Solar plants which may or may not be connected to the utility grid but contain batteries for backup are called off-grid solar power plant. Sometimes, a diesel generator input is provided in place of utility grid to charge batteries in the absence of solar energy and grid.
There are several configurations for this type of solar plant according to priority. These are:
- Solar > Battery > Grid
- Solar > Grid > Battery
- Battery > Solar > Grid
Consumer can choose any of the above configurations according to their requirements.
This type of solar plant arrangement is apt for those, who live in places where electricity is insufficient or unavailable as 24-hour back-up is provided by this system.
Components of Off-Grid Solar Power Plant
The major components of this arrangement are described below:
Solar panels are semiconductor devices which convert sunlight into direct-current (DC) electricity. These are connected either in series or in parallel to add up voltage and current respectively depending on the requirement/designing of the solar plant.
These are long life devices and the warranties provided by the companies are of 25 years. They may well exceed their warranty life in most cases.
Solar panels require very low maintenance as only periodic washing needs to be done. Period of washing varies from location to location but can generally be taken as once in two weeks.
Inverter is an electrical device which converts DC electricity from panels into AC electricity to be used by various appliances in homes, factories etc.
These devices have very high efficiency, generally more than 95%. Manufacturer’s generally provide a warranty of 5 years.
We use off-grid solar inverters having a pure sine wave output.
Batteries are storage devices that store charge for backup.
The sizing of the batteries can be done according to the necessity of backup required.
These are structures on which solar panels are installed. Sometimes, inverter may also be installed on these structures by making appropriate arrangement.
We use galvanized iron (GI) structure. Galvanizing makes the structure corrosion resistant and thus, provides it a long life. Structure’s foundation is designed to cater high wind speeds.
These are wires through which different components of the solar system are connected with each other.
Two types of cables are used in solar power plants, viz., DC cables and AC cables. DC cables are used between solar panels and inverter while AC cables are used between inverter and household appliances.
Direct Current Distribution Box (DCDB)
This is a protection device connected between solar panels and inverter. It also distributes the power feed into it to subsidiary circuits. It consists of various fuses and circuit brakers for protection from the DC circuit.
Alternating Current Distribution Box (ACDB)
This is a similar protection and distribution device as DCDB but connected on the AC side of the solar plant. These also contain various MCBs or MCCBs for protection from the AC circuit.
It is a device used to protect the solar plant from the damaging effects of lightening. It consists of a high potential terminal and a ground terminal. When a lightning strikes the building on which solar plant is installed, the arrestor captures this lightening and the current from the surge is diverted through the arrestor to the earth. Thus, protecting the building.
Several earthing are done while installing a solar power plant to protect the system from occasional over-currents, short-circuits and lightening. The size and number of earthing depends on the capacity of solar plant.
These Solar plants may or may not be connected to the utility grid, depending on the later's availability. These solar plants contain batteries and provide 24-hours power backup. Sometimes, a diesel generator input is provided in place of utility grid to charge batteries in the absence of solar energy and grid.
There are several configurations of these plants available in market. Consumer can choose one of these according to their requirements.
In one configuration, solar panels generate electricity during the day and charge the batteries. Batteries power the complete house load. When the battery level goes below a minimum threshold, the house runs on energy from the solar panels. When these two are insufficient to power the house load, power is drawn from the grid/diesel generator.
Complete 24-hours backup is available in these types of systems. The sizing the battery bank should be done carefully for best performance of the system.
So, this type of solar plant arrangement is apt for those, who live in places where electricity is insufficient or unavailable as 24-hour back-up is provided by this system.
Benefits of installing an On-Grid Solar Power Plant
- Reduce your electricity bill up to 100% for more than 25 years
- Solar power is a free source of energy
- Generate approx. 1600 units of electricity per kWp annually
- Get return on investment within 4 to 5 years.
- Plant life more than 25 years
- Zero maintenance
- Complete 24-hour battery back-up is provided in this system
- Get 25 years warranty on solar panels and 5 years complete system warranty
- No additional/hidden costs
- Save Earth by saving tons of carbon dioxide emissions per year
- Solar panels absorb heat making your roof cooler by several degrees
- Increases property value
- Makes your building a modern green building
In comparison to thermal power plants, solar power plant can save up to 1 kilogram of carbon dioxide emissions per 1 kWh (unit) of solar power. Therefore, by these estimates, one can save up to tons of carbon dioxide emissions per year.
These savings are equivalent to planting hundreds of trees every year.
This not only prevents climate change but also helps reduce respiratory and cardiovascular health issues faced by thousands of people around the world because of increasing pollution.