PV, short for Photovoltaic, derives its name from the process of converting light (‘photo’) directly into electricity (‘voltaic’). Simply put, a Solar PV system is a power station that generates electricity from sunlight.

The main components of a Solar PV system are:

Solar Panels or Modules: Solar panels consist of a group of small cells made from semiconductor material. When the sun’s light falls on the modules, it excites the electrons, thereby creating direct current (DC).

Solar Inverter: The DC electricity goes into an inverter that converts it into alternating current (AC). We use AC for running our household or office or factory equipment.

Storage Battery (optional): The best use of solar energy is to consume it while it is being generated. If the requirement is to store this power and consume it in the non-sunny hours, then solar energy can be stored in batteries for later consumption.

What is the difference between Solar PV and Solar Thermal? The majority of solar energy, coming to our earth through the sun rays, is in the form of ‘light’ and ‘heat’. A Solar PV system uses the ‘light’ energy and converts it into electricity, which can then be used to run electrical equipment or charge batteries. A Solar Thermal system uses the ‘heat’ energy of the sun where a solar collector captures this heat or thermal energy and uses it to heat water or air.

Which technology is suitable for me? Both Solar PV and Solar Thermal are suitable for you. If you need to run electrical and electronic equipment like lights, fans, TVs, computers, etc., Solar PV is the right solution for you. However, if you require a solution for water heating in your bathrooms or kitchens or swimming pools or for space heating, drying, cooling, etc., a solar thermal is more suitable.

Technically speaking, yes, if batteries are used. But practically, if grid power is available, then it is recommended to use solar in combination with grid. Solar PV can be integrated with your existing power sources (like grid power, inverter, diesel generator, etc.) in such a manner that the first priority is automatically always given to the solar power to be consumed first.

However, if you are using Solar PV for night time usage or in a remote location, it is quite common to have Solar systems which are battery-backed.

Should I reduce my existing sanctioned load if I decide to go solar?

The Sun and therefore solar power is available only during the day. Therefore, to cater to your night time load it is recommended not to reduce your existing sanctioned load. The MySun Solar Calculator shows your accurate savings potential considering all such factors.

What are my monthly savings?

Installing a solar PV system should lead to significant savings in your monthly electricity bill. The savings would depend on your location, consumer category and energy consumption pattern. As a thumb rule, the higher your tariff and the proportion of energy consumption during the day, the more are your savings

Solar PV is a highly proven and reliable technology and have been in use since 1950s. A PV system that is designed, installed, and maintained well will operate for 25 years or even more than 25 years. 

The Inverters, which are an integral part of a Solar PV system, may need a replacement once in the 25 years lifetime of the system. Moreover, since there are no moving parts (unless you are using tracking devices to move modules tilt with the movement of the Sun), there is practically negligible wear and tear.

Do I get any guarantees or warranties?

The Solar PV modules are backed by suppliers’ guarantee of 25 years or more. In fact, the modules have been known to generate electricity even up to 40 years. Know more about Solar PV system guarantees & warranties.

Do Solar PV panels degrade in performance with time?

Solar panels age with you, though at a much lower pace. It is usual to see a very small degradation in energy output with time which is due to the very nature of the solar module technology. Generally, annual degradation of modules is in the range of 0.3% to 0.5%. However, in the first year of your installation, this degradation may be higher. MySun calculator uses sophisticated algorithms to accurately estimate your customized lifetime solar energy potential.

Since Solar PV works on the basis of the intensity of sunlight it gets, your solar system typically wakes up at around 6am in the morning and goes to sleep at about 6 or 7pm in the evening. The energy output increases gradually and peaks at around noon and then gradually decreases as the Sun starts setting. 

But since the solar energy produced integrates either with your existing electrical connection or with your batteries, the running of your electrical equipment is not impacted. Moreover, if your Solar PV system is designed well, all your electrical equipment is totally safe.

What happens on cloudy days?

Solar PV system needs light to generate electricity. If Sunlight is low, as on a cloudy day, the solar system still generates electricity but the generation is lower. This reduced generation, however, may not create any disruptions for you. 

If you have a grid-connected Solar PV system, electricity will be automatically sourced from the grid in case Solar PV generates less. In case of an off-grid system with battery backup, energy will be sourced from the storage battery. 

What if I am not at home?

When you are not at home, your solar system continues to work and run any equipment that may be switched on such as refrigerators, security systems, etc. In case your energy consumption is less than the solar system’s generation, the excess energy will be fed to the grid. To avail this feature, you should opt for Net Metering.

When planning to go solar, it is important to consider: How much of your energy needs can you meet with solar? How much can you save by going solar? Do you have enough shadow-free space (land or roof)? How much do you want to invest in your solar PV system? 

Every Solar PV system is customized based on your site conditions. Therefore, you need a fair assessment of your energy requirements, site conditions and the solar energy generation potential at your site which would directly impact your savings.

How much space is required for Solar PV system?

A 1 kW rooftop system generally requires 10 to 12 sq. meters (110 to 130 square feet). Based on the space available, you can fulfil your entire electricity requirement through solar. Solar systems are modular in nature and you can increase your system size anytime if your energy needs go up.

How much energy can be generated from my solar system?

Solar Power generation depends upon several factors like location, orientation of roof/ land, shadowing objects, ambient temperature, solar system quality, etc. Considering all of the above factors, typically, in a sunny area, a 1 kW system generates 4.0 to 4.5 units (kWh) which can run 4 lights (4*20W), 2 fans (2*75W), 1 TV (80W) and 1 refrigerator (150W) for 10 hours.

The CPEX, OPEX(RESCO) and PPA are two models of buying solar energy. Here are what they mean and how they are different from each other:CAPEX: CAPEX stands for Capital Expenditure.

If you go solar under the CAPEX model, you are required to pay the total cost of the solar system upfront. This allows you to own the solar system and makes you eligible to avail the accelerated depreciation benefits. 

OPEX/ RESCO/ PPA: OPEX or RESCO stands for Open Expenditure. If you go solar under this model, you essentially choose to not buy the solar system but the solar energy produced by the solar system. 

The solar system in this mode is installed and owned by the solar installer or a third party and you are required to sign a Power Purchase Agreement(PPA) of purchasing the electricity from the solar system at a specified rate for a certain number of years. These agreements are usually signed for 15~25 years.

From the cost perspective, the CAPEX model of going solar is considered the best model of buying solar followed by DPA and PPA. 

The reason behind this consideration is that since the cost solar PV system is paid upfront under CAPEX, the cost of solar energy is lower in CAPEX than in DPA and PPA. Under DPA, the cost of the solar system is split into monthly instalments and the entire cost of installation is initially borne by the installer, you are therefore required to pay a minimum interest in your monthly instalments. 

This increases the overall cost of the solar system. Under PPA, the Solar PV installation cost is borne by the installer and you only pay for the per unit cost of electricity that you consume and therefore the Levelized cost of solar energy is higher in PPA than in CAPEX and DPA. Also, additional benefits like Accelerated depreciation and relaxation in taxes can only be availed in CAPEX or DPA, because availing these benefits requires ownership of the solar system.

A Feed-in tariff is the rate/cost at which you sell the electricity generated by your solar system to your discom either via net-metering or gross metering. This tariff rate varies from state to state depending upon the solar policy of the state. 

The tariff also differs across consumer categories. This tariff is often referred to as net feed-in tariff in case of net-metering and gross feed-in tariff in case of gross metering.

Solar tariff is the rate/cost at which you purchase the electricity from the installer/owner of a solar system under a Power Purchase Agreement(PPA). The rate is agreed upon for a certain period of time as per the clause of the agreement. 

This insulates you from any tariff hike in the near future. However, the solar tariff may be subject to an increase depending on the terms and conditions of the signed agreement. To get an estimate of the solar tariff that you may be required to pay if you solarize your business under PPA, you can run the MYSUN Solar Calculator. 

The calculator will show you your estimated solar tariff for a PPA ranging from 10 to 25 years. You will also be able to compare the solar tariff to the levelized cost of solar energy if you went solar under the CAPEX or DPA(Deferred Payment Agreement) model. 

With the advanced feature of the calculator you will also be able to check an estimate of the total cost of solar energy your business will be paying throughout its solar journey at a given solar tariff.

Gross metering is a mechanism in which the entire energy generated by your solar system is exported to the grid at a certain rate. In this case, the energy generated from your system is not consumed by you in any capacity. Once the energy is generated from your solar system it is transferred to the grid, and the grid further sells the energy to the power consumers at a certain tariff rate.

The payback period for your solar PV system stands for the amount of time it takes for your initial investment in the solar system to be recovered from the savings it yields.

The Return on Investment (ROI) refers to the effective returns that your investment would generate throughout the life of the solar system. The higher your monthly savings on power bills from solar is, the quicker your initial investment would be repaid and the higher your ROI would be. Typically, commercial & industrial consumers should expect payback in 3 – 5 years and residential consumers should expect payback in 5- 7 years. 

Once the initial cost of your system is paid back, the energy generated by it for the next 18 – 22 years is almost free of cost.

Diesel Generators (DG) are not just a highly expensive means of power generation but are also extremely damaging to the environment. And contrary to popular belief, the cost of energy from home inverters is also very high. 

The cost of power from a typical DG in a housing society is Rs. 17 – 18/ unit (kWh), while from a typical home inverter it is Rs. 14/ unit (kWh). In comparison, solar is a much cheaper and cleaner source of energy.

There are broadly five solar buying and solar financing options that you can opt for while going solar: 

Buying a Solar PV system under CAPEX Model: You purchase the Solar PV system and pay the 100% cost of the solar system upfront. This allows you to get the best deal as you would be saving any additional cost such as interest rates. 

Buying a Solar System under a Deferred Payment Agreement(DPA): You purchase the solar system at a downpayment of 25~30% and defer the remaining capital cost of the system in easy instalments at lucrative interest rates. The benefits of buying solar under DPA is that it makes going solar affordable and flexible. 

With MYSUN DPA you also get an option to make your own payment plan and keep your monthly instalment less than or equal to your monthly power bills. This will help your solar system pay for itself.

Buying a Solar System by opting for a Solar Loan: You purchase a Solar system and opt for a solar loan to pay the 100% cost of the solar system to your solar installer. Under this model of buying solar, though you buy the solar system at the CAPEX cost you are required to pay off the loan at an agreed-upon interest rate. 

Buying only solar power under RESCO/ Power Purchase Agreement(PPA) Model: You do not purchase the solar system but only the solar energy produced by the solar system. A solar power developer owns the Solar PV system set up on your rooftop/ land. 

You only pay for the generated electricity at a pre-agreed tariff. This usually requires a long-term buying commitment and guarantees from your side and entails a lengthy credit appraisal process. This mode of buying solar is usually available to only commercial and industrial power consumers. 

Equipment leasing: An equipment leasing company will lease the Solar PV system to you and will charge you a fixed monthly/ periodic fee. This also requires long term commitments and guarantees from buyers. However, equipment leasing is not widely available as of now.

Net metering is a billing mechanism which allows you to sell excess (unconsumed) solar power generated by your solar system to the DISCOM. For example, if on a given day you generated 20 units from your solar system and consumed only 18 units, the balance 2 units will be sold to the DSICOM at a set tariff. 

This ensures that you maximize your savings from solar. The mechanism of net-metering can be availed only if your building mains is connected to the grid. Therefore it can only be installed with on-grid and hybrid solar systems. The availability of net-metering varies from state to state and depends on the solar policy of your state. 

For example, in the state of Rajasthan, the net-metering is only available to power consumers going solar under the residential category. For commercial and industrial consumers of the state the facility is available only above a certain sanctioned load.

Solar PV systems are highly reliable if designed well. Moreover, the key components of a Solar PV system are backed by guarantees & warranties . However, since solar is like any other asset that you own, it is generally advisable to buy an insurance cover.

Yes, solar power today is cheaper than grid power for a lot of consumer categories across most states. Moreover, solar is a one time investment while grid tariff keeps increasing every year. Therefore, by choosing to go solar today, you are locking in a fixed energy price for the next 25 years. 

Illustration for an average residential customer in Delhi:

A 2kW Solar PV system costs around Rs 1.4 lacs and has a life of at least 25 years with low recurring costs. This translates to a per unit levelized cost of Rs7 – 8 /kWh for the next 25 years. 

Let’s compare this with the cost of grid power. The discom charges the consumer slab-wise but on an average the consumer pays Rs 7.3/kWh. And this price keeps increasing by about 5% per annum, which means you may be paying Rs 24.7/kWh at the end of 25 years. 

This translates to a per unit levelized cost of approx. Rs 10 – 11/kWh when compared with the 25 year life of Solar PV system.

It takes about 2-4 weeks to install a smaller system and about 4-8 weeks for larger systems. However, the actual construction time at the site is much lower since almost half of the time is spent on off-site activities such as design, engineering, procurement, etc. In certain cases, there may be variations to these timelines on account of access to the site, rains, etc.

What should I do to get my site ready for a solar installation?

Not much. You just need to ensure that there is clear access to the site for movement of material and manpower and that your site is clear from any unwanted material. The solar installer may need access to power & water. 

Will my power supply be affected during the Solar PV system installation?

No, there will not be any interruption in your power supply.

Good solar installers follow standard procedures and quality standards. So once you’ve chosen the right installer, you don’t have to worry about supervision. 

However, it may be a good practice to:

• Ask for layout drawing and bill of material.

• Ensure that the delivered material is as per the bill of material, is damage free and is kept at a safe place.

• Ensure that cables and wires are properly tied and clamped.

The annual maintenance and recurring costs are almost negligible, since there are no moving parts and the input fuel (sunlight) is free. For optimum performance, the system only requires cleaning of modules and basic preventive and corrective maintenance. 

However, for off-grid systems where batteries are used, the maintenance costs are higher on account of battery replacement every 3-5 years. To ensure high generation and low maintenance cost, regular monitoring through data loggers is highly recommended. 

Typically, the maintenance costs for smaller Solar PV systems is about 2% of the initial system cost, and for larger systems is about 1% of the initial cost.

What maintenance does a Solar PV system require?

The two primary aspects of maintaining a solar PV system are to regularly monitor your system’s performance through the data logger and to clean the panels about 6-10 times in a year.Beyond this, it is advisable to have your installer conduct at least two visits in a year just to check the general health of your system.

No permits would be needed, if you are going to install off grid Solar PV system or grid connected system for captive (self) consumption. For net metering and gross metering system, certain permits and approvals are required.

For Net & Gross Metering:

1. Approval from DISCOM for grid connectivity.

2. CEIG(Chief electrical inspector to the government of state) approval for the capacity more than 10 KW(This capacity may vary from state to state).

Will my system installer assist me in getting the permits and approval?

Yes, the system installer will! 

But it is better to discuss and finalize all of these things with the installer before signing the contract.

You should take the following steps:

• Register Your Rooftop with SOLARIS

• Get your site visit done and start receiving quotes from pre-qualified installers

• Compare quotes and select your installer

• Finalize the terms (pricing, guarantees, etc.) and the order with the selected installer and start your solar journey.

Depending on your energy consumption pattern (consumption during day vs night), power outage pattern, availability of policies like Net Metering and access to grid power (for rural areas), you can choose between an on-grid and an off-grid Solar PV system.

On grid systems are the most commonly used systems and are the least expensive and require very little maintenance. Off-grid systems use batteries which cost significantly more and need high maintenance.

What is an on-grid and an off-grid Solar PV system?

On-Grid: An on-grid system is interconnected with your existing electrical system. The solar energy generated is simultaneously consumed, and if the solar panels are not generating sufficient energy to cater to your consumption, the differential is automatically sourced from the grid. It is also possible to connect the system with batteries, home inverters, diesel generators, etc.

Off Grid: An off-grid system is an independent, battery-backed Solar PV system which is not connected with grid. During daytime, solar energy generated runs your appliances. Any excess energy is stored in the batteries, which can be utilized at night. Off-grid systems are used for standalone applications like traffic & streetlights, billboards, agricultural pumps, telecom towers, rural applications, etc. 

How can I use Solar during a power outage?

On-grid Solar PV systems are designed to run with grid power. Therefore the system will not be able to function if grid power is not available. This is a safety feature to avoid feeding power back into the grid while the line-men are working on the grid. If you want power from solar PV system during grid failure, you can choose an inverter that can use other sources of power like diesel generator or batteries etc.

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.

What is a data logger?

This is a device that helps you as well as your installer/ O&M contractor to monitor your Solar PV system’s performance on a real time basis on your mobile phone or laptop. Data logger indicates parameters like generation on a daily, monthly & yearly basis, plant performance ratio, etc. and can send alerts in case of any faults or low generation. The device can also be configured to send you regular performance reports through SMS and email. 

What are the typical Solar plant performance metrics?

The generation from your Solar PV system depends on the quality of your system, the solar irradiation and the quality of maintenance. Performance Ratio (PR) is a measure of the quality of your system, whereas, Capacity Utilization Factor (CUF) is the overall metric that takes into account both the quality as well as the solar irradiation. For example, if the quality (and hence the PR) of your system is low, even if the solar irradiation is high, your CUF (generation) will be low, and vice versa.

Electricity is measured in kWh (Kilo Watt Hour). It is the amount of electricity consumed by an appliance in a specified period. For example, 100W bulb * running for 1 hour = 100Wh which is equal to 0.1 kWh (unit).

Your electricity bill mentions the kWh (Units) consumed by you in your billing cycle.

What is the difference between kW & kWp in relation to Solar PV systems?

KWp is the nameplate rating of Solar PV modules and kW is the actual power delivered to the load. For instance, a 0.3kWp (300Wp nameplate) module under ideal conditions (25 degrees C and 1000 watts per sq. metre radiation, etc.) will give an output of 0.3kW. However, in real life weather conditions, the output will be lower than the nameplate rating which is denoted in kW. 

What is the difference between kW and kVA?

Both are units of power , kW is active power whereas kVA is the apparent power because only a certain portion of the available kVA can be utilized kVA=kW+kVAR. If you take a mug of coffee, you can see its two component coffee+ foam. Here the portion of coffee is active power(kW), foam is reactive power caused by certain electrical equipment, and coffee + foam is apparent power (kVA).

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

A Solar PV system generally weighs 15 to 20 Kg per square meter. This weight can be easily borne by most roofs. Since the life of a Solar PV system is about 25 years or more, do ensure that your roof is in good condition to bear the system’s load over its lifetime. 

Will the Solar PV system installation damage my roof/building?

Solar installation methodology is proven and safe. A wide range of installation techniques are available and depending on your roof type a suitable methodology can be adopted.