Solar Power : An Insight into the Technical FAQs

Solar Power FAQs

Will rooftop solar plant damage my roof?

Properly installed panels should not cause any damage to your roof. In fact, they add to the aesthetics of the roof. They also tend to protect the roofing materials they cover by shielding them from precipitation, light, and heat. Loom Solar does not drill into your rooftop for installing panels. For RCC roofs, concrete blocks are set up on the rooftop, and panels are mounted on these blocks. Hence, no drilling is required on the roof. For metallic roofs, rails are set up on the roof before the installation of solar power panels. For simple rooftop solar power solutions, please get in touch with us.

Is it worth installing solar panels in my house in India to power all my electrical equipment and completely cutting off power coming from the grid, keeping in mind the initial investment and long-term savings?

Installing a rooftop solar PV system is any day a wise choice. It will help you to reduce your monthly electricity bill. But going completely off power from the grid might not be the best thing to do.

Why? If you are completely cut-off from the grid, then you will be needing batteries for storing the light energy that is converted into electricity. This energy then shall be re-converted for use and it is here that efficiencies of conversion come into play. Also, batteries increase the cost as they need to be replaced every 4-5 years and require maintenance.

A grid-tied solution with net- metering is perhaps a better choice. You can enjoy all electricity generated by the panel during day time and during the night time; you can take power from the grid.

The math, therefore, is simple. A system with storage or an off-grid system requires a higher outlay of money owing to the batteries. For complete autonomy an even higher one!

Whereas, with a Grid-tied or an On-grid system you have a choice of power sources your own Solar Power Generation System or the Grid. If you consume more than you generate, you pay for the excess units. On the other hand, if you generate more than you "consume" then you get paid for the excess units.

What is the cost of installing an on-grid 5kw solar rooftop power generation system?

An On-grid solar power generation system with 5 kW capacity would typically cost between Rs. 70/watt to Rs. 80/watt depending on the brands you choose, the balance of system inclusions, and the quality of workmanship.

Let's say you consume 1,000 units monthly and your 5 kW system generates about 650 units per month, then your bill will be 350 units only.

The Return on Investment is in around 4.5 years. Then you earn a minimum of 20 years.

My electricity bill is huge, can I do something about it?

Choose an On-Grid solar power system. These systems are designed to work in conjunction with the grid or simply put your electricity supply. The electricity you generate using this system is fed back to the grid. A net meter is installed along with this system to keep track of the electricity consumed by you versus what you generated and fed back to the grid resulting in savings which get reflected in the bill. But keep in mind that it does not work when the grid is down, so if power back up is your objective, go for an off-grid solar solution.

I have a power cut issue, which type of solar solution should I go for?

Go for Off-grid solar power systems. These systems store the electricity produced by conversion in batteries and utilize the stored energy by converting it back to AC so that you can keep running your appliances during power cuts. It's a boon if you are living or planning to live in an area with no mains connectivity. The rising cost of other power sources as well as of and the increasing demand for electricity, especially in a high power cut or no grid areas, has resulted in increased demand for such systems. The reduction in battery prices over the years has further brought the system cost down. But if you don't have a power cut issue, then we suggest you go for an on-grid system as it will help you save big on your electricity bill.

What is a solar panel all about?

A solar panel comprises of multiple PV (photovoltaic) cells that convert sunshine to electricity. Two types of PV Panels are there.

1.  Poly Crystalline Solar Panels (A slice cut from a block of silicon, consisting of a large number of crystals. They have a speckled reflective appearance and are very thick. Low cost, generate lesser power, and lesser life span than mono cells).

2.   Mono-Crystalline Solar Panels (These cells are much thinner and have a smoother feel to them. High cost, generate higher power and also, it works during low-light and cloudy weather)

Loom Solar Technology: Superior quality Mono Crystalline Solar Panels in the Industry at a very low price.

What is the Efficiency of Solar panels?

The efficiency of a solar panel is calculated by the amount of sunlight it       converts into electricity per unit of area.

Loom Solar Efficiency = 20 %

What is the Temperature Coefficient?

While sunlight is important for the proper functioning of solar panels very high temperatures can lead to degradation. The temperature coefficient is measured as the effect of high temperatures on the functioning of solar panels. The lower the temperature coefficient, the better.

Loom Solar : Temp Coefficient of Pmax(%/°C) : -0.43,Voc(%/°C): -0.32, Voc(%/°C): 0.03, Electrical values measured at STC : 25°C, 1.5AM, 1000 W/m^2

What is the Durability of a Solar Panel?

The durability of a panel is estimated by its strength to endure heavy rains, hailstorms, high winds, excessive pressure, etc. Solar Panels in different countries undergo different stress tests under varied environmental conditions and external pressure. These panels are then given ratings by rating agencies in order for customers to compare and choose from.

Loom Solar =  Sustain Heavy wind load (2400Pa) and Snow Loads (5400Pa), hailstorm, excessive pressure, stone, monkey, and more. 

Is a solar solution same for all requirements or are there any types available?

There are broadly two types of rooftop systems that you will hear about -On-Grid solar power system - These systems are designed to work in conjunction with the grid or simply put your electricity supply. The electricity you generate using this system is fed back to the grid. A net meter is installed along with this system to keep track of the electricity consumed by you versus what you generated and fed back to the grid resulting in savings that get reflected in the bill. It does not work when the grid is down. Off-grid solar power system - These systems store the electricity produced by conversion in batteries and utilize the stored energy by converting it back to AC as and when required. The rising cost of other power sources and the increasing demand for electricity, especially in a high power cut or no grid areas, has resulted in increased demand for such systems. The reduction in battery prices over the years has further brought the system cost down.

What role does an inverter play in a solar power system?

The most crucial component of a residential solar power plant is an inverter. It acts as an interface that converts power produced by solar panels into electricity which can be consumed to appliances. The type of inverter being used depends on the kind of solar power system you are going for. Grid-tie solar power systems need high-efficiency power inverters for optimizing the performance. Another kind of high-efficiency solar inverters is there for the off-grid solar power system that can charge batteries both from solar and grid power. The inbuilt MPPT (Maximum Power Point Tracking) charge controllers in some good quality inverters extract up to 30% more power from solar panels.

How critical is the quality of the structure on which the solar panels are mounted?

It is the most critical part as it acts as the skeleton for the entire system, a sturdy structure will result in years of power generation as it needs to withstand strong winds and other natural forces. The type and orientation of the structure vary to a great degree depending on multiple factors associated with the location where the solar power system needs to be deployed. The structure for rooftop solar installation on a flat roof is completely different than that for a slanted roof. The height of your roof is another major factor that determines the composition and alignment of the structure. The quality of the material used has to be as per the MNRE (ministry of new and renewable energy) specified norms. The structure needs are mostly made of galvanized iron, which is not only stronger than normal iron but rustproof as well making the solar power system last longer.

Can I use normal cables in a rooftop solar system?

You can't use any regular cable for your solar power system. Specialized cables custom made for residential solar power plants are used to ensure minimal loss of electricity being generated. They are UV protected and strong and long-lasting enough to withstand the rigors of nature - be it peek of summers, incessant rains or thunderstorms. The use of any ordinary cable is a big health hazard as well with high chances of electrocution for the people in vicinity of the system. The bad quality wire will not only make you solar power system ineffective but will result in being more expensive as you will end up changing the wires of the entire system in the exposed parts get deteriorated resulting in the risk of electrocution.

When do the batteries come into the picture while installing solar?

If you are going for an off-grid solar solution, solar batteries are one of the crucial components as they allow you to store the electricity generated by the solar plant and use it in case of power outages or in case of no mains. A good battery would be the one which gives long back up and requires very less maintenance (less frequent water to up).

Apart from panels, inverter, batteries, and structure, what else is crucial for setting up a residential solar power plant?

These are the elements which are essential for the proper functioning and safety of the system. No compromise must be made on their quality or it will jeopardize the entire solar power system. In terms of their functioning, while Junction Boxes are used to conceal the wiring connections all across the system, Conduits on the other hand are used to protect the wiring of the solar power plants, they can be rigid or flexible or a mix of both based on the requirement. Lightning Arrestors are deployed to save the entire set up in case of a lightning strike, especially during monsoon while Earthing, which is a grounding system connecting the residential solar power plant to earth is done in order to give passage to excess electricity during the lightning strike and safeguarding the entire system in the process.

What all do one need to take into account while installing a rooftop solar power plant?

The installation of the solar power system needs to be done with precision in order to generate maximum electricity through the solar power plant. No two roof-tops are the same therefore the process requires system design and careful supervision to ensure proper installation of the solar rooftop power plant. Solar panels used in any solar power system should be installed facing south direction. The tilt angle of solar panel should be around 30% in India, but it varies as per the height of the installation. Solar panels must be grouted using anchor bolts or concrete foundation to ensure durability in rough conditions. UPS and batteries must be installed as close to the panels as possible to minimize DC transmission losses. One needs to ensure that the maximum permissible voltage is not exceeded when connecting the panels in the series. There should be a minimum gap of 5 mm between two solar panels to allow for any expansion in materials. The solar panels being interconnected must be of the same type (mono or poly) and the same power class. There should be no shade or shadow on the solar panels as this may lead to losses, the formation of hotspots, etc.

What effect does shading have on the performance of the solar panels?

The performance of solar (PV) panels are affected by the shading effect of surrounding trees and buildings, passing clouds basically anything that casts a shadow on to the panels. The sunlight converted into energy by the PV panels shall depend on the amount and duration of the shadow falling on it. Lesser the shadow, more the energy! No shadow - maximum energy!

Which direction should the solar panels face and why?

Solar panels need to face true south direction for maximum power generation. The reason behind it is that when the sun moves from the east and goes to the west, it leans towards the south direction. Irrespective of which part of the year it is, the inclination will always be towards the south. Hence for the optimum harnessing of sunlight, the solar PV panels should ideally face south.

At what angle do one needs to place the solar panels for maximum output?

The angle at which the solar panels are fixed according to your location's latitude. In general, the angle of tilt will lie between 9 to 12 degrees in the southern part of India and 25 to 30 in north India. The angle decreases as the altitude of installation increases to nullify the impact of high-speed winds on the installation.

What is the duration of the warranty on solar panels?

It is important as many companies might not be around to honor their promise later.

Loom Solar Warranty= 10 years product warranty and 25 years Linear Power Performance Warranty with 2.5% FOR 1st Year degradation and 0.67% from year 2 to 25

How important is the regular cleaning of solar panels?

India is a country where dust tends to accumulate very quickly on the panels hampering their optimum generation. Solar Panels have to be cleaned at least twice every week, would be great if you can manage to do it daily, to make the most of the sun rays falling on it. It is recommended to do it using a wipe after a strong water spray.

How should I go about the maintenance of my rooftop solar power system?

A solar rooftop power system will deliver the full return on investment only if it runs as smoothly as possible. This means periodic inspections of the individual components of the system. Timely intervention can prevent the threat of diminished output or downtime or a safety hazard. This way it's important to get in touch with a reputed brand to install your solar system so that all this can be taken care of. Click here to find out how.

How to go about govt. approvals & subsidies for residential rooftop solar plants?

In case of rooftop Grid-Tie solar power system, one must ensure that all the necessary govt. requirements for getting net-meter installed are being taken care of. This may require additional time and fees depending on the local electricity utility. For battery based systems, no permits are required. However, in case there are subsidies schemes offered by local government, additional documentation may be required for subsidy. Luminous products are designed as per IEC standards, and are eligible for subsidy schemes. Ministry of New and Renewable Energy (MNRE) regularly announces subsidy and its disbursement procedure on its website, it's recommended to visit the same.

Does solar power system work only on sunny days?

No, it even works when it's cloudy! Obviously the power generation will not be optimal but it does not stop working. Also, with 300 sunny days, India is blessed to be the best destination for solar power generation.

What types of buildings is this suitable for?

It's suitable for all type of buildings. The only prerogative is that there should be a roof on top of it, strong enough to support the structure. Installation also varies depending on whether the roof is slanted or flat. In India, we mostly have flat roofs and the structures are created accordingly. The position of the surrounding elements, such as buildings or trees, which can cause shade on the panels play a crucial role in determining the area on the roof suitable for optimum solar power generation. At times there are obstacles on the roof, such as water tanks, which affects how the structure to support the solar panels will be erected as well.

Can solar panel be used for running water pump?

Sure thing! One just needs to make the calculations correctly in terms of what all appliances are being run on solar. Power requirement of a water pump generally lies between 250 to 1100 watts. Just make sure that the total accumulated load does not exceed what is being generated by the solar panels. It also depends on what type of system do you have. If you have an on-grid system, you can use the solar power during the day part by directly connecting the water pump load to the solar set up. In case of an off-grid system, you can use the energy stored in the batteries to run your water pump any time during the day. The duration of usage will depend on the capacity of the batteries and the level of their charging.

What is the typical maintenance required for a solar power system?

The most crucial part of maintaining a solar power system and making sure of the optimum power generation is to keep the solar panels clean. Ideally, it should be done at least twice a week. If you can do it daily, nothing like it. Apart from this, all the main components come with performance warranties, so you don't have to worry about the other stuff too much. Solar panels come with 25 years of performance warranty while that of inverters and batteries keeps on varying.

What is the normal payback period?

The Return on Investment takes place in around 4.5 years. Then you earn for a minimum of 20 years. Not only you generate your own electricity, you also help reduce the carbon footprint contributing to a healthier environment and making money in terms of savings either due to reduced electricity bill (if you are using an on-grid solar system) or reduction in diesel cost (if you are using an off-grid solar system).

Do individuals get any subsidy/tax benefits for adopting solar systems?

Absolutely, In case of rooftop Grid-Tie solar power system, the owner must complete all the necessary requirements for getting net-meter installed. This may require additional time and fees depending on the local electricity utility. Any good service provider will assist you fully in the process. For battery based systems, no permits are required. However, in case there are subsidies schemes offered by local government, additional documentation may be required for subsidy. Luminous products are designed as per IEC standards, and are eligible for subsidy schemes. Ministry of New and Renewable Energy (MNRE) announces subsidy and its disbursement procedure on its website regularly, you may pay them a visit as well to know more.

How to know solar installation size for my home?

The best way to do it is to call a professional to help you out as there are many aspects and methodologies which needs to be taken into account before one arrives at the recommended system size for a particular site. Therefor it is advised to book a site survey with us and let our solar expert inspect your roof to suggest the best possible solution for you.

What benefit could a brand deliver as compared to local installer?

With a multitude of solar installers available, defining the parameters for choosing the right one is a tough decision. Even though price seems to be the sole lucrative parameter, industry experts wouldn't suggest the same. Right from solar panels, inverters to the services offered by your installer like mounting the structure and other necessary civil work, everything has to be seamless. This is where a brand scores over the local installers. While it is a pain to pay a little extra, but this solar system is going to last you for more than 25 years. So it is perfectly fine to bear that extra cost for warranty benefits and any assistance you might need in the future. Look for companies that have been around for a long time and use branded products, you don't want to end up probing for the original manufacturers to avail that warranty clause. If you choose to go ahead with a brand, you won't get the surprise of hidden costs in the middle of the project as there will be complete transparency, you will get efficient rooftop panel design ensuring maximum generation and there will be no compromise when it comes to your safety.

Is it worth installing solar panels in my house in India to power all my electrical equipment and completely cutting off power coming from the grid, keeping in mind the initial investment and long-term savings?

Installing a rooftop solar PV system is any day a wise choice. It will help you to reduce your monthly electricity bill. But going completely off power from the grid might not be the best thing to do. Why? If you completely cut-off from grid, then you will be needing batteries for storing the light energy that is converted into electricity. This energy then shall be re-converted for use and it is here that efficiencies of conversion come into play. Also batteries increase cost as they need to be replaced every 4-5 years and require maintenance. A grid-tied solution with net- metering is perhaps a better choice. You can enjoy all electricity generated by panel during day time and during night time, you can take power from grid. The math therefore is simple. A system with storage or an off-grid system requires a higher outlay of money owing to the batteries. For complete autonomy an even higher one! Whereas, with a Grid-tied or an On-grid system you have a choice of power sources your own Solar Power Generation System or the Grid. If you consume more than you generate, you pay for the excess units. On other hand, if you generate more than you consume then you get paid for the excess units.

Are batteries essential for solar power plants to perform?

Ideally, solar power plants are installed to directly convert the sun’s energy into electricity. Batteries help in storing the energy for later use. But, in general, batteries are costly and require huge maintenance. Thus the usage of batteries is still not a viable option in India in terms of cost incurred versus benefits accrued. Also, most of these are lithium batteries and hence, the purpose of going green gets defeated.

What are solar “trackers”? Where can they be used?

Solar trackers are the devices which direct solar panels or modules towards the sun. These devices change the module orientation throughout the day to follow the sun’s path to maximize energy radiated over them. It has been observed that trackers increase the efficiency of solar panels by 15-20%.

What is Net Metering?

Net Metering is a very important electricity policy for the promotion of distributed energy from renewable energy sources like solar energy.

All consumer establishments connected to the power grid have an electricity meter       installed which measures the amount of power consumed during a month in Kilowatt Hours (kWh) which is known as one unit. The power utility compiles the data for power consumption during 1 month and sends a bill which is usually the number of kWh multiplied by the retail electricity rate. A customer can reduce his electricity bills with the help of net metering policy if he has a solar system installed at his establishment. He can send the excess power back to the grid and claim a credit for the same in his monthly electricity bill, with the help of special meters called net meters.