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
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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
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(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].