Renewable Energy Systems and Technology

Centralized communication-based control is one of the main methods that can be implemented to achieve autonomous advanced energy management capabilities in DC microgrids. However, its major limitation is the fact that communication bandwidth and computation resources are limited in practical applications. This can be often improved by avoiding redundant communications and complex computations. In this paper, an autonomous communication-based hybrid state/event driven control scheme is proposed. This control scheme is hierarchical and heuristic, such that on the primary control level, it encompasses state-driven local controllers, and on the secondary control level, an event-driven MG centralized controller (MGCC) is used. This heuristic hybrid control system aims at reducing the communication load and complexity, processor computations, and consequently system cost while maintaining reliable autonomous operation during all possible scenarios. A mathematical model for the proposed control scheme using Finite State Machines (FSM) has been developed and used to cover all the possible modes/sub-modes of operation, and assure seamless transitions among them during various events. Results of some case studies involving severe operational scenarios were presented and discussed. Results verify the validity and effectiveness of the proposed communication-based control scheme. Index Terms—Communication-based control, DC microgrids, finite state machine, hybrid state/event driven control.

The output power produced by high concentration solar thermal and photovoltaic systems is directly related to the amount of solar energy acquired by the system. Therefore, it is necessary to track the sun's position with a high degree of accuracy. This can be achieved by the system called solar tracking system. Solar tracking system is the most common method of increasing amount of solar radiation from the sun to the solar collectors either Flat plate or concentrated collectors. The main objective of this research is to review different tracking mechanisms for solar tracking system, 18 papers were reviewed. The result showed that solar tracking system can either be dual axis or single axis trackers depending on freedom degree of motion. Dual axis trackers are the best option for places where the position of the sun keeps changing during the year at different seasons. Single axis trackers are a better option for places around the equator where there is no significant change in the apparent position of the sun.

Indian Automotive industry is under considerable strain to make their products more environmentally sound. Not only the automobile themselves, but also the whole production process has to become more sustainable to Achieve India's pledge to stop climate change at world forum. The Automobile industry is one of the major industries in India which have huge energy requirements in the form of both thermal and electrical energy. Manufacturing of automobiles and auto components involves many steps such as casting, forging, painting and electroplating etc that require heat or steam. Thermal energy in form of heat or steam accounts for around 70% of all automobile industry's total energy consumption and while solar collectors can provide a large share of this industrial process heat, the collector technology used depends upon a great deal on the temperatures involved. The use of an appropriate solar thermal technology can have a positive impact on the energy and environmental scenario of Automobile industry at a large. There are various solar thermal technologies including CST technologies that are available for Automobile industries. Flat plate collectors and evacuated tube collectors can be used with a reasonable level of efficiency at temperatures of up to around 130°C but for temperatures higher than this, concentrating collector systems such as Fresnel-Collectors, parabolic dishes and Parabolic-Trough-Collectors can give greater efficiency.

The Persistent power outage in the country due to faults has become alarming to the government and the body responsible for electricity generation in the country. It also creates a major problem for electricity consumers in Nigeria, there must be an improvement in the reliability of the transmission system in Nigeria. This research work is predominantly concerned with the analysis of outages on 330kV and 132kV transmission system, and system disturbances on generation and transmission system for five (5) years. The result shows that the forced outages are the most occurred outages on the 330 kV line, while on 132 kV line, emergency outages have the highest number of outages in 2014 but decreases rapidly over the years, similarly, twenty-seven (27) major system disturbances occurred in 2016 with 31% against ten (10) with 11% disturbances in 2015, while 2014 and 2018 with the same number of system disturbances of thirteen (13) with 15%, it is apparent that more disturbances occur on the transmission system, and there should be a proper protection scheme to maintain stable grid network. Consequently, Mini-grid and off-grid solutions will prominently address the issue of power supply shortage and instability in Nigeria.

"Although Nepal has been endowed with vast natural energy resources, such as solar, hydro, wind etc. it remains far behind in their fruitful utilization, with a per capita energy consumption of about 15 GJ only. At least 60% of her population is still deprived of access to electricity, which is a basic necessity in modern society, and has to depend upon the nonrenewable, imported fossil fuels as well as unsustainable supply of fuel wood for various domestic purposes like lighting, cooking, heating, agro processing, animal husbandry etc. This has been contributing to the indoor as well as the outdoor environment degradation. The emission of greenhouse gas (GHG) has been seen as one of the major problem associated with this energy use pattern. The impact of Global Climate Change due to the GHG emission has already shown devastating effect upon the climate of Nepal ranging from retreating of glaciers and increased seasonal variations with direct effect upon agriculture production, loss of biodiversity, increased desertification and changes in social structure.

This paper contains a brief account on the status and its contribution in the reduction GHG from various Renewable Energy Technology (RET) applications consisting of solar PV technology, solar thermal technology, micro and pico-hydro technology, biogas technology, biomass technology, and wind technology and their positive impacts upon overall development of the living condition of local population. It also highlights on the potential of incorporating these RETs in Clean Development Mechanism (CDM) for reducing subsidies being provided at present thus enabling economic viability and enhancing their sustainable utilization. Finally the paper contains some recommendations for different stakeholders in this sector for promoting RETs and contributing in GHG mitigation.
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The Persistent power outage in the country due to faults has become alarming to the government and the body responsible for electricity generation in the country. It also creates a major problem for electricity consumers in Nigeria, there must be an improvement in the reliability of the transmission system in Nigeria. This research work is predominantly concerned with the analysis of outages on 330kV and 132kV transmission system, and system disturbances on generation and transmission system for five (5) years. The result shows that the forced outages are the most occurred outages on the 330 kV line, while on 132 kV line, emergency outages have the highest number of outages in 2014 but decreases rapidly over the years, similarly, twenty-seven (27) major system disturbances occurred in 2016 with 31% against ten (10) with 11% disturbances in 2015, while 2014 and 2018 with the same number of system disturbances of thirteen (13) with 15%, it is apparent that more disturbances occur on t...

RESUMEN
Parte importante de las emisiones globales de CO2 –que en 2011 superaron el nivel crítico para el clima según el Panel Intergubernamental sobre el Cambio Climático de la ONU– proviene del transporte automotor, planteando severos cuestionamientos al sistema tecnológico de locomoción basado en combustión interna. El acelerado desarrollo  científico tecnológico en baterías e impulsión eléctrica está conformando sistemas disruptivos que promoverán industrias nuevas, impactando la economía y pudiendo incluso inducir una revolución tecnológica que modificará la matriz energética  imperante. El surgimiento de estos sistemas es impulsado básicamente por factores socioinstitucionales que responden principalmente al imperativo ambiental de disminuir las emisiones de carbono, y ocurre con participación de múltiples actores en diversos ámbitos globales.

Abstract
An important part of global CO2 emissions–which in 2011 exceeded the critical level for the climate established by the International Panel of Climate Change (IPCC)–are generated by motor transport, and poses major challenges to the technological system of locomotion based on internal  combustion. Current scientific and technological developments in batteries and electric drive are generating disruptive systems resulting in new industries that begin to impact the economy. And they might even promote a technological revolution that will change the prevailing energy matrix. Such systems are mainly
associated with socio-institutional factors answering to the environmental imperative of reducing carbon emissions, and are being developed by multiple actors in several global regions.

The output power produced by high concentration solar thermal and photovoltaic systems is directly related to the amount of solar energy acquired by the system. Therefore, it is necessary to track the sun’s position with a high degree of accuracy. This can be achieved by the system called solar tracking system. Solar tracking system is the most common method of increasing amount of solar radiation from the sun to the solar collectors either Flat plate or concentrated collectors. The main objective of this research is to review different tracking mechanisms for solar tracking system, 18 papers were reviewed. The result showed that solar tracking system can either be dual axis or single axis trackers depending on freedom degree of motion. Dual axis trackers are the best option for places where the position of the sun keeps changing during the year at different seasons. Single axis trackers are a better option for places around the equator where there is no significant change in the ap...