Thermoelectric Plants Research Articles

Screening of Morphophysiological, Anatomical, and Ultrastructural Traits to Improve the Elite Genotype Selection in Sugarcane (Saccharum officinarum L.)

Sugarcane is a highly productive crop with high water requirements. In addition, its growth and sugar content are limited by the water deficit, a major problem affecting agriculture due to climate change. However, monitoring strategies are being developed worldwide that seek to increase productivity in the same area and with less water consumption. The sugarcane plants are produced sugar table, ethanol, and, from the hydrolysis of biomass, produce second-generation bioethanol, in addition to generating energy in thermoelectric plants. This research described the strategies and mechanisms used by sugarcane to tolerate water deficit. For this, a series of physiological, biochemical, enzymatic, morphological, anatomical, and ultrastructural analyses were developed. We used four commercial varieties of sugarcane, two tolerant and two sensitives, which were tested in all phases of the study. It was concluded that the variety RB92579 is drought tolerant as well as RB867515 and RB72454 genotype is sensitive to drought stress. Therefore, we proposed that variety RB855536 be assigned as an intermediary due to tolerance and sensitivity to water deficit.

The Italian Pathway for Energy Transition: From the Coal Phase Out to the Problems Related to Natural Gas

In Italy, the de-carbonization process descending from the National Energy Strategy (NES) of the November 2017 and the National Energy and Climate Plans (NECPs) of December 2019 has led two specific effects: the progressive ending of coal use as a fuel for the production of electricity and the emanation of authorization acts for the conversion to natural gas of existing coal-fired power plants and/or for the construction of new power plants powered by natural gas. These new plants will be technologically advanced and designed to guarantee the safety of the national electricity grid in periods of greatest energy demand and will have to support the growing part of energy produced with plants powered by renewable energy sources (especially wind and photovoltaic). This reference context will necessarily have to take into account the recent gas supply difficulties due to the Russian-Ukrainian conflict, which could lead to a reconsideration of the projects for the construction of new gas plants by focusing on other energy sources. This paper hence aims to quantify and to evaluate the effective environmental benefits for atmospheric emissions, related to the replacement of coal with natural gas. Starting from the electrical powers replaced and installed, the potential reductions in greenhouse gas emissions will be examined, comparing the current emission situation in terms of CO2, with the future scenarios deriving from the construction of thermoelectric plants whose projects are currently under authorization.

Toward a New Nodal Pricing Policy of the Brazilian Transmission System Considering Multiple Hydrological Scenarios

This paper presents a new method for allocating transmission system costs in hydro prevailing energy markets. The proposed approach is based on nodal pricing, and it considers multiple hydrological scenarios obtained from optimized energy models. These models are much closer to the operational reality of hydro dominant systems and more adequate to the transmission operation planning. The nodal pricing strategy comprises two steps to recover the total costs of the transmission system. The first one calculates the charges corresponding to the utilized network capacity, estimated at a specified operating condition, and it brings the locational signal to the tariff. In the second step, the charges related to the transmission capacity available but not used in the system are assessed by a postage stamp. This latter step accomplishes the task of recovering the total transmission charges and defining the final tariff for specific operating dispatching. On the other hand, the optimized energy models, based on stochastic dual dynamic programming, are used to minimize the operating costs while penalizing possible energy spillages. These models create monthly sequences of hydrothermal coordinated generating scenarios and dispatching conditions, which are used by the nodal pricing strategy to produce the generation/load charges and tariffs and the corresponding statistics. The proposed method, combining the nodal pricing strategy and the optimized energy model, is applied to a Brazilian network configuration and the results are fully discussed. Moreover, probabilistic analyses are also performed to describe the annual costs of transmission of thermoelectric and hydroelectric plants and industrial electrointensive consumers installed in different areas of the network.

Location and concentration of the forest bioelectricity supply in Brazil: A space-time analysis

This article analyzed the location and concentration of forest bioelectricity in Brazil, from 2000 to 2019, available from the National Electric Energy Agency (ANEEL) and used the following indicators: Location Quotient (QL), Concentration Index [CR (k)], Herfindahl-Hirschman Index (HHI), Hoover Index (H) and Coefficient of Gini (G). The main results showed that the supply of electricity from Brazilian forest biomass increased from 562.90 MW and 11 thermoelectric plants in 2000 to 3532.61 MW and 115 thermoelectric plants in 2019, providing an average growth of 10.15% yy of the granted installed power and 13.20% p.a. of thermoelectric power plants. The QL inferred a high concentration of energy supply from black liquor (Rio Grande do Sul, Paraná, Espírito Santo, Bahia, Maranhão and Mato Grosso do Sul) and forest residues in several states, mainly in the North region. At the state level, the CR (4), CR (8) and HHI indexes indicated a deconcentration trend. The identification of the location and concentration pattern that the greatest offer was associated with industrial pulp and paper complexes. These results can indicate to investors the impact of electric power generation in the sector and the most relevant location for the installation of new thermoelectric plants.

Consumption, Extraction, Recharge and Availability of Water in the Main Subsectors of the Mexican Manufacturing Industry, Regional Levels

If the consumptive use of water in agriculture, domestic, thermoelectric plants and service enterprices does not decrease, will the water be available for consumption in the manufacturing industries? There is no certainty of the availability of this resource in the medium or long term. Aquifer recharge depends on temperature-precipitation cycles and desalination processes, where appropriate. Using gray forecast models, linear and non-linear regression, the main sustainability indicators were calculated considering the subsectors that most demand water, to obtain a medium-term vision, applying scenarios to 2030 of status of resource at the national level, (administrative) water region and federative entity, as well as, by surface or underground source. Pollutant aspects or water quality were not considered. The results show the urgent decision-making to ensure the availability of water.

Alkali-activated materials produced using high-calcium, high-carbon biomass ash

Eucalyptus ash (EA) was used in this study as a high calcium ash (HCA) precursor for alkali-activated binders. The EA used also has high carbon unburned (High loss on ignition). This type of ash is one of the waste products from biomass-fuelled thermoelectric plants, and annually thousands of tons are discarded as a by-product of the energy generation process in Brasil, but it is rich in unburnt carbon which means that it is challenging to use in cementitious systems. Eucalyptus is a biomass that removes CO2 from the atmosphere by photosynthesis and part of this carbon content remains in the ashes, generating CO2 capture when EA is incorporated in the production of alkali-activated binders. The objective of the present study was to evaluate the properties of the material obtained by the alkali-activation of the high-calcium high-carbon biomass ash to generate a cementitious binder, with different pastes proportions of EA and silica fume (SF), activated by sodium hydroxide. With the different pastes, mortars were produced using standardized sand. The results obtained from the pastes and mortars were satisfactory in several aspects. The mechanical results of the alkali-activated mortars were comparable those of Portland cement mortars. Mortars degraded methylene blue more efficiently in illuminated conditions, even after high adsorption for 24 h in the dark. The content of leached ions in the remaining solutions met potability standards.

Empirical Evidence of the Cost of Capital under Risk Conditions for Thermoelectric Power Plants in Brazil

This article analyzed the cost of capital under risk conditions for thermoelectric plants in Brazil, applying the Capital Asset Pricing Model—CAPM and the Weighted Average Capital Cost—WACC. To estimate the local CAPM, we used information from the Electric Energy Index—IEE of publicly traded companies in the electricity sector in Brazil and for the global CAPM, we observed the companies associated with the Edison Electric Institute—EEI, listed on the New York Stock Exchange—NYSE and at the National Association of Securities Dealers Automated Quotations—NASDAQ—USA. The risk conditions for capital costs were represented by Monte Carlo simulation using, as a basis, the WACC of a fuel oil thermoelectric plant and the local and global CAPM. The main results show that the IEE and EEI companies obtained a positive average daily return. Due to the Brazil risk, under deterministic conditions, the local WACC (11.13% p.a.) was more attractive to investors when compared to the global WACC (10.32% p.a.) and the regulatory WACC of 10.55% p.a., established by the National Electric Energy Agency—ANEEL. The most risk-sensitive input variables were: unleveraged beta, net debt and equity. Under risk conditions observed by the market from the point of view of Brazilian companies, the chances of the WACC of the fuel oil thermoelectric plant being 11.1% p.a. was 68.30% and from a global perspective, the chance of WACC being 10.32% p.a. was 99.51%. It is concluded that the cost of capital under risk conditions provides a more realistic view of decision-making for privately held companies.

Project of a cogeneration system using biogas

Brazil has been among the countries with the cleanest energy matrix in the world. The country showed high growth rates on the economy during the first years of the 21st, which brought to a rapid demand on energy supply. The situation got worser with long dry seasons, resulting on the commissioning of several thermoelectric plants. In the sugar-alcohol sector, the cogeneration became essential. In this context, the use of biomass for the generation and burning of biogas shows great potential in the production of electricity and heat. The discussed study involves the design of a biogas cogeneration system for the Federal University of São Carlos. The considered biomass originates from the campus itself and is composed of organic waste. The system consists of a modified diesel engine, accoupled to an electric generator and three heat exchangers. The monthly production of electricity is 7,7 MWh with a power of 30 kW. The monthly production of thermal energy is 9,8 MWh with a power of 37,6 kW. The costs are quoted adding up to R$ 162,877.00 for the complete system. The annual savings with the system is estimated at R$ 91,126.40, reaching an amortization time of one year and ten months.

Distributed generation asset lease model for public administration

In 2021, according to Portal Solar, distributed generation reached the sum of 6.9 GW of operational capacity, with a growth projection of around 31.25%. According to Absolar (Brazilian Association Photovoltaic Solar Energy), point out that even with the pandemic, solar energy generation in Brazil reached a capacity of 7GW, with more than 4GW of distributed generation. This growth is due to consumers' search for projects and actions that can reduce electricity costs. Electricity bills were the biggest person in the disclosure of official inflation in the last 12 months (2020-2021) and consumers, both individuals and companies, felt the impact of this expense, especially in the period of water scarcity, with the activation of the thermoelectric plants generating the tariff flag. Solutions to reduce electricity costs include the implementation of solar plant projects in homes and businesses, as well as large plants in the remote self-consumption or shared generation model, based on ANELL resolution nº 482/2012. The objective of this article is to describe the asset leasing model of the distributed generation system and its applicability in a public financial institution and its respective results.

Too many solar panels? Oversizing or undersizing of hybrid renewable energy systems based on different sources of information

This research evaluates the impact of information sources on the feasibility of a Hybrid Renewable Energy System (HRES). Due to their isolation and low population density, island communities satisfy their demand for electricity through thermoelectric plants. Diesel is the main fossil fuel used. This fuel must be imported, which translates into high logistics and operating costs. HRES are a feasible solution, integrating renewable resources, thermoelectric plants, and energy storage systems. The proper characterization of the variability of a renewable resource is decisive in the feasibility of an HRES. We used three sources of information on solar radiation and wind speed: the NASA Power Database (Case a), results of atmospheric and solar radiation models (Case b) and prospecting campaigns for wind and solar resources (Case c). The main findings point to an undersizing in the three best solutions: PV-Diesel, PV-Diesel-Battery and PV-Wind-Diesel-Battery with data from Case a, compared to measurements on site (Case c). On the other hand, a clear oversizing of the main architectures obtained with HOMER is evidenced, when using information sources from Case b compared with data from Case c. Therefore, the feasibility of an HRES begins with the selection of the information source of local renewable resources.

Floating photovoltaic plants as an electricity supply option in the Tocantins-Araguaia basin

Brazil has high solar potential. The yearly sum of solar irradiation is approximately 1924.07 kWh/m2, therefore, harnessing this potential is promising. The country is dependent on hydroelectric plants, however, increasingly frequent droughts have severely affected hydrogeneration. The installation of floating photovoltaic (FPV) systems in existing hydropower reservoirs, would provide additional electricity to help compensate hydropower production during dry periods and reduce evaporation losses while helping to sustainably meet Brazil's electricity demand. This study provide an analysis of FPV potential in Brazil's region, named the Tocantins-Araguaia Basin, by using water surface data from 30 hydropower reservoirs. In addition to the new electricity production, evaporation savings and its extra potential hydroelectricity were also estimated. A survey of the reduction in CO2 emissions was conducted, given that the complementary electricity to hydroelectric plants would be through solar generation, thus avoiding the activation of thermoelectric plants. The main results indicate the high FPV potential, corresponding to an electricity production that varies from 25.04 to 2555.04 TWh/year, and a range of 19.86–2024.30 million tCO2/year of avoided emissions. Regarding the potential arising from the evaporation water savings, the values vary between 16.17 and 892.95 GWh/year.

Treatment of Oily Effluents Through the Combination of Flotation and Wetland in Thermal Plants Under the Focus of Patent Documents: A Prospective Study

This study aimed to present a technological search for technologies in the processing of oily effluents through the physical-chemical flotation and biological wetland process generated in thermoelectric plants in the patent database of the Derwent World Patents Index (DWPI) using keywords. We found few studies for thermal power plant-effluent processing technologies and combined technologies for flotation and wetland effluent treatment. Patents indicated high efficiency in the combination of the processes. We did not find studies in Brazil for treatment technologies of effluents in thermoelectric plants. However, due to the country's energy scenario, investments in research in this area are recommended.

Subspace Predictive Control Tuning with Multiobjetive Optimization

In this paper, a tuning method for data-driven, subspace predictive controllers is proposed. The tuning approach is based on the solution of a multiobjective optimization, in which the optimization problem is defined as the minimization of the quadratic error between closed-loop response and some desired reference trajectories. In its turn, these trajectories are described in function of user-defined time-domain objectives. The tuning parameters are obtained as the compromise solutions of the multiobjective optimization problem. Design choices and performance are discussed and the method is validated in computational simulations of some common types of process. Additionally, the tuning methodology is implemented in a multivariable pilot-scale thermoelectrical plant.

Sediment mercury concentration changes as a response to increased industrial activity in Coronel Bay, Chile

Among the main sources of atmospheric mercury emissions are thermoelectric plants that use coal to generate electricity. This heavy metal is transported by air from its origin to neighboring coastal areas, where it is deposited in the sediment record. This research evaluated the content and temporal distribution of Hg in the coastal sediments of Central Chile, Coronel Bay, industrialized zone with two operative thermoelectric plants, and Coliumo Bay, reference zone free of industry. To this end, sediment cores from the centers of the two bays were obtained. Laboratory results show that the greatest Hg contents were found in the surface strata of the Coronel Bay core, with concentrations up to an order of magnitude greater than those obtained in the same strata in Coliumo Bay. This increase in Hg concentration coincides with the beginning of industrial activity in Coronel, with greater concentrations observed from 2012 on, the year in which the industrial operation of two coal-fired thermoelectric plants on the bay began. Based on 210Pb activity and the relationships between Hg content and organic matter, it was established that the main pathway of Hg to sediment is atmospheric deposition, while Coliumo presented inputs that reflect local non anthropogenic sources.

Technical and Economic Analysis of the Implementation of a Self-Sustainable Briquetting Process for Electric Generation

The wood industry is an essential part of the economy of some regions in Brazil. Although the excess of wood residue is an environmental concern, it is also an alternative source for electricity generation. This allows for compliance with current legislation to minimize environmental impacts such as strategies to control the emission of pollutants and the decarbonization in the wood exploration activity. Despite this, the thermoelectric plants based on wood residues face problems associated with the low efficiency in generation due to the high moisture content of the residues, and challenges related to transport and storage. In this sense, this work is to evaluate the application of a self-sustainable briquetting plant as an alternative for solving the problems associated with the high moisture content, transport, and storage of wood residues. The aspects related to the construction of the briquetting plant and economic indicators associated with the economic feasibility, such as, the estimation of the net present value over the project lifecycle, internal rate of return and pay-back period, are also presented and discussed. The results demonstrated the feasibility of the plant mainly due to the better energy/volume ratio of the briquette (drying and compaction) and the transportation cost savings associated to the density of the compacted material.

Cogeneration of energy in the reuse of blast furnaces gases in a steel manufacturing company / Cogeração de energia na reutilização gases de altos-fornos de uma empresa siderúrgica

In the present work, using the tools and the concepts of energy for the steelmaking process, a detailed study of the electric energy generation system (Cogeneration) in a non-integrated steel mill coupled with a thermoelectric plant was carried out, where the production process of this steel industry, which is located in a city in the Midwest region of Minas Gerais (Brazil), was analyzed. A pig iron producer that sells in the internal and external markets, this steel industry is continuously seeking to increase its competitiveness in the steel sector and to become an ecologically sustainable company. The intention is to propose a better utilization of the gases generated in the production of pig iron in a charcoal blast furnace. That is, since the gas flow from the blast furnace, which serves as fuel in the combustion process in the boiler, does not have a regular or constant flow, it is necessary to monitor the air/fuel ratio almost in real time, in order to obtain the highest power in the turbo-generator set of the steam system. Through the energy analyses performed for each of the components of the energy generation cycle of the steel mill, improvement proposals are suggested to increase the energy efficiency of the components and, consequently, of the cycle as a whole.

Spray Dryer Ash from Thermoelectric Power Plants as Civil Construction Materials

AbstractInstalling flue gas desulphurization systems before particulate collectors in thermoelectric plants generates spray dryer ash (SDA), a mixture of fly ash and sulfur products. SDA carries a ...

Temporal distribution patterns of metals in water, sediment, and components of the trophic structure in a tropical coastal lagoon of the Gulf of Mexico.

Trophic transfer and bioaccumulation of trace metals have a profound impact on the structure and function of coastal areas; however, the metal accumulation patterns in detritus-based food webs and the influence of climatic variability have not been thoroughly investigated. The Tampamachoco Lagoon (Gulf of Mexico) is a coastal system impacted by emissions from a thermoelectric plant. We evaluated the spatial-temporal distribution patterns of Al, Cd, Hg, Cr, Cu, and Pb in water, sediments, and in organisms categorized by trophic levels (TLs), trophic guilds, and habitat preferences. The sediments had the highest concentrations of metals with no significant differences between seasons. The indices of geo-accumulation and potential ecological risk classified sediments as "moderately contaminated", evidencing a threat to human health through consumption of detritivores and filter-feeders. The lowest TLs (filter-feeders and detritivorous) reached the maximum Metal Pollution Index in the rainy season. According to discriminant analyses of metals and species, omnivorous and zoobentivorous organisms were associated with Hg during the rainy and dry seasons; while Al, Cd, and Cu were related to low TLs, and seston was associated with Pb. Food web magnification factor analysis showed that: (a) Pb, Cu, and Cr were biodiluted as trophic levels increased; (b) Cd and Hg showed temporal biomagnification trends; (c) Al, Pb, Cu, and Cd showed significant biodilution from the lowest TL to intermediate TLs; and (d) Hg was transferred from the lowest to intermediate TLs with clear biomagnification effects.

Forest Bioelectricity in Brazil: Distribution and Spatial-Time Dependence

This study was to present a methodology for analyzing the distribution and spatial-time dependence of the supply of forest bioelectricity in Brazil, from 2000 to 2019. The data for the granting of forest biomass thermoelectric plants were obtained from the National Electric Energy Agency (in Portuguese Agência Nacional de Energia Elétrica –ANEEL). It used the exploratory analysis of spatial data, and as neighborhood criteria the spatial weighting matrices of k-neighbors closest and based on distance, as well as the global and local Moran indices to detect the presence of spatial dependence. The analysis of the situation, by quartile, showed the states of the central-southern portion of Brazil as the main locations of forest thermals. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{I}_{\mathrm {Moran\_{}Global}}$ </tex-math></inline-formula> highlighted the decrease in spatial autocorrelation between the years 2000 and 2019, associated with the implementation of new thermoelectric plants by the large groups Fibria, Klabin and Suzano Celulose throughout the national territory. The local index ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{I}_{\mathrm {Moran\_{}Local}}$ </tex-math></inline-formula> ) pointed out high-powered clusters, especially in the early years, highlighting: the Bahia, Espírito Santo and Minas Gerais axis, the Paraná thermal plants and Mato Grosso do Sul thermal plants. The local index also pointed outliers, which indicated possibility of associating thermoelectric plants with other activities, such as wood production and industries in the steel and paper and cellulose segment. The knowledge of the spatial pattern of the forest bioelectricity sector presented can help new feasibility studies for the implementation in bioelectricity and/or stimulate the development of public policies, focused on cluster regions and adjacent areas, which results in the growth of forest generation.

Bioenergetic valorization of &lt;i&gt;Sargassum fluitans&lt;/i&gt; in the Mexican Caribbean: The determination of the calorific value and washing mechanism

&lt;abstract&gt; &lt;p&gt;The advent of large volumes of &lt;italic&gt;Sargassum sp&lt;/italic&gt;. on the Mexican Caribbean coast has become an emerging issue for the Mexican population. The most frequent action is harvesting, but a correct treatment or energy recovery strategy is still missing. This work aimed to evaluate the energy potential of &lt;italic&gt;Sargassum fluitans&lt;/italic&gt;, through elemental calculations and direct measurements, considering the effect of its washing. The calorific value determined by the direct method was 9.24 ± 0.28 MJ/kg and 12.64 ± 0.18 MJ/kg for dirty and washed &lt;italic&gt;Sargassum&lt;/italic&gt;, respectively. The washing effect increased the calorific values in &lt;italic&gt;Sargassum fluitans&lt;/italic&gt; by 36.80%. The washing effect increased the calorific values determined by indirect methods, increasing 10.10% and 41.04%, each method, respectively. The content of toxic metals was lower in both materials than that established for non-woody biomass from energy use, concerning the ISO 17225:2014 standard. The unit energy cost of &lt;italic&gt;Sargassum fluitans&lt;/italic&gt; is ＄0.007 and ＄0.011 per MJ for dirty and washed conditions, respectively. Finally, the results of this work indicate that the &lt;italic&gt;Sargassum&lt;/italic&gt; wash provides better characteristics to be considered an alternative fuel option in combustion systems such as thermo-electric plants (based on carbon), sugar mills, and cement kilns with co-processing of solid waste. Attending from a bioenergetic approach, &lt;italic&gt;Sargassum's&lt;/italic&gt; emerging seasonal problem affects the Mexican Caribbean coast.&lt;/p&gt; &lt;/abstract&gt;