Hybrid Power

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HYBRID POWER SYSTEM

1. INTRODUCTION Energy is a requirement that is endlessly and exhaustingly utilized the world over. With the increase in the rate of various developmental activities around the world the energy being consumed is also increasing with the result that conventional energy resources are fast getting depleted and even hydrel reserves are proving less than sufficient to satisfy the growing energy demand. As a result consumers around the world have to bear the brunt of increasing power cuts and power costs. Hence for the future power independence is fast becoming a vital requirement. The concept design therefore formulates a system which provides internally generated energy for homes and also integrates a sub system into the household such that the dependence on the electricity board is eliminated. When thinking about nonconventional source of energy what usually comes to our mind are the existing and extensively used nonconventional sources of energy like solar, tidal, wind, geo thermal heat, biomass .But in countries where we have so fluctuant weather and temperature, to depend on these resources are highly unreliable .That made think out of the box and find a new method of generating energy which should be highly reliable and cost effective, which is a hybrid power system. A hybrid power system has more than one type of generator-usually a gasoline or dieselpowered engine generator and a renewable energy source such as PV, wind, or hydropower system. For explanation, a solar-wind hybrid system is mainly considered in this report. A hybrid system is most often used for larger applications such as village power; residential systems where generators already exist; and in applications like telecommunications where availability requirements are near 100 percent. Almost all PV generator hybrid systems include batteries for storage. The most common configuration for a W-generator system is one in which the PV array and the generator each charge the batteries. Hybrid energy system usually consists of two or more energy sources used together to provide increased system efficiency as well as greater balance in energy supply. Example of a hybrid energy system can be a solar electric (PV) array that could be coupled with a wind turbine, which would create output from the wind turbine during the winter, whereas during the summer the solar panels would produce their output with a better efficiency.
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2. NEED OF HYBRID POWER PLANT Conventional combustion type power generation methods include the combustion of primary fuels like gasoline, natural gas, coal etc where mechanical power is produced by a heat engine that transforms thermal energy, from combustion of a fuel, into rotational energy. Most thermal power stations produce steam, and these are sometimes called steam power stations. Not all thermal energy can be transformed into mechanical power, according to the second law of thermodynamics. Therefore, there is always heat lost to the environment. On the other hand, we have nuclear power stations, in which the mechanical energy required for rotating a turbine is obtained from converting water into high energy (KE or PE) steam. For the heating purpose, we use nuclear reaction. The heat emitted from nuclear reactors is used to heat up the water stored in a container. But this method has the main disadvantage of a nuclear power station is the risk factor. If leakages of these nuclear plants occur, it will cause high damage to both biotic and abiotic factors in the surrounding. Also both of these have a disadvantage of atmospheric pollution. 2.1. DISADVANTAGES OF CONVENTIONAL COMBUSTION GENERATORS       It is costlier in running cost as compared to Hydro electric plants. It pollutes the atmosphere due to production of large amount of smoke and fumes. Over all capital investment is very high on account of turbines, condensers, boilers

reheaters etc .maintenance cost is also high on lubrication, fuel handling, fuel processing. It requires comparatively more space and more skilled operating staff as the operations

are complex and required precise execution A large number of circuits makes the design complex Starting of a thermal power plant takes fairly long time as the boiler operation and steam

generation process are not rapid and instantaneous

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2.2. SOLUTION Usage of clean energy sources is the most acceptable solution. A clean energy source means one which produces energy without making much disturbance to the environment. The examples of such sources are solar energy, wind energy, wave energy, fuel cells etc. But electricity should be produced exactly at the time it is needed. Sun and wind do not meet this requirement. So a special type of power plant should be built to avoid shortage of power and to utilize all available sun and wind power. There are at least two ways to achieve this aim:   Power plant using two (or more) primary sources with additional control system. Electricity energy storage.

All these factors necessitate the use of a hybrid power system.

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3. HYBRID POWER SYSTEMS A hybrid power system is nothing but a system that uses more than one source to produces electrical energy. Apart of the existing system in which tying up of outputs of different generating stations, here the different sources of energy are tied up at the point of production that is using two or more fuels for the same device, that when integrated, overcome limitations inherent in either. The different types of hybrid power systems that are commonly used are:       Solar-wind hybrid power plant. A solid oxide fuel cell combined with a gas turbine or micro turbine. A wind-fuel cell hybrid system. Wave wind hybrid system. Wind turbine with battery storage and diesel backup generator. DC hybrid system and micro grid.

A hybrid power system should contain a controlled source like gasoline or diesel powered engine generator in addition to the renewable energy sources like PV, wind or hydropower system. This is because the energy produced from a renewable energy sources such as solar energy or wind energy is fluctuating, so that it can‘t meet the load demand efficiently at all the time. The diesel engine generator ensures power generation whenever the former fails to operate. The hybrid systems always contain a backup battery. Its main application is to ensure continuous energy supply when the other two sources fail to operate. It also helps to smoothen the sharp fluctuations in the output of a renewable energy source. In this seminar we have explained a solar wind hybrid power plant as an example.

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4. SOLAR-WIND HYBRID POWER STATION

Fig: 1

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Hybrid system is a combined system of wind and solar power generation system. Aero turbines convert wind energy into rotary mechanical energy. A mechanical interface, consisting of a step-up gear and a suitable coupling transmits the energy to an electrical generator. The output of this generator is connected to the Battery or system grid. The battery is connected to the inverter. The inverter is used to convert DC voltages to AC voltages. The load is drawn current from the inverter. Main parts of the wind mill section are:    Generator Main shaft with Leafs Gear Wheel Arrangement Wind power ratings can be divided into three convenient grouping, small to 1kW, medium to 50 kW and large 200 kW to megawatt frame size. Solar energy means all the energy that reaches the earth from the sun. It provides daylight makes the earth hot and is the source of energy for plants to grow. Solar energy is also put to two types of use to help our lives directly solar heating and solar electricity. Solar electricity is the technology of converting sunlight directly in to electricity. It is based on photo-voltaic or solar modules, which are very reliable and do not require any fuel or servicing. Solar electric systems are suitable for plenty of sun and are ideal when there is no main electricity.

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4.1. SOLAR-WIND HYBRID SYSTEM BLOCK DIAGRAM

WIND TURBINE

POWER SYSTEM MONITOR

ENGINE GENERATOR

BATTERY SOLAR PANEL/ PHOTO VOLTAIC ARRAY DC LOAD CENTRE BATTERY STORAGE BANK AC LOAD CENTER DC CONTROL CENTRE INVERTER CHARGER

DC LOADS

AC LOADS

Fig: 2

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4.2. INTRODUCTION TO WIND ENERGY Wind result from air in motion. Air in motion arises from a pressure gradient. On a global basis one primary forcing function causing surface winds from the poles toward the equator is convective circulation. Solar radiation heats the air near the equator, and this low density heated air is buoyed up. At the surface it is displaced by cooler more dense higher pressure air flowing from the poles. In the upper atmosphere near the equator the air thus tend to flow back toward the poles and away from the equator. The net result is a global convective circulation with surface wins from north to south in the northern hemisphere. There is the further complication of boundary layer frictional effects between the moving air and the earth‘s rough surface. Mountains, trees, buildings, and similar obstructions impair stream line air flow. Turbulence results and the wind velocity in a horizontal direction markedly increase with altitude near the surface. Local winds are caused by two mechanisms. The first is differential heating of land and water. Solar isolation during the day is readily converted to sensible energy of the land surface but is partly absorbed in layers below the water surface and partly consume in evaporating some of that water. The land mass becomes hotter than the water, which causes the air above the land to heat up and become warmer than the air above water. The warmer lighter air above the land rises and the cooler heavier air above the water moves into replace it. This is the mechanism of shore breezes. At night, the direction of the breezes is reversed because the land mass cools to the sky more rapidly than the water, assuming a sky. The second mechanism of local winds is caused by hills and mountain sides. The air above the slopes heats up during the day and cools down at night, more rapidly than the air above the low lands. This causes heated air the day to rise along the slopes and relatively cool heavy air to flow down at night. Wind turbines produce rotational motion; wind energy is readily converted into electrical energy by connecting the turbine to an electric generator. The combination of wind turbine and generator is sometimes referred as an aero generator. A step-up transmission is usually required to match the relatively slow speed of the wind rotor to the higher speed of an electric generator. In India the interest in the windmills was shown in the last fifties and early sixties. A part from importing a few from outside, new designs was also developed, but it was not sustained. It is only in the last few years that development work is going on in many institutions. An important reason for this lack of interest in wind energy must be that wind, in India area relatively low and
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vary appreciably with the seasons. Data quoted by some scientists that for India wind speed value lies between 5 km/hr to 15-20 km/hr. These low and seasonal winds imply a high cost of exploitation of wind energy. Calculations based on the performance of a typical windmill have indicated that a unit of energy derived from a windmill will be at least several times more expensive than energy derivable from electric distribution lines at the standard rates, provided such electrical energy is at all available at the windmill site. The above argument is not fully applicable in rural areas for several reasons. First electric power is not and will not be available in many such areas due to the high cost of generation and distribution to small dispersed users. Secondly there is possibility of reducing the cost of the windmills by suitable design. Lastly, on small scales, the total first cost for serving a felt need and low maintenance costs are more important than the unit cost of energy. The last point is illustrated easily: dry cells provide energy at the astronomical cost of about Rs.300 per kWh and yet they are in common use in both rural and urban areas. Wind energy offers another source for pumping as well as electric power generation. India has potential of over 20,000 MW for power generation and ranks as one of the promising countries for tapping this source. The cost of power generation from wind farms has now become lower than diesel power and comparable to thermal power in several areas of our country especially near the coasts. Wind power projects of aggregate capacity of 8 MW including 7 wind farms projects of capacity 6.85 MW have been established in different parts of the country of which 3 MW capacities has been completed in 1989 by DNES. Wind farms are operating successfully and have already fed over 150 lakes units of electricity to the respective state grids. Over 25 MW of additional power capacity from wind is under implementation. Under demonstration

programmer 271 wind pumps have been installed up to February 1989. Sixty small wind battery charges of capacities 300 watts to 4 kW are under installation. Likewise to stand-alone wind electric generators of 10 to 25 kW are under installation.

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4.2.1. WIND ENERGY CONVERSION Traditional windmills were used extensively in the middle Ages to mill grain and lift water for land drainage and watering cattle. Wind energy converters are still used for these purposes today in some parts of the world, but the main focus of attention now lies with their use to generate electricity. There is also growing interest in generating heat from the wind for space and water heating and for glass-houses but the potential market is much smaller than for electricity generation. The term ―wind mill‖ is still widely used to describe wind energy conversion systems, however it is hardly adopt. Modern wind energy conversion systems are more correctly referred to as ‗WECS‘, aero generations‘, ‗wind turbine generators‘, or simply ‗wind turbines‘. The fact that the wind is variable and intermittent source of energy is immaterial of some applications such as pumping water for land drainage – provided, of course, that there is a broad match between the energy supplied over any critical period and the energy required. If the wind blows, the job gets done; if it does not, the job waits. However, for many of the uses to which electricity is put, the interruption of supply may be highly inconvenient. Operators or users of wind turbines must ensure that there is some form of back-up to cover periods when there is insufficient (or too much) wind available. For small producers, back-up can take the form of:   Battery storage, Connection with the local electricity distribution system For utilities responsible for public supply, the integration of medium – sized and large wind turbines into their distribution net work could require some additional plant which is capable of responding quickly to meet fluctuating demand.

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4.2.2. ADVANTAGES  The wind is free and with modern technology it can be captured efficiently.  Once the wind turbine is built the energy it produces does not cause green house gases or other pollutants.  Although wind turbines can be very tall each takes up only a small plot of land. This means that the land below can still be used. This is especially the case in agricultural areas as farming can still continue.  Many people find wind farms an interesting feature of the landscape.  Remote areas that are not connected to the electricity power grid can use wind turbines to produce their own supply.  Wind turbines have a role to play in both the developed and third world.  Wind turbines are available in a range of sizes which means a vast range of people and businesses can use them. Single households to small towns and villages can make good use of range of wind turbines available today. 4.2.3. DISADVANTAGES  The strength of the wind is not constant and it varies from zero to storm force. This means that wind turbines do not produce the same amount of electricity all the time. There will be times when they produce no electricity at all.  Many people feel that the countryside should be left untouched, without these large structures being built. The landscape should left in its natural form for everyone to enjoy.  Wind turbines are noisy. Each one can generate the same level of noise as a family car travelling at 70 mph.  Many people see large wind turbines as unsightly structures and not pleasant or interesting to look at. They disfigure the countryside and are generally ugly.  When wind turbines are being manufactured some pollution is produced. Therefore wind power does produce some pollution.  Large wind farms are needed to provide entire communities with enough electricity. For example, the largest single turbine available today can only provide enough electricity for 475 homes, when running at full capacity.

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4.3. INTRODUCTIN TO SOLAR ENERGY

The most useful way of harnessing solar energy is by directly converting it into electricity by means of solar photo-voltaic cells. Sunshine is incident on Solar cells, in this system of energy Conversion that is direct conversion of solar radiation into electricity. In the stage of conversion into thermodynamic from is absent. The photo-voltaic effect is defined as the generation of an electromotive force as a result of the absorption of ionizing radiation. Energy conversion devices, which are used to convert sunlight to electricity by use of the photo-voltaic effect, are called solar cells. In recent years photo-voltaic power generation has been receiving considerable attention as one of the more promising energy alternatives. The reason for this rising interest lie in PV‘s direct conversion of sunlight to electricity, the non polluting nature of the PV widespread are of PV generation has been hampered by economic factors. Here to force, the low cost of

conventional energy sunlight has obviated the development of a broad-based PV technology. At the present time, PV generation can be justified only for special situations mostly for remote sites where utility lines on other conventional means of furnishing energy may be prohibitively expensive and is one of the most attractive non-conventional energy sources of proven reliability from the micro to the Mega-watt level.

4.3.1. PHOTOVOLTAIC PRINCIPLES

The photo-voltaic effect can be observed in nature in a variety of materials that have shown that the best performance in sunlight is the semiconductors as stated above. When photons from the sun are absorbed in a semiconductor, that create free electrons with higher energies than the created there must be an electric field to induce these higher energy electrons to flow out of the semi-conductor to do useful work. A junction of materials, which have different electrical properties, provides the electric field in most solar cells.

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Fig: 3

Fig: 4

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Fig: 5

To obtain a useful power output from photon interaction in a semiconductor, three processes are required.  The photon has to be absorbed in the active part of the material and result in electrons being excited to a higher energy potential.  The electron hole charge carriers created by the absorption must be physically separated and moved to the edge of the cell.  The charge carriers must be removed from the cell and delivered to useful load before they lose extra potential.

For completing the above processes a solar cell consists of:  Semi-conductor in which electron hole pairs are created by absorption of incident solar radiation.  Region containing a drift field for charge separation.  Charge collecting fronts and back electrodes.

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The photo-voltaic effect can be described easily for p-n junction in a semi-conductor. In an intrinsic semi-conductor such as silicon, each one of the four valence electrons of the material atom is tied in a chemical bond, and there are no free electrons at absolute zero. If a piece of such a material is doped on one side by a five valance electron material, such as arsenic or phosphorus, there will be an excess of electrons in that side, becoming an n-type semiconductor. The excess electrons will be practically free to move in the semi-conductor lattice. When a three valence electron material, such as boron dopes the other side of the same piece, there will be deficiency of electrons leading to a p-type semi-conductor. This deficiency is expressed in terms of excess of holes free to move in the lattice. Such a piece of semi-conductor with one side of the p-type and the other, of the n-type is called p-n junction. In this junction after the protons are absorbed, the free electrons of the n-side will tends to flow to the p-side, and the holes of the p-side will tend to flow to the n-region to compensate for their respective deficiencies. This diffusion will create an electric field from the n-region to the p-region. This field will increase until it reaches equilibrium for V, the sum of the diffusion potentials for holes and electrons.

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4.3.2. SOLAR ENERGY ADVANTAGES         

The power source of the sun is absolutely free. The production of solar energy produces no pollution. The technological advancements in solar energy systems have made them extremely cost

effective. Most systems do not require any maintenance during their lifespan, which means you

never have to put money into them. Most systems have a life span of 30 to 40 years. Most systems carry a full warranty for 20 to 30 years or more. Unlike traditional monstrous panel systems, many modern systems are sleeker such as

Unit-Solar rolls that lay directly on the roof like regular roofing materials. In 35 states, solar energy can be fed back to the utilities to eliminate the need for a

storage system as well as eliminating or dramatically reducing your electric bills. Solar energy systems are now designed for particular needs. For instance, you can convert your outdoor lighting to solar. The solar cells are directly on the lights and can‘t be seen by anyone. At the same time, you eliminate all costs associated with running your outdoor lighting.

4.3.3. SOLAR ENERGY DISADVANTAGES    

There are locations in the world where this energy is collected efficiently and some of the

locations are not with the appropriate sunlight. The initial cost of the solar panels is an expensive investment. You can collect it only during the day. Depends on the climate conditions.

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4.4. COMBINING WIND TURBINE AND SOLAR PANELS

If the amount of energy consumption increases, it makes sense to combine PV with wind. The reason is that these other technologies can provide lower cost per Kilowatt-hour if they are scaled up to a certain level. The hybrid PV-Wind systems offer the most adequate solutions for the electrification of small rural settlements, the combination and the ratio of the two types of energy depending greatly on the resources locally available in each geographical area. These resources can be accurately evaluated only after a period of typically one year of monitoring the basic parameters (wind speed, solar radiation), necessary for sizing and implementing such systems in the respective areas. Combining Wind Turbine and Solar Panels into a hybrid system offers several advantages. In many places, wind speeds are low in the summer when the sun is plentiful. The wind is strong in the winter when less sunlight is available. Because the peak operating times for wind and solar systems occur at different times of the day and year, hybrid systems are better balanced and more likely to produce power when you need it. Wind Solar Hybrid power System includes: 1. Solar Array: A number of PV panels connected in series and/or in parallel giving the required DC output from the available irradiance. Orientation and tilt of these panels are important design parameters, as well as avoiding as much shading as possible from surrounding obstructions. 2. Wind turbine: This is installed on top of a tall tower, collects kinetic energy from the wind and converts it to electricity that is compatible with a home‘s electrical system. 3. Hybrid controller: This controls the battery bank charge and discharge keeping it within optimum safety limits. 4. Battery bank: This can be a single battery or multiple batteries connected together to create essentially one large battery of the required voltage and amp- hour capacity. The battery configuration and capacity are the most important electrical power decisions that have to be made, and a wise choice in this regard can help guarantee a steady supply of electrical power as well as a system that is simple to operate and maintain. 5. Inverter: A converter that changes the DC power from the batteries into AC power suitable for the required loads. Loads being the network connected appliances in the building that are fed from the inverter (AC loads), or from the battery bank (DC loads).
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Wind solar hybrid power system is an integrated system of solar energy and wind energy. The rational allocation of every part‘s capacity of generating system is very important to guarantee the reliability of generating system. To satisfy the requirement of users‘ electricity consumption, our company will analyze the electricity consumption and local solar and wind resources conditions to allocate the most suitable system for different users. Many hybrid systems are stand-alone systems, which operate "off-grid"—not connected to an electricity distribution system. For the times when neither the wind nor the solar system are producing, most hybrid systems provide power through batteries and/or an engine generator powered by conventional fuels, such as diesel. If the batteries run low, the engine generator can provide power and recharge the batteries. Adding an engine generator makes the system more complex, but modern electronic controllers can operate these systems automatically. An engine generator can also reduce the size of the other components needed for the system. Keep in mind that the storage capacity must be large enough to supply electrical needs during non-charging periods. Battery banks are typically sized to supply the electric load for one to three days. Hybrid generator systems can be created either as grid-assisted or grid-inter-tied and offgrid. Grid assisted systems can use both electrical grid and various energy sources. The electrical energy provided from these multiple sources can then be stored in battery systems. There's a bonus to grid-assisted different energy sources. When the wind does not blow, or the sun will not shine, the electrical system will still be storing power in the battery system. In these systems, hybrid generators operate as a method to reduce utility costs. Off-grid systems on the opposite hand are designed to supply alternative energy sources that are fully become independent from grid power. Hybrid generators in this case are the sole technique of electrical input to the battery storage system. Initial, they minimize the environmental footprint of someone's electrical consumption. Second, they eliminate an individual's reliance upon utility firms and utility costs. Lastly, hybrid generator systems can be created nearly anywhere replacing the requirement for expensive utility connections to remote areas. With any natural disaster electricity may be out for an unknown period of time. When a large disaster strikes (hurricane, terrorist attack, earthquake, tornado, etc.) many of the necessities of life are suddenly gone, poof! - Instantly gone. Electricity is always the first to go. After a massive disaster, emergency lighting may need to be used for a long time - days, weeks,
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even months. If you are trying to mitigate or plan for the above "massive disaster" scenario, on a small personal scale, it would make much more sense to have a reliable means of using natural energy than storing gasoline or batteries which go bad and age over time. What if you had to move around a stricken area or totally "Bug out" and evacuate an area? There an off grid solar wind hybrid generator will help you.

4.4.1. PV-WIND HYBRID SYSTEM FUNCTION PROCEDURE.

During day time, DC power generated by the solar PV array is stored in the battery bank through a hybrid controller, which maximizes charging current and prevents excessive discharge/overcharge. Wind turbine generator started generating power when wind speed exceeds cut-in speed of the mini wind turbine (above 2.7m/s). Out from the wind battery charger is also stored in the battery bank through hybrid controller. The wind turbine is self-regulated type with protection for over speed. Energy stored in the battery is draw by electrical loads through the inverter, which convert DC into AC power. The inverter has in-built protection for short-circuit, reverse polarity, low battery voltage and over load. The batter bank is sizing to feed loads up to two days, during non sun/wind days.

4.4.2. METHODS OF SIZING PV-WIND HYBRID SYSTEM

The yearly monthly overage sizing method: In this method, photovoltaic and wind generators size are measured from the average annual monthly values of energies statement E pv, Ew and the load EL. This calculates is basing on the average annual monthly data of sunning and the wind. The most unfavorable month method: For this method the size of the PV and Wind generators is being calculated in the most unfavorable month. Generally the month most unfavorable in wind is favorable in irradiation. So we are obliged to dimension the system in two most unfavorable months (unfavorable irradiation month and unfavorable wind month). When the system functioned in this month it‘s automatically functioned in the other month.

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Loss of power supply probability (LPSP) method: This sizing method consists in determining the optimal number of the batteries and the photovoltaic modules according to the optimization principle knowing: the reliability, which is based on the concept of the probability of loss of energy (Loss of Power Supply Probability _ `LPSP‘) [2], and on the cost of the system. LPSP' is defined as being the fraction of the deficiency energy and that required by the load. It explains the rate of not satisfaction of the load, in term of state of batteries charging.

4.4.3. FACTORS CONSIDERED FOR SIZING A HYBRID SYSTEM

The key factors to be determined while selecting the size of a solar generator are    The load mix between PV and generator, The size and type of generator, and The battery size. The sizing method assumes that a stand-alone PV system has already been considered-the load has been estimated and the solar radiation at the site is known. The primary decision is the load mix between generators. Selecting the mix is simplified by using the graph given in Figure below.

Fig: 6; Source: Stand – alone Photovoltaic System

The designer selects a hybrid array to load ratio for the system realizing that the higher up the curve, the higher the percentage of load supplied by the PV array. The load mix will be a key
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determinant in the type and size of the generator and the battery. The most cost-effective system is obtained by selecting a point on or slightly below the knee of the curve. For example, a hybrid array/load ratio of 0.25 should give a hybrid system design where the PV array supplied 90 percent of the annual load demand. An array/load ratio of 0.15 would give a system with lower initial cost because the amount of load provided by the PV array would be about 57 percent. The generator would operate more in this latter design with corresponding increases in fuel cost and maintenance. If the generator is in a remote location the cost of this maintenance may be exorbitant. These are the design tradeoffs that must be made. If high reliability is required, the system should be designed for 90 to 95 percent PV contribution. The generator is used only for back-up during worst-case conditions, typically in the winter months when it is most difficult to get a generator started. Therefore, having two power sources at an unattended site does not, in itself, guarantee 100 percent reliability. Similarly the sizes of the wind mills are also selected scientifically and in the most economical way. The control system must be properly designed for fail-safe operation and regular maintenance performed, particularly on the generator. Also, the control system for a hybrid system is more complex because the regulation of the batteries and load must be maintained under all operating conditions. All generators require periodic routine maintenance (i.e., oil change, engine tune up, and eventually engine rebuilding). With a generator available for back-up power, the battery size in the hybrid system may be decreased without lowering system availability. However, the battery must be carefully matched to the loads and power sources. Integration of a generator into a PV system requires a more sophisticated control strategy. Most controllers are custom designed by an experienced electronic engineer / technician. Controls for PV - generator systems perform two main functions--battery regulation and subsystem management.

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4.5. ADVANTAGES OF A SOLAR WIND HYBRID POWER STATION

Wind speeds are often low in the summer season when the suns power availability is at its best. Speculatively, the wind is often stronger in seasons winter months when the days are shorter and offer less sunshine resources. This is why a solar-wind hybrid solution is an alternative to consider. We notice that even during the same day there are different and opposite availabilities of wind and solar power possibilities. And those different patterns can make the hybrid systems the best option for electricity production.         

Fuel saving (up to 50%). Lower atmospheric contamination. The possibility to combine two or more renewable energy sources, based on the natural

local potential of the users Environmental protection, especially in terms of CO2 emissions reduction Low cost – wind energy, and also solar energy can be competitive with nuclear, coal and

gas especially considering possible future cost trends for fossil and nuclear energy. Diversity and security of supply Rapid deployment - modular and quick to install Fuel is abundant, free and inexhaustible Costs are predictable and not influenced by fuel price fluctuations, although fluctuations

in the price of batteries will be an influence where these are incorporated.

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5. WIND-WAVE HYBRID SYSTEM

The hybrid wave power rig uses two wave converting technologies in addition to wind mills. The main system is a pneumatic float in the category of overtopping as Wave Dragon. In addition the pneumatic float can house point absorbers. The hybrid wave power rig is based on the patented wave energy converter from 2005. A floating foundation which works as a platform for extracting energy from both wind and wave power. That is Poseidon – wind and wave in one. Poseidon is developed by Floating Power Plant A/S (FPP), a Danish company holding all rights to develop and build the patented floating power plant, Poseidon. During the last 10 years FPP has managed to develop today‘s operation unit from idea, through design and modeling to test of various scale models. Today FPP runs Poseidon 37, a 360 tonnes heavy and 37 metres wide hybrid renewable energy demonstration plant. Being the first and biggest test plant of its kind ever build, Poseidon went into real sea test in 2008 off the shores of Lolland in southern Denmark. The Poseidon concept is unique world-wide, because of 1. The unique wave energy concept. FPP´s patented wave energy concept has one of the highest efficiency rates known not the least due to the unique shape of the floaters which are able to extract both the lift and push forces of the waves. This is documented in both wave basins and off-shore. 2. The floating foundation for wind turbines. The wave energy forces are the key dimensioning criteria, which ensure a rigid and solid platform, compared to other concepts for floating foundations for off-shore wind. The platform stability for floating foundation for wind turbines has been documented in basin tests by DHI, and the stability of FPP`s off-shore plant has been documented by Riso through measurements and simulations/ calculations. 3. The combination of wind and wave.

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5.1. HIGH CAPACITY

Designed to be anchored in the open sea with deep waters, high flux, and good wind conditions, the highly efficient wind and wave energy concept secures high capacity and energy production. A 240 meter wide platform can produce over 50 GWh/y equal to the yearly power consumption of approx 12,500-15,000 private households. For the first time ever, Poseidon makes it possible to utilize sea areas with water depths above 35 meters for manufacturing of renewable energy solutions. Supply & demand in balance by combining wind and wave FPP also addresses the known problem with end-user power demand and supply not being synchronized. Waves are inherently more stable and predictable than wind, especially in deep waters. Furthermore waves continue to roll long after the wind has subsided.

5.2. WAVE ENERGY IN OCEAN

While both wave and tidal energy exist in great quantities, energy conversion devices for these sources are in their infancy and by no means take advantage of the energy available. Conversion from the natural kinetic energy in waves to usable electricity is made difficult by the unpredictable nature of the ocean, which explains the hesitancy to investigate harnessing methods. The ocean wave energy is modeled, at best, as an irregular, oscillating, low frequency energy source that can be converted to a 60-Hertz frequency, which can then be added to the electric grid. Compared to the more familiar renewable energy source of wind, it has been estimated that improved technology will enable wave energy conversion devices to produce electricity at a cost comparable to wind turbine outputs within the next decade. Benefits that would make wave-derived power preferable to wind or solar power include a smaller space requirement since wave energy contains roughly 1000 times the kinetic energy of wind, and the ability to generate power throughout the entire day, not just during the sunny hours as with solar. This study will be limited to calculating the usable power in sets of deepwater ocean waves.

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6. LIFECYCLE COST

Doing a life-cycle cost analysis (LCC) gives you the total cost of your hybrid system-including all expenses incurred over the life of the system. There are two reasons to do an LCC analysis: 1) To compare different power options, and 2) To determine the most cost-effective system designs. For some applications there are no options to small PV systems so comparison of other power supplies is not an issue. A hybrid system produces power where there was no power before. For these applications the initial cost of the system is the main concern. However, even if a particular power source is the only option, a life-cycle cost (LCC) analysis can be helpful for comparing costs of different designs and/or determining whether a hybrid system would be a cost-effective option. An LCC analysis allows the designer to study the effect of using different components with different reliabilities and lifetimes.

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HYBRID POWER SYSTEM

7. ADVANTAGES               Provides independence from energy crisis. Higher efficiency based on the generating source. Control centre design comparatively more integrated than existing systems. Produce more power then Wind energy Wave energy individual. Non Conventional energy source, so ecofreindly. Both Wind and Wave energy converter are present hence so reliable. Economic. Reliable, continuous power maximizing renewable usage Reduced fuel consumption 50-60%, requiring less diesel storage Reduced operating costs Less electricity No Power Outages- The next time a hurricane goes through you will not have to worry

about losing power for a week in the summer. Provided that your system was not damaged. Pollutants-No pollutants are being released into the air. Cells only become a problem

when it comes time to replace them (about twenty years) High power quality Other advantages of using a hybrid system are: Improved Economics - A large part of the cost of PV stand-alone systems results from the need to size the array and batteries to support the load under worst-case weather conditions. In many applications, this marginal power may be less expensive if provided by a generator. In regions with variable climate, where average daily insolation in winter is two or three times less than in summer, the use of a hybrid system may be a good option. Figure 20 demonstrates how the marginal cost of photovoltaic systems changes relative to power availability. This plot indicates that a PV system providing 90 percent of the load will cost about $3,600 but the cost rapidly goes past $8,000 before an availability of 98 percent is reached. It may be more economical to provide some of this power with a generator. However, maintenance, logistics, and fuel costs can be quite expensive for generators operating in remote areas. These factors must be considered in any cost estimate of the hybrid system.

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HYBRID POWER SYSTEM

Increased Reliability - The two independent power systems provide redundancy and possibly greater overall reliability if the hybrid system is properly maintained and controlled. Design Flexibility - The design of a hybrid system depends on the load mix between the engine generator and the PV system. As the size of the PV array increases the operating time of the generator goes down. This saves fuel, lowers maintenance, and prolongs generator life but the initial cost will be higher than a power system with a smaller PV array. For a hybrid system the size of the battery bank is usually smaller than for a stand-alone PV system designed for the same application. This is because the fueled generator will be available to keep the battery stateof-charge above the recommended limit. When sizing the batteries, be sure the generator charging current does not exceed the recommended charge rate for the battery

8. DISADVANTAGES    Application on large scale cannot be predicted. Installation cost is very high. Under analysis.

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9. APPLICATION In electricity generation it can be used to produce high electricity with more reliability. India is developing country and power is first need of developing country. So non conventional energy sources are more helpful in development. It helps to improve the tourism sector. People have an interest to visit village or rural areas. But the lack of good facilities withdraws a large percentage of people from it. So by providing electricity to such places, the tourism sector will be benefitted. Non conventional energy sources are environment friendly and available in huge amount. It is hybrid of wave and wind energy so it produces more power than individual wind and wave. Distributed Generation Applications, Constant Speed and Variable Speed Wind Energy Conversion Systems, Photovoltaic Energy System.

10. FUTURE EXPANSION The key to cost reductions of this order is, of course, the right sort of support for innovation and development - something that has been lacking for the past and, arguably, is still only patchy at present. Research and development efforts in solar, wind, and other renewable energy technologies are required to continue for:   improving their performance, Establishing techniques for accurately predicting their output reliably integrating them

with other conventional generating sources.

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11. CONCLUSION A hybrid power system is economic since when wind or sunlight is available, the fuel generator will be shut down by reducing the fuel cost. Due to source diversity, these power systems are so reliable. Hybrid power systems can offer solutions and value to customers that individual technologies cannot match. HPS are a good way to have available sources of electricity which optimize utilization of primary energy sources. Hybrids offer market entry strategies for technologies that cannot currently compete with the lowest-cost traditional options. Some renewable hybrid power systems are commercially available today. Many options for the configuration of hybrid systems -Depend on load, resource, and costs. The overall performance of the hybrid renewable energy system was as expected. We were able to determine that this system would be a viable source of power production for outdoor and remote area applications. Due to time constraints some additional alterations could not be made to the wind turbine in order to get optimal performance. If time were available for further alterations the size of the stepper motor used should have been increased. Further improvements that should be made are in the portability. Economic aspects of these technologies are sufficiently promising to include them in developing power generation capacity for developing countries.

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12. REFERENCES

Website references:

[1] www.cere-tunisia.com/administrateur/article/CERG-WC-3.pdf [2] photovoltaics.sandia.gov/docs/HybridDescript.html [3] cleantechnica.com/.. -thermal-electricity [4] www. renewableenergydev.com [5] http://seminarprojects.com/Thread-hybrid-power-system#ixzz20K7WB2eE [6] http://www.inhabitat.com/2009/06/15/worl...-complete/ [7] http://www.adityasolar.in/solar_hybrid_power_plant.htm [8] Uses-Soar-Wind-amp-Natural-Gas#ixzz20KIS67Yy

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