Comision Federal De Electricidad Research Articles

Distributed generation with a photovoltaic generating plant interconnected to a medium voltage network in the marginalized town of Xbilincoc, Campeche

In this paper, it is proposed to lay the foundations for the implementation of a Photovoltaic Systems Interconnected onto Network Distribution Systems that benefits the marginalized population of the town of Xbilincoc, Campeche. Through Distributed Generation (DG) it will be possible to direct the electrical energy produced by this plant for its own consumption and / or sale to the electrical company denomined Comision Federal de Electricidad (CFE), depending on the analysis of consideration for services that is most convenient for the producers. The power generating plant will be managed by the fishing cooperative formed by the commissioner and the most active fishermen of the town and the economic resources necessary for its construction and commissioning will be through a financing mechanism granted by a governing body denomined Fideicomiso de Ahorro de Energía (FIDE) and when it has been paid in full, the economic benefits for families will be to ensure that the cost of their consumption of electric energy does not increase, and to strengthen the economic development of the town of Punta Xen by administering the resources obtained from the sale of electrical energy to the CFE.

Fluid geochemistry of the Los Humeros geothermal field (LHGF - Puebla, Mexico): New constraints for the conceptual model

Geothermal power in Mexico is mainly produced in four geothermal fields operated by the Comision Federal de Electricidad (CFE): Cerro Prieto, Los Azufres, Los Humeros, and Las Tres Virgenes. The Los Humeros Geothermal Field (LHGF) is ranked third in terms of generated capacity, and in the last decade its installed capacity has doubled (up to 95.0 MW). Further increases in the geothermal power generation capacity in Mexico are planned, and thus the LHGF warrants further examination. The development and growth phases of any geothermal project must start from an awareness of the conceptual model of the natural system studied. The recharge mechanism, feeding zones, and fluid flow-path must be identified, along with the estimation of the temperature at the productive level and of phase separation (liquid – steam). To accomplish this, detailed fluid geochemical surveys were carried out in June 2017 and March 2018, in which 57 and 87 samples were collected, respectively, from cold and thermal springs, water wells and maar lakes located around and inside the LHGF. Samples from fumaroles inside the producing area were also collected for the first time, together with fluid from re-injection wells. The presence of a meteoric component, which plays an important role at the regional scale, is confirmed by the chemical and isotope data, and its contribution in terms of recharge may be higher than previously assumed. The Sierra Madre Oriental, on the west side of the LHGF, is characterized by widespread outcrops of limestone belonging to the same geological formation as those at the bottom of the LHGF. The isotope composition (δD and δ18O, respectively -77.3‰ and -10.50‰ for the hypothetical Infiltration Water - IW) is similar to that observed in cold springs located in the Sierra Madre Oriental, and from this the evolution of isotopes in the liquid-rock-steam system during water-rock interaction and phase separation processes can be modelled. Thus, the experimental data obtained for natural gas emissions (fumarolic condensates) and for geothermal fluids can be reproduced. These findings suggest that geothermal fluids in the LHGF are likely to be derived from meteoric water infiltrating (IW) the limestone outcrops of the Sierra Madre Oriental. During their flow-path, the infiltrating waters exchange isotopes at a high temperature with the crustal rocks, which have a much higher 18O/16O ratio, resulting in a shift towards higher δ18O (-4.35‰ ± 1) as the water O exchanges with rock O. The vapor phase can be separated from this deep water (DW) and it is discharged from the fumarolic effluents of Loma Blanca. Single Step Vapor Separation (SSVS) and Continuous Steam Separation processes (CSS) were modelled using stable isotopes of water. The results of geochemical modeling agree with available data for geothermal liquids discharged from several geothermal wells, suggesting that steam separation may be interpreted either as SSVS or CSS. Other processes can affect the chemistry and isotope composition of geothermal fluids (e.g. phase segregation, gas exchange, contributions from magmatic-volcanic deep fluids and re-injection fluids). The proposed conceptual model is consistent with both the geochemical data and the geological setting, and provides a useful point of reference for examining the fluid flow-path and geochemical processes active in the LHGF, at least at a general level.An involvement of magmatic-volcanic deep fluids in the feeding mechanism of the geothermal system cannot be excluded at priori, but the regional meteoric end-member is supported by the data and it seems the most important component.

EVALUACIÓN DEL FACTOR DE SEGURIDAD EN TALUDES DE TERRAPLENES CARRETEROS ALTOS ANTE CARGA SÍSMICA

Cuando se construye un terraplén carretero, una de las variables analizadas en el diseño es la obtención del factor de seguridad para determinar la estabilidad y seguridad de los taludes. Este diseño se realiza haciendo uso de un análisis estático y, en casos más específicos y aislados haciendo un análisis sísmico. En el presente trabajo se realiza un estudio del comportamiento del factor de seguridad en taludes de terraplenes carreteros altos frente a la solicitación sísmica. Para llevar a cabo el presente estudio se realizó un diseño de experimento 32. En el diseño de experimento se varió la altura del terraplén en tres niveles y el nivel de sismicidad, construyendo acelerogramas a partir de los espectros de diseño considerando los parámetros de la sección 3.1 del Manual de diseño de obras civiles de la comisión federal de electricidad de México. En la obtención de los resultados se empleó el método de los elementos finitos (MEF) y el método de Newmark. Como herramienta computacional se empleó el software especializado Geo-Studio con el sub-módulo para el análisis dinámico QUAKE/W, y el sub-módulo para el análisis de estabilidad SLOPE/W. Los resultados obtenidos muestran la necesidad de revisar estas obras frente al sismo sobre todo en zonas de sismicidad alta cuando su altura supere los 12 m.

Wind speed forecasting using the NARX model, case: La Mata, Oaxaca, México

This study presents the generation of a nonlinear autoregressive exogenous model (NARX) for wind speed forecasting in a 1 h, in advance horizon. A sample of meteorological data of hourly measurements taken during a year was used for the generation of the model. The variables measured were as follows: wind speed, wind direction, solar radiation, pressure, and temperature. All measurements were taken by the Comision Federal de Electricidad (CFE) at La Mata, in the state of Oaxaca, Mexico. Using the Mahalanobis distance, the sample of data was treated in order to detect deviated values in multivariable samples. Later on, the statistical Granger test was conducted to establish the entry variables that would be incorporated into the model. Since solar radiation was the only one determined as the cause for wind speed, it was the variable used in the configuration of the model. To compare the NARX model, a one-variable, nonlinear autoregressive model (NAR) was also generated. Both models, the NARX and the NAR were compared against the persistence model by means of applying the statistical error forecast measurements of mean absolute error, mean squared error, and mean absolute percentage error to the test data. The results showed the NARX model as the most precise of the three, reflecting the importance of the inclusion of additional meteorological variables in the wind speed forecasting models.

Scenarios for a hierarchical assessment of the global sustainability of electric power plants in México

Today, there are indicators to assess the sustainable development of a country and the energetic sector in general, but not to assess electric power plants. This work is aimed at evaluating the sustainability of specific technological systems. A multi-criteria method called Analytical Hierarchization Process was applied to analyze sustainability throughout the life cycle of various electric power plants in Mexico (such as hydroelectric, coal, heavy oil thermoelectric, natural gas thermoelectric, geothermal, nuclear, wind energy, photothermal and photovoltaic plants). An analysis throughout the whole life cycle makes it easier to assess and prepare an inventory of all sustainability indicators, resulting in a useful report for decision-making purposes in order to drive sustainable development in the electric sector. Four scenarios were analyzed using information provided by the Comision Federal de Electricidad (Electric Power Federal Commission), the opinion of experts, and scenarios with ecological and technocrat tendencies. The global result, using the measure of central tendency, reflects the benefit of renewable energies: wind energy is the most sustainable energy under the current circumstances of our country.

Analysis of the Mexican lightning activity monitored by NASA satellites

Lightning is the main cause of transmission line outages in Mexico. For this reason, it is necessary to investigate the areas where lightning occurs more frequently in order to improve or establish necessary countermeasures. Since 1998, the Mexican Institute for Electrical Research has been gathering the database recorded by the operational line scan (OLS), optical transient detector (OTD) and lightning imaging sensor (LIS) systems from USA-NASA. These systems have been installed in satellites to detect and count lightning occurring all around the world. This information has been analyzed by the IIE to perform seasonal maps of atmospheric discharge frequency along the Mexican Republic. The obtained maps have shown a good agreement with the statistic of transmission line outages caused by lightning. Namely, the zones determined with the highest discharges frequency are those where the highest number of line outages have been reported by the Mexican electrical utility Comision Federal de Electricidad (CFE).

Weathered pumice influence on selected alluvial soil properties in west Nayarit, Mexico

Parent material and pumiceous alluvial soils, located in a tropical region of Mexico, were studied to supply information on soil suitability for agricultural production in the context of sustainable agriculture. In recent alluvial soils, an understanding of how soil characteristics vary with parent material and topography provides a basis for determining land utilization type, land suitability as well as land quality. The main objective of this study was to establish the relationship of soil properties to parent material in west Nayarit, Mexico. Field studies were initiated in 1993 by a request for technical assistance from the Comision Federal de Electricidad. The studied soils were derived from pumice that has been reworked and mixed with detrital material from other sources. We found that such soils have unique physical, chemical and mineralogical characteristics that are rarely found in soils derived from other parent materials. Data for two selected alluvial soil profiles are presented. These soils were developed on Holocene volcanogenic pumiceous alluvial river terraces and river floodplains, under current udic-isohyperthermic soil-climate conditions. The agronomic properties, tillage influences and fertilizer requirements of these soils have been studied extensively. To maximize their productivity and minimize deterioration, proper management must be based on an understanding of the unique physical, chemical and mineralogical properties. Results indicate that such soils have physical properties that provide a good environment for deep rooting and can supply the water necessary for vigorous plant growth. In both soils, water retention at 33 and 1500 kPa, particle surface area, calculated clay, cation exchange capacity, Al exchangeable percentage and P retention, and the occurrence of isotropic coatings on rock fragments and peds tend to increase in the presence of the large amounts of hydrolyzed pumice that are found in the 0.02–2.0 mm fraction. Scanning electron microscope–energy dispersive X-ray analyses demonstrate that the coatings dominantly consist of noncrystalline material, probably allophanic-like material as suggested by the Si/Al molar ratio of 1.0. Selective dissolution analysis reveals that these abundant noncrystalline materials consist of ferrihydrite and allophane with an atomic ratio (Al o−Al p)/Si o of approximately 1.4. Both ferrihydrite and allophane have very large specific surface area and absorptive capacity that make a significant contribution to the overall properties of these soils. X-ray diffraction analysis and transmission electron microscope observation show that the major group of crystalline clay minerals in the upper section of studied soils are tubular and spheroidal halloysite. These soils were classified as Vitrandic Udifluvents according to Soil Taxonomy.

A reconnaissance geochemical study of La Primavera geothermal area, Jalisco, Mexico

Abstract The Sierra La Primavera, a late Pleistocene rhyolitic caldera complex in Jalisco, Mexico, contains fumaroles and large-discharge 65°C hot springs that are associated with faults related to caldera collapse and to later magma insurgence. The nearly-neutral, sodium bicarbonate, hot springs occur at low elevations at the margins of the complex, whereas the water-rich fumaroles are high and central. The Comision Federal de Electricidad de Mexico (CFE) has recently drilled two deep holes at the center of the Sierra (PR-1 and Pr-2) and one deep hole at the western margin. Temperatures as high as 285°C were encountered at 1160 m in PR-1, which produced fluids with 820 to 865 mg/kg chloride after flashing to one atmosphere. Nearby, PR-2 encountered temperatures to 307°C at 2000 m and yielded fluids with chloride contents fluctuating between 1100 and 1560 mg/kg after flashing. Neither of the high-temperature wells produced steam in commercial quantities. The well at the western margin of the Sierra produced fluids similar to those from the hot springs. The temperature reached a maximum of 100°C near the surface and decreased to 80°C at 2000 m. Various geothermometers (quartz conductive, Na/K, Na-K-Ca, δ 18 O(SO 4 -H 2 O) and D/H (steam-water) all yield temperatures of 170 ± 20° C when applied to the hot spring waters, suggesting that these spring waters flow from a large shallow reservoir at this temperature. Because the hot springs are much less saline than the fluids recovered in PR-1 and PR-2, the mixed fluid in the shallow reservoir can contain no more than 10–20% deep fluid. This requires that most of the heat is transferred by steam. There is probably a thin vapor-dominated zone in the central part of the Sierra, through which steam and gases are transferred to the overlying shallow reservoir. Fluids from this reservoir cool from ∼170°C to 65°C by conduction during the 5–7 km of lateral flow to the hot springs.

Large Scale Testing of Rockfill Materials

A brief description is made of the rockfill laboratory of the Comision Federal de Electricidad in Mexico. Equipment is available for large-scale (specimens 113 cm in diam) triaxial and compressibility testing of granular materials with maximum particle size up to 20 cm, under lateral pressures up to 25 kg per sq cm. Results of triaxial tests run with three different rockfill materials are presented. The influence of gradation, confining pressure and particle breakage are discussed.

The San Bartolo Vertical Impulse Turbine

Abstract The San Bartolo Hydroelectric Station, which is part of the Miguel Aleman Hydroelectric System of the Comision Federal de Electricidad, Mexico, was designed to operate about six months a year, during the dry season. During the rainy season, water will be stored in the reservoir above this plant. Because of this intermittent operation, certain economies in the design and construction of the power plant were possible. The impulse turbine is a six-jet vertical unit which has certain advantages over a single-jet turbine, both in design and operating efficiency. Also, a vertical impulse turbine has a number of advantages over a horizontal unit, both in simplicity of design and in cost. The runner is of a unique design, in that it is integrally fabricated out of plate steel with the bucket bowls welded directly to the wheel disk, thus eliminating bucket bolts. A special needle-control mechanism permits operation of the turbine with any combination of six jets. The penstock shutoff valve consists of a rotary valve, which proved to be very satisfactory when tested in the shop.

International Bank for Reconstruction and Development

On January 11, the International Bank for Reconstruction and Development made a loan of $29,700,000 for electric power development in Mexico. The loan was to be used to finance imports of equipment and materials needed to carry out seven major projects in the 1952–1955 construction program of Mexico's Federal Electricity Commission. The loan, made for a term of 25 years and bearing interest at the rate of 4J½ percent per annum, was the third made to Mexico for power development, in support of that country's current industrial and agricultural expansion. It was estimated that, together with the loans of 1949 and 1950, the loan would contribute to the near doubling of Mexico's electric generating capacity in a span of seven years. The joint borrowers were the Comision Federal de Electricidad, a government agency charged with the development of electric power, and Nacional Financiera, the official financing institution of the Mexican government. The loan was guaranteed by the Mexican government.