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The thematic area studied in this paper considers environmental issues such as atmospheric pollution from the combustion of fossil fuels, and the environmental impacts from the generation of urban agricultural solid wastes. This study has estimated the potential for hydrogen and biogas production from solid urban waste (SUW) and wine waste from Bento Goncalves, which is a region in Brazil with the largest wine throughput and subsequent waste generation, thus providing a potential high-energy feedstock. The resulting hydrogen and biogas are assumed to displace the existing fuels in the local bus fleet. The analytical work consisted of three scenarios - scenario 1: production of biogas using SUW, sourced exclusively from the municipality of Bento Goncalves; Scenario 2: the possibility to supply SUW from Bento Goncalves and surrounding cities, to produce biogas; Scenario 3: the possibility to use wine waste and SUW for biogas production. Scenario 3 showed the greatest energy yield with 37.9 Gg of biomethane produced per year, which can supply the entire public bus fleet of Bento Goncalves. The resulting hydrogen production potential using steam reforming of biomethane is 1.09 E+08 Nm3H2.d−1 which can generate 2.62 TW h.year−1 of electrical energy, avoiding approximate emissions of 355 ktonCO2.year−1. These findings indicate value in the production of biogas from urban and agricultural wastes, especially for the generation of methane, hydrogen and useful energy outputs. Its production from renewable and clean sources contributes to the gradual transformation of an economy currently dependent on non-renewable resources into a circular and renewable economy.

The increasing global energy demand and environmental concerns around fossil fuels have been propelling research on biodiesel. Despite the benefits of biodiesel to the environment, its properties as a fuel are still not ideal. Babassu oil produces good quality biodiesel, but there are problems associated with its use as a fuel, mainly due to its susceptibility to oxidation. One way of improving the oxidative stability of biodiesels is by adding substances capable of hindering the oxidation process, the antioxidants. Most antioxidants used for biodiesel are synthetic antioxidants opposing the premise of using biodiesel, which is to be a better environmentally friendly alternative. Therefore, in this study three natural antioxidants were tested in the babassu biodiesel, for which an experimental design 23 was used. The viscosity, specific mass and oxidative stability of the samples were evaluated, and to determine the best conditions for the use of antioxidants, a statistical analysis was performed applying a variance analysis and the response surface methodology. It was verified that there was an improvement in the oxidative stability of babassu biodiesel for all the natural compounds tested with an improvement ranging from 52 to 92%.

Food wastage is a relevant problem all over the world. Remains of prepared foods increase the waste of resources due to energy and labor used in their preparation. However, food waste has a high energy potential can be converted in the form of methane via anaerobic digestion. This study evaluated the potential for recovery of energy contained in food wastes and presented a way to stablish the anaerobic digestion process using solely food waste. For this purpose, a prototype anaerobic digester was used of complete mixture with a volume of 408 L, 15% of total solids, temperature of 29.4 °C and an agitation system. The system was operated at steady state for 51 days in hydraulic retention time of 103 days, volatile solids and chemical oxygen demand of 0.80 g L−1 rd−1. According to the literature, the stabilization period presented typical inconvenient of food wastes digestions processes, that was solved monitoring at more frequent intervals the volatile fatty acids and with the maintenance of a compatible volume of organic load according with the size of the reactor. It was obtained a reduction of 90% in volatile solids and 82% in chemical organic demand. The methane production was 0.51 L.g−1CODc, 0.44 L.g−1VSc and volumetric yield of 0.32 L.L−1rd−1, representing 59% of the composition of the biogas. The adequate levels of agitation frequency, feeding load, temperature and C/N ratio were found in this study using the prototype anaerobic biodigester.

Excess heat on photovoltaic panels can limit their efficiency owning to an increase in internal resistance and consequent energy losses. This work aims to evaluate the effect of a water-cooling sprinkler system underneath polycrystalline photovoltaic modules. Voltage, current, power, and efficiency were monitored to quantify system performance. Three periods of analysis were defined. The first had intermittent cooling, the second had no cooling and the third had continuous cooling in the hottest hours of the day. The analysis occurred at two levels of irradiation – high and low. The use of the cooling system at a high level of irradiation resulted in a 12.26% relative increase in power and a 12.17% relative increase in efficiency. At a low irradiation level, the relative power and efficiency increased by 8.48% and 9.09%, respectively. The cooling system had a significant effect on the power and efficiency of the studied photovoltaic panel.

The containment in pig farming generates a large volume of effluent that can be treated by anaerobic digestion. To use the biogas generated in the process, in electricity generation, a better understanding of the variables involved is necessary. The objective of this study was the evaluation of biogas production parameters, power generation, performance of the generator group in the biogas conversion into electric energy and the avoided cost of electric energy of a pig farming property. Parameters of concentration, biogas production and consumption, and generation of electric energy were monitored, and the information generated was stored in a database. The results have indicated an average daily production of 443 m3, with an average of 0.10 m3 of biogas per pig and an average concentration of 68% methane. The average of electric energy generation was 324.5 kWh/day, and the efficiency of the generator was 17% with an average active power of 70 kW and a daily operation of 6.5 h. The avoided cost by self-consumption of electric energy generated in the property was R$ 13718.20, and during the monitoring period there was a total generation of electric energy of 70.5 MWh, of which 26.6 MWh were exported to the distribution network. The study also emphasizes that the appropriate choice of sensors and the methodology for monitoring and collecting data continuously could lead to an important data to use in correlated studies concerning generation of electricity from biogas.

The soxhlet oil extraction method provides a large amount of oil when compared to other methods, however the commonly used solvents are not always effective. The objective of this work was to compare the efficiency of two solvents in different moisture contents in the extraction of peanut oil (Arachis hypogaea L.), sunflower (Helianthus annuus L.), soybean (Glycine max), crambe (Crambe abyssinica) and canola (Brassica napus L.). The experiment was conducted in a 5 × 2×2 factorial scheme, and five grain moisture contents (9.44%, 7.76%, 6.68%, 6.82% and 7.77%) were tested for canola, crambe, peanut, sunflower and soybean, respectively, two solvents (petroleum ether and hexane) and four repetitions, totaling 80 experimental units. The solvents presented have no influence on the content of sunflower oil and soybean, while extractions of dry grains result in an increase in the content of sunflower oil, regardless of the solvent used. The interaction between the solvent of hexane (without moisture in the grains) optimizes the extraction of canola oil. It was also verified the highest percentage of peanut oil content (43.49%) extracted with petroleum ether with moisture in the grains (6.69%). For the grains of crambe, the humidity of (7.76%) presented the best percentage with 11.95% of oil.

Partial load operation of SI engines is conventionally achieved by the use of a throttle to control the airflow or air-fuel mixture into the engine. When the engine operates at partial load the throttle causes high pumping losses which has an effect on decrease of the engine efficiency. One of the possible ways to decrease the pumping losses during partial loads is to operate the engine under lean mixture condition. The limitation in this case can be misfiring of used fuel. The combustion limits can be extended by addition of hydrogen to the regular fuel. This work presents an analysis of use of hydrogen-methane taking into account aspects related to the efficiency and emission of pollutants. To carry out this study an experimental system composed of a SI engine was used. Two important differentials were used. First, the engine was supplied with simulated biofuels according to the typical biogas composition of the Brazilian landfills (Bio60); second, the system was operated in partial load, with the addition of H2, forming the HBio60 blend, in an attempt to increase efficiency and reduce pumping losses by increasing lambda value and variation in trottle position. The same aspects were evaluated with the engine operating with biogas composed of 95% of methane (Bio95) and in mixture with hydrogen (HBio95). The tests were performed at different ignition angles and air/fuel ratio. The results showed that adding H2 allows the combustion limits to be extended, with an effective increase of indicated efficiency. On the other hand, the reduction of NOx emissions was greater than 95% in the lean mixture provided by the presence of H2. The idea is to encourage change in the control algorithm of SI engines typically fueled with natural gas and use the H2-methane blends as fuel. Furthermore, diesel-powered buses in Brazil could be converted to SI gas engines without the loss of efficiency.

Residences in Brazil consumed much energy through water heating systems. The electric shower uses most energy of the electric power system, and the main source of energy is hydroelectricity, which depends on climatic variations. To minimize the pressure on the electrical system by water heating, an alternative use of solar thermal water heating panels is needed. The objective of this study is to evaluate three different types of low-cost solar thermal panels: PET bottles, PVC lining and aluminum cans. The experiments were carried out in Cascavel-PR, campus of State University of Western Parana. The collection of temperature data was simultaneously carried out in the three systems, using a PT100 sensor, with hourly readings from 10 to 16 h, for 30 days. Solar radiation data on the period were provided by SIMEPAR. After the collection and data analysis, it was found that the system with aluminum cans showed the best performance reaching 54.3 °C, presenting an efficiency of 41.6%. Thus, for these experimental conditions, this system is recommended for use in residential water heating to reduce the electric bill.

The experiment was conducted at the Experimental Center in Agricultural Engineering (NEEA), at the State University of West Parana (UNIOESTE), Cascavel – Parana, with a totally randomized experimental design. Treatments used were petroleum diesel and three different types of biodiesel: crambe (Crambe abyssinica Hochst), soybean (Glycine (L.) Merrill) and waste frying oil. The biodiesel was used in its pure form (B100) and in binary mixtures B10, B20 and B50. Resistive loads of 1, 2, 3, 4, and 5 kW were used for each type of fuel, with a total of five replications. Specific consumption (SC) and energy efficiency (EE) were evaluated. The best SC levels were achieved with diesel, with 349 g kW h−1 under the load of 5 kW, followed by CB20-2, with 524 g kW h−1 and CB50-3, with 433 g kW h−1. Biodiesel presented SC values close to those of diesel as resistive loads were increased, what indicates that its use in operations closer to the nominal capacity is more efficient. Among the biodiesel forms used, the crambe oil-based biodiesel presented lower SC and some of the values did not present significant differences (Tukey 5%) from diesel's SC, such as CB20-4, with 383 g kW h−1 and CB10-5, with 367 g kW h−1. The best energy efficiency values were found with DI-5 (25.6%), CB-100-5 (25.5%), CB50-5 (25.0%), SB100-5 (24.8%) and WFOB100-5 (24.6%). Pure biodiesel (B100) tends to present better EE than the mixtures used in the study. CB100 presented EE of 9.9%, 17.8%, 21.8%, 24.3% and 25.5%, according to resistive loads of 1, 2, 3, 4, and 5 kW, respectively. Regarding the biofuels assessed, crambe oil-based biodiesel presented the EE values that were closer to those of diesel. The energy efficiency of CB100 was higher than diesel's with loads of 2, 3 and 4 kW.

Sugarcane had its participation in the Brazilian energy sector boosted when PROALCOOL was enacted, a program that encourages the production of ethanol fuel made from sugarcane. The ethanol production process generates a residue in large proportions, called vinasse. This study aimed to assess the economic feasibility of using vinasse to produce electricity in an ethanol plant located in the northwestern region of the state of Parana, Brazil. The electricity generated will be consumed by the plant itself, and the sugarcane bagasse, which was used to be burned in a boiler to generate that electricity, will now be sold to other consumers. The study was conducted considering two operating modes. For each operation, it was considered five scenarios, ranging from the most optimistic (highest salesprice per ton of sugarcane bagasse) to the most pessimistic (lowest sales price per ton of sugarcane bagasse). It was calculated the feasibility of the project by using the Internal Rate of Return (IRR), Net Present Value (NPV) and the discounted payback period. All indexes indicated great economic feasibility to project development. It was conducted an NPV sensitivity analysis considering the variation of the sales price of sugarcane bagasse, the quantity sold and the fixed costs involved. It was also carried out a Probability Analysis, using 1000 NPV simulations, considering that the change in the selling price of the bagasse has a normal distribution. The energy production cost for the expected scenario in Operations 1 and 2 were, respectively, US$51.98MWh−1 and US$ 86.64MWh−1.

The goal of this research is to evaluate the effect of adding different concentrations of biodiesel to ethanol, analyzing its heating value, viscosity, flash point and density. Eight different compositions were carried out (4 blends with soybean biodiesel and 4 with castor bean oil), by varying the percentage of biodiesel at 1%, 3%, 5% and 10% (m/m) hydrous ethanol. The highest heating value increase was achieved in the blend with 10% soybean biodiesel (+8.70%). The blend with 10% castor bean biodiesel showed a viscosity increase of 23.8% whereas blends with 5% castor bean oil and 10% soybean biodiesel presented a viscosity increase of 15%. The flash point for blends with 10% soybean and castor bean biodiesel increased by just over 1 °C, improving safety condition in the handling of the fuel. The density exceeded the specified limit of 1.42% for the blend with 10% castor bean oil. This parameter is dependent on the amount of water present in ethanol, which in this study achieved the maximum limit, thus making the density of the blends exceed the threshold.

In the last decades, the whole world has been feeling the effects of environmental pollution, especially air pollution in large cities, with the transport sector as a major contributor to this scenario. In this sense, Brazil presents 27 states with great potential for biogas generation from landfills through anaerobic digestion. Only in the year 2016, the calculations presented in this paper point to a methane production in landfills of 5.57E+09 m3. On the other hand, the high number of rivers and hydroelectric dams in the country makes possible the generation of electricity that reached 90.27 TWh in 2016. However, the water that is drained by the floodgates to control the level of the reservoirs becomes an interesting wasted energy source for other uses, such as the production of other clean fuel, hydrogen, through classical processes such as electrolysis. It is pointed out the possibility of producing 2.76E+06 tons of hydrogen only with the energy drained in these hydroelectric plants. These two fuels together can be used to fuel vehicles powered by the hydrogen–methane blends, like HBio95 and HBio60. The promise of harmful and CO2 emissions by focusing on mixture of gases has recently attracted the interest of vehicle manufacturers and transport operators. In this scenario, this work presents an analysis on the use of mixture of gases in the urban bus fleet of the 27 Brazilian states, using as energy source derived from secondary energy from Brazilian hydroelectric plants and biogas from sanitary landfills, comparing this scenario with the use of only methane from landfills or only H2 from hydroelectric plants, assessing issues such as pollutant emissions, engine performance and deployment facilities.

In Brazil, biomass appears as one the most promising alternative energy sources for electricity generation, due to the large amount of agricultural, forest and livestock activities. In addition, biomass is widely available, less intermittent and uniformly distributed, when compared to some renewable sources (wind power, solar photovoltaic, e.g.). To access the power generation from biomass, gasification has been pointed as more adequate to the small-scale deployments (less than 150 kWe) indicated for distributed generation, mainly at isolated rural communities, where centralized grid is not available or feasible. This work aims to contribute with a techno analysis about the small-scale electricity generation through gasification of wood wastes associated to an engine generator. For this purpose, it was assembled a pilot power generation plant, composed by a downdraft gasifier and a spark-ignition engine (SIE) coupled to electric generator. The parameters evaluated were related to the biomass gasification (gasification yield of 2.5 N m3 kg−1, fuel wood consumption of 5.6 kg h−1, e.g.) and generation (specific fuel wood consumption of 1.9 kg kW h−1, e.g.). In general, biomass gasification conversion was performed with high efficiency (about 70%); however, on conversion of the producer gas into electricity, the efficiency dropped to 17%, mainly due to low thermal efficiency of SIE and calorific value of gas. Even though, the technology is a promising alternative to supply electricity from biomass, especially on places where electrical distribution network is not yet available.

Solar energy is a clean and renewable option for energy production, being used for several purposes, such as water pumping, which is one of the most disseminated technologies regarding the use of photovoltaic solar energy. This work was developed in order to assess a water pumping system activated by monocrystalline and polycrystalline photovoltaic panels set at the State University of West Parana – UNIOESTE, Cascavel-PR. The research showed that the daily average volumes of water pumped during the experiment were 3536.45 and 4182.55 L respectively, for the monocrystalline and polycrystalline systems. Monocrystalline and polycrystalline photovoltaic panel efficiency was 9.40% and 6.57%, respectively. As for the system with complete pumping, the monocrystalline system presented an average global efficiency of 4.27%, at a cost for volume of water pumped and energy consumed during the system׳s life cycle of 0.10417 US$ m −3 and 0.70417 US$ kW h −1 , respectively, whereas the polycrystalline system showed global efficiency of 5.00% and costs of 0.09583 US$ m −3 and 1.2917 US$ kW h −1 .

The growth in the sugar and alcohol sector in Brazil has led to a significant increase in vinasse production, what aggravates the issue of its destination. Anaerobic biodigestion is an alternative for the treatment of this byproduct, presenting a relevant economic factor: its use as a source of energy. This work presents a technical–economic assessment of the electric energy production from vinasse biogas, obtained from an alcohol plant located in the state of Parana, Brazil, under three different operations. For each operation, it was considered five scenarios, varying from the most optimistic (best energy selling price) to the most pessimistic (worst energy selling price). The viability of the proposed project was calculated by using the Internal Rate of Return (IRR), Net Present Value (NPV) and Discounted Payback Period (DPP), showing that the plant is feasible for almost all scenarios. The energy production costs for the expected scenario for Operations 1, 2 and 3, were US$ 38.91 MW h −1 , US$ 56.32 MW h −1 and US$ 46.93 MW h −1 , respectively.

Due to the energy crisis caused by the progressive depletion of fossil fuel sources, the search for alternative fuels from renewable sources is in growing demand. Therefore, the manufacturing of biodiesel from fish waste might help the environment as an alternative for the reduction of residues that are harmful if incorrectly disposed. Biodiesel from residual oil of tilapia waste was manufactured by means of transesterification, basic catalysis and methyl route. This study assessed mandatory parameters regulated by the Brazilian National Agency of Petroleum, Natural Gas and Biofuels (ANP) for biodiesel commercialization. It also determined values for specific mass, kinematic viscosity, water content, acidity level, flash point, oxidative stability and calorific value of fish oil biodiesel. Biodiesel calorific value analysis reported levels that are similar to those of diesel. Other parameters that characterize fish oil biodiesel physically and chemically according to specifications of ANP resolution No. 7/2008 were evaluated, and indicated that fish oil is a promising alternative for biodiesel manufacturing.

The ceaseless search for renewable sources of energy puts biodiesel as a great alternative to replace oil-based fuels. This work aimed to assess the specific consumption of fuel, thermal efficiency and emission of exhaust gases when crambe biodiesel and diesel oil are used in a diesel-cycle internal combustion engine-generator, with different levels of resistive loads. A diesel-cycle engine generator was used, with 7.36 kW (10 cv) of power and 5.5 kVA/5.0 kW of nominal power, with monophasic output tension of 120/240 V. The used fuels were crambe biodiesel (B100) and diesel oil (B0). Nominal resistive loads applied ranged between 1.0 kW and 5.0 kW. In order to quantify the emission of gases, fuel quality and emission analyzer were used. Crambe biodiesel׳s data for specific consumption and efficiency of energetic conversion proved to be statistically equal to those of diesel. With the usage of crambe biodiesel there was a significant reduction in the analyzed exhausted gases.

This paper presents a methodology for sizing and simulating an autonomous photovoltaic-wind hybrid energy system with battery storage, using simulation tools and linear programming. The developed model is useful for energizing remote rural areas and produces a system with minimum cost and high reliability, based on the concept of loss of power supply probability (LPSP), applied for consecutive hours. To calculate the solar power and the wind power, a statistical model based on Beta and Weibull probability density functions, respectively, is used. Some scenarios are calculated and compared, using different numbers of consecutive hours and different LPSP values. As a result, a complete sizing of the system and a long-term cost evaluation are presented.

The generation of electric energy distributed throughout Brazil′s rural area contributes in the supply and logistics of energy production all over the country. This work aimed to analyze biogas production from swine waste and the generation of electric energy using biogas as primary source. Biogas was produced in Sao Miguel do Iguacu - Parana, Brazil, in a rural property which uses two biodigesters to produce biogas, whose electric conversion is performed in an engine-generator set of 100 kVA. With an average of 4672 housed animals, 554 Nm 3 day −1 of biogas were used in the generation of 847 kWh day −1 of electricity and the rest was incinerated in a flare. The average specific consumption of biogas in the engine-generator set was 0.68 m 3 kW h −1 and its efficiency was 22.21%. The cost of electric energy production using biogas was 0.12 R$ kW h −1 and the cost of the supplier′s electricity was 0.14 R$.kWh −1 . One can observe the economical feasibility of electricity production from biogas, even without receiving carbon credits.

One of the largest sources of energy available in rural and agro-industrial areas is the biomass, which is found in the form of vegetal and animal residues, such as crop leftovers, animal manure, energetic plantations and agro-industrial effluents. Such residues may be used by rural producers or agro-industries for direct burning, aiming to produce heat or biogas in biodigesters. Swine production generates a large amount of manure that causes environmental issues when not treated properly, due to its high levels of methane. When it is released in the atmosphere, it expressively contributes to the greenhouse effect. The co-generation of electric energy is still one of the ways to utilize biogas generated from food production. Apart from generating energy, it is also possible to sell carbon credits, what provides the producer with higher income. The present work aimed to determine the cost of installation, as well as the feasibility of biogas-based electricity production, by studying the scale economy in several scenarios of swine, biogas and electric energy production, sale or not sale of carbon credits, and investment costs with the estimated amortization period. One can notice that when carbon credits generate profit, production costs decrease and the LPV (Liquid Present Value) increases. Energy production only leads to loss when there is no additional income with carbon credits.

Biodiesel is an alternative energy source used in internal combustion engines (ICE), as a replacement for diesel oil. In general, the farming and livestock activities can be used to obtain biomass sources for bioenergy production. Several raw materials (fatty acids sources) obtained from renewable sources can be employed to biodiesel production, providing biofuels with distinct physicochemical properties. Also, in Parana State, Brazil, products such as soybean oil, sunflower oil, beef tallow, and chicken fat are used for biodiesel manufacturing. Thus, this work aimed to evaluate the engine generator performance using biodiesels obtained from soybean, sunflower, chicken fat and beef tallow compared to mineral diesel. The tests were performed using an engine with power of 7.36 kW on an electric generator with power of 5.5 kW. In engine load simulation, it was used as resistor bank, being the power generation selected on dashboard controller in the following sequences: 1.0 kW, 2.0 kW, 3.0 kW and 4.0 kW. The engine generator performance was evaluated by specific fuel consumption (SFC) and efficiency ( η ). In general, the engine SFC using biodiesels was higher, when compared to diesel oil. However, the overall efficiency of engine generator with biodiesels was higher, with gain of up to 2.0%. Among the biodiesels compared to diesel oil, the best results for engine generator performance were obtained, respectively, from sunflower and soybean oils, due to lower increase in the SFC (7.6%) and slight increase in the overall efficiency.

This project verified the potential for the production of hydrogen via water electrolysis by using the exceeding electrical energy resultant from alcohol and sugar plants that use sugar cane bagasse as fuel. The studies were carried out in cogeneration plants authorized by the Electrical Energy National Agency (ANEEL). The processing history of sugar cane considered was based on the 2006/2007 harvests. The total bagasse produced, electrical energy generated and exceeding electrical energy in a year were calculated. It was obtained an average energy consumption value of 5.2 kWh Nm−3 and the hydrogen production costs regarding the amount of sugar cane processed that ranged from US$ 0.50 to US$ 0.75 Nm−3. The results pointed that the costs for the production of hydrogen via the bagasse exceeding energy are close to the production costs that use other sources of energy. As the energy generated from the bagasse is a renewable one, this alternative for the production of hydrogen is economical and environmentally viable.

An optimal operating mode for a sequencing batch reactor was determined via a model-based optimization. Synthetic wastewater containing mainly organic matter (as glucose) and nitrogen (as ammonium chloride) was treated without any addition of an external carbon source to accomplish denitrification step. A simplified model was used to describe process dynamics, comprised of six ordinary differential equations and an empirical correlation for oxygen consumption rate. Batch cycle time was the chosen objective function to be minimized for a fixed volume of waste to be treated. Furthermore, as SBR operation is divided in two major phases - aerobic and anoxic, to achieve total pollutants removal within minimum time, these phases can be repeatedly alternated. To ensure availability of organic matter necessary for denitrification, these two phases were combined with feed steps. Different feed strategies were tested using one, two or three feed steps. A successive quadratic programming algorithm was used, and maximum values for final COD, nitrate and ammonium concentrations, as well as maximum feed pump flow rate were some the process constraints. One step feed strategy was indicated by the optimization leading to a batch cycle time of 5h.