scholarly journals GHG diffuse emissions estimation, and energy security to ENSO using MERRA-2 for largely hydroelectricity-based system

Author(s):  
J. S. Chiriví Salomón ◽  
Yohén Cuellar ◽  
Harold David Cuadros Tejeda ◽  
Marco Guevara

In Colombia, hydropower share was 70 % of the total installed capacity and more than 50 % of the monthly generation share in 2015, which coincided with the strongest El Niño Southern Oscillation (ENSO) phenomenon reported in the region. ENSO has been recognized as an influential climate pattern on meteorological variables. The generation via hydropower implies the construction of dams and water reservoirs; these flooded areas generate an important amount of Green House Gases (GHG). In this regard, the main aim of this research was to quantify the diffusing emissions of CO2 and CH4 in the flooded areas of the main hydroelectric power generation facilities in Colombia. GHG emissions were calculated by the implementation of an IPCC methodology. The obtained results show that more than 1,042,500 t CO2-Eq (i.e. CO2 and CH4) are emitted in Colombia per year from this source, representing 4.4 % of the total GHG emissions in the country. As the second aim, the vulnerability of Colombia’s energy independence, in terms of power supply to ENSO and climate change was analyzed using the MERRA-2 dataset from NASA, for the years between 2010 and 2017.

Author(s):  
Petro Lezhnyuk ◽  
Iryna Hunko ◽  
Juliya Malogulko ◽  
Iryna Kotylko ◽  
Lіudmyla Krot

Urgency of the research. Current trends of distributed generation development in Ukraine indicate a rapid generation in-crease from renewable energy plants. Most developed countries gradually refuse from the fossil fuels use and invest more and more to the “green” energy. Therefore, there is a need for a detailed study of the operation conditions of distributed energy sources due to their instability, as well as the processes that arise in distribution electric networks with diverse types of distributed energy sources. Target setting. In the producing process of power energy by distributed energy sources due to the increase in their num-ber, there are situations where several renewable sources of energy operate to only one system of buses. Thus, such distributive networks acquire the features of a local power system, which complicates the control process of such systems, and also there is a problem with the electricity supply of consumers. Actual scientific researches and issues analysis. The analysis of publications suggests that in literature more attention is paid to studying the operating modes of solar power plants, or small hydroelectric power plants. However, almost no attention was paid to the study of their cooperation work. Uninvestigated parts of general matters defining. Only a few works are devoted to the study of the cooperation of the diverce sources of distributed energy sources in the local electrical systems. That is why, their impact on power distribution networks and on the grid in general has not been studied extensively. The research objective. In this article was considered the influence of asynchronous generators on small hydroelectric power plants on the operation modes of distribution electrical networks, and were investigated the processes that are occurring in local power systems with different types of distributed energy sources. The statement of basic materials. Based on the research results, was developed a computer model of a such system in the PS CAD software environment. Two solar stations and one small hydroelectric power station with an asynchronous generator were connected to the power supply. It was shown the simulation of two modes of operation: a joint operation of a small hydroelectric power station, two solar power stations and a power supply center; a joint operation of a small hydroelectric pow-er plant, two solar power stations and a power supply disconnected. Conclusions. As a result of computer simulation, it is shown that by switching on a small hydroelectric power plant with an asynchronous generator in the case of an emergency shutdown of centralized power supply, it is possible to restore the work of solar power plants, and thus partially or completely restore the power supply of consumers.


2016 ◽  
Vol 38 (3) ◽  
pp. 509-539 ◽  
Author(s):  
JAIME C. AUTON ◽  
MARK W. WIGGINS ◽  
BEN J. SEARLE ◽  
NAN XU RATTANASONE

ABSTRACTThe readback/hearback loop is a communicative protocol used in many high-risk environments to ensure that a verbal instruction has been heard correctly by a receiver. However, it does not necessarily ensure that an instruction has been understood. Using an international sample of hydroelectric power generation controllers, this study examined whether particular linguistic (complete and partial readbacks) and prosodic (final intonation, filler, and interturn delay) cues contained within a readback response could signal to listeners the extent to which speakers had understood an instruction. The results indicated that different prosodic cues are used to detect nonunderstandings, depending upon the linguistic content of the readback. The results have implications for training and system design in distributed environments.


RBRH ◽  
2019 ◽  
Vol 24 ◽  
Author(s):  
Maurício Andrades Paixão ◽  
Masato Kobiyama

ABSTRACT Mountain rivers are situated in a large portion of the terrestrial surface, especially in headwaters regions, and have been used for various purposes such as recreation, sporting activities, water resources and hydroelectric power generation. However, hydrogeomorphic characteristics of mountain rivers are not fully understood. In this context, the present paper aimed to identify relevant parameters for characterizing rivers in these environments based on bibliographical review. It was identified which parameters have been used and how they have been used to characterize mountain rivers in distinct classifications. The most cited parameters were channel gradient, relation between river width and depth, entrenchment ratio, discharge, sediment transport and grain-size distribution. Also, the current situation related to researches in fluvial geomorphology in mountain rivers in Brazil was evaluated, and the strong need of field survey as basis for the best understanding of mountain fluvial dynamics and characterization was verified.


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