were also considered to be good biomass resources, and were given an A2 or B1 classification. However, greenhouse vegetable residues (tomato and pepper) did not have suitable technical parameters (M ar = 82.6-29.6%, A r = 35.5-6.4%, V d = 75.1-59.1%, Q p,net,d = 17277-11529 kJ/kg and Cl = 1196-751 mg/kg) for use in the gasification process. Concerning the economic criteria, the best cost per kilogram (0.01€/kg) was found for the greenhouse vegetable residues, followed by the olive tree prunings (0.04€/kg); the highest cost corresponded to almond shells (0.07€/kg). With regard to the logistic-agronomic criteria, the theoretical hours of production in the power station are determined by the total availability of the resource in the particular location. The results indicate that the amount of almond shells available in the area was not sufficient (3854 h) to ensure the operation of the power station at full load (8760 h) but it would be possible in conjunction with other biomass types. The final decision regarding the optimal biomass to use was made on the basis of a multivariable analysis using the Visual Preference Ranking Organization Methods for Enrichment Evaluations (PROMETHEE) tool. From this analysis, olive tree prunings were selected as the optimum biomass to use because of their extensive local availability (58,080 t/year), in addition to them having suitable physical-chemical characteristics (M ar = 6.2%, A r = 5.5%, V d = 83.4%, Q p,net,d =18,193 kJ/kg and Cl =15 mg/kg)) and a reasonable cost (0.07€/kg). [ABSTRACT FROM AUTHOR]

Highlights • Genetic gain of durum wheat in Spain slowed after the green revolution until reach a plateau in the last decade. • However, genetic gain was positively related with the mean and maximum daily temperatures of the testing sites. • The genetic advance was related to improvement in kernels m−2 and kernels spike−1. Abstract This paper addresses the question of whether there has been any genetic gain in yield for durum wheat released in Spain after the Green Revolution and assesses the agronomical and physiological traits associated with evolution of the crop during this time. Field experiments were carried out with a wide range of durum wheat cultivars (released in Spain from 1980 to 2009) and were conducted in different sites embracing a wide range of growing temperatures and water regimes at Aranjuez and Zamadueñas during three consecutive growing seasons (2013/14, 2014/15, 2015/16) under rainfed and supplemental irrigation and at Coria for two consecutive seasons (2014/15 and 2015/16) under rainfed conditions alone. Grain yield increased with the year of release of cultivars at a rate of 24 kg ha−1 y−1 (0.44% y−1) from 1980 to 2003, with no clear additional improvements thereafter. The moderate grain yield improvement from 1980 and 2003 was associated with kernels m−2 and kernels spike−1, with an increase of 117 kernels m−2 y−1 and 0.24 kernels spike−1 y−1, respectively. Moreover, aerial biomass at harvest and grain nitrogen yield increased with the year of release of cultivars for the entire period. However, no differences were found for thousand kernel weight, number of spikes m−2, days to heading, plant height, harvest index, canopy temperature depression, carbon isotope discrimination or grain nitrogen concentration. Overall, these results indicated that the rate of genetic progress in the yield of durum wheat in Spain after the Green Revolution has been low and has even stopped during the last decade, while no clear trend in some grain quality traits (TKW and grain N concentration) was recorded. However, the absolute and relative genetic gains estimated for yield were positively associated with the average mean and maximum daily temperatures from sowing to harvest of the testing site, which suggest that breeding has been performed under high-temperature environments. [ABSTRACT FROM AUTHOR]

Fire has been one of the main causes of disturbance of vegetation over time, and since the Neolithic has become an irreplaceable tool for the opening of forest spaces and maintenance of pastures. Previous studies showed that the intensity and effects of wildfires are related to the biomass and controlled by climate factors. However, in regions such as Cantabria, where agriculture and livestock have spread throughout the territory since prehistory, fires should also be closely related to human land uses. The aim of this paper was to investigate the history of fires and vegetation since the Neolithic in the Cantabrian Mountains, using sedimentary charcoal and pollen data to study the role of human activities in the processes that have shaped ecosystems throughout the Holocene. The asynchrony and quantitative differences in the results obtained at different sites indicate significant variations in fire patterns at regional scale since the Neolithic, although the type and size of each basin also had a strong influence on charcoal accumulation. Maximum values for charcoal accumulation rate at La Molina were observed between the Neolithic and the Bronze Age but occurred after about 3500 cal years BP at El Cueto de la Avellanosa. At El Sertal, low charcoal accumulation rate values were observed, probably because the sequence begins in a space that already had been cleared; the maximum values occurred during the most recent millennium. These data provide evidence that fire has been a key factor in forest retreat and in maintaining open landscapes since the Neolithic. [ABSTRACT FROM AUTHOR]

Sustainable and circular production models, such as the circular economy and circular bioeconomy, have become key mechanisms to leave behind the traditional linear model of food production. Under this approach and considering the waste biomass potential available in Spain and the Czech Republic, the main objective of this study is to analyse the most relevant aspects of the generation, use and regulation of agricultural waste biomass (AWB) in both countries. For this purpose, a scientometric analysis and systematic review of published research in the Scopus database were carried out. A complementary analysis of AWB management policies and regulations was also part of the methodology. The results show that Spain has published almost twice as much research as the Czech Republic. Furthermore, 91% of the retrieved research prioritizes the characterization and estimation of the potential of more than 15 AWB types. Among the main ones are olive residues, horticultural residues and wheat straw, which are used for producing organic amendments, bioenergy and biofuels. The results confirm that the reduction and valorization of AWB is an issue that has become more important in the last 13 years, mainly due to the policies and strategies for circular economy and circular bioeconomy. With this in mind, this study provides relevant information for governments on the aspects that need to be improved to advance in the valorization of AWB. This study also provides guidance to farmers on the reduction and/or recovery alternatives that they can implement to move towards sustainable and circular agriculture. [ABSTRACT FROM AUTHOR]

Bio-based supply chains are by nature complex to optimize. The new logistic concept of integrated biomass logistical center (IBLC) provides us the opportunity to make full use of the idle capacity for a food/feed plant to produce biobased products so that the entire chain efficiency can be improved. Although research has been conducted to analyze the IBLC concept, is yet to be an optimization model that can optimally arrange the activities in the supply chain where an IBLC stands in the middle. To fill the knowledge gap in the literature, this paper makes the first step to develop a MILP model that enables biobased supply chain optimization with the IBLC concept, which supports logistic and processing decisions in the chain. The model is applied in a case study for a feed and fodder plant in Spain where managerial insights have been derived for transferring the plant to a profitable IBLC. [ABSTRACT FROM AUTHOR]

Studies in the agro-industry sector have shown the importance to evaluate the feasibility of an IBLC (a multi-product transformation plant). This paper develops a model to simulate the performance of an IBLC in Spain, using a combined approach: AHP, TOPSIS, and a hybrid simulation model. Results show that profits can be incremented by about 55.7% and environmental emissions of KgCO2e per tonne of bio-commodity produced, reduced by 24.2%. The scientific contribution covers the development of a simulation model that dynamically select suppliers based on a combination of social, environmental, and economic criteria. In addition, the model can be used to evaluate the economic and environmental feasibility of the IBLC by integrating the suppliers selection with the operations of a multi-product transformation plant. [Display omitted] • We provide a list of criteria that are relevant to choose suppliers of wheat. • We introduce the concept of ÍBLC and test its economic feasibility. • We develop an approach to integrate AHP and TOPSIS in a simulation environment. • We show, based on a case study in Spain, that the IBLC can be profitably run. • Profits increase by 55% while KgCO2e emissions reduces by 24.2%. [ABSTRACT FROM AUTHOR]

This paper performs technical, economic and environmental feasibility analyses of two different solar cogeneration plants, consisting of a solar system (a parabolic trough collector field coupled with thermal energy storage), an Organic Rankine Cycle (ORC), and mechanical chillers, that should cover the electrical and cooling demands of a commercial center located in Zaragoza (Spain). System A is hybridized with an auxiliary biomass boiler that complements the solar system's thermal production, providing a constant heat supply to the ORC, which operates at full load during the operating hours of the solar system. In contrast, system B is not hybridized with biomass, so the ORC is fully driven by the solar system, operating at partial load according to the solar resource availability. Both systems are connected to the electrical grid, allowing electricity purchases and sales when needed. The design procedure involves the sizing of the equipment as well as the modelling of the hourly behavior of each system throughout the year. The physical analysis is complemented by an economic assessment, which considers investment and variable costs, as well as an estimate of the significant environmental benefits of the proposed plants. The solar plants are compared to a conventional system in which all the electrical consumption is covered with electricity purchased from the grid. The costs of the electricity produced by systems A and B are estimated at 0.2030 EUR/kWh and 0.1458 EUR/kWh, which are about 49% and 7% higher than the electricity purchase price in Spain (0.1363 EUR/kWh). These results indicate that while none of the solar plants are presently competitive with the conventional system, system B (without biomass hybridization) is actually closer to economic feasibility in the short and medium term than system A (with biomass hybridization). [ABSTRACT FROM AUTHOR]

Climate change, other environmental impacts due to increased energy use worldwide, and the exhaustion of energy resources are some of the major challenges facing today's society. Considering this, this paper assesses the importance of biomass-based heating and hot-water systems in the achievement of more sustainable buildings. Using a simplified calculation method, we jointly analyzed the potential operational cost savings and reduction of CO2 emissions that would be achieved when the traditional energy model, based on the use of fossil fuels, is replaced by biomass-based heating systems. Evidence stems from a case study in public buildings in the province of Pontevedra, in the northwest of Spain. The results of this research not only show a huge impact on CO2 emission reduction just by adapting the kind of fuel use, but also considerable annual cost reduction without compromising activity development and workers' comfort. Thus, the findings obtained should encourage governments to support the transition toward cleaner sources of energy, acting as first movers toward a locally produced and renewable-based energy supply. [ABSTRACT FROM AUTHOR]

The characterization of aboveground biomass is important in forest management planning, with various objectives ranging from prevention of forest fires to restoration of burned areas, especially in fire-prone regions such as NW Spain. Although remotely sensed data have often been used to assess the recovery of standing aboveground biomass after perturbations, the data have seldom been validated in the field, and different shrub fractions have not been modelled. The main objective of the present study was to assess different vegetation parameters (cover, height, standing AGB and their fractions) in field plots established in five areas affected by wildfires between 2009 and 2016 by using Sentinel-2 spectral indices and LiDAR metrics. For this purpose, 22 sampling plots were established in 2019, and vegetation variables were measured by a combination of non-destructive measurement (cover and height) and destructive sampling (total biomass and fine samples of live and dead fractions of biomass).The structural characterization of gorse shrublands was addressed, and models of shrub cover—height, total biomass, and biomass by fraction and physiological condition—were constructed, with adjusted coefficients of determination ranging from 0.6 to 0.9. The addition of LiDAR data to optical remote sensing images improved the models. Further research should be conducted to calibrate the models in other vegetation communities. [ABSTRACT FROM AUTHOR]

The use of by-products from agricultural and forestry activity, apart from many other environmental benefits, constitutes an alternative source of income, cost reduction, and support for the principles of the circular economy. The bobal grape is a variety of red grape that is cultivated on 65 thousand hectares only in Spain. Periodic maintenance of the crop must be carried out through winter pruning from December to March. The pruning biomass is burned or crushed and incorporated into the soil, producing environmental contamination and disease transmission. The objective of this work was to use the biomass from vineyard residues in the production of binderless particleboards without using any adhesives, thereby obtaining an ecological product that would benefit the environment. In the manufacturing process, the press temperature (130 °C) and pressure (2.6 MPa) were fixed, varying the particle size (<0.25, 0.25 to 1.00, and 1.00 to 2.00), and the pressing time (15, 30, and 45 min). The results showed that by using particles smaller than 0.25 mm and applying 45 min in the hot press, panels were manufactured that are suitable for general use in a dry environment and for the manufacture of furniture according to European standards. [ABSTRACT FROM AUTHOR]

Estimation of forestry aboveground biomass (AGB) by means of aerial Light Detection and Ranging (LiDAR) data uses high-density point sampling data obtained in dedicated flights, which are often too costly for available research budgets. In this paper we exploit already existing public low-density LiDAR data obtained for other purposes, such as cartography. The challenge is to show that such low-density data allows accurate biomass estimation. We demonstrate the approach on data available from plantations of Pinus radiata in the Arratia-Nervión region, located in Biscay province located in the North of Spain. We use public data gathered from the low-density (0.5 pulse/m2) LiDAR flight conducted by the Basque Government in 2012 for cartographic production. We propose a linear regression model based on explanatory variables obtained from the LiDAR point cloud data. We calibrate the model using field data from the Fourth National Forest Inventory (NFI4), including the selection of the optimal model variables. The results revealed that the best model depends on two variables extracted from LiDAR data: One directly related with tree height and a second parameter with the canopy density. The model explained 80% of its variability with a standard error of 0.25 ton/ha in logarithmic units. We validate the predictions against the biomass measurements provided by the government institutions, obtaining a difference of 8%. The proposed approach would allow the exploitation of the periodic available low-density LiDAR data, collected with territorial and cartographic purposes, for a more frequent and less expensive control of the forestry biomass. [ABSTRACT FROM AUTHOR]

Background: Energy efficiency in buildings must be increased in order to reduce both energy intensity and greenhouse gas emissions. This study proposed the replacement of existing diesel boilers with biomass boilers, using four fuels (bulk pellets, wood chip, olive kernel and milled nutshell) to meet the energy demands of educational buildings in the region of Extremadura (Spain). High uncertainty surrounds biomass price prediction affecting the accuracy of economic feasibility analyses; thus, stochastic processes are suitable to support an improvement in the accuracy of predictions. The objective of the study is to demonstrate the feasibility of replacing diesel boilers with biomass boilers in order to revalorize agroforestry residues. Results: A stochastic simulation of the feasibility of replacing oil-fired boilers with biomass-fired boilers was carried out in this research. Up to 20 million possible scenarios of 10 years of fuel price evolution were simulated by Monte Carlo method based on empirical price trends data. Regression models were built to relate Net Present Values with discount rates, whose statistical dependency was significant. Predictions on financial indicators showed biomass fuels as the most profitable investment, rather than fuel oil. Specifically, in this study, milled nutshell was found the most profitable fuel in the simulation runs, with Net Present Value = 27,151.09 € (standard deviation = 7939.88 €) and Internal Rate of Return = 16.9% (standard deviation = 3.4%). Conclusions: Continuing to use oil-fired boilers costs more than the purchase and operation of new biomass-fired boilers, since the latter produce a higher cumulative cash flow than the initial investment within the next years. The payback period lies within the range of 4 to 6 years depending on the type of biomass fuel. Getting on the path to sustainability in education buildings can reduce up to 94.4% GHG emissions. This research contributes to promoting the use of low-emission fuels to meet the energy demand of educational buildings. Its results will have a positive effect in the region of Extremadura (Spain), as it boosts the appreciation of agro-industrial waste and economically strengthens the sector. [ABSTRACT FROM AUTHOR]

The Water Framework Directive (Directive 2000/60/EC) emphasises the need for simple tools and studies to characterise aquatic ecosystems. A wide range of methods has been developed, including different groups of biota and different taxonomic resolutions. Among these, the abundance biomass comparison (ABC) method is an important methodology widely used in marine benthic systems and well-founded from the ecological point of view. This method - with a slight modification using genera and families instead of species - was applied in a Mediterranean river (Eliche-Frío, northeast of Andalusia, Spain) using the macroinvertebrate community, together with the Margalef richness index and the Iberian BioMonitoring Working Party (IBMWP) to determine the quality of the water. The obtained results show the suitability of the ABC curves method to analyse the macroinvertebrate community and estimate the ecological status of river ecosystems. Although both, the genus and family aggregations, showed a similar trend, the values obtained with the family level indicate a worse state of contamination than those shown with the genus level. The comparison between genus and family levels with other biological indices shows that the evaluation obtained with family aggregation is more similar to those obtained with the Margalef and IBMWP indices than the evaluation based on genera; therefore, we could conclude that this level of taxonomic resolution is adequate for the use of the ABC method in assessing the ecological status of Mediterranean rivers. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to optimize the size (electric power) of a cogeneration plant based on a biomass-fired Organic Rankine Cycle and connected to an existing district heating network, maximizing profitability. First, a model to determine the hourly thermal energy demand profile of a location in Spain has been derived, from open access meteorological data included in Spanish building regulations. Partial load model of an organic Rankine plant has also been obtained to increase the operation hours. These tools have been applied to two locations in Spain with different climatic severities, calculating the optimal size of the plant. The business model does not include subsidies. Calculations show that for population between 10,000 and 20,000 inhabitants the size of the plant ranges from 2 to 9 MWe and the internal rate of return ranges from 6% to 18%. The coverage of the thermal energy demand ranges from 40% to 80%. Regarding the trigeneration mode, it is concluded that cooling is only worth in locations with high summer severity and in full load operation mode, being the optimal size of the plant smaller in trigeneration mode than in cogeneration. [ABSTRACT FROM AUTHOR]

Olive sector residues could contribute to increased use of renewable energies, especially in those areas where the olive crop is produced. This paper determines the maximum amount of electrical and thermal energy which could be obtained in Andalusia from olive sector residues, and the economic value that could be obtained from these energy uses. For this, the current data on installed power and electrical and thermal generation are compared with the calculated potential data which would be obtained at full capacity. The results show there is a 69.23% wastage of olive sector residues for energy purposes. Thus, using the resources at full capacity, 3.9 million tons of biomass per year could be obtained for energy purposes. Currently, only 2 million tons of biomass are used for energy purposes. This wastage translates into a below potential generation of electrical and thermal energy. The full use of these residues would allow 83.9% and 64.9% higher generation of electrical and thermal energy, respectively. The results obtained also show that the economic value of olive sector biomass is higher than the market price value, with the average values for each use being 248.20 €/t for domestic thermal use, 165.04 €/t for electrical use and 139.50 €/t for industrial thermal use. Thus, it is considered feasible that the olive sector biomass could be used to a greater degree than at present. In this sense, it is recommended that more electricity generation plants and thermal-generating systems be put into operation. • There is a 69.2% wastage of olive sector residues that could be used for energy purposes. • The full use of olive by-products would account for 6.2% of renewable electricity. • The full use of olive by-products would account for 26.7% of thermal generation. • Better use of residues would promote the start-up of 55 and 1762 electricity and thermal plants, respectively. • The economic value of olive sector biomass allows the value chain to be covered. [ABSTRACT FROM AUTHOR]

The leather industry is an example of circular economy, as it uses meat industry wastes (hides and skins) as raw materials. However, the process of tanning also produces a substantial amount of organic waste. This research project studies the case of a tannery located in Navarra, in the North of Spain, committed to a circular economy and environmental protection, which produces around 2 tons per day of leather shavings and buffing dust and 10 tons per day of discarded bullock hair. The study tackles the challenge of whether the discarded waste material might be used as a new resource for products or processes related with the building sector. Three different types of solid wastes (chromium free tanned shavings, chromium buffing dust, and discarded hair) were categorized and analyzed. The paper examines two proposals to reuse the weekly tons of leftovers (both shavings and hair) produced by the tannery, instead of taking them to an external composting plant or to the landfill. The first exploration path proposed to use the discarded material to obtain biomass for the company's thermal production plant. After establishing the calorific values of the discarded hair and the shavings, these were found to offer competitive value in comparison with the biomass products used at present, such as wood pellets. The second approach to the waste upcycling involved seeking new products in the building sector, acoustic panels in this case. After a mechanical behavior analysis, different binders were blended with diverse proportions and particle sizes of shavings to obtain samples for a sound absorption coefficient determination. The results show coefficients close to those of cork panels or carpets. This experimental experience serves as a preliminary study for the use of leather industry wastes in the construction sector. • Further circular economy in leather industry: two proposals for industrial symbiosis. • Holistic approach for waste material recycling challenge. • Recycling tools for a market of more than US$100 billion per year. • Use of waste as biomass might reduce by more than half the dependency on natural gas. • Competitive performance of leather by-products as acoustic absorption panels. [ABSTRACT FROM AUTHOR]

Biomass is a key element within the Europe's Bioeconomy Strategy. This paper aims at contributing to a better knowledge of the evolution and current state of biomass trade in Spain by adopting a raw material equivalent approach. Instead of measuring trade flows in actual physical quantities, this approach expresses international trade flows in terms of the raw material needed to produce the traded products. The results obtained show that while raw material input of biomass increased by 3560 thousand tonnes over the period 2008–2016, raw material consumption decreased by 15,086 thousand tonnes. This is explained by the different pace of growth registered by raw material equivalent of exports and of imports: while raw material equivalent of exports rose from 49,485 thousand tonnes in 2008 to 68,131 thousand tonnes in 2016 recording a double digit growth of 38%, the increase in raw material equivalent of imports was considerably lower: from 64,560 thousand tonnes to 66,106 thousand tonnes, an increase of 2%. By categories, biomass from agriculture was the main driver of overall trade of biomass. Two groupings deserve special mention: fodder crops, which accounted for one quarter of raw material equivalent of exports, and cereals, which represented almost one third of raw material equivalent of imports in 2016. • Raw material input of biomass increased by 3560 thousand tonnes. • Raw material consumption of biomass diminished by 15,086 thousand tonnes. • Raw material equivalent of exports grew faster than that of imports (38% compared to 2%). • Fodder crops accounted for one quarter of raw material equivalent of exports. • Cereals represented almost one third of raw material equivalent of imports. [ABSTRACT FROM AUTHOR]

A microalgal strain was established from Cepsa's refinery wastewater treatment plant in Huelva (southwest of Spain). Genetic analysis of the chloroplastic rbcL gene encoding for the large subunit of the ribulose bisphosphate carboxylase enzyme (Rubisco) showed the strain had high homology with other known rbcL sequences of the genus Chlorella. The strain grows well autotrophically in minimum mineral medium, with a growth rate of 0.28 ± 0.012 day−1 and a biomass productivity of 138.9 ± 6.7 mg L−1 day−1. N-starvation and/or over illumination with 650 µmol photons m−2 s−1 of PAR light on the cultures induced a significant increase in the intracellular content of lipids in this microalga. Total lipids were extracted from the strain biomass with 2:1 chloroform-methanol, and they accounted for approximately 50% of the dry biomass. Polyunsaturated fatty acids ( PUFAs) represented 60.4% of the total fatty acids found in the strain, thus making this biomass attractive as a high added-value product source. The strain was able to grow efficiently in the refinery treated wastewater from which it was isolated, providing an attractive advantage for further development of more sustainable algal biomass production processes at reduced costs close to a petrol refinery area. [ABSTRACT FROM AUTHOR]

Despite the low timber productivity of Mediterranean Pinus halepensis Mill. forests in south-eastern Spain, they are a valuable carbon sequestration source which could be extended if young stands and understories were considered. We monitored changes in biomass storage of young Aleppo pine stands naturally regenerated after wildfires, with a diachronic approach from 5 to 16 years old, including pine and understory strata, at two different quality sites (dry and semiarid climates). At each site, we set 21 permanent plots and carried out different thinning intensities at two ages, 5 and 10 years after fires. We found similar post-fire regeneration capacity at both sites in terms of total above-ground biomass storage ~6 Mg ha (3 Mg ha of the above-ground pine biomass plus 3 Mg ha of the above-ground understory biomass), but with a contrasting pine layer structure. Generally, across the diachronic study, the earlier thinning reduced biomass stocks at both sites, except for the best quality site (the dry site), where the earliest thinning (applied at post-fire year 5) enlarged carbon storage by 11 % as compared to non-thinned plots. We found root:shoot ratios of an average 0.37 for the pine layer and 0.45 for the understory layer. These results provided new information which not only furthers our understanding of carbon sequestration in low timber productivity Mediterranean forests, but will also help to develop new guidelines for sustainable management adapted to the high-risk terrestrial carbon losses of fire-prone areas. [ABSTRACT FROM AUTHOR]

Climate change is one of the environmental issues of global dominance and public opinion, becoming the greatest environmental challenge and of interest to researchers. In this context, planting trees on marginal agricultural land is considered a favourable measure to alleviate climate change, as they act as carbon sinks. Aerial laser scanning (ALS) data is an emerging technology for quantitative measures of C stocks. In this study, an estimation was made of the gains of C in biomass and soil in carob (Ceratonia siliqua L.) plantations established on agricultural land in southern Spain. The average above-ground biomass (AGB) corresponded to 85.5% of the total biomass (average 34.01 kg tree−1), and the root biomass (BGB) was 14.5% (6.96 kg tree−1), with a BGB/AGB ratio of 0.20. The total SOC stock in the top 20 cm of the soil (SOC-S20) was 60.70 Mg C ha−1 underneath the tree crown and 43.63 Mg C ha−1 on the non-cover (implantation) area for the C. siliqua plantations. The allometric equations correlating the biomass fractions with the dbh and Ht as independent variables showed an adequate fit for the foliage (Wf, R2adj = 0.70), whereas the fits were weaker for the rest of the fractions (R2adj < 0.60). The individual trees were detected using colour orthophotography and the tree height was estimated from 140 crowns previously delineated using the 95th percentile ALS-metric. The precision of the adjusted models was verified by plotting the correlation between the LiDAR-predicted height (HL) and the field data (R2adj = 0.80; RMSE = 0.53 m). Following the selection of the independent variable data, a linear regression model was selected for dbh estimation (R2adj = 0.64), and a potential regression model was selected for the SOC (R2adj = 0.81). Using the segmentation process, a total of 8324 trees were outlined in the study area, with an average height of 3.81 m. The biomass C stock, comprising both above- and below-ground biomass, was 4.30 Mg C ha−1 (50.67 kg tree−1), and the SOC20-S was 37.45 Mg C ha−1. The carbon accumulation rate in the biomass was 1.94 kg C tree−1 yr−1 for the plantation period. The total C stock (W-S and SOC20-S) reached 41.75 Mg ha−1 and a total of 4091.5 Mg C for the whole plantation. Gleaned from the synergy of tree cartography and these models, the distribution maps with foreseen values of average C stocks in the planted area illustrate a mosaic of C stock patterns in the carob tree plantation. [ABSTRACT FROM AUTHOR]

Energy demand is steadily growing as society becomes more industrialised. Renewable energy sources (RES) have long been used for various applications by thermal energy systems in the European Union (EU). Biomass and solar energy represent important RES in the development of energy transition in some regions such as coal-mining areas of Europe. Bioenergy is a key renewable energy storage mechanism for solar energy which, when combined, can tackle many of the barriers to the use of solar energy. Against this background, this study evaluates the potential implementation of both biomass and solar energy for energy production in coal-mining areas in Spain as a direct alternative to coal. The shown methodology relies on a comprehensive analysis of existing resources and their conversion to thermal energy from a multi-parametric point of view. The obtained results show that the solar–biomass combination can be used for thermal energy systems as a challenging option. The theoretical total hybrid-modular systems if implemented in the study area are equivalent to 1165 MWth and supply thermal energy for 170,000 single-family houses. [ABSTRACT FROM AUTHOR]

The Authors conducted a long-term follow-up study of a John Deere 1490 forwarder-mounted bundler owned by a Portuguese company and used for bundling logging residues from fast-growing eucalypt plantations located in Portugal and Spain. The study spanned 7 years, from 2011 to 2016. During this time, the machine clocked over 11,500 h and produced more than 200,000 bundles or 75,000 green tons of biomass. Bundle length was commonly 2.4 m, and bundle mass averaged 350 kg. Overall, the database contained 1752 daily records. Bundling productivity averaged 19 bundles per productive machine hour (meter hour, excluding all major delays). Mechanical availability was very high and averaged 93%. Utilization commonly ranged between 65% and 75%. Use and productivity showed a predictable seasonal trend and a slight decline over time. The latter might be due to wear, but also due to the increasingly challenging conditions faced by the company as the average worksite size sharply decreased from 2011 onwards. While almost extinct elsewhere, bundling seems to thrive in the Iberian plantations, possibly due to the industrial character of both eucalypt farming and bioenergy generation in the region. That allows the reaping of all integration benefits offered by bundling, while the cost of setting up a parallel biomass chain is minimized. Furthermore, bundling seems the ideal technique for efficient residue recovery where slash yields are low and roadside storage space is limited: these are the typical constraints of industrial eucalypt plantations, where planted area is maximized (=little landing space) and the largest possible proportion of the tree mass is turned into pulpwood (=relatively low residue yield). [ABSTRACT FROM AUTHOR]

In this study, we used Landsat Earth observations and gridded weather data along with global soil datasets available in Google Earth Engine (GEE) to estimate crop yield at 30 m resolution. We implemented a remote sensing and evapotranspiration-based light use efficiency model globally and integrated abiotic environmental stressors (temperature, soil moisture, and vapor deficit stressors). The operational model (Global Yield Mapper in Earth Engine (GYMEE)) was validated against actual yield data for three agricultural schemes with different climatic, soil, and management conditions located in Lebanon, Brazil, and Spain. Field-level crop yield data on wheat, potato, and corn for 2015–2020 were used for assessment. The performance of GYMEE was statistically evaluated through root-mean-square error (RMSE), mean absolute error (MAE), mean bias error (MBE), relative error (RE), and index of agreement (d). The results showed that the absolute difference between the modeled and predicted field-level yield was within ±16% for the analyzed crops in both Brazil and Lebanon study sites and within ±15% in the Spain site (except for two fields). GYMEE performed best for wheat crop in Lebanon with a low RMSE (0.6 t/ha), MAE (0.5 t/ha), MBE (−0.06 t/ha), and RE (0.83%). A very good agreement was observed for all analyzed crop yields, with an index of agreement (d) averaging at 0.8 in all studied sites. GYMEE shows potential in providing yield estimates for potato, wheat, and corn yields at a relative error of ±6%. We also quantified and spatialized the soil moisture stress constraint and its impact on reducing biomass production. A showcasing of moisture stress impact on two emphasized fields from the Lebanon site revealed that a 12% difference in soil moisture stress can decrease yield by 17%. A comparison between the 2017 and 2018 seasons for the potato culture of Lebanon showed that the 2017 season with lower abiotic stresses had higher light use efficiency, above-ground biomass, and yield by 5%, 10%, and 9%, respectively. The results show that the model is of high value for assessing global food production. [ABSTRACT FROM AUTHOR]

Developing a circular bioeconomy based on the sustainable use of biological resources, such as biomass, seems to be the best way of responding to the challenges associated with global change. Among the many sources, short rotation forest crops are an essential instrument for obtaining quality biomass with a predictable periodicity and yield, according to the areas of cultivation. This review aims to provide an overview of available knowledge on short rotation coppice Populus spp. plantations under Mediterranean conditions and specifically in Spain, in order to identify not only the status, but also the future prospects, for this type of biomass production. The analysis of available information was conducted by taking into consideration the following aspects: Genetic plant material; plantation design, including densities, rotation lengths and the number of rotations, and mixtures; management activities, including irrigation, fertilization, and weed control; yield prediction; biomass characterization; and finally, an evaluation of the sustainability of the plantation and ecosystem services provided. Despite advances, there is still much to be done if these plantations are to become a commercial reality in some Mediterranean areas. To achieve this aim, different aspects need to be reconsidered, such as irrigation, bearing in mind that water restrictions represent a real threat; the specific adaptation of genetic material to these conditions, in order to obtain a greater efficiency in resource use, as well as a greater resistance to pests and diseases or tolerance to abiotic stresses such as drought and salinity; rationalizing fertilization; quantifying and valuing the ecosystem services; the advance of more reliable predictive models based on ecophysiology; the specific characterization of biomass for its final use (bioenergy/bioproducts); technological improvements in management and harvesting; and finally, improving the critical aspects detected in environmental, energy, and economic analyses to achieve profitable and sustainable plantations under Mediterranean conditions. [ABSTRACT FROM AUTHOR]