Photovoltaic system has electricity-generating solar panels mounted on the rooftop of a residential or commercial building or structure.

It generates power at your own space by utilizing un-used roof space at a reasonable cost.

 
• Gain freedom from power cuts and exposure to unstable power pricing.
• Commit to a stable/reliable source of solar power.
• Added incentive of going green
• Reduce dependency on grid power & diesel generators

 
• Photovoltaic roof-top installations at the tail-end of the grid can enhance grid-stability and reduce losses.
• Savings in land requirement and costs.
• Creation of value from under-utilized /unutilized rooftops.
• Good choice for distributed power generation system.

 
• Need a shadow free area on the rooftop.
• Even a small shadow could affect generation output on the entire string of panels.
• Approx 100-120 sqft is required for installing a 1kWp system.
• Ideally, the wiring b/w solar panel on the roof and inverter placed indoor shouldn’t be more than 20m to avoid DC losses.
• Inverter and meters should be placed at a conveniently accessible location indoors away from sun/rain.
• Batteries need to be placed separately indoors.

Generation depends on local weather and other conditions like temperature etc

• Most places in India have 300 days of good sunshine.
• Ideal temperature for maximum generation is 25^oC.
• Dust on the panels will reduce generation. Hence it is advised to clean the panels once every week atleast.

 
• For grid-tied systems, the local electrical authority will decide to allow the installation depending on the neighborhood transformer ability to take the load etc.
• Should be an existing consumer and regularly paying the bills.

• This is a breakup of the total system cost for a 1kWp system without batteries. Final cost would depend on each installer.
• Solar usually is an upfront investment, maintenance is at a minimal.

 
1. The cheapest quote might not necessarily provide the best quality of equipment and service.
2. Solar systems are long term investment, hence selecting a good quality professional installer will reap benefits in the long term.
3. Look for past projects that the installers have done and market credibility.
4. MNRE approved installers are the best bet.
5. Ask for certified products only from the installers.

Grid-tied : Here the solar energy generated during the day is immediately consumed by the electrical load without any storage. The system powers the load in conjunction with the Grid power. Any surplus power is fed back to the grid via the net meter for which you reduce your monthly bill or earn money from local EB depends on the local state policy.
It is NOT a backup and cannot be considered as a standalone power solution for the loads. It does NOT produce power during power failure as the inverter shuts down the system to stop sending power into the grid and avoids the risk of electrocuting utility personnel who are working to repair the grid.

Grid-interactive : This system is everything that a grid-tied system is and it works in conjunction with either a battery backup or diesel generator to support the load even during a power failure. Supports multiple input power sources.

Off-grid : This system does not work with the grid and is designed to work only with a battery backup or diesel generator in off-grid applications. It is a backup and a standalone power solution for the loads.

Solar PV panels : They work by converting sunlight into electricity. They do not use the heat from the sun, and in fact can see a reduction in power output in hot climates. The electricity generated by the PV panels is Direct Current (DC).

Mounting structures : To mount the panels on the rooftop. Design will depend on the type of roof. It should last the lifetime of the solar panels i.e 20-25 years.

Inverters : Converts Direct Current (DC) into Alternating Current (AC). Various types of inverters are available for various applications. Good inverters provide stable power output.

Battery : If solar power is required to be stored for night time use when solar power is not available, backup is required.

Charge controller : required to regulate the charging of batteries. Protects solar panels and batteries.

Cables, Switchgear and Fuses : required to connect panels to inverters, load and control flow of electricity.

Except for in off-grid scenarios, rooftop solar is best used in grid-tied systems where it is doesn’t serve as a primary backup or main power but works along with existing grid and helps in reducing your bills or earn depending on the state solar rooftop policy.

For grid connected systems- If your installed solar capacity is more than day-time peak load then it runs completely on solar. If it is less then it runs on solar with the rest from the grid.

During the day-time, solar runs the loads and the excess solar power will be sent back to the grid via the net meter which captures the number of units consumed from the grid and number of units sent back to the grid.

The net meter will capture both the values accumulated for a month - number of units of EB power consumed from the grid and number of units of solar power sent back to the grid.
Net units consumed: total monthly units of grid consumed– total monthly units of solar sent back – This reduces your monthly electricity bill.
If your net units consumed are negative, then your local EB owes money to you.

A grid-tied system does NOT produce power during power failure as the inverter shuts down the system to stop sending power into the grid and avoids the risk of electrocuting utility personnel who are working to repair the grid.
A grid-interactive system can use the solar power to power the loads or charge the batteries even during a power failure.

Karnataka : Net metering policies promote distribution generation where consumers with roof availability can generate and sell electricity to the utility. The utility will pay the customer if the net export exceeds the import for the month.

KERC approved tariff in INR per kWh

Tamil Nadu : Consumers who install grid-connected solar PV systems can apply for solar net metering. It is advisable that your solar PV system size has an annual estimation generation of not more than 90% of estimated consumption (TANGEDGO will only credit 90% of energy export if energy export is greater than energy import for a 12 month period).