The ultimate source of much of the world's energy is the sun, which provides the earth with light, heat and radiation. While many technologies derive fuel from one form of solar energy or another, there are also technologies that directly transform the sun's energy into electricity.
The sun bathes the earth in a steady, enormous flow of radiant energy that far exceeds what the world requires for electricity fuel.
Since generating electricity directly from sunlight does not deplete any of the earth's natural resources and supplies the earth with energy continuously, solar energy is a renewable source of electricity generation. Solar energy is our earth's primary source of renewable energy.
There are two different approaches to generate electricity from the sun: photovoltaic (PV) and solar-thermal technologies.
* Initially developed for the space program over 30 years ago, PV, like a fuel cell, relies upon chemical reactions to generate electricity. PV cells are small, square shaped semiconductors manufactured in thin film layers from silicon and other conductive materials. When sunlight strikes the PV cell, chemical reactions release electrons, generating electric current. The small current from individual PV cells, which are installed in modules, can power individual homes and businesses or can be plugged into the bulk electricity grid.
* Solar-thermal technologies are, more or less, a traditional electricity generating technology. They use the sun's heat to create steam to drive an electric generator. Parabolic trough systems, like those operating in southern California, use reflectors to concentrate sunlight to heat oil which in turn creates steam to drive a standard turbine.
Two other solar-thermal technologies are nearing commercial status. Parabolic dish systems concentrate sunlight to heat gaseous hydrogen or helium or liquid sodium to create pressurized gas or steam to drive a turbine to generate electricity. Central receiver systems feature mirrors that reflect sunlight on to a large tower filled with fluid that when heated creates steam to drive a turbine.
What are the environmental impacts?
PV systems operate without producing air, water or solid wastes.
When constructed as grid-connected central station systems, they require significant land, which can impact existing ecosystems. Nevertheless, most PV installations come in the form of distributed systems that use little or no land since the panels are installed on buildings.
Manufacturing PV cells involves the generation of some hazardous materials. Nonetheless, appropriate handling of these small quantities of hazardous material reduces risks of exposure to humans and to the environment.
Like PV, solar-thermal technologies generate zero air emissions, though some emissions are created during the manufacture of both technologies. Water use for solar thermal plants is similar to amounts needed for a comparably sized coal or nuclear plants.
The biggest concern with solar technologies may be land use...
...since five acres of land are often needed for each megawatt of capacity. PV can eliminate the land use impacts by integrating the generators into building construction, eliminating the need for dedicating land use to PV generation.
Tuesday, July 6, 2010
How Do You Produce Electricity From Solar Energy
he answer to the question of how do you produce electricity from solar energy is fairly easy to understand once you have a slight knowledge of the subject.
Before you are able to produce electricity through solar energy, there needs to be some form of solar cell or panel.
The solar panels are made of a semi-conductive material, the most common material is silicon.
The semi-conductive material contains electrons which are quite happy just sitting there.
When photons (contained within the suns rays) hit the solar cells, the electrons absorb this solar energy, transforming them into conduction electrons.
If the energy of these photons is great enough, then the electrons are able to become free, and carry an electric charge through a circuit to the destination.
Any electrons that do not receive enough energy simply warm up, which heats your cell or panel, resulting in lowering the efficiency of the cell.
The lowering in efficiency is down to two main factors and they are; that the cell is not working to its full potential (e.g. some electrons may be lost), the second factor is when the electrons release heat, the panel also becomes warm, interfering with other aspects of the solar cells.
The more solar cells contained in a solar panel, or solar array, means the more output you will receive.
Quality cells are also a major factor in efficiency. If you purchase more expensive natural energy technologies, you are more likely to have a more efficient cell.
Another factor which affects solar panel efficiency is location. Obviously nearer the equator, you will receive a slightly better output with a given cell, but solar cells should always be facing the direction of the sun, and have no objects blocking the suns rays.
So there we have a basic understand of how you produce solar electricity from using energy within the suns rays.
Sunday, June 6, 2010
Power Shortage
Expressing concern over load shedding in the twin cities, President Islamabad Chamber of Commerce and Industry (ICCI) Nasir Khan has said that solar energy is one of the solutions of power shortage, as sun is abundantly available without any cost. Addressing to the business community, he said that prolonged load shedding is affecting the business activities of industrialist and small traders badly. He regretted that during the moon soon rains IESCO still could not overcome problems of load shedding in the federal capital. He said the continuous power shortage is creating hurdles in the current pace of economic growth of the country. The growing gap between demand and supply of power and interrupted supply of power to industrial sector is retarding the country exports, he added.
While giving a presentation on importance of solar and wind energy, Nasir Khan, Erector of Solar and Winter Wind Plants said that solar energy is one of the solutions of power shortage, as sun is abundantly available without any cost. Solar energy systems can also work in overcast situations, he stated. But solar energy products, he said is out of reach of most of the population’s purchasing power. To solve this problem, a number of companies have manufactured low cost and affordable solar energy products.
He said that Pakistan lies in the region of trade winds, which give it a competitive edge to utilize this priceless resource to overcome the problem of energy shortage. In this respect Mr. Nasir Khan identified a few areas of Karachi and Gwader near Hawkes Bay and National Highway for installing both solar and wind energy plants to produce electricity.-SANA
While giving a presentation on importance of solar and wind energy, Nasir Khan, Erector of Solar and Winter Wind Plants said that solar energy is one of the solutions of power shortage, as sun is abundantly available without any cost. Solar energy systems can also work in overcast situations, he stated. But solar energy products, he said is out of reach of most of the population’s purchasing power. To solve this problem, a number of companies have manufactured low cost and affordable solar energy products.
He said that Pakistan lies in the region of trade winds, which give it a competitive edge to utilize this priceless resource to overcome the problem of energy shortage. In this respect Mr. Nasir Khan identified a few areas of Karachi and Gwader near Hawkes Bay and National Highway for installing both solar and wind energy plants to produce electricity.-SANA
Solar Investment
A “typical home” in America can use either electricity or gas to provide heat — heat for the house, the hot water, the clothes dryer and the stove/oven. If you were to power a house with solar electricity, you would certainly use gas appliances because solar electricity is so expensive. This means that what you would be powering with solar electricity are things like the refrigerator, the lights, the computer, the TV, stereo equipment, motors in things like furnace fans and the washer, etc. Let’s say that all of those things average out to 600 watts on average. Over the course of 24 hours, you need 600 watts * 24 hours = 14,400 watt-hours per day.
From our calculations and assumptions above, we know that a solar panel can generate 70 milliwatts per square inch * 5 hours = 350 milliwatt hours per day. Therefore you need about 41,000 square inches of solar panel for the house. That’s a solar panel that measures about 285 square feet (about 26 square meters). That would cost around $16,000 right now. Then, because the sun only shines part of the time, you would need to purchase a battery bank, an inverter, etc., and that often doubles the cost of the installation.
If you want to have a small room air conditioner in your bedroom, double everything.
I’ve been monitoring the usage of my house, and we consume about 10 Kilowatts per day (STEEP!!!). Now, in order to have solar panels for that, i would need a number of panels, from this site, i picked one at random, which produces 170 watts for an investment of $839 per panel. A quick calculation (from the data provided on the site), tells me i need atleast 6 of these panels to power my house meaning an investment of $5034 (or Rs. 3,02,040) without addding any sort of tax or extra charges on the modules and i need a space of about 30×15 feet to house it. (again from data provided for this module).
Now the KESC rate for domestic supply is about 7.5 per kilowatt (at their lowest slab), meaning that my monthly electricity bill becomes 2250 (without the charges, surcharges, and extra surcharges :S).
So, just on these ideal figures (just the power usage, no infrastructure costs), it would take me about 135 months or about 11 years just to breakeven the cost of the cells.
I think we should wait another decade or something, or encourage NEDians and other engineering universities to come up with solutions.. and let the prices fall down a bit. Its expected that the price will fall down to about 1/5 of what it costs now over the next decade.. which just may make this a viable option.
From our calculations and assumptions above, we know that a solar panel can generate 70 milliwatts per square inch * 5 hours = 350 milliwatt hours per day. Therefore you need about 41,000 square inches of solar panel for the house. That’s a solar panel that measures about 285 square feet (about 26 square meters). That would cost around $16,000 right now. Then, because the sun only shines part of the time, you would need to purchase a battery bank, an inverter, etc., and that often doubles the cost of the installation.
If you want to have a small room air conditioner in your bedroom, double everything.
I’ve been monitoring the usage of my house, and we consume about 10 Kilowatts per day (STEEP!!!). Now, in order to have solar panels for that, i would need a number of panels, from this site, i picked one at random, which produces 170 watts for an investment of $839 per panel. A quick calculation (from the data provided on the site), tells me i need atleast 6 of these panels to power my house meaning an investment of $5034 (or Rs. 3,02,040) without addding any sort of tax or extra charges on the modules and i need a space of about 30×15 feet to house it. (again from data provided for this module).
Now the KESC rate for domestic supply is about 7.5 per kilowatt (at their lowest slab), meaning that my monthly electricity bill becomes 2250 (without the charges, surcharges, and extra surcharges :S).
So, just on these ideal figures (just the power usage, no infrastructure costs), it would take me about 135 months or about 11 years just to breakeven the cost of the cells.
I think we should wait another decade or something, or encourage NEDians and other engineering universities to come up with solutions.. and let the prices fall down a bit. Its expected that the price will fall down to about 1/5 of what it costs now over the next decade.. which just may make this a viable option.
Solar energy
Solar energy is the most readily available source of energy. It does not belong to anybody and is, therefore, free. It is also the most important of the non-conventional sources of energy because it is non-polluting and, therefore, helps in lessening the greenhouse effect.
Solar energy has been used since prehistoric times, but in a most primitive manner. Before 1970, some research and development was carried out in a few countries to exploit solar energy more efficiently, but most of this work remained mainly academic. After the dramatic rise in oil prices in the 1970s, several countries began to formulate extensive research and development programmes to exploit solar energy.
When we hang out our clothes to dry in the sun, we use the energy of the sun. In the same way, solar panels absorb the energy of the sun to provide heat for cooking and for heating water. Such systems are available in the market and are being used in homes and factories.
In the next few years it is expected that millions of households in the world will be using solar energy as the trends in USA and Japan show. In India too, the Indian Renewable Energy Development Agency and the Ministry of Non-Conventional Energy Sources are formulating a programme to have solar energy in more than a million households in the next few years. However, the people’s initiative is essential if the programme is to be successful.
India is one of the few countries with long days and plenty of sunshine, especially in the Thar desert region. This zone, having abundant solar energy available, is suitable for harnessing solar energy for a number of applications. In areas with similar intensity of solar radiation, solar energy could be easily harnessed. Solar thermal energy is being used in India for heating water for both industrial and domestic purposes. A 140 MW integrated solar power plant is to be set up in Jodhpur but the initial expense incurred is still very high.
Solar energy can also be used to meet our electricity requirements. Through Solar Photovoltaic (SPV) cells, solar radiation gets converted into DC electricity directly. This electricity can either be used as it is or can be stored in the battery. This stored electrical energy then can be used at night. SPV can be used for a number of applications such as:
a. domestic lighting
b. street lighting
c. village electrification
d. water pumping
e. desalination of salty water
f. powering of remote telecommunication repeater stations and
g. railway signals.
Solar energy has been used since prehistoric times, but in a most primitive manner. Before 1970, some research and development was carried out in a few countries to exploit solar energy more efficiently, but most of this work remained mainly academic. After the dramatic rise in oil prices in the 1970s, several countries began to formulate extensive research and development programmes to exploit solar energy.
When we hang out our clothes to dry in the sun, we use the energy of the sun. In the same way, solar panels absorb the energy of the sun to provide heat for cooking and for heating water. Such systems are available in the market and are being used in homes and factories.
In the next few years it is expected that millions of households in the world will be using solar energy as the trends in USA and Japan show. In India too, the Indian Renewable Energy Development Agency and the Ministry of Non-Conventional Energy Sources are formulating a programme to have solar energy in more than a million households in the next few years. However, the people’s initiative is essential if the programme is to be successful.
India is one of the few countries with long days and plenty of sunshine, especially in the Thar desert region. This zone, having abundant solar energy available, is suitable for harnessing solar energy for a number of applications. In areas with similar intensity of solar radiation, solar energy could be easily harnessed. Solar thermal energy is being used in India for heating water for both industrial and domestic purposes. A 140 MW integrated solar power plant is to be set up in Jodhpur but the initial expense incurred is still very high.
Solar energy can also be used to meet our electricity requirements. Through Solar Photovoltaic (SPV) cells, solar radiation gets converted into DC electricity directly. This electricity can either be used as it is or can be stored in the battery. This stored electrical energy then can be used at night. SPV can be used for a number of applications such as:
a. domestic lighting
b. street lighting
c. village electrification
d. water pumping
e. desalination of salty water
f. powering of remote telecommunication repeater stations and
g. railway signals.
Energy changes from one Form to Another
Solar Energy is the energy from the Sun. The Sun is a big ball of heat and light resulting from nuclear fusion at its core. The nuclear reaction releases energy that travels outward to the surface of the Sun. Along the way to the surface the energy transforms so that by the time it is released it is primarily light energy. Sunlight. The two major types of solar energy that make it to Earth are heat and light.
Solar energy is often called "alternative energy" to fossil fuel energy sources such as oil and coal.
One example of our use of solar heat energy is for water heating systems. A solar panel is used to collect heat. The heat is transferred to pipes inside the solar panel and water is heated as it passes through the pipes. The hot water, heated by the Sun, can then be used for showers, cleaning, or heating your home.
We also use solar thermal energy through passive solar designs. Windows or skylights in your home can be designed to face the Sun so that they let heat into the house, keeping you warmer in the winter.
The light energy from the Sun can be transformed into electrical energy and used immediately or stored in batteries. Photovoltaic (PV) panels are the devices that convert light energy into electrical energy.
Let's look at a solar powered vehicle that runs on electricity directly from solar energy as a simple example in the transformation of energy from one form to another.
Sunlight hits the PV panel and the panel transforms the light energy into electrical energy.
The electrical energy (electricity) passes through the wire circuit to the motor.
The motor transforms the electrical energy into mechanical energy to turn the drive shaft which turns the wheels.
The wheels rotate on the ground to move the vehicle transforming mechanical energy into vehicle motion (kinetic energy).
Solar Vehicle Ideal Energy Chain:
Light Energy >> Electrical Energy >> Mechanical Energy >> Kinetic Energy
Solar energy is often called "alternative energy" to fossil fuel energy sources such as oil and coal.
One example of our use of solar heat energy is for water heating systems. A solar panel is used to collect heat. The heat is transferred to pipes inside the solar panel and water is heated as it passes through the pipes. The hot water, heated by the Sun, can then be used for showers, cleaning, or heating your home.
We also use solar thermal energy through passive solar designs. Windows or skylights in your home can be designed to face the Sun so that they let heat into the house, keeping you warmer in the winter.
The light energy from the Sun can be transformed into electrical energy and used immediately or stored in batteries. Photovoltaic (PV) panels are the devices that convert light energy into electrical energy.
Let's look at a solar powered vehicle that runs on electricity directly from solar energy as a simple example in the transformation of energy from one form to another.
Sunlight hits the PV panel and the panel transforms the light energy into electrical energy.
The electrical energy (electricity) passes through the wire circuit to the motor.
The motor transforms the electrical energy into mechanical energy to turn the drive shaft which turns the wheels.
The wheels rotate on the ground to move the vehicle transforming mechanical energy into vehicle motion (kinetic energy).
Solar Vehicle Ideal Energy Chain:
Light Energy >> Electrical Energy >> Mechanical Energy >> Kinetic Energy
Solar Energy, Power, Electricity
Basic about Solar Energy, Solar Power and Solar Electricity.
In basic about solar energy, solar power and solar eletricity we will talk about the basic things behind this power. Formulas that will be used to find out which Solar Panel you should use and which battery you should select. And how much Solar Panels do you need to power up lights and other applications. Here are the main things you need to know and that will be used to calculate your needs. AC-DC system, Volt, Current(Ampere), Power(Watt), Resistance, Series and Parallel connecting.
AC-DC system
Ac stands for Alternative Current. Alternative current is almost that we found in wall outlet or electric outlet. Clever say'd that we found in wall. It is 230 Volt. DC stands for Direct Current. In solar panels it is used 12 volt dc system. DC is that current we can found in cells, batteries, and using adapters or regulators. See the picture of a dell charger. Dell charger also converts AC Current to DC 5.4 Volt and 2410mA. Solar Panels also uses DC voltage and Current.
Volt
Voltage is the electromotive force (pressure) applied to an electrical circuit measured in volts (E).
Example. P=200W, I=4.0A. If we have a value of watt and ampere and we want to find out how much volt does it use then we should use this from Power Circle. E=P/I. 200/4.0=50V. So we found voltage is 50V.
Current
Current is the flow of electrons in an electrical circuit measured in amperes (I).
Example. P=100W, E=12V. We want to find out how much ampere does it use. We take a look at circle. I=P/E. 100/12=8.33A. Current usage is 8.33A.
Power
Power is the product of the voltage times the current in an electrical circuit measured in watts (P).
Example. E=220V, I=0,4A. This example is taken from picture of Dell Charger. We have 400mA=0,4A. Take a look at circle P=E*I. 220V * 0,4A=88W. Answer is dell charger use 88Watt.
Resistance
Resistance is the opposition to the flow of electrons in an electrical circuit measured in ohms (R). Increased resistance gives higher voltage and higher power(watt).
Example. E=12V, I=3.0A. We want to find out resistance. We use formula R=E/I. 12V/3.0A = 4 Ohm.
Parallel Connecting - 12V System
Parallel Connecting solar panels gives higher current. And voltage will remain the same. Parallel Connecting is best for us. Because we do not need high voltage. Normal battery is 12v. And by selecting high voltage require higher voltage charge controller. To connect solar panels in parallel we have to connect plus + to plus and minus - to minus.
Series Connecting - 24V System
By connecting Solar Panels in series connection. It will increase Voltage and current Amps. will remain the same. To connect solar panels in series we have to connect plus + to - minus on next panel. See the picture for details. In this example we have connected 2 solar panels in series which will give 24v output.
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