Way back in the 1800s, a French physicist named Edmund Henri Becquerel realized that some materials produced a small electric current simply by being exposed to the sun. His discovery of this photovoltaic effect provided the operating principle for the solar cell.

The most common solar cells are made of two different types of silicon layered together to encourage electron movement. The silicon is sandwiched between two outer conductive layers and covered by glass with an antireflective coating (light that bounces off a solar panel is wasted). When light hits these cells it catalyzes a specific movement of the electrons, which creates the flow or current that we call electricity.

For a visual, think of meandering cattle being herded into a cattle chute. The cows won't enter the chute on their own, but under the direction of the herder, the cows travel to their required destination. In a solar cell, sunlight is the herder of electrons.

Since a single solar cell can only produce one-half volt of electricity, these cells are wired in parallel to create a PV module, otherwise also known as a Solar panel.

Several solar PV modules can be connected to form a PV Array.

Solar panels absorb the sun's energy throughout the day and convert it into direct current (DC) electricity. Most homes and businesses run on alternating current (AC) electricity, so the DC electricity is then passed through an inverter to convert it to usable AC electricity. At that point, you either use the electricity in your house or send it back to the electric grid.

The amount of power your solar energy system can generate is dependent on sunlight. As a result, your solar panels will produce slightly less energy when the weather is cloudy, and no energy at night. However, because of high electricity costs and financial incentives, solar is a smart decision even if you live in a cloudy city.

Although there are no mechanical parts that can wear out, because of natural chemical breakdown, a solar panel can lose up to 1% of its efficiency each year. When it drops to 80% efficient, it's time to start thinking about getting a new panel. Using this data, it’s safe to say that most panels will last at least 20 years.

Dust, dirt, debris, and bird droppings can accumulate and cause your solar panels to be less efficient. The best way to clean the glass that covers your panels is with water from a garden hose. If that's not enough, fill a bucket with warm water and gentle soap – nothing harsh or abrasive. Use a soft cloth or sponge to gently wipe away grime, being careful not to mar the glass in any way.

The moon itself isn’t a source of light; it’s merely illuminated by the sun. Because of this, it produces no photons, the key element in catalyzing electric current in silicon. Without photons, solar panels will not work.

When you install solar panels on your property, you will still be connected to the grid. This allows you to draw from the grid when your system is not producing all of the power that you need, and send power back to the grid when you produce more than you use. It is possible to go off the grid with a solar energy system that includes battery storage, but it will cost significantly more and is unnecessary for the majority of homeowners.

Unless your solar energy system includes battery storage and you are fully off the grid, you will still receive a bill from your utility. However, you can dramatically reduce your bill, or even cut the amount you owe to Rs.0, with a solar panel system that matches your energy use.

Solar panel systems are made of durable tempered glass and require little to no maintenance for the 25 to 35 years that they will generate power. In most cases, you don’t even need to clean your solar panels regularly.

The technology of solar power is advancing rapidly. New materials, techniques, and processes are constantly being discovered and tested. Currently, however, there are only three broad categories under which we can place all solar panels: mono-crystalline, polycrystalline, and thin film.

Mono-crystalline

Mono-crystalline is "grown" from a single seed crystal that is dipped into molten silicon. The seed is drawn up and rotated, forming a tubular ingot. This ingot is shaved and sliced to make the familiar flat black wafers with rounded corners that you see on many solar panels.

Pros:

• Mono-crystalline panels perform well in warm weather (up to about 77°F)
• Made from the highest-grade silicon, these panels are the most efficient.
• These panels offer the highest output.
• These panels last the longest.

Cons:

• Because of the process and the waste, these panels are the costliest to produce.
• If a panel is only partially covered by debris or shade, the entire panel can cease to function. The efficiency of these panels decreases as the temperature climbs over 77°F (losing about 1% efficiency for every few degrees hotter).

Poly-crystalline

Poly-crystalline is created by dropping the seed crystal into molten silicon. The mixture is then poured into a square mold. These panels feature square-shaped silicon that has a more uneven or crystalline appearance on the surface.

Pros:

• Since the process for creating polycrystalline panels is less involved and creates less waste, this is a more affordable option.
• These panels are a more environmentally friendly choice.
• Many argue that the lower price makes these panels the better value.

Cons:

• Polycrystalline panels are not as efficient as mono-crystalline panels.
• These panels don’t last as long as mono-crystalline panels.
• You'll need more of these panels to accomplish the same task.

Thin film

Thin film panels are made by layering any of several different photovoltaic materials (amorphous silicon, cadmium telluride, copper indium gallium selenide, or organic photovoltaic cells) onto a substrate. Thin film panels are a rapidly emerging technology and not as readily available to the consumer as other types. It is a category to watch as technological advances continue.

Pros:

• These panels are flexible and lightweight.
• Thin film panels are adaptable to many different situations.
• Higher temperatures and shade have less impact on the performance of these panels.

Cons:

• Thin film panels are the least efficient of the three types.
• These panels require more room for the same power output as other types.
• Thin film panels are the most susceptible to the effects of weather.

Between monocrystalline and polycrystalline there isn’t a lot of difference except that a polycrystalline panel is slightly larger than the equivalent wattage in monocrystalline.

The answer is virtually anything! Solar modules can be used to power small devices, such as a handheld calculator or decorative outdoor lighting. Solar panels can make stop signs flash with attention-getting lights. They can power traffic signals and light up a traffic message board. You can use them to charge your USB devices and recharge larger batteries when camping. If you have enough voltage in your array, you can even power household appliances.

Some of the more popular uses for solar panels include powering phones, tablets, speakers, radios, mini fridges, and more. The technology has even been integrated with clothing so you can wear your power while hiking. If the conditions are optimum where you live, your entire home could be powered by the sun. And if you make more electricity than you use, you can sell it to your local power company.

Anything you can do with electricity, you can do with the right array of solar panels.

When you install a solar energy system on your property, you save money on your electricity bills and protect yourself against rising electricity rates in the future. How much you can save depends on the utility rates and solar policies in your area, but going solar is a smart investment regardless of where you live.

Solar power, like other renewable energy resources, has many environmental and health benefits. Going solar reduces greenhouse gas emissions, which contribute to climate change, and also results in fewer air pollutants like sulphur dioxide and particulate matter, which can cause health problems.

Net metering is the system that utilities use to credit solar energy system owners for the electricity produced by their solar panels. With net metering, you only pay for the electricity that you use beyond what your solar panels can generate. Net metering policies differ from state to state – so make sure to do your homework ahead of time.

The rooftop solar systems can vary from 1 kWp upto 500 kWp or in combination can be set up on the roofs.

About 10sq.m area is required to set up 1 kWp rooftop solar system.

1 kWp solar panels weigh about 80kgs and the Rooftop Solar System weight can increase upto 100kgs including Mounting structure and concrete installation.

• Electricity generation at the consumption center and hence Savings in transmission and distribution losses
• Low gestation time
• No requirement of additional land
• Improvement of tail-end grid voltages and reduction in system congestion with higher self-consumption of solar electricity
• Local employment generation

To ensure that the generation from your Solar PV system is maximized, the following should be kept in mind:

• Location (Solar Irradiation/ weather conditions)
• Plant layout
• Shading and roof orientation
• System design
• Equipment quality
• Operations and maintenance

To keep a regular check on your system performance, it is recommended that you install a data logger (data monitoring device) along with your Solar PV system. This device will allow you to compare the actual with the estimated performance on a daily, monthly and annual basis.

Yes. Additional solar panels can be added at any time to increase generating capability but you might have to upgrade to a larger inverter. Alternatively you could purchase a larger inverter when installing the system initially and then plan to add some extra solar panels later.

Using a comparison to a car, an average vehicle travelling 20 000 km per annum, emits about 3.3 tons of carbon dioxide. A 2kw grid connected system will prevent 3.3 tons of carbon dioxide being generated through coal fired power generation – so it’s the equivalent of taking a car off the road each year.

Part of going solar is altruistic. An early study conducted in the United States and Europe concluded that switching from fossil fuel to solar power could potentially cut air pollution by 90%. That's a remarkable number. But there's a second, more immediate and personal benefit to using solar panels. Free electricity anywhere there is sun! Solar panels are amazingly versatile. You can start small and affordable with a portable panel designed to charge your USB devices, or you can step up to something that brings convenience to camping, allowing you to charge batteries with nothing more than a clear day. Of course, you can make the big commitment and cover your roof in solar panels. Whatever you want to power, there's a way to get the job done with solar.

Yes, the Central Govt. gives 30% subsidy for PV On-grid systems for domestic consumers and certain special categories such as Trusts, Societies etc