• Energy Research

In the context of a changing climate and increasing efforts to use renewable energy sources and waste materials and to green the environment, new sources and technologies for energy recovery from waste are being sought. This study evaluates the possibilities of energy generation potential from waste products of fruit species used in the food processing industry. The results indicate good potential for energy use of materials from fruit processing due to low input moisture content of around 15 wt. %, an average energy lower heating value (LHV) of 16.5 MJ·kg−1, an average low ash content of 4.9% and meeting most of the emission limits of similar biofuels. Elemental analysis and combustion residue studies indicate safe operation within existing standards. The results of our analyses and experience from similar studies allow us to recommend most of the studied waste materials for energy generation use directly in processing plants at the local level.

The most important sources of biomass energy are currently coming from agricultural activity. A sizeable portion in production areas is waste wood after the winter cut of orchards and vineyards, which cover areas exceeding 30,000 ha in the Czech Republic. The most important are species like apples, peaches, apricots, plums, sweet cherries, sour cherries and grapevines. Average production of wood mass for individual species of fruit trees and grapevines ranges from 1,540 kg/ha up to 6,762 kg/ha, i.e. 1.5 t/ha to 6.8 t/ha. The calorific value for these species ranges from 14.70 to 16.39 MJ/kg, with moisture between 6 and 8%. The results show that the total measured energy potential of the fruit species-cultivated areas is 1,469.7 TJ for the whole Czech Republic.

Abstract This study presents the thermogravimetric analysis results of various samples of vineyard pruning residues from Rakvice Stand in the Moravian viticultural region. The samples of Welschreisling, Grüner Veltliner, Gewürztraminer, and Palava were investigated in several heating-isotherm steps. Based on the results, three of these samples were found to not meet the conditions for the B category (≤3%) according to the EN ISO 17225 in terms of ash content. Only the Palava sample showed 2.76% of ash content in dry matter, which makes it suitable for technological applications, such as combustion in small residential biomass boilers. Considering the other samples, the results indicate that it is more appropriate to combust them as a part of mixture with added content of different wood biomasses.

Due to ongoing changes in the European energy market, there is currently a need to find new and additional uses for waste materials. Horticultural waste, which has not yet been fully recognized, offers a relatively wide potential in this area. Although the properties of these wastes are not ideal for combustion, they can be used as a solid biofuel. The pellets that are produced, however, may have useful properties, either energetic or environmental, and are valuable when utilized in boilers. In this study, six examples of typical input raw materials were selected, analysed, and subsequently pelletized. The experimental results provided an overview of the physio-chemical properties of the evaluated samples. Specifically, the moisture content (9.2–27.8%), bulk density (131.4–242.8 kg·m−3 wt), ash content (3.0–28.0%), lower calorific value (11.3–16.2 MJ·kg−1), and major and minor elements, were evaluated. The pelletization process and resultant pellet characteristics, such as durability (96.3–98.8%), moisture content (7.5–11.5%), and dimensions, were also evaluated. In the statistical evaluation, significant differences were found between individual samples. In particular, both the branches and the mixture of perennial plants met the industry standard limits, showing that they are of sufficient quality. On the contrary, the sample of fallen leaves was particularly problematic with regard to a number of parameters (moisture, ash content, and calorific value). The overview of the analyses performed expands the current state of knowledge on the potential to use selected types of horticultural waste in the field of energy and for the production of shaped biofuels.

In recent years, research has focused on verifying various ways of dosing organic matter into the soil in Central European conditions. The main reason for this is to search for the optimal management methods for soils with permanent vegetation. In this article, we state and evaluate the results of experiments carried out at the Lednice experimental site (Sauvignon Blanc variety) and the Velké Bílovice experimental site (Pinot Gris variety) between 2018 and 2020. The experiments evaluated the deep placement of compost and compost enriched with lignohumax at a rate of 30 t·ha−1 in the areas around vineyard tree trunks on the basic physical properties of the soil and the yield and quality of grapes. Results proved the positive effect of compost heaps and compost combined with the applied lignohumax on improving soil density (2–10% difference compared with the unfertilized reference variant) and porosity, which ultimately resulted in improved soil moisture conditions at both experimental sites (8–25% difference compared with the unfertilized reference variant). At the same time, the results demonstrated the positive effect of the applied compost and the chosen method of application on the yield and quality of grapes. In the case of Sauvignon Blanc, the increase in yield in the fertilized variants was 12–34%, while, in the case of Pinot Gris, it ranged from 24 to 33%. Among qualitative indicators, the grapes of both varieties were evaluated for sugar content, total acidity, pH, and amount of yeast assimilable nitrogen. In this case, results were not unambiguous in favor of fertilized variants; however, in most cases, fertilization had a positive effect.

A number of factors will increasingly play a role in the sustainability of wine production in the coming period. The current situation suggests that the analysis of energy consumption and greenhouse gas (GHG) emissions will play a particularly important role. The so-called carbon footprint, expressed in CO2 equivalents, is used to express the sum of GHG emissions. This study presents an analysis of vine cultivation in a particular Central European region, with the main focus on quantifying the inputs, yield, fuel consumption, and GHG emissions. The emphasis was placed on conventional, integrated, and ecological production systems of growing, evaluated with the help of the developed AGROTEKIS version 5 software. A total of 30 wine-grower entities in the Morava wine-growing region, the subregion Velké Pavlovice, in the Czech Republic weather climate, were included in the input data survey. By analyzing the aggregated values, the real savings in energy and curbing of CO2 emissions of vineyards could be observed, relating to individual work procedures with lower energy demand used in the vineyard treatment as well as the amounts and doses of agrochemicals used. The average values of the total impacts did not show any statistically significant differences between the conventional (971 ± 78 kg CO2eq·ha−1·year−1) and integrated production systems (930 ± 62 kg CO2eq·ha−1·year−1), whereas the values for the ecological production system were significantly higher (1479 ± 40 kg CO2eq·ha−1·year−1). The results show that growing vines under ecological production conditions generates a higher proportion of the carbon footprint than under conventional production conditions. Overall, the best results can be achieved in an integrated production system.