Solid Biofuels Research Articles

Trends in Energy Security Education with a Focus on Renewable and Nonrenewable Sources

Energy security education explores various issues, such as a secure and competitive economy and nuclear safety. In the context of energy transition and sustainable development, it also addresses the world’s reliance on nonrenewable and renewable energy sources. The aim of this study was to identify research trends pertaining to energy security education, paying particular attention to renewable and nonrenewable sources. This was accomplished with the use of mixed-method research in two steps. The first step was a text-mining and content analysis of publications on energy security education published on the Web of Science platform between 2016 and 2021. From 660 publications on energy security education, titles, abstracts, and keywords were extracted and analysed with NVivo software to identify the most frequent concepts on energy sources in publications. The concepts were associated with nonrenewable energy sources (coal, natural gas, uranium, petroleum, and fossil fuels), nuclear power, and renewable energy sources (hydro, geothermal, solar, tide/wave/ocean, wind, solid biofuels, biogases, liquid biofuels, and renewable municipal waste). The second step was conducting detailed searches with Boolean operators, where “energy security education” was juxtaposed with the distinguished keywords. All searches on energy security education showed that publication activity tended to decrease, while citations increased. The most explored topics concerned: “fossil fuels”, “oil, petroleum”, “renewable” energy, and “solar” energy sources. An increasing trend was observed for all renewable energy sources as well as selected nonrenewable sources: “oil, petroleum”, “nonrenewable”, and “coal”. Additionally, R-squared values were calculated to indicate the fit of the trendline to the model. Due to the technologically enhanced energy transition and didactic innovations, education focussing on energy sources is expected to remain in demand. Curricula will need to be revised in the future to better reflect this reality.

Improved energy recovery from food waste through hydrothermal carbonization and anaerobic digestion

Here we studied energy valorization of food waste by hydrothermal carbonization coupled with anaerobic digestion. Hydrothermal treatment was carried out at 200 °C and 230 °C for 1 h, obtaining hydrochar with properties suitable for solid biofuel according to ISO/TS 17225–8. The increase in temperature improved the fuel properties of hydrochar (higher heating value 20.3 and 23.7 MJ kg−1, fuel ratio 0.33 and 0.37, energy density 1.07 and 1.25). The anaerobic digestion of process water achieved methane yields around 150 mL CH4 STP g−1 CODadded and made it possible to remove some specific recalcitrant compounds, such as 2-methylpyridine and 2-ethyl-3-methylpyrazine. Energy recovery from hydrochar and process water seems to be an interesting alternative way to sustain the process energetically and economically, despite the significant energy inputs required for hydrothermal carbonization.

Conversion of biomass blends (walnut shell and pearl millet) for the production of solid biofuel via torrefaction under different conditions

The torrefaction of lignocellulose biomass was conducted to produce biochar with properties compatible with coal. Two lignocellulose biomasses, pearl millet (PM) and walnut shell (WS), were torrefied at different process temperatures (230–300 °C), residence times (30–90 min), and different compositional biomass blends to improve the characteristics of the biochar product. The resulting biochar product exhibited favorable changes in their properties. The pure biomasses and their blends obtained a high biochar yield (41–91%). The gross calorific value (GCV) ranged from 22 to 27 MJ/kg, showing an increase of 22–59% compared to the raw biomass. The torrefaction temperature had the most notable effect on the biochar quantity and quality. The biochar samples obtained from the torrefaction of different blends showed a higher GCV and other physicochemical characteristics than the pure biomasses. Scanning electron microscopy showed that these products might also be used for other applications.

Physicochemical Characteristics of Biofuel Briquettes Made from Pecan (Carya illinoensis) Pericarp Wastes of Different Particle Sizes.

Pecan nut (Carya illinoensis) pericarp is usually considered as a waste, with no or low value applications. Its potential as a densified solid biofuel has been evaluated, searching for alternatives to generating quality renewable energy and reducing polluting emissions in the atmosphere, based on particle size, that is an important feedstock property. Therefore, agro-industrial residues from the pecan nut harvest were collected, milled and sieved to four different granulometry: 1.6 mm (N° 12), 0.84 mm (N° 20), 0.42 mm (N° 40), and 0.25 mm (N° 60), used as raw material for biofuel briquette production. The carbon and oxygen functional groups in the base material were investigated by Fourier transform infrared spectroscopy (FTIR) and proximate analyses were performed following international standards, for determining the moisture content, volatile materials, fixed carbon, ash content, and calorific value. For the biofuel briquettes made from base material of different particle sizes, the physical characteristics (density, hardness, swelling, and impact resistance index) and energy potential (calorific value) were determined to define their quality as a biofuel. The physical transformation of the pecan pericarp wastes into briquettes improved its quality as a solid biofuel, with calorific values from around 17.00 MJ/kg for the base material to around 18.00 MJ/kg for briquettes, regardless of particle size. Briquettes from sieve number 40 had the highest density (1.25 g/cm3). Briquettes from sieve number 60 (finest particles) presented the greater hardness (99.85). The greatest susceptibility to swelling (0.31) was registered for briquettes with the largest particle size (sieve number 20). The IRI was 200 for all treatments.

Sustainability Assessment of Solid Biofuels from Agro-Industrial Residues Case of Sugarcane Bagasse in a Mexican Sugar Mill

Motivated by the environmentally driven energy transition we live in, the valorization of biomass residues from the agro-industry as renewable energy can play an essential role in GHG emissions mitigation. To overcome the debate on the production and use of solid biofuels (SBF), in this study, we apply an integrated multicriteria tool for the assessment of the sustainability use of agro-industrial residues (AIR) as solid biofuels. Mexico has a vast AIR production, but frequently, the AIR are considered waste biomass. Still, when valorized, SBF do not have adverse effects on soil quality, are not responsible for biodiversity loss, and compete against food production as first-generation SBF. Nevertheless, the AIR present other environmental, social, and economic impacts that have not been adequately evaluated; therefore, we identified the need for a sustainability assessment of energy systems based on the use of SBF–AIR as input fuels. After reviewing previous work on sustainability assessment methodologies, multicriteria decision analysis methods, and indicator weighting methods, we considered it appropriate for this problem to apply a tool that integrates the entropic indicator weighting method into the discrete multicriteria decision analysis method called PROMETHEE. In terms of selected sustainability indicators, this tool was used to assess four electric energy supply systems of a Mexican sugar mill as a case study: current bagasse cogeneration, efficient bagasse cogeneration, a power generation system fueled only with fuel oil, and grid electricity only. Finally, after evaluating the mentioned energy systems with four sustainability indicators: GHG emissions, PM emissions, employments per energy unit (JOBS), and the net present value (NPV) of each alternative, we found the net outranking flow of the efficient bagasse system (EBS). which is the most sustainable system because it has the highest outranking flow value from the four considered alternatives, since it has the lower GHG emissions, reducing the current bagasse GHG emissions by 55% and the PM emissions by 58%. The EBS also shows the highest NPV system due to surplus electricity sales, resulting in the most profitable energy system analyzed.

A Methodological Framework for Assessing the Sustainability of Solid Biofuels Systems.

This paper introduces a methodological framework for assessing the sustainability of solid biofuels in Mexico. The designed framework comprises 13 normalized indicators and two diagnostic studies, covering the economic, social, environmental, and institutional sustainability dimensions, and their intersections. Indicators are normalized using the concept of load capacity of a system, similarly to the planetary boundaries. Thus, the graphical representation of results facilitates their multidimensional analysis. The framework was applied to three case studies: traditional fuelwood in rural households, charcoal for restaurant grilling, and electricity cogeneration from sugarcane bagasse. This was part of an iterative process of testing and refining the framework and simultaneously demonstrating its application in the Mexican bioenergy context. This led to the conclusion that the resulting framework (a) provides a useful, quantitative, and comprehensive overview of both broad and specific sustainability aspects of the assessed system; (b) requires a balance of accessible but also scattered or sensitive data, similarly to most existing frameworks; (c) is highly flexible and applicable to both modern and traditional solid biofuels; and (d) is simple to communicate and interpret for a wide audience. Key directions for improvement of the framework are also discussed.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12155-021-10365-2.

Development of a total Ash Quality Index and an Ash Quality Label: Comparative analysis of slagging/fouling potential of solid biofuels.

Biomass combustion generates considerable amounts of ash that are related to slagging/fouling problems in combustors. Numerous indices have been proposed in the literature for the evaluation of slagging/fouling tendencies. This paper is focused on the characterization of various biomass ashes in terms of their slagging/fouling tendency. For this purpose, the chemical composition of ash samples from fourteen solid biofuels (and a lignite sample as a reference) was analyzed by scanning electron microscope, energy-dispersive spectroscopy, ion chromatography and elemental analysis. Modification/normalization of the available ash indices was performed by taking into account not only the chemical composition of the ash but also the Gross Calorific Value of the fuels and the amount of the produced ash. Two versatile tools were developed, a total Ash Quality Index (tAQI) and an Ash Quality Label (AQL), in order to express the information derived from various indices with a single number or letter. The modified indices result in different characterization from the unmodified ones and lead to a more objective/fair evaluation of the slagging/fouling tendency. The comparison of large number of indices of large number of samples is enabled via the tAQI and the AQL. Samples with a tAQL ≤ 1 belong to class 'A' (low slagging/fouling problems) while samples with a tAQL > 6 belong to class 'G' (extremely high tendency to slagging/fouling problems). The tAQI and AQL are a novel concept for the categorization and labeling of solid biofuels regarding their slagging/fouling tendency and could contribute to the waste/biomass residue market for energy proposes.

Carbon dioxide-assisted Torrefaction of Maize Cobs by Thermogravimetry: Product Yield and Energy Recovery Potentials

The objective of this study is to examine the potential product yields and energy recovery of maize cobs (MC) through carbon dioxide-assisted torrefaction using thermogravimetric analysis (TGA). The CO2-assisted torrefaction of MC was performed from 240 °C to 300 °C (Δ 30 °C) for the residence time of 30 minutes based on the selected non-isothermal/isothermal heating program of the TGA. Furthermore, the physicochemical, microstructure and mineral characteristics of MC were examined. The results showed that the CO2-torrefaction of MC resulted in a mass loss (ML) ranging from 18.45% to 55.17%, which resulted in the mass yield (MY) ranging from 81.55% to 44.83%. The HHV of the solid product was in the range from 22.55 MJ/kg to 26 MJ/kg, which indicates the CO2-torrefaction process enhanced the energy content of MC by 40% – 60%. In conclusion, the findings showed that the CO2 torrefaction is a practical, sustainable, and cost-effective approach for the valorization of MC into a clean solid biofuel for enhanced energy recovery.

Biochar production via pyrolysis of citrus peel fruit waste as a potential usage as solid biofuel

Renewable energy sources such as biomass have been proven to be one of the promising sustainable alternatives to fossil fuels. However, using biomass directly as a fuel is less attractive due to its high moisture content, poor grindability, low bulk density, and low energy density nature. Hence biomass can be converted into biochar to overcome these challenges. In this study, biochar was derived from citrus peels biomass by slow pyrolysis over the temperature range of 300–700 °C. The effect of pyrolysis temperature on the quality of citrus peels-derived biochar was examined based on the physical and chemical properties obtained from various analyses. The citrus peels biomass and biochar were characterized by means of higher heating value (HHV) analysis, field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX), Fourier transform infrared ray (FTIR) analysis, proximate and thermogravimetric analysis. Based on the characterization results, the potential usage of the derived biochar as a solid fuel was discussed. Results obtained from the pyrolysis experiments indicated that a lower pyrolysis temperature produced a higher char yield. The carbon content and energy content of biochar were found to be increasing with pyrolysis temperature. Biochar produced at 500 °C presented the best fuel properties by having the highest value of HHV and carbon content. The results from this study provided great insights into biomass waste reutilisation to generate value-added biochar for renewable energy production in Malaysia.

INVESTIGATION OF COCOA HUSKS DENSIFICATION POSSIBILITIES

During the biomass densification can be recognized various technological variables and also material parameters which significantly influences the final solid biofuels (pellets, briquettes) quality. In this paper, we will present the research findings concerning relationships between technological and material variables during densification of cocoa husks. Cocoa husks, as an unused raw feedstock after chocolate production, is a typical product of food factory. The main goal of presented experimental research is to determine the effect of compression pressure and material particle size on final biofuels quality, and thus investigate the possibilities for densification of cocoa husks. Experimental research described in this paper was realized by single-axis densification, which was represented by experimental pressing stand. The effect of mentioned investigated variables on the final pellets density was determined. Mutual interactions of these variables on final pellets quality are showing the importance of mentioned variables during the densification process. Impact of raw material particle size on final biofuels quality was also proven by experimental research on semi-production pelleting plant. Research findings dealing with pelleting and briquetting possibilities are included.

INVESTIGATION OF COCOA HUSKS DENSIFICATION POSSIBILITIES

During the biomass densification can be recognized various technological variables and also material parameters which significantly influences the final solid biofuels (pellets, briquettes) quality. In this paper, we will present the research findings concerning relationships between technological and material variables during densification of cocoa husks. Cocoa husks, as an unused raw feedstock after chocolate production, is a typical product of food factory. The main goal of presented experimental research is to determine the effect of compression pressure and material particle size on final biofuels quality, and thus investigate the possibilities for densification of cocoa husks. Experimental research described in this paper was realized by single-axis densification, which was represented by experimental pressing stand. The effect of mentioned investigated variables on the final pellets density was determined. Mutual interactions of these variables on final pellets quality are showing the importance of mentioned variables during the densification process. Impact of raw material particle size on final biofuels quality was also proven by experimental research on semi-production pelleting plant. Research findings dealing with pelleting and briquetting possibilities are included.

Hydrothermal pretreatment of cotton textile wastes: Biofuel characteristics and biochar electrocatalytic performance

The amount of waste cotton textiles presents an uptrend with the demand for textiles increasing. In this work, hydrothermal pretreatment of waste cotton textiles was conducted at 240 ℃–340 ℃ to obtain bio-crude oil and biochar. The hydrothermal pretreatment at 320 ℃ for 60 min yielded the highest bio-crude oil of 23.3%, in which ketones, diverse oxygen-containing functional group compounds, alcohols, furans, phenols, esters, carboxylic acids, ethers, nitrogencompounds, hydrocarbons and aldehydes were main compounds. Carbon-rich (as high as 76.86%) biochar with low oxygen shows high heating value as high as 30.505 MJ/kg, and lower atomic H/C and O/C ratios, which could be used as alternative solid biofuel. To broaden the utilization of biochar, it was further characterized by SEM, Raman spectra, and XRD. The biochar was the first time to use as electrocatalytic material. It significantly reduced both the overpotential (η10) from 403.6 mV to 247.6 mV and the Tafel slope from 192.5 mV dec-1 to 120.8 mV dec-1. It could speed up charge transfer rate and made H2 release facilely to promote the hydrogen evolution reaction activity with good stability. These results evidence the feasibility of converting waste cotton textiles to high-quality biofuels or even electrocatalytic carbon material via hydrothermal treatment.

Assessment of Quality Indicators of Pressed Biofuel Produced from Coarse Herbaceous Plants and Determination of the Influence of Moisture on the Properties of Pellets

Three coarse herbaceous energy plants—such as Miscanthus (Miscanthus sinensis), sida (Sida hermaphrodita Rusby) and cup plant (Silphium perfoliatum L.)—were grown and investigated in the experimental fields of Vytautas Magnus University Agriculture Academy, and the technical means of plant processing and utilization for solid biofuel were investigated. The physical–mechanical properties and quality indicators (moisture content, biometrical properties, density, and resistance to compression) of coarse stem herbaceous plants milled and compressed into 6 mm diameter pellets were investigated. The moisture content of the tested pellets was sufficiently low and ranged from 8.7% to 9.6%. The highest density was that of sida pellets (1072.3 ± 43.4 kg m−3 DM), and the lowest density was that of Miscanthus pellets (713.5 ± 67.1 kg m−3 DM). In order to evaluate the influence of moisture content on the properties of biofuel pressed into pellets, the density and the destructive compressive force of the different-moisture pellets were investigated and their change in the range of 5–15% pellet moisture content was evaluated. Criterion k was calculated to determine the effect of moisture on the pellet quality indicators (density, destructive compressive force, and lower heating value), and the following results were obtained: the highest influence of moisture on density was observed in sida (k = 34.280), on destructive compressive force in Miscanthus (k = 14.5), and on the lower heating value, also in Miscanthus (k = 0.198). After a comprehensive investigation and evaluation of these properties, an empirical model suitable for practical use was developed and prepared. Emissions of harmful gases, such as carbon monoxide, carbon dioxide, and nitrogen oxides, were determined when various coarse stem herbaceous energy plants were burned. The determined emissions of harmful gases into the environment did not exceed the permissible values.

Electronic trading system of solid biofuels as a means of ensuring sustainable development: problems of legal regulation

The present article is dedicated to the problems of legal regulation of the creation and functioning of the electronic trading system for solid biofuels. The paper analyses the latest initiatives, including draft regulations, which propose to introduce the trading system for solid biofuels. Special consideration is given to the mandatory percentage of both sales and purchases of solid biofuels in the e-trading system for a certain list of entities, primarily of state and municipal ownership in order to ensure a guaranteed demand and supply. It is argued that it is not appropriate to exclude contracting authorities that are covered by the Law of Ukraine “On Public Procurement from such list of entities, which is stipulated by the following: 1) it may negatively affect the very idea and purpose of creating such a system, as the State is one of the largest buyers; 2) the transfer of procurement by contracting authorities covered by Law of Ukraine “On Public Procurement” to another e-trading system will not contradict the main purpose of legal regulation of relations in the field of public procurement, as the principles of such system correspond to the principles of public procurement (principle of non-discrimination, competition, transparency and efficient use of public funds). It is also mentioned that Prozorro could be considered as a platform for an e-trading system for solid biofuels, which will ensure a high degree of transparency and interconnection of information on all purchases of contracting authorities who are buyers of biofuels; 3) it is emphasized that the imposition on contracting authorities covered by Law of Ukraine “On Public Procurement” who are buyers of solid biofuels, the obligation to purchase fixed volumes of solid biofuels using e-trading system will ensure implementation of goals and objectives defined in program and strategic documents for achieving Goal 7 of sustainable development and implementation of Ukraine's international obligations.

Investigation of Pressed Solid Biofuel Produced from Multi-Crop Biomass

The paper presents the preparation and use of pressed solid biofuel of multi-crop plants (fibrous hemp (Cannabis sativa L.), maize (Zea mays L.) and faba bean (Vicia faba L.)) as mono, binary and trinomial crops. The results of the investigation show that three main chemical elements (carbon, oxygen and hydrogen) accounted for 93.1 to 94.9% of the biomass pellet content. The moisture content varied from 3.9 to 8.8%, ash content from 4.5 to 6.8% and calorific value from 16.8 to 17.1 MJ·kg−1. It was found that the density (DM) of all variants of pellets was very similar; the faba bean biomass pellets had the highest density of 1195.8 kg·m−3 DM. The initial ash deformation temperature (DT) of burning biomass pellets was detected, which varied from 976 to 1322 °C. High potassium (K), calcium (Ca) and phosphorus (P) concentrations were found in all types of biomass ash. The quantities of heavy metals in pellet ash were not large and did not exceed the permissible values according to Lithuanian legislation. These chemical properties of multi-crop biomass ash allow them to be used in agriculture for plant fertilization.

Solid biofuels properties of Miscanthus X giganteus cultivated on contaminated soil after phytoremediation process

Following the objectives of the 2030 climate and energy framework as well as the European Green Deal strategy to 2050, renewable energy sources have been defined as an important factor in the process of climate change mitigation. Renewable energy sources are the basis of the aspirations of the EU to achieve low-carbon energy self-sufficiency. Under the classification of renewable energy sources biomass obtained by cultivating energy crops is also included. In order to avoid collisions between energy production and food/feed production, the cultivation of energy crops should be based on marginal soils, which also include soil contaminated by heavy metals. The use of energy crops in the process of phytoremediation is a multifunctional methodology that manifests itself through the cleaning of contaminated soil with the biomass production. The usefulness of using certain biomass types in the ignition process is valorized by the determination of biomass properties. The aim of this three years’ investigation was to analyze the biomass quality (proximate and ultimate analysis, calorific values, micro and macroelements) of Miscanthus x giganteus cultivated on soils with three cadmium (Cd) and mercury (Hg) contamination levels. All analyzed parameters, except Cd, K and Cr, are compatible with or have only expected differences from the literature data and/or ISO 17225–1:2014 norm for solid biofuels. The values of ash, volatile matter, C content and lower heating value as one of the most important energy parameters, are in the range 1.35–3.66%, 86.28–90.39%, 46.34–49.91% and 16.24–16.93 MJ/kg respectively.

Influence of Geometrical Features of Solid Biofuels on the Implementation of the Combustion Process

ABSTRACT The article discusses the influence, in a broad spectrum, of geometric features of various solid biofuels (pellets and briquettes in several sizes) of plant origin (wheat straw, rye straw, oat straw, birch, and pine sawdust) on the combustion process, in particular on the ignition time, flame duration and fuel afterburning in a low-power boiler. The research used a test stand, an essential element of which was the standard grate boiler with a cuboidal combustion chamber surrounded by a water jacket. This type of device allowed for the combustion of fuels with various geometrical features – pellets and briquettes – in the same combustion chamber. The particles of the combusted fuel had a surface area (S) from 281 to 13188 mm2, a volume (V) from 345 to 115 787 mm3 and a density (ρ) from 602 to 1127 kg·m−3, which resulted in a total combustion total time from 600 to 1500 s. The duration of individual combustion stages of the tested biofuels was proportional to the product of the square of the volume/area quotient and the fuel density. It was found that the coefficients C0 (start combustion time coefficient), C1 (flame combustion time coefficient), C2 (afterburning combustion time coefficient) of their duration increase with the decrease in the value of the product of the square of the ratio of the volume to the area and the fuel density, which is characteristic for pellets. The distribution of the fuel ignition, flame combustion, and afterburning constants as a function of the product of the square of the volume/area quotient and the fuel density takes the power distribution with the fit values of 0.9017; 0.9779; 0.9322 respectively. The conducted correlation tests showed quite strong dependencies between the geometrical features of the fuel and the time of its combustion. At the same time, the correlations between the ash content in fuels and the duration of individual combustion stages did not show solid, regular relationships. The analysis of the course of their combustion concerning the duration of the various stages of combustion regarding variable geometrical features given to formed biofuels allows predicting the course of their combustion. It is essential at the level of exploitation of heating devices. From the perspective of this research fuels with a higher value of the square of the quotient of the volume to the area and the fuel density would be optimal.

Emission characteristics from the combustion of Acacia Mangium in the automatic feeding pellet stove

The study provides new insights on the empirical facts and figures of Acacia Mangium graded wood pellets in non-industrial thermochemical applications. The test material was characterized according to normative solid biofuel specifications that confirmed a relevant net calorific value, a considerable mass fraction of the ash content, and the sign of ash softening initially observed at a notable temperature. The instrument readings of six major combustion gaseous components and particulate matter in the exhaust gas verified consistent emission profiles of woody solid biofuels in small-scale combustion installations. The calculated values of CO, CO2, NO, SO2, TOC and PM were analyzed in depth. The emission characteristics obtained revealed the apparent correlations of the fractions of gaseous components subjected to the elemental content determined by the ultimate analysis of Acacia Mangium wood pellets. The particulate matter emitted containing unburnt carbonaceous solid residues and inorganic materials remaining as byproducts were comparatively evaluated according to the different fuel types and variable test devices in earlier works. The mechanism of production and removal of volatilized alkali metals that influence solid particle formation was discussed. The excessive amount of ash-forming elements could potentially cause uncertain fluctuations in emission characteristics, which were remarked upon by further ash-related investigations requiring additional analysis.

Biofuels as an element of energy storage in the electrical supply systems of agro-industrial enterprises

Purpose. Creation of a reliable system of energy supply of agricultural production by accumulating energy in the form of solid biofuels from crop waste. Methods. Methods of system analysis and design of technical systems. Results. The structure of the autonomous system of electrical supply of farm premises on the basis of its own renewable energy sources. Justification of the feasibility of using solid biofuels as an element of energy storage in the conditions of agro-industrial enterprises. Conclusions 1. By 2035, Ukraine should increase the share of renewable energy in its total energy balance to 25%. 2. The most promising natural renewable energy source for Ukraine’s conditions is solar energy (up to 1500 kW٠h/m2). 3. Among renewable energy sources of own production, solid biofuel has significant advantages for the energy supply of agricultural facilities, the cost-output ratio of which is 1:13–17. 4. The use of solid granulated biofuels from crop waste as an accumulation of energy is a defining element of reliable autonomy of energy supply of farm premises. Keywords: autonomous electricity supply, renewable energy, energy storage, solid biofuels, plant waste.

ВИРОЩУВАННЯ ЕНЕРГЕТИЧНОЇ ВЕРБИ В УМОВАХ ЗАХІДНОГО ПОЛІССЯ

The research results of influence of the planting density, fertilization and soil type on the productivity of the energy willow in the conditions of Western Polissia are presented. On average over five years of research in the cultivation of energy willow it was found that the highest yield of dry biomass 102.9 t/ha was obtained on dark gray light loamy soil with a planting density of 20 thousand pcs/ha and fertilizer application at the rate of N60 P200 K200. The lowest yield of dry biomass was at planting density of energy willow of 10 thousand pcs/ha in the variant without fertilizers on dark gray light loamy soil and sod-podzolic cohesive sandy soil – 49.1 and 26.9 t/ha, respectively. The mineral fertilizer application with rate of N60 P100 K100 ensured an increase in the yield of dry biomass by 13.5 and 7.5 t/ha depending on the type of soil. The increase of phosphorus and potash fertilizers rate to 200 kg a.i./ha contributed to an increase in dry mass up to 23.6 and 13.0 t/ha compared to the variant without fertilizers. A similar result was obtained on sod-podzolic cohesive-sandy soil. The lowest indicators were in the variant without fertilizers at the planting density of 10 thousand pcs/ha – 26.9 t/ha, 15 thousand pcs/ha – 30.2 t/ha and 20 thousand рcs/ha – 35.6 t/ha dry biomass. The application of mineral fertilizers with rate of N60P100K100 for all planting densities increased the dry biomass yield to 34.4; 38.5; 45.3 t/ha, respectively. Increase of phosphorus and potash fertilizers rate up to 200 kg a.i./ha against the background of N60 contributed to an increase of energy willow yield up to 39.9 t/ha (with a planting density of 10 thousand pcs/ha), 44.1 t/ha (15 thousand pcs/ha) and 52.3 t/ha (20 thousand pcs/ha) of dry biomass. On average for five years, the application of fertilizer with N60P200K200 rate on dark gray light loamy soil, and at planting density of 20 thousand pcs/ha provided the highest yield of solid biofuel from energy willow of 22.7 t/ha and energy of 363 GJ/ha, while on sod-podzolic cohesive-sandy soil under the same growing conditions the yield of solid biofuel from willow was less by 11.1 t/ha and energy of 178 GJ/ha. Keywords: energy willow, dry biomass, solid biofuels, energy, soil.