. What will happen when the fossil fuel and other resources of power and electricity will end within few years? With the current world situation this question has the most logical base and why not the reserves of crude oil is over 1000 billion barrels that is available for usage and it is assumed that with the current utilization of 84.1 millions barrels a day, the world can run only another 32 (Thirty Two) years. After the stock report of fossil fuel; let’s check out where this fuel is utilizing: - the main consumption of fossil fuel is to produce the power and electricity. The second most usage is to run the vehicle and to run a smooth transportation system too. Other than these: mills, factories, heavy industrial instruments and equipments are run by the fuel. So, it is natural to come in mind what will happen after 32 years from now when we will finish off all the reserve of oil. Will we stop our power and electricity production? Will we stop the heavy industries? Will we stop the transportation and vehicle? Any one can guess that is not possible for us. World can’t pass a second with out power and energy nowadays. So, there is need to use of alternative and renewable energy resources to make substitute of the fossil fuel and the coal & natural gas. The sustainable renewable energy is getting popular as clean and green energy. Most of the countries are investing on this natural and renewable energy sector. There is no other way left for the human civilization ahead other than this. The next generation survival is depending on the perfection of proper utilization of invested capital in research of sustainable and renewable energy resources production and implementation system. USA president Mr. Barak Obama called for the country to reduce its oil import by one third by the year 2025. This is not that they are in short of budget for buying oil from other countries but they would like to secure its energy supply in the future. May be question will arise how? We can mention Mr. Obama’s speeches here,” When I was elected to this office, America imported 11(eleven) million barrels of oil a day. By little more than a decade from now we will cut that by one third”. Actually his emphasis on using of alternative of oil and fossil fuel; he said “The only way for American energy supply to be truly secure is by permanently reducing our dependence on oil. We are to have to find ways to boost our efficiency so we use less oil. We have got to discover and produce cleaner renewable sources of energy that also produce less carbon pollution”. He said that meeting this new goal of cutting US oil dependence depends largely on two things finding and producing more oil at home and reducing our dependence on oil with cleaner alternative fuels and greater efficiency. The USA president pointed on not to make a quick fix of the solution. Here we can mention another project that is completely hydro project and the location is in Himachal. This project is established by a consortium of TATA Power and Norwegian hydro power company. This project is build to produce 236 Mega Watt of electricity in Chenab Valle in Himachal Pradesh, India. In Srilanka rural electricity schemes has launched very recently. Several projects are going to establish by the government of Srilanka to achieve target of 100 percentages electricity needs of country’s rural sectors by 2012 set by Minister Patali Chapika Ranwake. The 4th project is for lighting Srilanka, Ranpura, Kague, Central province. The rural electricity project No.8 issued by the power and energy commission is the project under which new electricity connection had been provided for 720 houses in the Galle and Matara districts. There is a plan to another 516 electricity schemes of Rs. 85.7 million are in operation covering Elipitya, Nagoda, Karon, Deniya, Yakkalamulla,Beddegama and Thavalama divisions in the Gale district. While 203 electricity schemes will be started at the cost of Rs. 134.1 million of cover Kotapola, Pitabed, Passara, Dickweili and Akuresra DS divisions in Matara district. The International Energy Agency 794(IEA) is saying that the wide spread development of “Smart Grids” networks that monitors and manage the transport of electricity from all sources to meet the varying electricity demands of end users is crucial to achieving a more secure and sustainable future. Not only that the World Bank has taken an initiative to allocate the loan and subsidies in the sector of renewable energy nowadays. The IMF has prepared fund for set up the renewable energy plant, such as; the electricity production by the photo voltaic (PV) solar cell
I have tried to give some detail discussion and information in this article so that people can get a general idea about the solar panel that is used for generation of electricity. Basically the solar Photovoltaic (PV) or solar cells are PN junction Semiconductor devices. It converts sun light into direct current electricity. There are some types of solar cells or PV solar panels in market. Such as:
Mono Crystalline Solar cell
Poly Crystalline Solar Cell
Amorphous silicon solar cell
Flexible amorphous silicon
We can remember that one silicon solar cell produces 0.5V to 0.6V; these cells are combines together to get a module. Usually 33/36 cells are connected together to make one module. This connection are made keeping the fact in tact the cells are connected electrically in series and/or parallel circuits to produce higher voltages, currents and power levels. One module is capability to produce enough voltage to charge 12 volt batteries and run pumps and motors. The PV module is basic building block of a PV power system. Most of the time PV modules are combined in series parallel manner to make PV array of required power complete power-generating unit.
For two cells connected in series, the current through the two cells is equal. The sum of total voltage produced is the total of the individual cell voltages. As the current should same, a mismatch in current means that the total current from the configuration is equal to the lowest current.
Incase of parallel connected solar cell the voltage across the cell combination is always the same and the total current from the combination is the sum of the currents in the individual cells.
The performance of PV modules and arrays are generally rated according to their maximum DC power output (watts) under. Standard Test Conditions (STC).
Standard Test Conditions are defined by a module (cell) operating temperature of 25o C (77 F), and incident solar irradiance level of 1000 W/m2 and under Air Mass 1.5 spectral distribution. Since these conditions are not always typical of how PV modules and arrays operate in the field, actual performance is usually 85 to 90 percent of the STC rating.
Today’s photovoltaic modules are extremely safe and reliable products, with minimal failure rates and projected service lifetimes of 20 to 30 years.
With the above PV modules the solar systems and electricity generating solutions are developed.
These solutions can be different in category. Following is the category of solution those are possible to develop usually. They are:
1. Stand-alone PV systems
(a) Simple single module DC system (PV Home system)
(b) Large DC PV system
(c) PV system for DC and AC power
2. Hybrid PV systems:
(a) Hybrid-PV diesel
(i) Hybrid PV-Diesel system for DC and AC power
(ii) Hybrid PV-Diesel system for DC and AC with generator
for rectified DC
(c) Hybrid PV-Thermal systems
(d) Hybrid PV-Wind systems
3.Grid-connected PV power systems
(a) Self-commutated
(b) Line commutated
> Simple single module DC PV systems (PV Home systems) are used for low cost rural electrification. Usually a single module is connected to the load for sunny day use.
> Simple single module DC PV system (PV Home system) is connected to a single low cost battery through a simple charge controller as the regulator that is connected to a CFL. The regulator may have a relay that could tern off the light if the battery voltage became too low. The user would have to wait until the module charged the battery back to an acceptable intermediate voltage before they could turn on the light again.
> Large DC PV power system consists of large number of modules and large number of batteries to drive heavy DC loads. A large heavy duty controller having high current driving capability is required. Usually Loads are connected through the charge controller via DC circuit breaker distribution box.
> PV system for DC and AC power consists of large number of modules. Charge controller regulates the charging and discharging of the battery and the DC loads are supplied power through controller. Inverter generates AC power for the AC loads such as computers, fax machine, radio, TV, VCR and CD players.
Hybrid PV-Diesel system
(i) Hybrid PV-Diesel system for DC and AC power:
Instead of relying purely on PV system for power, a system can be designed with other generators available as well. A common choice is a diesel generator. This generator produces AC power for AC loads which can be passed directly on to AC loads through transfer switches. Generator power can also be used after (converting AC to DC) rectification to charge batteries or to supply required DC input to the inverter.
(ii) Hybrid PV-Diesel system for DC and AC with generator
for rectified DC
A hybrid system can be designed to have the generator act only as a battery charger. AC power is not used to run the AC loads. All AC loads are driven by the power generated by the inverter only. The generator is turned on when the battery voltage is very low or weather is bad. After rectification generator output is used to charge the battery.
The generator needs to operate only for few hours to recharge batteries.
Generator is operated at its full rated output for maximum output and
long life. When batteries are sufficiently recharged, the generator is turned off, and the finishing charge is supplied by the solar modules. If the bad weather continues, the generator is turned on again for a few days, and repeats the charging process. In this way the battery is kept fully charged having longer useful life.
(iii) Hybrid PV-Thermal systems
Hybrid PV-thermal systems, sometimes known as hybrid PV/T systems or PVT, are systems that convert solar radiation into electrical and thermal energy. These systems combine a photovoltaic cell, which converts electromagnetic radiation (photons) into electricity, with a solar thermal collector, which captures the remaining energy and removes waste heat from the PV module. Photovoltaic (PV) cells suffer from a drop in efficiency with the rise in temperature due to increased resistance. Such systems can be utilized to carry heat away from the PV cells thereby cooling the cells and thus improving their efficiency by lowering resistance.
Hybrid PV-Wind systems
There are some places where wind speeds are often low in periods when the sun resources are at their best. On the other hand, the wind is often stronger in seasons when there are less sun resources. That can make solar PV-wind hybrid solutions an alternative to consider. Even during the same day, in many regions worldwide or in some periods of the year, there are different and opposite wind and solar resource patterns. And those different patterns can make the hybrid systems the best option for electricity production.
Hybrid PV-Wind system is the combination of PV and wind turbine for the generation of electricity.
Grid-connected PV systems
DC power generated by PV is converted into AC and is supplied to the national grid. Energy storage is not necessary in this case. On sunny days, the solar generator provides power, e.g., for the electrical appliances in the house. Excess energy is supplied to the national grid. During the night and overcast days, the house draws its power from the grid. In this way, the electricity grid can be regarded as a large “storage unit”. In the case of a favorable rate-based tariff for PV electricity, as in force in some countries, it is more advantageous to feed all solar electricity into the grid.
Grid-connected PV systems can be subdivided into two kinds
Decentralized Grid-connected PV systems and
Centralized Grid-connected PV systems
Single phase less than or equal to 25kW
Three phase less than or equal to 300kW
Decentralized Grid-connected PV systems
Decentralized Grid-connected PV systems have mostly a small power range and are installed on the roof-top of buildings (roof-top or flat-roof installation) or integrated into building facades.
For example, in Germany around 80% of the more than 50,000 existing grid-connected PV systems are installed either on the roof-top of a building or integrated into a building façade. The benefit of the installation of a PV system into or onto a building is that no separate area for the solar generator is needed.
Central Grid-connected PV systems:
Central Grid-connected PV systems have an installed power up to MW range. With such central photovoltaic power stations it is possible to feed directly into the medium or high voltage grid. Mostly central photovoltaic power stations are set on unused land, but in some cases an installation on buildings, mostly on the flat roof of greater buildings, is also possible.
The main equipments in a solar home and commercial system connection set-ups are:
1. PV solar panels/module
2. Battery for storing the electricity
3. Charge controller for the battery indicator
4. Inverter for converting the DC current to AC out put usage equipment
5. Accessories as cable, switch board, switch, clip, array junction box for large system, main junction box, and steel frame structure to set-up the PV panels and some more as required to design and looking the solution in descent shape.
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