Frequently Asked Questions on Solar

Solar Panels are cost effective as it saves money on energy bills. New schemes have been introduced to generate electricity from solar which are cost friendly to the users and any households who install Solar Panels in 2018, can expect a return on investment within 14 years and make a 4.8% return over 20 years.

Solar Panels get more efficient by the use of more efficient cells used to produce more power, which helps to lower the cost of producing electricity and provides a quicker return on investments for homeowners or power plant developers.

Solar Panels installed on your roof work best during daylight hours. When the sun is shining directly onto them, sunlight can be converted into electricity. Your solar panel efficiency drops at night because there is no sunlight to convert to electricity and Solar Panels can’t generate power in darkness.

Yes, a real threat to solar technology could be an Electro-Magnetic Pulse but, is very unlikely that Solar Panels are vulnerable to the EMP effect. The danger of it is not from a direct strike to humans but is dangerious from indirect effects which occur later.

To Run Air conditioners on Solar Panels we need to consider the tonnage capacity of the AC and the heat load in a room. Normally Ac would consume about 1-2 units of electricity in an hour. Solar Panels of 1 KW would produce 5-7 units per day. if the air-conditioner is in use on solar pannel, in 4-5 hours the energy would get utilised completely.

During cloudy days, Solar Panels can still generate some amount of electricity, essientially when the weather’s as dull as watching paint dry.
Can solar panel be used as an alternate source of heating?
Yes, Solar Panels can be used as an alternate source of heating during the winter, spring, autumn and summer. The centralized heating systems work to their best when they are used with underfloor heating, convectors or solo radiators/ high efficiency aluminium radiators.

Possibility is bleak, however during the process of making Solar Panels, certain steps are taken to protect the panels from overheating. One thing to remember is that you never want to spray your Solar Panels with water during the hotter parts of the day by doing this it can irreparably damage your panels forever.

The working of Rooftop Solar and Battery Storage’s work by the output of a Solar PV systems (Solar Panels plus inverter) produce power proportional to the solar energy coming from the sun. This energy is instantly converted into electricity that can be used in the home or business.

For an example let’s assume a house may require 1100 kWh per month. Now divide your average monthly usage by 30 to get your average daily kWh usage. In this case, it would be about 37kWh per day. Assuming that you use about 37 kWh per day, you would need about 37 Solar Panels to meet 100% of your average energy needs.

A Rooftop Photovoltaic Power Station, or Rooftop PV System, is a photovoltaic system that has its electricity-generating Solar Panels mounted on the rooftop of a residential or commercial building or structure.

Solar water heating (SWH) is the conversion of sunlight into heat for water heating using a solar thermal collector.They are heated directly or via light-concentrating mirrors. They operate independently or as hybrids with electric or gas heaters.

Solar Panels are a sustainable way to provide energy, but they can be troubling for first responders. In case of a fire, firefighters usually cut ventilation holes in the roof and turn off the electricity, and roofs covered with Solar Panels can create serious issues for them. Fixed, electrified Solar Panels barely leave . According to firefighters, Rooftop Solar Panels can cause roofs to collapse faster during fires and even stop some firefighting techniques from being used. This risk of roof collapse forces firefighters to go on “defense” outside of burning buildings, rather than attacking them from fire inside the premises.

No, Solar will not heat radiators as Solar Panels will provide hot water for your domestic needs. Providing anywhere up to 60% of your year round hot water needs, as per SEAI’s guidance. Although a solar thermal system can help make your entire house’s heating system more efficient.

Yes, but we need to know that most of the solar module frames in the market are made of anodized aluminum which is a highly resistive material for salt air/water conditions. The sailboat rigs are made of the same material.The air between the back-sheet of the module and the tempered glass is vacuumed in order to avoid corrosion in the cells. Unless there is a crack in the module, they are all safe. You can rely on the solar module warranty conditions.For the racking & mounting systems; Galvanized steel is highly corrosive, Mill finish aluminum could be corrosive – not recommended for locations nearby sea or ocean, Clear or bronze anodized aluminum is totally safe! But need to be careful with cracks and dirt. The buildup of dirty surface deposits can provide sites for corrosion, particularly if there is associated acidity.

The major difference between Monocrystalline & Polycrystalline Solar Panels is that Polycrystalline Solar Panels are low in Silicon Purity, hence polycrystalline Solar Panels are not quite as efficient as monocrystalline Solar Panels. Due to Lower space-efficiency, generally need to cover a larger surface to output the same electrical power as you would with a solar panel made of monocrystalline silicon

The major differences between Solar Panels and solar cells are: They are 2 types of Solar Panels : Photovoltaic (PV) Solar Panels and Solar Thermal Collectors. These devices convert sunlight into electricity. Solar thermal collectors use the same solar energy that photovoltaic panels do, but they generate heat instead of electrical power. Solar Cells are building blocks of Solar Panels. Multiple Solar Cells that are oriented in the same way makes up what we call Solar Panels. The electrical power out depends on how many of them are put together.

A major difference between Solar Panels and solar modules are: Solar Panels absorb sunlight as a source of energy to generate electricity or heat. A photovoltaic (PV) module is a packaged, connect assembly of typically 6×10 photovoltaic Solar Cells.A single solar module can produce only a limited amount of power, most installations contain multiple modules.

Implementing solar energy system at a residential or workplace can help you save money on utility bills while you stay eco-friendly. You will not be affected by the hikes associated with fossil fuel prices. Solar power adds value to your home or workplace in case of renting or selling the property. Government of India also provides various subsidies to the consumers of solar energy.

Net metering is the billing mechanism that allows the Solar PV System owner to Credit the excess energy that is produced and added to the grid for future usage. In this case a customer can generate more electricity than the home uses.

The homeowners get various measurable benefits by installing a solar power plant. Solar power plants lower energy costs and increases value of the house. They also manage utility and reduce power interruptions. They are a secure investment unlike utilities which fluctuate from time to time.

Owners of property are given solar loans to install solar panels and produce energy. They are similar to any other loan as they have a interest rate, payback period and a principal amount.

Solar loan refers to collecting capital from individuals and investors for installing a solar power plant and sharing the benefits. Solar loans are also called community solar project, solar garden or shared renewable energy plant.

Primarily there are four different types of Solar Water Pumps-Submersible pumps,surface pumps, direct current pumps and alternate current pumps.
Submersible pumps:It is located deep below the ground level and remains submerged under water.
Surface pumps: The pump remains out of water and they are easier to install and maintain.
Direct current pumps: Pumps runs only throug direct current, there is no need of battery and inverter.
Alternate current pumps: These types of pump requires inverter which convert the direct current produced by the solar panels to alternate current.

Solar Water pump consists of Solar Panels made of solar cells which convert sunlight into electricity(DC). The DC current can be fed to a DC motor to pump water or DC can be converted into AC through an inverter and AC can be fed to a AC pump for drawing water.

Surface or underground water drawn using Solar panels is used for irrigation, for feeding livestock or other useful purposes.

  • Solar Water Pumps do not need grid power to function and need Sunlight for its functioning. This eliminates the dependence on grid power.
  • Its very helpful in remote areas where there is intermittent power failures and there is need for power for irrigation purposes.
  • Grid power cost for irrigation reduces, with low maintenance costs.

The different types of Solar Water pumps are:

  • Surface Water pumps
  • Submersible Water pumps
  • AC pumps
  • DC pumps
  • Submersible water pumps can lift the water from great depths of over 600 feet.
  • Surface water pumps can pump surface water from the depths of 10-15 ft
  • Check out the water requirements needed for irrigation or other purposes
  • Install the Solar panels in a shadow free area for maximum solar exposure
  • Ensure that there are no bird droppings or other kind of debris which can obstruct sunlight exposure. This can reduce efficiency.

Solar Water pumps work best when Solar panels receive maximum solar exposure. During cloudy or foggy day, chances are Solar panels may not receive the optimum solar exposure and hence the output would be less. In these cases it is best to have a backup like a diesel generator to take up the load of pumping the water.

  • Solar panels need to be cleaned on regular basis, to enjoy maximum efficiency.
    Check whether the water pump is working properly so that water gets pumped properly.

Solar Water Pumps are systems that are powered by solar energy. To pump from surface or underground water for irrigation or other useful purposes.

The Solar Water Pump consists of :

  • Water pump(submersible or surface water pump)
  • Solar panels
  • Control Panel
  • Batteries

Solar Street Lighting is the system where Solar Energy is used to light streets compared to using grid power to power street lights. Ensure that The solar panels are installed in a shadow free area for maximum solar exposure.

The solar panels are installed on a pole in a shadow free area for maximum solar exposure. Solar PV panels consist of solar cells that convert sunlight into electricity. Electricity thus produced is stored in the batteries to be used at night. The Charge controller manages the transfer of current to the battery ensuring its not overcharged or drained and proper voltage is supplied to the battery.

The advantages of Solar Street light are:

Works independent of the grid power, hence reduces costs.
Less Maintenance
Environment friendly – Reduced Carbon footprint

The different components of Solar Street lighting are:

Solar Panels
Led lights
Rechargeable battery
Solar Charge controller

Yes monitoring Solar light is possible  remotely based on the defined lighting profiles, light levels set in the remote managing software.

It depends on how much power gets stored in the Battery. The amount of power stored in the battery depends on the sunlight received.

Maintenance required for Solar Street lights is very less. Occasional cleaning of the solar panels helps clear dirt and other materials that can reduce the efficiency of the Solar panels.

Feed-in tariff or NetMetering is a method by which electricity produced from the Solar PV system is supplied to the Grid, and the building recieves power from the grid. The difference in energy units (Power Fed – Power consumed) is credited to the building owner. This is called Feed-in Tariff.

There are 2 types of Feed-In Tariff –

  • Gross Feed-In tariff – In this case the building owner is paid a premium for all the electricity produced.
  • Net Feed-In tariff – In this case the building owner is paid a premium for surplus power produced.

Both are methods by which the building owner is credited for supplying extra power from the Solar PV system to the grid. In simple terms the difference between the two is: Feed-in tariff requires 2 meters and Netmetering requires 1 meter. In case of Feedin tariff there is one meter for measuring consumption and another for generation. In case of NetMetering there is single meter which measures the difference between the energy units consumed from the grid and the energy units fed into the grid.

The average cost of grid connected rooftop solar systems is about Rs. 80 per watt or Rs.8.0crore per MWp capacity. The prices vary from any where between 70,000 – 90,000 per kWp and these can rise to higher ranges with higher brands.

A roof area of 10sqm is needed to set up 1kWp grid connected solar PV systems on the roof.

There are different business models used:

  • The Solar installation can be owned, operated and maintained by the owner completely by himself.
    The power completely rests with the owner in this case.
  • Build Operate Transfer (BOT) – In this model the Solar Installation funding is done by the customer
    and then the operation and maintenence are taken over by the 3 party vendors.
  • Build Operate Own (BOO) – In this model the funding, opperation and maintenence are done by
    the 3 rd party vendors but the customer has to pay for the current utilization. The client pays on a
    KWh basis.
  • Build Operate Own Transfer (BOOT) – This model works like a BOO model working for a
    stipulated/contracted period (for ex -10 to 12 years) after that the ownership is transferred to the
  • The Solar installation can be owned operated and maintained by the DISCOM’s.

The size of the Solar PV system depends on a number of factors like:

  • The Energy requirements of the building
  • Solar PV site orientation
  • Efficiency of the Solar Panels
  • Rooftop space.

After analyzing these factors do a proper Solar sizing. This involves considering the sizing of the different components that make up the solar PV system.

For more information about the system sizing check out this blog.

In case of a Grid connected system, when there is a blackout , the system switches off. For a grid connected system to work there needs to be the grid power. Otherwise a battery backup can be provided to store power in case of power failure. This then becomes a Hybrid Solar PV system.

In a Grid connected system there is no battery used. Here the grid acts as a Virtual battery. The power of the grid is used during night as Solar PV system does not provide power..

  • Convert DC power generated from Solar panels to usable AC power.
  • Sync the Ac power voltage with that of the grid power.
  • Maximize the power output with MPPT

The Grid connected system is made up of different components and each lasts for different time periods.

  • Solar Panels – The Solar Panels last for more than 40 years. But warranties given by the manufacturers would be around 20-25 years. Even after the warranty periods, the efficiency of the Solar panels are quite high. The efficiency drops by 1% every year.
  • Solar Inverters which are important components of the Solar PV system come with a life time of 10-12 years with warranties for 1-2 years.
  • Batteries – Deep batteries which are used with Solar PV systems come with a lifetime of 5-6 years with warranties for 1-2 years. These need to be replaced to provide good battery backup.

The capacity of the Solar PV system to installed depends on the energy requirements of the building and rooftop space available.

The maintenance required to maintain Solar PV systems is low. But ensure regular cleaning of the Solar Panels and checkup of Solar Inverters for a smooth Solar PV system functioning.

No Solar regulator, are not required for Grid connected system. But a Solar regulator or Charge controller is required for On-grid system to regulate the amount of current and voltage when current flows into batteries. Since there are no batteries involved in Ongrid systems there is no need for Solar regulators.

If you are availing Net Metering yes, there is a need for installing a new bidirectional meter which measures the difference of energy units feeding into the grid and fetching from the grid. [ Power going into Grid – Power supplied from the grid]

. Bases on this the building owner is credited for supplying power to the grid.

Yes you can upgrade the Solar On-grid system. Inverter with higher capacity needs to be installed during the upgade. The capacity of the Inverter should be equal to that of the Solar panel capacity or greater than that of the Solar panel capacity.

Consider the different features of the different types of Solar Panels. Consider factors like rooftop space requirements, shading and other. Know more about the different types of Solar Panels and what best suits you from this article.

There are 2 kinds of Solar Street light systems

Standalone Systems – These kind of systems have individual solar panels per pole to collect solar light and convert it into electricity. THey use batteries to store power or electricity from the solar panels.
Grid Based systems – These kind of systems use a large central solar grid to power a number of solar street poles or solar street lights.

Solar Off-grid solutions are preferable for buildings in remote locations that do not have access to grid power. This also suits people who want to go offgrid and don’t want to depend on grid power.

Batteries enable power to be stored from Solar Panels.This ensures that even if Solar Panels are not generating electricity power can be got from the stored power of batteries. For additional power supply one can supplement the Solar PV systems with diesel generators to provide extra power.

No the Net Metering benefits cannot be availed in case of Off-grid systems. Since Offgrid systems are completely disconnected from the grid power this benefit cant be availed.

This has to do with the sizing of the batteries. First, get to know the energy requirements of the building. The Solar Panels are then sized according to the energy requirements of the building. Other factors are considered like the efficiency of the Solar Panels, Solar panel orientation and others.The battery needs to accommodate the current supplied from the Solar panels. To know more about the sizing check the blog.

The key to long life cycle of the batteries is to ensure the batteries are properly charged and the discharging is limited. We recommend Deep cycle batteries as they manage deeper discharges in a better manner.

As we know Inverters convert DC current generated from the Solar Panels to AC(Alternating Current). The DC current is stored in Batteries and inverters are needed in case of converting DC to usable AC power.

A Charge controller is needed in case of an Off-grid system since a battery is included in the system.The Charge controller ensures that the amount of current and current voltage supplied from the Solar PV systems to the battery is regulated.This ensures the safety of the battery.

The size of the Solar system depends on a number of factors like:

  • The Energy requirements of the building( Consider bringing in Energy Efficiency)
  • Solar Panel Orientation
  • Type of Solar Panels (Consider factors like Solar Panel efficiency, Rooftop space…)
  • Quality of the products installed(Solar Panels, Solar Inverter, Battery)

Check out the sizing of the Solar PV System for more details.

The main reason for getting Hybrid Solar PV system is to keep electricity going even when the grid power goes down.

Yes, you can.  A thing to note is if you want to upgrade the system, it can be very expensive.

Check the system size before retrofitting.

A system size of 5kW is ideal to set up the system with batteries. If the system capacity is less than 5kW consider adding more solar panels with additional inverter capacity to sustain the solar panel addition.

The cost per watt of a Hybrid Solar system is 85Rs per Watt. So a 1KW Solar system costs 85000 rupees. Compared to this the Ongrid Solar system costs around 82 Rs per Watt and and for an Offgrid Solar PV system it cost around 133 Rs per Watt.

LION batteries which are used in consumer electronics are the most preferred batteries for Hybrid Solar PV systems. These batteries  are light and small and provide long lasting life with their deep discharging abilities.

Yes it is worth installing given that the costs of the battery and storage systems are coming down in the recent years.

DC Coupled Systems :

These kind of systems are used for low voltage DC loads.The Direct current output of the Solar Array is converted to voltage of the the DC appliance. In case of a battery bank it is the charge controller. In case of AC loads its the Solar Inverter or Inverter-Charger that converts DC to Ac power.

AC Coupled Systems :

In an AC coupled system the PV array is directly connected to a Solar Inverter. The Inverter converts the DC output of the Solar panels to Direct Current which is supplied to the AC loads. The network can be setup to work as an Ongrid Solar system or Hybrid Solar system. A hybrid solar system can utilize a single hybrid solar inverter or  in case of a retrofit installation have an inverter charger in addition to the existing solar inverter.The inverter-charger is employed to charge and discharge the battery storage bank.

The main component of the Solar PV system is the Solar PV module/Solar Array.
The rest of the components of the Solar PV system are called Balance of the System(BOS). These
include components like Inverters, Charge Controllers, Battery, Wiring, Mounting systems, switches
and others.

  • Solar Module / Array : Are made up of components called Solar cells which are made of
    semiconductor materials like silicon. The Solar cells convert the sunrays falling on the solar modules
    to electricity.(DC)
  • Balance of Components:
    Inverters : These are devices that convert Direct Current(DC) generated from the Solar Panels to
    usable AC(Alternating Current)
  • Charge Controllers: these devices control the voltage and current supplied to the battery from the
    current generated from the Solar Panels.
  • Battery: These devices store energy in the form of Direct current (DC).
  • Trackers: Devices are attached to the Solar Panels in order to track sunlight and to get maximum Solar exposure.

PV stand for Photovoltaic where the solar cells convert incident sunlight on the solar panels into electricity.

The Solar cells are made of silicon wafers. The solar cells are made of 2 layers: Ntype and the Ptype.
The Ntype loses electrons and the Ptype accepts electrons. When sunlight falls on the solar cells. The solar cells absorb sunlight and when enough of sunlight has been absorbed, the N-type releases the outer most electrons (free electrons) and the P-type accepts the electrons. These electrons are made to flow through a circuit in the solar cells creating electricity.

  • A Grid Connected system is the output generated from the Solar PV system is connected to a bidirectional meter. The meter ensures current is either supplied to the the building or in case of excess current produced, is fed to the grid. Here the Grid acts as a virtual battery. The system doesn’t work if there is no grid supply.
  • Offgrid system is the Solar PV system is completely disconnected from the grid. The system can operate with a backup energy system like generator to provide power incase the solar is not generating power.
  • Hybrid system works as a hybrid i.e it can work either as a grid connected or an offgrid system. This is basically an On-grid Solar PV system with a battery backup.

Both Monocrystalline and Polycrystalline solar modules are made of silicon wafers. Monocrystalline Solar Modules are made of single silicon crystal. They are a lot more efficient in the electron flow. But they are lot costly compared to Polycrystalline panels.

The Polycrystalline panels are made by fusing different types of semiconductor materials, with less efficient in electron flow compared to monocrystalline panels. But these are a lot cheaper compared to monocrystalline panels.

Thin film modules are made by the depositing semiconductor material on a ceramic substrate. There are no silicon wafers used as in the case of Monocrystalline and Polycrystalline solar modules. These too are a lot efficient and produce more energy and are shadow tolerant.

The size of the Solar Plant depends on several factors like:

  • Load of the building
  • Rooftop space
  • Efficiency of the Solar panels

The rooftop space needed depends on the energy output of the Solar panels. More the energy output of the Solar Panels bigger is the Solar PV system and more space it occupies. On an average a 1 kW peak power capacity requires about 100 sq.ft. shadow free area on the rooftop

Major costs(around 80%) would be that of the Solar Panels. On an average a solar pv sytem with a 5 KW capacity costs around 3-4 lakh rupees.

There are a number of factors that can affect electricity produced from Solar PV systems. These include:

  • Solar PV rooftop orientation – The direction of the Solar panels in relation to the incident sunlight determines the Solar exposure that directly correlates with the energy output. To track sunlight path solar trackers and Solar panels are used.
  • Shading and Solar Soiling – Shading reduces the efficiency of the Solar panels due to reduced Solar exposure.Efficiency can also reduce due to Solar Soiling – It refers to things that may fall on the Solar panels like dust leaves and so on that reduces the efficiency of the Solar panels. Hence Solar Panel maintenance helps in improving the efficiency of the Solar panels.
  • Weather and climate of the place – This affects the amount of sunlight incident on the Solar Panels.
  • Efficiency of the Solar panels – This determines the amount of electricity output by the solar panels in relation to the incident sunlight.
  • Prevailing Temperature – This affects the efficiency of the Solar Panels and in turn the output of the Solar Panels.

Benefits of going Solar:

  • Attractive ROI and IRR
  • Payback of 4-6 years thereafter revenue up to 25 years
  • Reduce your Electricity Bills
  • Attractive PPA with DISCOM
  • Locked in Electricity tariffs
  • Reliable and proven technology
  • Third party sale, REC’s, Carbon Credits
  • Contribute to India’s energy independence
  • Reduce Your carbon footprint .There are several grants provided by the government of India. Banks are also availing low interest loan schemes to promote Solar. Check out the link for more info:

Home owners can avail NetMetering by which they can get credited for the surplus power supplied to the power distribution companies. It lowers energy costs by reducing the dependence on grid power. They are a secure investment unlike utilities which fluctuate from time to time. It also increases the value of the house with the demand for green sustainable homes.

Other Financial Benefits include:

Acceleration Depreciation

  • Invest in solar and claim accelerated depreciation in your business
  • 80% depreciation on WDV of asset for first 5 years reduces the effective capital cost
  • Save now on your Income Tax, for every Rs.100 invested in Solar, Rs.27 is saved in the first year
  • Project Payback period has reduced by more than a year.

Income Tax Holiday
Income tax holiday for 10 Consecutive years for revenue generated from Solar Plant