Renewable Energy Resources

Planning and optimisation of micro grids in specified area studied in this paper micro grid is connected to with and without grid to meet the load profiles, distinct micro grid configurations with generation from renewable energy sources are constructed. Better studies are then carried using HOMER energy software to determine cost of economy, sizing, and sighting and system configurations. Micro grid is also connected to the grid due to dearth of sustained renewable energy sources. This paper presents a brief contrast among the diverse cost equipments, power management and ejections for all the configurations.

The optimization results exhibits the lowest cost per unit and it allocates the ranking for each systems.


Increment in outflow levels, consumption of fossil stores and a consistently expanding interest for vitality has been a noteworthy worry in the last numerous years. These worries have filled a quick advancement in the territories of dispersed sustainable power source ages. What’s more, to coordinate these cleaner and more effective inexhaustible sources inside the power framework organize, miniaturized scale networks presents itself to be a reasonable arrangement .

They have a few different points of interest which incorporates decrease in transmission misfortunes, enhancement in influence quality and dependability, decrease in discharges and even gives arrangements to heterogeneous influence quality . What’s more, above all, it likewise gives a probability to zap of remote towns which are a long way from reach of the traditional network.

Load profiles from Indian country and urban regions are considered for the investigation. Utilizing these load profiles distinctive arrangements of microgrid systems are built and re-enacted in homer energy software .

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Homer gives its yield as the ideal network arrangement that is required for a solid system activity. The improvement result likewise gives the aggregate expense and the expense of vitality for a microgrid setup. Right off the bat, the heap profile for a town in Nellore, India is utilized to develop a rustic ac microgrid system.

The system consists of energy sources and storage in the form of PV array, wind turbine and lead acid batteries. Then using Homer, optimization studies are carried out to achieve a minimal cost of operation for the system to be completely individual. After this, using the same load, a similar study for partial connectivity to the grid is also conducted. This study is important as most part of the grid connected small town areas (especially in India). For both the cases in with connected grid or without connected grid, the microgrid system consisted of biodiesel generators as the loads care considerably larger as compared to small town areas. Similar simulations studies are then carried out to identify the optimal system configuration.

Finally, the result of optimization study shows that the AC microgrid is connected to grid and without connection of grid can be designed by cost considerations. The system with grid connectivity, a much better result is observed with a continuous supply of electricity and a significant reduction in emissions. Here, it should be noted that most other available study on optimization of hybrid renewable energy system using Homer concentrates on a single system or load type . While in the case of this study, with the results from a wide range of system configurations for load centres, a comparative study is made possible. And with such comparative results, a broader picture on the advantage and drawbacks of each system type can be drawn. Moreover, as the study is conducted using realistic load profile, real resources data and real prices of components, the outcome or a similar optimization approach can be used for an actual system implementation.

At last, the consequence of enhancement think about demonstrates that the AC microgrid is associated with matrix and without association of network can be structured by cost contemplations. The system with lattice network, a vastly improved outcome is seen with a consistent supply of power and a critical decrease in outflows. Here, it ought to be noticed that most other accessible examination on enhancement of crossover sustainable power source framework utilizing Homer focuses on a solitary system or load type . While on account of this examination, with the outcomes from an extensive variety of framework designs for load focuses, a near report is made conceivable. Also, with such similar outcomes, a more extensive picture on the favourable position and downsides of every system type can be drawn. In addition, as the investigation is led utilizing practical load profile, genuine assets information and genuine costs of segments, the result or a comparative enhancement approach can be utilized for a real system execution

In the first section of this paper system components of a AC microgrids is connected to the with grid without grid and the different operations used for microgrid optimization. The next section discusses the various components of the microgrid and resources that are required to model the complete system in Homer. This is followed a detailed discussion on the simulation processes to obtain the optimization result. The following section provides results for each of the microgrid systems. A detailed discussion on the results obtained is also presented in the same section. Finally, the paper concludes with a brief note on the importance and feasibility of microgrid systems.

In the first section of this paper systems parts of an AC microgrids is associated with the with grid without grid connection and the diverse activities utilized for microgrid advancement. The following segment examines the different systems of the microgrid and assets that are required to show the entire system in Homer. This is pursued a definite exchange on the re enactment procedures to get the advancement result. The accompanying segment gives results to each of the microgrid system. A point by point discourse on the outcomes got is likewise exhibited in a similar area. At last, the paper finishes up with a concise note on the significance and attainability of microgrid systems.

System Components

In micro grid system diesel generator bio gas as a fuel, PV system, wind turbine, energy storage devices and converters to survive the loads. Microgrid  systems implemented in homer software here   two systems considered the fist system is without grid and the second system is with grid.  According to this particular place need to take source of resources like solar irradiance and wind data, load data, especially cost of the all components in the systems. The fallowing sections are described full details all the components, resources and design of microgrid and its operation.

During the time spent arranging and improvement of a microgrid display utilizing Homer programming, certain essentials can be recognized. Right off the bat, the parts of the smaller scale matrix should be resolved which will incorporate the different sources, burdens and converters. The sort, size, cost and different properties of every one of the parts are given as contributions to these Homer models. After the parts are set, there is a need to acquire the models of assets which will comprise of hourly variety of wind speed and sun oriented radiation information. In addition, the sort and costs of fuel assets utilized are additionally given. Just with this arrangement of Data sources one can proceed with the reproduction and streamlining procedure of the microgrid framework. The accompanying subsection gives a point by point depiction on the general schematic of the created microgrid, every one of the parts and assets inputs required for the reproduction procedure.

Overall Schematic

The general schematic of the microgrid with its different parts is given beneath in Fig. 2. It comprises of a spiral AC transport to which every one of the parts are associated. As far as sustainable power source age a variety of photovoltaic modules and Wind Turbines (WT) are considered. Bio Diesel Generators (DG) filled by diesel is additionally taken as a hotspot for a portion of the designs. Yield of the different sources are associated with the DC transport through legitimate converters. The heaps of the framework can either be household and business stack which can have a place with either a provincial or a urban territory. These heaps can be further sub delegated essential and secondary stacks as appeared in the figure. As the inexhaustible sources are discontinuous in nature and the microgrid framework is considered to work self-ruling, vitality stockpiling turns into a significant segment. What’s more, thus, vitality stockpiling as lead corrosive batteries are considered.

Energy Generation and Storage Components

Photovoltaic Generation

A conventional level plate type PV (Photovoltaic) board is considered for this investigation. The lifetime of the PV boards is considered as 20 years and the power otput rating is 1 kW with a derating factor is considered at 80%. The photovoltaic (PV) derating factor is a scaling factor that HOMER applies to the PV array power output to account for reduced output in real-world operating conditions compared to the conditions under which the PV panel was rated. Use the derating factor to account for such factors as soiling of the panels, wiring losses, shading, snow cover, aging, and so on.

Where, YPV is the rated capacity of the PV in kW, fPV is the PV derating factor, GT is the solar radiation incident on the PV array in kW/m2, GT,STC is the incident radiation at standard test conditions (1 kW/m2), is the temperature coefficient of power (%/°C), TC is the PV cell temperature in °C, TC,STC is the PV cell temperature under standard test conditions (25 °C).

We can see that the capital cost of PV generation is further subdivided into three parts. The prices mentioned are the actual prices incurred while designing a laboratory setup of a DC micro grid at the Electrical Engineering, JNTU HYD, and India. Cost components and the breakdown of capital cost for PV generation capital cost is 3000 $, replacement cost is 2900$ and operating & maintenance cost is10 $ per 1 .

Wind Turbine Generation

A model of generic 3 kW wind turbine which is already available in HOMER library is used for modelling the generation from wind energy. The power curve of the WT is given in Fig. 4. Using this power curve, the output of the WT is calculated in a three-step process.

The capital, replacement and operation & maintenance cost of the WT are taken as 18,000 $/kW, 17,500 $/kW and 180 $/kW/year respectively. The various cost components that makes up the capital cost includes the cost of turbine rotor, tower, control system, wiring and installation. Here, the lifetime of the wind turbine is considered as 20 years and hub height is 17 m.

Battery Energy Storage

A model of generic 1 kW h lead acid battery is used for modelling the energy storage unit. This particular type of battery is chosen due to its relatively good performance and low cost. The various properties of the battery are provided in Table 5. After considering some of the popular battery manufacturing brands in India, the capital cost of a 1 kW h lead acid battery is taken as 154$. This includes the battery mounting unit, installation and wiring costs. The replacement cost is taken same as the capital while the operation and maintenance cost is taken as 15.4$/kW h/year.

Diesel Generator

In some of the simulation work carried out in this paper, generation from diesel generators are also considered. The major physical properties of a generator are the maximum and minimum electrical power output, lifetime in number of operating hours, the fuel type, and its fuel curve, which gives the relation between quantities of fuel consumed to electrical power produced . The fuel curve is assumed as a straight line with a y intercept which is given by the following equation for fuel consumption:

Where, F0 is the fuel curve intercept coefficient, F1 is the fuel curve slope, Ygen is the rated capacity of the generator in kW and Pgen is the electrical output of the generator in kW.

A generic 500 kW gen set which is readily available in Homer resources library is used for this purpose. The lifetime of the generator is considered as 15,000 h. The capital and replacement cost is taken as 385$ per kW of the generator ratings. While the operation and maintenance cost of the generator unit per kW is taken as 0.15$/h. Other than these inputs, the prices of the fuel are discussed in the next section. As the generator output is in the form of ac, converters are needed to connect it to the DC micro grid network. Here a generic converter is considered for modelling in Homer. As the flow of power back to the grid is not considered in this study, the primary function of the converter is to rectify the ac output to dc. And hence the prices of the converter are also comparatively lesser as compared to a bidirectional converter. Here, for this study, after a good amount of survey on the Indian markets, the capital cost of the converter is considered as 154$ per kW. The lifetime and efficiency of the converter is considered as 15 years and 90% respectively.

Resources Data

Assets can be depicted as anything that originates from outside the microgrid framework and that is utilized by the framework to produce electrical power. The inexhaustible assets can change massively with area. The sort and nature of accessible asset impacts the conduct and financial aspects of the microgrid framework, since they decide the amount and timing of intensity generation. What’s more, subsequently a watchful choice or displaying of sustainable asset information is a fundamental component for the general recreation and streamlining process. Assets information as sun powered light, wind speed and fuel costs are given as one of the contributions for the recreation procedure in Homer. With the end goal to create reasonable displaying consequences of the planned microgrid, wind speed and sun oriented light information are acquired from the National Renewable Energy database. For a given territory in the Indian subcontinent, the dataset contains hourly estimations of climate information for the era of 2011– 2017. A year from this dataset is picked and is given as a contribution to Homer.

For this examination, the information of sun powered Global Horizontal Irradiance (GHI) is acquired for the zone of nellore. The normal day by day illumination for every one of the month during the time is given in Fig. 4. The clearness list for every one of the month is additionally given in a similar figure. Here clearness record is a proportion of clearness of the environment. It is the bit of the additional earthbound sunlight based radiation that achieves the earth surface. For wind speed information, Indian city of Nellore in Andhra Pradesh is considered. At long last, the kind of fuel for use in the diesel generator is likewise given as an asset contribution for the re enactment. Here, rather than typical diesel, biodiesel is taken as a fuel of decision. Despite the fact that it has a lower warming quality (38.50 MJ/kg) than that of typical diesel, it produces lesser discharges. The costs of the biodiesel are considered as 0.53$ per liter which is additionally impressively lower than typical diesel costs

Microgrid Simulation and Optimization

Simulation of the microgrid system is carried out in Homer to predict the optimal system configuration. The simulation process models the performance of a system configuration to determine its technical feasibility and life-cycle cost. Again, the optimization process simulates many different system configurations in search of one which satisfies the technical constraints at the lowest life cycle cost. For this study, depending on the type of load, components of the microgrid system are chosen properly. It is to be noted that the selection of renewable energy generation purely depends on the availability of the corresponding resources in the area. After this, proper inputs of wind speed data, solar irradiation data and fuel prices are also provided. Homer also accepts a range of inputs in terms of the capacity of each generation, storage units, fuel prices etc. And from within the specified capacity, Homer selects the optimum size of each of the components. The final simulation result yields a set of system configuration which are arranged in order of least prices of energy. And along with this optimization result economic analysis are also carried out in further sections. Two of the main economic elements for the optimization process are the total Net Present Cost (NPC) and levelized Cost of Energy (COE). Here, NPC (or Life Cycle Cost) of a component is the present value of all the costs of installing and operating that component over the project lifetime, minus the present value of all the revenues that it earns over the project lifetime . Both factors depend on the annualized cost of the system.

The Levelized Cost of Energy

Where, Els is the electrical energy that is supplied by the microgrid and Egrid is the amount of electricity sold by the microgrid to the main grid. Here in HOMER, the total NPC is the economically preferred element and not the levelized COE as each of these decisions is somewhat arbitrary.

A system dispatch strategy is also put into place which gives a set of rules to control the operation of the dispatch able system components (generators, battery bank etc.). For each hour of the year, the simulation study determines if the renewable sources (which are non dispatchble) can supply the loads. If the loads cannot be met, the best possible way to dispatch the dispatchable components is determined. The fundamental principle that is followed in dispatching is minimization of cost. And hence, a combination of dispatchable sources with a least operating cost is thus determined and implemented. The same cost based dispatch logic is used in all the system configurations. For all the simulations, the lifetime of the project is taken to be 25 years. The following subsection details the simulation procedures of the different microgrid configuration considered for the study.

Results and Discussions

Simulation studies explain out for the overall and categorise results different types of micro grid. In overall results figure the system configurations all the combinations of the micogrid and it will give the rankings of each system according to the least unit price COE. Here it explains best configuration design in the list of results and detailed discussions are presented in below sections.


The paper investigation the sizing and rankings of AC micro grids for with and without grid connections. The results give a very clear in the table 3 and 4, each system components and the cost of energy for each system setup. The grid connected microgrid investment is low and without connection of microgrid is investment is high but conventional source are running out that’s why it has to go for renewable energy sources. The cost of economy COE is for grid connected is $0.100 per unit and without grid connected system of COE is $0.627 per unit. When comparing the two systems without grid connection is little bit high but it not issue for increasing of utility of renewable energy sources.


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