A small hybrid electric system that combines wind and solar technologies can offer several advantages over either single system.According to many renewable energy experts, a small "hybrid" electric system that combines home wind electric and home solar electric (photovoltaic or PV) technologies offers several advantages over either single system.In much of the United States, wind speeds are low in the summer when the sun shines brightest and longest. 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 more likely to produce power when you need it.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.Hybrid renewable energy systemFrom Wikipedia, the free encyclopediaJump to: navigation, search This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2010)

Hybrid renewable energy systems (HRES) are becoming popular for remote area power generation applications due to advances in renewable energy technologies and subsequent rise in prices of petroleum products. A hybrid energy system usually consists of two or more renewable energy sources used together to provide increased system efficiency as well as greater balance in energy supply.Contents[hide] 1 Examples 1.1 Biomass-wind-fuel cell 1.2 Photovoltaic-wind 1.3 Completely Renewable an Idea 2 Drawbacks 3 How to Overcome? 4 Areas Of Research 5 Regulation 6 Need for research 7 See also 8 References 9 External linksExamples[edit]Biomass-wind-fuel cell[edit]For example, let us consider a load of 100% power supply and there is no renewable system to fulfill this need, so two or more renewable energy system can be combined. For example, 60% from a biomass system, 20% from a wind energy system and the remainder from fuel cells. Thus combining all these renewable energy systems may provide 100% of the power and energy requirements for the load, such as a home or business.Photovoltaic-wind[edit]

Block diagram of a PV/wind hybrid energy systemAnother example of a hybrid energy system is a photovoltaic array coupled with a wind turbine.[1] This would create more output from the wind turbine during the winter, whereas during the summer, the solar panels would produce their peak output. Hybrid energy systems often yield greater economic and environmental returns than wind, solar, geothermal or trigeneration stand-alone systems by themselves.Completely Renewable an Idea[edit]Completely Renewable Hybrid Power Plant (solar, wind, biomass, hydrogen) A hybrid power plant consisting of these four renewable energy sources can be made into operation by proper utilization of these resources in a completely controlled manner. Hybrid Energy Europe-USA. Caffese in Europe introduce hybridizing HVDC transmission with Marine hydro pumped Energy Storage via elpipes.The project of Caffese is 3 marine big lakes producing 1800 GW and transmission with elpipes. A part 1200 GW produce waterfuels-windfuels-solar fuels 210 billion liter year. (IEEE Power and Engineering Society-General Meeting Feb.9.2011,Arpa-E,Doe USA,MSE Italy,European COmmission-Energy-Caffese plan and Consortium)Drawbacks[edit]Most of us already know how a solar/wind/biomass power generating system works, all these generating systems have some or the other drawbacks, like Solar panels are too costly and the production cost of power by using them is generally higher than the conventional process, it is not available in the night or cloudy days. Similarly Wind turbines cant operate in high or low wind speeds and Biomass plant collapses at low temperatures.How to Overcome?[edit]So if all the three are combined into one hybrid power generating system the drawbacks can be avoided partially/completely, depending on the control units. As the one or more drawbacks can be overcome by the other, as in northern hemisphere it is generally seen that in windy days the solar power is limited and vice versa and in summer and rainy season the biomass plant can operate in a full flagged so the power generation can be maintained in the above stated condition. The cost of solar panel can be subsided by using glass lenses, mirrors to heat up a fluid, that can rotate the common turbine used by wind and other sources. Now the question arises what about the winter nights or cloudy winter days with very low wind speeds. Here comes the activity of the Hydrogen. As we know the process of electrolysis can produce hydrogen by breaking water into hydrogen and oxygen, it can be stored; hydrogen is also a good fuel and burns with oxygen to give water. Hydrogen can be used to maintain the temperature of the biomass reservoir in winter so that it can produce biogas in optimum amount for the power generation. As stated above biogas is a good source in summer; in this period the solar energy available is also at its peak, so if the demand and supply is properly checked and calculated the excess energy can be used in the production of hydrogen and can be stored. In sunny, windy &hot day, the turbine operates with full speed as the supply is maximum, and this excess power can be consumed for the process of manufacturing hydrogen. In winter, the power consumption is also low so the supply limit is low, and obtained with lesser consumption.Areas Of Research[edit] Amount of Hydrogen produce by amount of power utilized and reusing the hydrogen for maintaining the temperature. Is it cost efficient? Limited to areas near equatorial regions (23deg N-23deg S), at low altitudes. Infrastructure cost may be high. Hybrid renewable energy system is a way to use less energy then what people use today.This energy is not just regular energy its almost just like wind energy but they have something the same about each other that is they are both renewable energy sources.Regulation[edit]To get constant power supply, the output of the renewables may be connected to the rechargeable battery bank and then to the load. If the load is alternating current (AC), then an inverter is used to convert the direct current (DC) supply from the battery to the AC load. Consideration about voltage transition among modules starting from Wind Generator,Battery Charger Controller and Inverter should be subject to voltage standard which mainly focus about voltage compatibility.Need for research[edit]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 sourcesEconomic aspects of these technologies are sufficiently promising to include them in developing power generation capacity for developing countries.See also[edit] List of energy storage projects Solar Flower Tower Professional Hybrid Renewable Energy Systems discussions on LinkedInReferences[edit]1. Jump up ^ "Hybrid photovoltaic systems". Denis LenardicAdding 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.Wind hybrid power systemsFrom Wikipedia, the free encyclopediaJump to: navigation, search This article may require cleanup to meet Wikipedia's quality standards. No cleanup reason has been specified. Please help improve this article if you can. (June 2011)

Wind hybrid power systems combines wind turbines with other storage and/or generation sources. One of the key issues with wind energy is its intermittent nature. This has led to numerous methods of storing energy.Contents[hide] 1 Wind-hydro system 1.1 Advantages 1.2 Proposals 2 Wind-hydrogen system 3 Wind-diesel system 3.1 History 3.2 Technology 3.3 List of communities using wind-diesel systems 3.4 Wind-Diesel hybrid power systems at mining sites 4 Wind-compressed air systems 5 Wind-solar systems 5.1 Wind-solar building 5.2 Wind-solar lighting 6 References 7 External linksWind-hydro system[edit]A wind-hydro system generates electric energy combining wind turbines and pumped storage. The combination has been the subject of long-term discussion, and an experimental plant, which also tested wind turbines, was implemented by Nova Scotia Power at its Wreck Cove hydro electric power site in the late 1970s, but was decommissioned within ten years. Since, no other system has been implemented at a single location as of late 2010.[1]Wind-hydro stations dedicate all, or a significant portion, of their wind power resources to pumping water into pumped storage reservoirs. These reservoirs are an implementation of grid energy storage.Advantages[edit]Wind and its generation potential is inherently variable. However, when this energy source is used to pump water into reservoirs at an elevation (the principle behind pumped storage), the potential energy of the water is relatively stable and can be used to generate electrical power by releasing it into a hydropower plant when needed.[2] The combination has been described as particularly suited to islands that are not connected to larger grids.[1]Proposals[edit]During the 1980s, an installation was proposed in the Netherlands.[3] The IJsselmeer would be used as the reservoir, with wind turbines located on its dike.[4] Feasibility studies have been conducted for installations on the island of Ramea (Newfoundland and Labrador) and on the Lower Brule Indian Reservation (South Dakota).[5][6]An installation at Ikaria Island, Greece, had entered the construction phase as of 2010.[1]The island of El Hierro is where the first world's first wind-hydro power station is expected to be complete.[7] Current TV called this "a blueprint for a sustainable future on planet Earth". It is designed to cover between 80-100% of the island's power and is set to be operational in 2012.[8]Wind-hydrogen system[edit]

One method of storing wind energy is the production of hydrogen through the electrolysis of water. This hydrogen is subsequently used to generate electricity during periods when demand can not be matched by wind alone. The energy in the stored hydrogen can be converted into electrical power through fuel cell technology or a combustion engine linked to an electrical generator.Successfully storing hydrogen has many issues which need to be overcome, such as embrittlement of the materials used in the power system.This technology is being developed in many countries and has even seen a recent IPO of an Australian firm called Wind Hydrogen that looks to commercialise this technology in both Australia and the UK.[9] Essentially Wind Hydrogen offers a source of domestic and vehicular energy for rural communities where current energy transmission costs are prohibitive. Test sites include:CommunityCountryWind MW

Ramea, Newfoundland and Labrador[10]Newfoundland, Canada0.3

Prince Edward Island Wind-Hydrogen Village[11]PEI, Canada

Lolland[12]Denmark

Bismarck[13]North Dakota, US

Koluel Kaike[14]Santa Cruz, Argentina

Ladymoor Renewable Energy Project (LREP)[15]Scotland

Hunterston Hydrogen ProjectScotland

RES2H2[16]Greece0.50

Unst[17]Scotland0.03

Utsira[18]Norway0.60

Wind-diesel system[edit]

Wind Diesel system on Ramea in CanadaA wind-diesel hybrid power system combines diesel generators and wind turbines,[19] usually alongside ancillary equipment such as energy storage, power converters, and various control components, to generate electricity. They are designed to increase capacity and reduce the cost and environmental impact of electrical generation in remote communities and facilities that are not linked to a power grid.[19] Wind-diesel hybrid systems reduce reliance on diesel fuel, which creates pollution and is costly to transport.[19]History[edit]Wind-diesel generating systems have been under development and trialled in a number of locations during the latter part of the 20th century. A growing number of viable sites have been developed with increased reliability and minimized technical support costs in remote communities.Technology[edit]The successful integration of wind energy with diesel generating sets relies on complex controls to ensure correct sharing of intermittent wind energy and controllable diesel generation to meet the demand of the usually variable load.The common measure of performance for wind diesel systems is Wind Penetration which is the ratio between Wind Power and Total Power delivered, e.g. 60% wind penetration implies that 60% of the system power comes from the wind. Wind Penetration figures can be either peak or long term. Sites such as Mawson Station, Antarctica, as well as Coral Bay and Bremer Bay in Australia have peak wind penetrations of around 90%.Technical solutions to the varying wind output include controlling wind output using variable speed wind turbines (e.g. Enercon, Denham, Western Australia), controlling demand such as the heating load (e.g. Mawson), storing energy in a flywheel (e.g. Powercorp, Coral Bay).Some installations are now being converted to wind hydrogen systems such as on Ramea in Canada which by Clint OumaThe word hybrid is used to refer to something made by combining different elements [1]. Modern science has seen dramatic advances in hybrid technology, giving birth to hybrid cars such as the Toyota Prius [2] and incorporating information and communications technology (ICT) systems that automate smart-houses and eco homes. Similarly, hybrid energy systems have been designed to generate electricity from different sources, such solar panels and wind turbines.Hybrid energy systems often consist of a combination between fossil fuels and renewable energy sources, and are used in conjunction with energy storage equipment (batteries). This is often done either to reduce the cost of generating electricity from fossil fuels or to provide back up for a renewable energy system, ensuring continuity of power supply when the renewable energy source fluctuates. One of the biggest downfalls of renewable energy is that energy supply is not constant [3]; sources like solar and wind power fluctuate in intensity due to the weather and seasonal changes [3]. Therefore, a reliable backup system is necessary for renewable energy generating stations One of the primary needs for socio-economic development in any nation in the world is the provision of reliable electricity supply systems. This work is a development of an indigenous technology hybrid Solar -Wind Power system that harnesses the renewable energies in Sun and Wind to generate electricity. Here, electric DC energies produced from photovoltaic and wind turbine systems are transported to a DC disconnect energy Mix controller. The controller is bidirectional connected to a DC-AC float charging-inverter system that provides charging current to a heavy duty storage bank of Battery and at the same time produces inverted AC power to AC loads. The 2002-2009, 8years wind velocity data for Abeokuta and its environs were collected. The two parameters Wielbull distribution was used to simulate power in W/m2 densities for the 8-years period. The step by step design of 1000W solar power supply systems was done as a sample case. Load estimates of a typical rural community and for rural ICT infrastructures were estimated. Simulation of wind power capacity in W/m2 in Abeokuta, Ogun State Nigerian was done based on the obtained wind data. The results showed that the average exploitable wind power density between 4W/m2 and 14.97W/m2 is realizable and that development of hybrid wind-solar system for off- grid communities will go a long way to improve socio-economy lives of people. Keywords: Socio Economic development, Nigeria, Hybrid system, Solar and Wind Power, Rural Communities ICT infrastructure, Simulation 1. INTRODUCTION One of the primary needs for socio-economic development in any nation in the world is the provision of reliable electricity supply systems. In Nigeria, the low level of electricity generation in Nigeria from conventional fossil fuel, has been the major constraint to rapid socio-economic development especially in rural communities. Moreso, about sixty-five percent(65%) of 140million Nigeria populace are rural dwellers with majority of them living far-off grid areas [1]. These rural dwellers are mostly farmers whose socio-economic lives can only be improved when provisions are made to preserve their wasting agricultural products and provide energy for their household equipment such as refrigerator, fan, lighting etc. There is also such a need to provide electricity for e-information infrastructures in our rural communities to service school, rural hospital, rural banking and rural e-library. Hence, there is the need to develop an indigenous technology to harness the renewable energies in Sun and Wind to generate electricity. 1.1 Importance of Renewable energy The global search and the rise in the cost of conventional fossil fuel is making supply-demand of electricity product almost impossible especially in some remote areas. Generators which are often used as an alternative to conventional power supply systems are known to be run only during certain hours of the day, and the cost of fueling them is increasingly becoming difficult if they are to be used for commercial purposes. There is a growing awareness that renewable energy such as photovoltaic system and Wind power have an important role to play in order to save the situation. Figure 1 is the schematic layout of Solar-Wind Hybrid system that can supply either dc or ac energy or both. 2. SOLAR ENERGY Solar energy is energy from the Sun. It is renewable, inexhaustible and environmental pollution free. Nigeria, like most other countries is blessed with large amount of sunshine all the year with an average sun power of 490W/m2/day [2]. Solar charged battery systems provide power supply for complete 24hours a day irrespective of bad weather. Moreso, power failures or power fluctuations due to service part of repair as the case may be is non-existent. IJRRAS 9 (1) October 2011 Adejumobi & al. Hybrid Solar and Wind Power 131 2.1 Solar Systems There are two types of solar systems; those that convert solar energy to D.C power, and those that convert solar energy to heat. 2.2 Solar-generated Electricity Photovoltaic The Solar-generated electricity is called Photovoltaic (or PV). Photovoltaics are solar cells that convert sunlight to D.C electricity. These solar cells in PV module are made from semiconductor materials. When light energy strikes the cell, electrons are emitted. The electrical conductor attached to the positive and negative scales of the material allow the electrons to be captured in the form of a D.C current. The generated electricity can be used to power a load or can be stored in a battery. Photovoltaic Wind DC Diversion Load (for Wind Generator) Diversion Load Controller DC Disconnect DC Charge Controller Vent (Inlet) Vent (Outlet) Battery Temperature Sensor (BTS) Battery Bank Inverter/Charger AC Loads AC Distribution Panel To Primary System Ground AC Output Energy Mix (Controller) DC Control Box DC-AC DC Combiner Box Figure 1: Schematic diagram of Hybrid (Renewable) Solar Wind Power Source IJRRAS 9 (1) October 2011 Adejumobi & al. Hybrid Solar and Wind Power 132 Photovoltaic system is classified into two major types: the off-grid (stand alone) systems and inter-tied system. The off-grid (stand alone) system are mostly used where there is no utility grid service. It is very economical in providing electricity at remote locations especially rural banking, hospital and ICT in rural environments. PV systems generally can be much cheaper than installing power lines and step-down transformers especially to remote areas. Solar modules produce electricity devoid of pollution, without odour, combustion, noise and vibration. Hence, unwanted nuisance is completely eliminated. Also, unlike the other power supply systems which require professional training for installation expertise, there are no moving parts or special repairs that require such expertise [3]. 2.3 Basic Components of Solar Power The major components include P.V modules, battery and inverter. The most efficient way to determine the capacities of these components is to estimate the load to be supplied. The size of the battery bank required will depend on the storage required, the maximum discharge rate, and the minimum temperature at which the batteries will be used [4]. When designing a solar power system, all of these factors are to be taken into consideration when battery size is to be chosen. Lead-acid batteries are the most common in P.V systems because their initial cost is lower and also they are readily available nearly everywhere in the world. Deep cycle batteries are designed to be repeatedly discharged as much as 80 percent of their capacity and so they are a good choice for power systems. Figure 2 is a schematic diagram of a typical Photovoltaic System. Solar panel 80 - 380 controller DC AC Load Battery A / C Inverter Figure 2: Photovoltaic System 2.4 Photovoltaic (P.V) Solar Modules The photovoltaic cell is also referred to as photocell or solar cell. The common photocell is made of silicon, which is one of the most abundant elements on earth, being a primary constituent of sand. A Solar Module is made up of several solar cells designed in weather proof unit. The solar cell is a diode that allows incident light to be absorbed and consequently converted to electricity. The assembling of several modules will give rise to arrays of solar panels whose forms are electrically and physically connected together. To determine the size of PV modules, the required energy consumption must be estimated. Therefore, the PV module size in Wp is calculated as[5]: Daily energy Consumption (1) Isolation x efficiency Where Isolation is in KWh/m2/day and the energy consumption is in watts or kilowatts. IJRRAS 9 (1) October 2011 Adejumobi & al. Hybrid Solar and Wind Power 133 2.5 Batteries and Batteries Sizes of the Solar System As mentioned above, the batteries in use for solar systems are the storage batteries, otherwise deep cycle motive type. Various storage are available for use in photovoltaic power system, The batteries are meant to provide backups and when the radiance are low especially in the night hours and cloudy weather. The battery to be used: (a) must be able to withstand several charge and discharge cycle (b) must be low self-discharge rate (c) must be able to operate with the specified limits.

The battery capacities are dependent on several factors which includes age and temperature. Batteries are rated in Ampere-hour (Ah) and the sizing depends on the required energy consumption. If the average value of the battery is known, and the average energy consumption per hour is determined. The battery capacity is determined by the equations 2a and 2b[3] BC = 2*f*W/Vbatt (2a) Where BC Battery Capacity f Factor for reserve W Daily energy Vbatt System DC voltage The Ah rating of the battery is calculated as[3]: Daily energy that are not connected to a national power grid. These systems consist of a variety of power control methods and storage equipment which include battery banks and diesel generators among others. The power systems that are connected to the national grid dont have this problem because, in most cases, there are many different sources of power contributing to the national electricity supply. Different Hybrid Power Technologies

There are several types of hybrid energy systems such as wind-solar hybrid, solar-diesel, wind-hydro and wind-diesel. The design of a system or the choice of energy sources depends on several considerations. The factors affecting the choice of hybrid power technology can also tell us why people use hybrids and some of the advantages. The main factors are cost and resources available.The cost hybrid power technology greatly affects the choices people make, particularly in developing countries. This also depends on the aim of the project. People who are planning to set up a hybrid energy project for their own use often focus on lowering the total investment and operational costs while those planning to generate electricity for sale focus on the long-term project revenue. As such, systems that incorporate hydrogen storage and fuel cells [4] [5] are not very common with small scale projects. The viability of one hybrid energy system over another is usually pegged on the cost of generating each kilowatt.The availability of the natural resources plays an enormous part when selecting the components of a hybrid energy system the right power generation location and method must be chosen.Often, a hybrid system is opted for because the existing power resource is not enough to generate the amount of power needed which is often the case when using micro-hydro plants. In some developing countries, such as parts of Ethiopia, a wind-solar hybrid power system, consisting of wind turbines and solar photovoltaics was found to be most viable. This was because the wind resource alone was not sufficient to meet the electric load. Solar P.V. cells were very expensive, so it wasnt feasible for the project developers to use solar power alone [6]. Hybrid systems are most suitable for small grids and isolated or stand-alone systems as hybrid power generation is, by definition, a solution for getting around problems where one energy source isnt sufficient. The popularity of hybrid energy systems has grown so much that it is now a niche-industry in itself with custom systems being engineered for specific functions. For instance, Enercon, a German wind power company, has come up with unique factory-designed hybrid power technology, including the worlds first hybrid wind-diesel powered ship, the E-Ship 1 [7].