WORKING of an on-grid solar system for home
The generation of electricity in an on-grid solar system starts with solar panels and then goes through several steps to keep your house powered up during the day as well as at night.
Here's what happens when you install an on-grid solar system:
Solar panels absorb sunlight and convert it into direct current (DC)
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The DC current goes into the inverter that converts it into alternating current (AC)
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The alternating current is fed into a bidirectional meter
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The bi-directional meter supplies AC power to your home to run all household appliances
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This meter supplies excess electricity (units that are not consumed) to the grid
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When the exported units are needed later (eg. at night), the bi-directional meter imports them from the grid
The exchange of electricity back and forth from the grid via the bi-directional meter is called net metering.
COMPONENTS of the residential on-grid solar system
#1. Solar panels
Solar panels in a solar grid for home are the most visible parts. They’re installed on the rooftop, facing the South direction. When sunlight falls on these panels, they absorb that sunlight and convert it into electricity.
The solar electricity directly from the panels is in the form of DC power. Since homes require alternating current (AC), there’s the need for a solar inverter to convert direct current into alternating current.
#2. Solar inverter
The entire solar system would have been an impractical model had there been no solar inverter. The solar inverter takes up the role of converting DC into AC.
This conversion is essential because that’s the only way to convert electricity generated from an on-grid solar panel into a usable form (AC) that can run household appliances.
#3. Solar mounting structures
These are the pillars that carry the weight of solar panels. They have to be of a standard grade so that they can withstand heavy winds during storms & cyclones and hold the weight of the solar panels for 25 years (that’s the life of a solar system).
The best solar mounting structures are prefabricated in precision labs. They’re coated with hot-dip galvanizing on steel to make them rust-proof.
They must be designed to sustain the wind speeds as defined for the installation location and height of the building.
#4. Solar accessories
These include the AC and DC cables that are required for wiring solar panels and connecting different parts to make the entire solar grid functional.
The next most important accessories required to set up an on-grid solar system are DC combiner boxes and AC combiner boxes.
A DC combiner box works like an isolation box. All the cables carrying DC current from the panels are isolated in this box. DC power coming from the panels can be as high as 1000 volts, even more. It’s dangerous (potentially lethal); hence, the requirement of a DC combiner box.
This box feeds the DC current into the solar inverter and the solar inverter produces alternating current. This AC power is fed into an AC combiner box (all cables carrying the AC current from multiple inverters are combined in this box.)
Once the entire on-grid solar system is set up, earthing is done using earthing strips and wires.
Please note: all the DC cable connections are made using MC4 connectors.
#5. Bi-directional meter
This is a smart tracking meter that is basically designed to keep a track of:
1- Electricity supplied to the grid
2- Electricity imported from the grid
An on-grid solar system does not get functional until and unless the regular meter is replaced with a bi-directional meter.
NET METERING on on-grid solar system
The entire concept of an on-grid solar system works on the principle of net metering.
Net metering can be best understood as a means for the discom to keep a track of the power that was generated by the solar plant, the power that was consumed, the power that was supplied to the grid, and the power that was imported.
At the end of every month when the electricity bill is generated, the readings from the bidirectional meter give an account of:
1- How many units were supplied to the grid
2- How many units were taken from the grid
If you supplied more than you consumed, those units will be deducted from your bill. It will reduce the bill further.
If you had to use extra units from the grid on top of what your solar plant generated, those units would be added to your bill.
TOP 8 BENEFITS of using an on-grid solar system
A solar system is of 3 types: on-grid, off-grid, and hybrid
Although there are three types, it’s the on-grid solar system that’s used and trusted by most homeowners in India.
Naturally, there ought to be some extraordinary benefits of an on-grid solar system for home.
Those are the benefits we’re focusing on:
1- It’s easy to keep a track of the units of electricity that your solar system generated
2- It’s easier to understand the solar electricity bill
3- Once the solar on-grid system’s price breaks even in 3 to 5 years, you get free solar electricity for the next 20-22 years
4- The monthly electricity bill reduces substantially
5- There’s no battery requirement. Your grid plays the role of the battery. The system will directly supply excess units to the grid and take them back when needed
6- Since there’s no battery, there are no battery replacement charges involved
7- Out of all the 3 types of solar systems, the on-grid solar system for homes is the most affordable option
8- The government offers a subsidy only on an on-grid solar system for residential homes (that use DCR panels)
POWER OUTAGES on on-grid solar systems
Every system has benefits as well as certain limitations - an on-grid solar system is no different.
Although its connection with the grid is a sure benefit, it's also a limitation. When there's a power cut from the grid, the on-grid solar system automatically shuts down.
This interruption in the supply of power is known as a power outage. Nevertheless, on-grid solar systems in urban areas with a reliable grid are unbeatable when it comes to meeting all the power requirements of a home.
The main reason that an on-grid solar inverter is designed in a way that it automatically shuts down if the grid fails is to eliminate safety risks. This particular feature that differentiates on-grid inverters from all other types is called Anti-Islanding Protection.
During power outages, an on-grid inverter will stop generating AC power immediately. Otherwise, the electrical maintenance personnel working directly with the wiring at the location of the electrical fault may suffer from electric shocks.
On-grid Solar system types based on their capacities CAPACITIES
In terms of subsidy, the government offers a subsidy for an on-grid solar system that uses DCR panels. For those consuming 0-150 units per month, a subsidy ranging from ₹30,000 to ₹60,000 is available for 1-2 kW solar plants. Households with a consumption of 150-300 units can receive between ₹60,000 and ₹78,000 for 2-3 kW systems, while those consuming over 300 units are eligible for ₹78,000 for systems above 3 kW.
Let’s find out the basics since the calculations will also help you in finding out the size of the solar system that you should install at your home.
1 kW on-grid solar system
A 1 kW grid-tied solar system produces roughly 1400 units of electricity on an average/year, which means:
1- The approximate units generated by a 1 kW on-grid solar system in a month will be 116 units (1400/12)
2- If the average electricity tariff/unit in your city is ₹8, you will save approximately ₹11,200 in one year (1400 X 8)
2 kW on-grid solar system
A 2 kW grid-tied solar system will produce roughly twice the units produced by a 1 kW system i.e., 2800 units on an average/year. It means:
1- The approximate units generated by a 2 kW on-grid solar system in a month will be 232 units (116 x 2)
2- If the average electricity tariff/unit in your city is ₹8, you will save approximately ₹22,400 in one year (2800 X 8)
3 kW on-grid solar system
A 3 kW grid-tied solar system will roughly produce three times the units produced by a 1 kW system i.e. 4200 units on an average/year. It means:
1- The approximate units generated by a 3 kW on-grid solar system in a month will be 348 units (116 x 3)
2- If the average electricity tariff/unit in your city is ₹8, you will save approximately ₹33,600 in one year (4200 x 8)
5 kW on-grid solar system
A 5 kW grid-tied solar system will produce roughly 5 times the units produced by a 1 kW on-grid solar system i.e., 7000 units on an average/year. It means:
1- The approximate units generated by a 5 kW on-grid solar system in a month will be 580 units (116 x 5)
2- If the average electricity tariff/unit in your city is ₹8, you will save approximately ₹56,000 in one year (7000 x 8)
10 kW on-grid solar system
A 10 kW grid-tied solar system will produce roughly 10 times the units produced by a 1 kW on-grid solar system i.e., 14,000 units on an average/year. It means:
1- The approximate units generated by a 10 kW on-grid solar system in a month will be 1160 units (116 x 10)
2- If the average electricity tariff/unit in your city is ₹8, you will save approximately ₹112,000 in one year (14,000 x 8)
On-grid solar system PRICE WITHOUT SUBSIDY
The price range of an on-grid solar system depends on many factors. It varies based on:
- The type of solar panels
- The type of inverter
- The type of panel mounting structures
- Whether the solar installation company provides a maintenance service with the installation
- Product variant (including the guarantees and warranties provided by the installer)
Here's a reference table concerning the price range of a grid-tied solar system:
| The capacity of the solar system |
Cost of the solar system |
| 2Kw |
₹1.6L to ₹1.9L (without subsidy)
₹0.8L to ₹1.15L (with subsidy) |
| 3Kw |
₹2.15L to ₹2.55L (without subsidy)
₹1.4L to ₹1.8L (with subsidy) |
| 5Kw |
₹3.05L to ₹3.6L (without subsidy)
₹2.3L to ₹2.8L (with subsidy) |
| 10Kw |
₹5.9L to ₹6.6L (without subsidy)
₹5.1L to ₹5.8L (with subsidy) |
The government of India offers a subsidy on the installation of a solar system, but there are a few conditions:
- The subsidy is offered for the installation of a solar system for residential installation only.
- The subsidy is applicable only for made-in-India (dcr) solar panels.
- The subsidy is capped at ₹78,000 for on-grid solar systems above 3 kW when the average monthly electricity consumption will be more than 300 units
SUBSIDYfor homeowners
New rates for subsidy on solar panel systems
For 1-2 kW systems: ₹30,000 to ₹60,000
For 3 kW systems: ₹78,000
- ₹60,000 for 1st 2 kW
- ₹18,000 for the next 1 kW
The rates of govt subsidy on solar under the new scheme are capped at ₹78,000 for systems above 3 kW when the average monthly electricity consumption will be more than 300 units.
Here is an example calculation for your reference:
| System size |
New subsidy rates (for applications filed on or before February 13, 2024) |
| 1Kw |
₹30,000 |
| 2Kw |
₹60,000 |
| 3Kw |
₹78,000 |
| 5Kw |
₹78,000 |