Solar photovoltaic energy converting sun light into electrical energy. The most commonly associated component are the photovoltaic panels or solar panels that you see mounted on roofs.

This article will be focusing on how photovoltaic solar power (solar panels) and systems work.

Why are solar photovoltaic panels always on the south (or north) side of the roof?
In order to get the maximum electrical output from photovoltaic panels they need to be oriented to solar south in the northern hemisphere and solar north in the southern hemisphere. Solar north and solar south are the same as magnetic or compass north or south. There is about a fifteen degree difference between them.

Most solar photovoltaic panels are set at home latitude plus fifteen degrees or home latitude minus fifteen degrees. Depending on if you want a summer or winter bias to the angle of the solar panels. In higher latitudinal areas it makes more sense to have the photovoltaic panels set on a winter bias, so that during the winter the solar panels still get enough sun light to produce electricity.

How does a photovoltaic cell produce electricity?
A solar panel consists of a collection of photovoltaic cells. Each photovoltaic cell is made up of silicon wafer. Silicon in its pure state is a poor electrical conductor. During the manufacturing process, an impurity is added to the silicon so that when the photons (light) strikes the wafer electrons are released and create electrical current.

The type of electrical current produced by a solar panel is a low voltage direct current, or DC, typically in the range of six to twenty four volts. Photovoltaic panels have a nominal output voltage of 12 volts and an effective operating voltage of 17 or more volts.

A solar panel’s electrical output is affected by several factors. They are angle of the photovoltaic panels to the sun, time of day, time of the year and weather conditions. Solar photovoltaic panels produce more electricity during the middle of the day when the sun is directly overhead compared to the early morning and late evening when the sun light is striking the solar panel at a shallow angle.

Components of a residential solar power system
A residential solar power system consists of four components are: photovoltaic panels, charging controller, battery pack and an inverter. The photovoltaic panels convert sun light into electricity. The electricity is sent to the charging controller who keeps the battery pack fully charged, but not over charged. The battery pack sends the electricity to the inverter who converts the DC voltage to household AC at 120 volts and 60 hertz.

Photovoltaic panel
The output of a solar panel is stated in watts. The wattage is stated is typically for peak sun hours. Since the amount of sun light varies through the course of a day, to level out the variations the peak sun hours has been adopted by most manufactures to help installers and customer’s compare different solar panel models.

Suppose a solar panel is rated for 100 watts and an average of six peak sun hours is available per day. Then the solar panel would produce 100 watts * 6 peak hours = 600 watt hours of electricity or 0.6 kilo watt hours (KWh).

Charging controller
Charging controller or charge regulator controls the charging of the battery pack. It continually monitors the battery pack’s charge state. If the batteries are low, it will send electricity from the solar panels to the batteries. It also prevents over charging of the battery pack.

Don’t allow someone to convince you that a charging controller is not really required. Directly connecting the photovoltaic panels to the battery pack can permanently damage the batteries and possibly cause them to explode.

Battery pack
The battery pack’s purpose is to store electricity generated by the solar panels during the day and then at night or during extremely cloudy days provide electricity to the inverter.

The battery pack typically consists of lead acid batteries. Lead acid batteries are relatively inexpensive and readily available. There are many different types, sizes and capacities of batteries available. The most popular are gel cell and AGM deep cycle batteries because they are maintenance free and last a lot longer than wet cell lead acid batteries.

The most important thing to remember about the batteries is that the need to be deep cycle. Deep cycle batteries are designed to be discharged then recharged hundreds if not thousands of times. A deep cycle battery is designed to discharged to nearly empty, but not completely and then be slowly recharged over time. A common mistake for home owners is to think that they can use automotive batteries instead of deep cycle batteries. Car batteries are shallow cycle batteries. They are designed to discharge a lot of current quickly and then be immediately recharged.

Inverter
An inverter converts the DC electricity stored in the battery pack into household 120V AC. Almost everything in your home is powered by 120V electricity. Things like table lamps, freezer, lights, motors, dishwasher, and so on.

There are two main types of inverters sine wave and modified sine wave. The power company provides electricity as a sine wave. The electricity’s charge value goes smoothly from positive 120V to 0V to negative 120V and then back up to 0V and finally up to positive 120V. Then the cycle begins all over again. The time it takes to go through the entire cycle is one second.

Modified sine wave is also known as a square wave. Here the electricity’s charge value goes from positive 120V to negative -120 volts in effectively zero seconds.

Most household devices will function on a modified sine wave power. Light bulbs and motors will work, just not quite as efficiently as they would on sine wave electricity. However, there are some electronic devices that will not work on square wave electricity. It will be necessary to check with the manufacture to determine if the device will work on square wave electricity.

Now you have a basic understanding of solar power how it works to power your home. Now you have enough information about how solar power works to determine if it is a technology that you would want to invest in for your house.

The Original Post is Located Here: Solar Power How It Works To Power Your Home

Six Easy Steps To Estimate Cost of a Solar Power System
Solar power energy systems are not inexpensive. That said it’s important to compare them within context of other types of home improvement projects. Home buyers and realtors view a solar photovoltaic or solar hot water heating system as a significant value-added improvement – similar to adding a deck or remodeling your kitchen. Plus unlike a deck or kitchen remodel, you also gain one-up on your power bills.

Solar power systems often get an additional financial boost as well: many jurisdictions and utilities across the USA offer attractive financial incentives to drive down the upfront capital costs associated with a solar power system.

Here are some foolproof ways to estimate the cost of a solar photovoltaic or solar thermal system and to figure out if a solar energy system makes sense for you. Let’s start with a home photovoltaic (PV) system.

Step 1: Estimate your home’s electricity needs
To get started, it’s good to have a sense of how much electricity you use. You’ll have a better point for comparison if you find out how many kilowatt hours (kWh) you use per day, per month, per year. Your utility bill should include that information.

Of course, the utility bill will also display your costs and many utilities include a graph that displays how your monthly energy use/cost varies throughout the year. That helps you estimate where your highest energy use is and at what time of year.

New Home Construction
If you are constructing a new home, then you’ll need to estimate your demand based on the type of equipment you plan to install and your home’s square footage. The pross call this “your load”.

To figure out your anticipated load, create a table to record the watt use for each appliance. Each appliance – be it a water heater, electric light, computer, or refrigerator – should have a nameplate that lists its power rating in watts. Or you can get the information from the manufacturer’s website.

Some labels list amperage and voltage only; to obtain watts multiply the two together (amperage x voltage = watts). In another column, record the number of hours each appliance is expected to operate. Then multiple the watts and hours together to estimate watt-hours used per day. Since it’s hard to anticipate all electric loads (it may get tedious scouting out every toothbrush and mobile phone cell charger), you might want to add a multiplier of 1.5 to be safe.

Step 2: Anticipate the future
In 2005, average residential electricity rates across the USA ranged from about 6 to nearly 16 cents per kilowatt hour depending on where you lived. Average retail and commercial electricity rates have increased roughly 30% since 1999 and the upward trend will likely continue especially as costs for the coal and hydropower used to generate that electricity rise as well. So think about your home electricity needs and present and future cost in relation to one another.

Step 3: How much sun do you get?
The Florida Solar Energy Center has conducted a study to examine how a 2-kW photovoltaic system would perform if installed on a highly energy efficient home across the continental USA (http://www.fsec.ucf.edu/en/publications/html/FSEC-PF-380-04/).

The study accounted for all factors that impact a PV system’s performance such as the temperature effect on the photovoltaic cells, the amount of sun peak hours in various regions, and the efficiency of inverter to convert solar derived energy from DC to AC.

As the study implies, solar photovoltaic systems work just about anywhere in the US. Even in the Northeast or in “rainy Seattle”, a pv system can pencil out if designed and installed properly. In New York or New Jersey, a one kilowatt system should produce about 1270 kilowatt hours of electricity per year, in Seattle, a one kilowatt system should produce about 1200 kilowatt hours per year. In the Southwest, of course, those ratios will be much greater.

Solar contractors in your area can help determine the best size for your solar photovoltaic system.

Step 4: Size your system
In general, solar photovoltaic systems sized between 1 to 5 kilowatts are usually sufficient to meet the electricity needs of most homes. One advantage of grid-tied systems is that you can use solar PV to supplement or offset some of your electricity needs; therefore you can size your system to match your budget and always add to the system later if needed.

Also as a side note, here’s a rule of thumb to remember to help you estimate the physical space your PV system might need: one square foot yields 10 watts. So in bright sunlight, a square foot of a conventional photovoltaic panel will produce 10 watts of power. A 1000 watt system, for example, may need 100 – 200 square feet of area, depending on the type of PV module used.

Step 5: Know your rebates
Many states and local jurisdictions offer rebates, tax credits and other types of incentives to homeowners for installing residential photovoltaic and solar domestic water systems. To view a comprehensive database of the incentives available for renewable energy visit http://www.dsireusa.org.

At the Federal Level, you can take advantage of a 30% tax credit (of up to $2,000) for the purchase of a residential solar system at least until December 31, 2008.

The Original Post is Located Here: Six Easy Steps to Estimate Cost of a Solar Power System

Prime Minister Kevin Rudd said the photovoltaic plant would cost A$1.4 billion (US$1 billion) and will have an output of 1,000MW – equivalent to that of one coal-fired power station. He said he wanted Australia to be a ‘solar leader’ rather than a ‘solar follower’.

The solar farm will consist of up to four individual plants – two based on solar thermal technology, and two on photovoltaic cells. Eventually, said Rudd, it could lead to a network of solar power stations across the country.

Tender specifications are expected to be drawn up within the next six months, and successful bidders chosen in the first half of next year. The plan is to have the installation finished by 2015.

Rudd also announced that Australia had joined 80 other countries in the the International Renewable Energy Agency. Established in January, this aims to speed up the global renewable industry.

But it’s a tricky line for the government to tread, as the country currently uses coal for over 80 per cent of its domestic energy generation, and is the world’s largest coal exporter.

By Emma Woollacott

The Original Post is Located Here: Australia plans world’s largest solar power plant

Solar Energy Collectors

Harnessing the power of the sun’s ray to create energy to power our house is very appealing. But the question is, “Is everything about solar energy good?”

Looking at the current price of fossil fuel-based electricity, it is quite impractical to convert into solar energy system. However, with the growing concern on the state of the earth, there is really a need to find other means of energy aside from what power plants are using right now. Where do you place yourself?

Whether you are an advocate of clean energy or simply care about where your finances go, looking at the pros and cons of residential solar energy system will help you decide on whether to convert or not.

Advantages
Solar energy is free. Did you know that the earth absorbs 174 pettawatts of solar radiation? This means that we have more than enough source of free energy to power every house in the world. Unfortunately, most of our energy is still drawn from oil, gas and coal. But in recent years, there is a steady increase of demand for alternative and renewable energy like solar power. It is estimated that the demand for alternative sources of energy will increase by 53% between 1999 and 2020.

Solar energy is clean, renewable and sustainable. Because the energy created from the sun’s rays does not produce byproducts like those from fossil fuel power plants (sulfur dioxide, nitrogen oxide, mercury or carbon dioxide), it does not contribute to pollution. Accordingly, the increase in the use of solar energy and other alternative forms of energy will decrease the demand for greenhouse gases-producing power plants.

The price of photovoltaic cells is steadily decreasing. The demand for solar panels has risen by 57% in the United States in 2007 and is steadily increasing on a monthly basis. The increase in demand results to the improvement of solar technology as a whole. The prices of photovoltaic cells have declined on the average of 4% every year over the past 15 years.

Solar panels can be installed on most rooftops, eliminating the problem of finding a suitable place for installation. Solar panels require little or no maintenance. The original photovoltaic cells technology is used for most satellites orbiting our earth today which are not maintained at all. Many solar panel manufacturers give 25 to 40 years warranty on their products.

Because most areas of the country receive a substantial amount of sunlight throughout the year, solar panels can be installed anywhere.

Many states in the country give tax credits and rebates to households who want to install solar energy system. Check with your state government the cost of these incentives.

Disadvantages
While the prices of PV cells are in constant decline, the cost of installation is substantially high compared to the current electric cost. But the good thing is, after your initial cash out, you don’t have to pay every month on electric bills for the rest of your life.

On areas cities and areas with heavy pollution problem, solar energy may not work as fine. Weather can also affect the efficiency of solar energy. If it is raining, overcast weather or if there is a hurricane, the solar panels’ efficiency is decreased.

You are only producing energy during day time.

These are general pros and cons you might encounter when considering the conversion to solar energy system. It would be best if your decision is based on location, cost, budget, rebates, tax credits and practicality.
[relatedposts]

The Original Post is Located Here: Solar Energy – The Advantages and Disadvantages