scholarly journals Variable Speed Diesel Generators: Performance and Characteristic Comparison

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 592
Author(s):  
Mohammadjavad Mobarra ◽  
Miloud Rezkallah ◽  
Adrian Ilinca

Diesel generators (DGs) are set to work as a backup during power outages or support the load in remote areas not connected to the national grid. These DGs are working at a constant speed to produce reliable AC power, while electrical energy demand fluctuates according to instantaneous needs. High electric loads occur only for a few hours a day in remote areas, resulting in oversizing DGs. During a low load operation, DGs face poor fuel efficiency and condensation of fuel residues on the walls of engine cylinders that increase friction and premature wear. One solution to increase combustion efficiency at low electric loads is to reduce diesel engine (DE) speed to its ideal regime according to the mechanical torque required by the electrical generator. Therefore, Variable Speed Diesel Generators (VSDGs) allow the operation of the diesel engine at an optimal speed according to the electrical load but require additional electrical equipment and control to maintain the power output to electrical standards. Variable speed technology has shown a significant reduction of up to 40% fuel consumption, resulting in low GHG emissions and operating costs compared to a conventional diesel generator. This technology also eliminates engine idle time during a low load regime to have a longer engine lifetime. The main objective of this survey paper is to present the state of the art of the VSDG technologies and compare their performance in terms of fuel savings, increased engine lifetime, and reduced greenhouse gases (GHG) emissions. Various concepts and the latest VSDG technologies have been evaluated in this paper based on their performance appraisal and degree of innovation.

Many times, Armed Forces are deployed in bases in remote areas on the borders or Islands, which are far flung areas away from mainland. In many such cases, these areas do not have their power requirements through the main grid supply and entire power requirement of the deployment is supplied by diesel generators. These diesel generators have high environmental impact due to emission of greenhouse gases and are highly uneconomical as logistic sustenance of remote bases for supply of fuel is very challenging, Fossil fuel has to be supplied by vehicles, helicopters, boats or manually carried to hill tops. This increases the overall cost of deploying armed forces in remote areas. In recent years with the advancements in power electronic components and renewable energy, development in Microgrids (MGs) have shown a way to reduce dependency on main power grids. Hence, with the help of MGs, renewable energy can be used to fulfill power requirements of the armed forces deployed in remote places. In this work, a MG with capacity of 1MW has been designed keeping the special needs of armed forces as a major consideration. Solar power has been used as a primary renewable energy source in the proposed design. In order to mitigate the adverse effects of meteorological and extreme conditions on the solar power generation capacity, energy storage system in the form of batteries has also been provided. Batteries store power when excess power is generated from the photo voltaic (PV) system and discharge the power when power demand is higher than the PV generated power. Diesel generator sets have also been used to run critical loads, provide reliability and as backup to critical operations catering for outages, night time needs and un-expected meteorological conditions. MATLAB has been used to design and simulate the proposed MG. Working of the MG has also been demonstrated for varying meteorological and varying load conditions as well. The proposed design works satisfactory in all cases.


Author(s):  
Shwetank Avikal ◽  
Rahul Singhal ◽  
Rajat Sajwan ◽  
Rahul Kumar Tiwari ◽  
Rohit Singh

Installation of telecom towers in remote areas especially in developing countries like India is a major problem for telecom industries because of the unavailability of reliable power supply. The grid supply is not regular in these countries and up to some extent, they are dependent on diesel generators for power supply. But these diesel generators have some major issues such as high operating cost due to high cost of fuel, transportation cost of fuel, high maintenance cost, and these diesel generators also emits pollution to the environment. In presented work, an approach has been proposed for telecom companies for providing power supply to their telecom towers. An economic cost analysis has been proposed by considering various criteria such as cost, air & noise pollution and reliability, etc. Some power supply alternatives including unconventional and hybrid of conventional and unconventional alternatives have been compared to find the solution such as diesel-powered telecom towers, solar powered telecom towers, and their hybrids. The main objective of this work is to provide a reliable, cost effective and environment friendly Remote Area Power Supply (RAPS) system for a particular site in India (Uttar Pradesh). A number of criteria are involved in discussed problem in order to select an effective power supply source. Therefore, the problem has been considered as a Multi Criteria Decision Making (MCDM) problem. To select the best alternative, a Fuzzy AHP and TOPSIS based approach has been proposed. Fuzzy AHP (Analytic Hierarchy process) has been used for calculating the weightage of criteria and the concept of Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) has been applied for ranking the alternatives. The results give assured reliability and sustainability for remote areas using a solar photovoltaic (PV)-diesel generator hybrid energy system.


Author(s):  
Dmitry Sergeevich Kobyakov ◽  
Evgeniy Mordcovich Burda ◽  
Andrey Borisovich Daryenkov ◽  
Ilya Aleksandrovich Tarpanov ◽  
Oleg Stanislavovich Khvatov

The paper focuses on the operation of the ship's single power station with a common link of direct current and a diesel generator of variable speed are considered. It is shown that the operation of a diesel generator set at a constant (nominal) rotational speed, but variable load is characterized by a nonoptimal (overrated) specific fuel consumption. At the same time, forced regulation of the internal combustion engine rotation speed in accordance with the electric load of the generator make it possible to provide energy-efficient mode of generating electricity. One way to improve the energy performance of the ship single power station is to convert one of the parallel operating diesel generators into a variable speed mode. In this case, the load between the parallel operating diesel generators is distributed in proportion to their rotation frequencies, regardless of the individual loading of the propulsion motors. To stabilize voltage of the diesel generators operating in the variable speed mode, a power semiconductor converter is used. Functional scheme and mathematical simulation model of the ship single power station, graphs of transient processes with load changes in the channel of electric propulsion system of the vessel are presented.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2224
Author(s):  
Mohammadjavad Mobarra ◽  
Bruno Tremblay ◽  
Miloud Rezkallah ◽  
Adrian Ilinca

Variable speed generators can improve overall genset performance by allowing the diesel engine to reduce its speed at lower loads. In this project, a variable speed diesel generator (VSDG) uses a rotating stator driven by a compensator motor. At lower loads, the stator turns in the opposite direction of the rotor, a process that can be used for purposes like maintaining a fixed relative speed between the two components of a generator. This allows the diesel engine to turn at a lower speed (same as the rotor) and to increase its efficiency. The present research addresses the control of the compensator motor driving the generator’s stator using a variable-frequency drive that adapts the speed to its optimal value according to the load. The performance of the proposed control strategy was tested using a Freescale microcontroller card programmed in C-code to determine the appropriate voltage for the variable-frequency drive. The control algorithm uses a real-time application implemented on an FDRM-KL25Z signal processor board. The control performance of a 2 kW asynchronous motor (LabVolt EMS 8503-00/208 V/3 ϕ/60(50) Hz) was demonstrated experimentally at different operating conditions.


Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.


Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1988
Author(s):  
Ioannis E. Kosmadakis ◽  
Costas Elmasides

Electricity supply in nonelectrified areas can be covered by distributed renewable energy systems. The main disadvantage of these systems is the intermittent and often unpredictable nature of renewable energy sources. Moreover, the temporal distribution of renewable energy may not match that of energy demand. Systems that combine photovoltaic modules with electrical energy storage (EES) can eliminate the above disadvantages. However, the adoption of such solutions is often financially prohibitive. Therefore, all parameters that lead to a functionally reliable and self-sufficient power generation system should be carefully considered during the design phase of such systems. This study proposes a sizing method for off-grid electrification systems consisting of photovoltaics (PV), batteries, and a diesel generator set. The method is based on the optimal number of PV panels and battery energy capacity whilst minimizing the levelized cost of electricity (LCOE) for a period of 25 years. Validations against a synthesized load profile produced grid-independent systems backed by different accumulator technologies, with LCOEs ranging from 0.34 EUR/kWh to 0.46 EUR/kWh. The applied algorithm emphasizes a parameter of useful energy as a key output parameter for which the solar harvest is maximized in parallel with the minimization of the LCOE.


2018 ◽  
Vol 164 ◽  
pp. 01038
Author(s):  
Ridho Hantoro ◽  
Cahyun Budiono ◽  
Ronald Kipkoech Ketter ◽  
Nyoman Ade Satwika

Over 70 000 000 people in Indonesia have no access to electricity. This study was carried out in Bawean Islands which are located in the Java Sea about 150 km North of Surabaya, the headquarters of East Java. The study to determine the energy services available in the Bawean Island was done through interviewing a random sample of 72 households in two villages namely Komalasa and Lebak. Based on the average monthly electricity consumption of the sampled households connected to the grid, a hybrid renewable energy based electrical supply system was designed for Gili Timur Island, one of the satellite islands around Bawean Island. The system was designed with the aid of a time step simulation software used to design and analyze hybrid power systems. A sensitivity analysis was also carried out on the optimum system to study the effects of variation in some of the system variables. HOMER suggests that for the expected peak load of 131 kW, an optimum system will consist of 150 kW from PV array, two wind turbines each rated 10 kW, a 75 kW diesel generator and batteries for storage.


2016 ◽  
Vol 56 (7) ◽  
pp. 1070 ◽  
Author(s):  
S. G. Wiedemann ◽  
M.-J. Yan ◽  
C. M. Murphy

This study conducted a life cycle assessment (LCA) investigating energy, land occupation, greenhouse gas (GHG) emissions, fresh water consumption and stress-weighted water use from production of export lamb in the major production regions of New South Wales, Victoria and South Australia. The study used data from regional datasets and case study farms, and applied new methods for assessing water use using detailed farm water balances and water stress weighting. Land occupation was assessed with reference to the proportion of arable and non-arable land and allocation of liveweight (LW) and greasy wool was handled using a protein mass method. Fossil fuel energy demand ranged from 2.5 to 7.0 MJ/kg LW, fresh water consumption from 58.1 to 238.9 L/kg LW, stress-weighted water use from 2.9 to 137.8 L H2O-e/kg LW and crop land occupation from 0.2 to 2.0 m2/kg LW. Fossil fuel energy demand was dominated by on-farm energy demand, and differed between regions and datasets in response to production intensity and the use of purchased inputs such as fertiliser. Regional fresh water consumption was dominated by irrigation water use and losses from farm water supply, with smaller contributions from livestock drinking water. GHG emissions ranged from 6.1 to 7.3 kg CO2-e/kg LW and additional removals or emissions from land use (due to cultivation and fertilisation) and direct land-use change (due to deforestation over previous 20 years) were found to be modest, contributing between –1.6 and 0.3 kg CO2-e/kg LW for different scenarios assessing soil carbon flux. Excluding land use and direct land-use change, enteric CH4 contributed 83–89% of emissions, suggesting that emissions intensity can be reduced by focussing on flock production efficiency. Resource use and emissions were similar for export lamb production in the major production states of Australia, and GHG emissions were similar to other major global lamb producers. The results show impacts from lamb production on competitive resources to be low, as lamb production systems predominantly utilised non-arable land unsuited to alternative food production systems that rely on crop production, and water from regions with low water stress.


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