Rooftops ideal for harnessing solar energy
In urban and rural India, millions of homes and commercial buildings have rooftops that receive ample sunlight during the day. These are ideal for harnessing the sun’s energy by converting it into electric power. This can be done by adding an interface known as an inverter to convert the DC power generated by the solar panels on the rooftop to AC power as most appliances/devices run on AC.
Although rooftops can be used for creating rooftop energy sources, there are various factors to be considered before deciding to install solar panels on a rooftop.
Types of solar systems
There are three types of solar systems that can be considered.
1. On-grid systems
One of them is the on-grid system in which the rooftop solar system is integrated with the main grid supply. This system allows power to be used from the grid supply only when the rooftop solar system is unable to supply the required power. Thus, a well-planned rooftop system can efficiently supply power without using grid supply saving expenses otherwise incurred on using power from the grid. In fact, this system can earn revenues as any excess power generated can be fed to the grid for which DISCOMs pay compensation using ‘net metering’.
2. Off-grid systems
The second one is the off-grid system in which the rooftop solar system is not linked to the main grid. This system can run on its own with its own battery. The solar power generated from the rooftop solar system charges the battery which is then used to power various applications. This system is very useful when there is no grid supply or when the supply is very erratic with frequent breakdowns.
3. Hybrid systems
The third one is the hybrid system in which both on-grid and off-grid systems work in tandem. In this type of system, though a battery is used, the advantage here is that after the battery is fully charged the excess power generated is fed to the grid which generates additional revenues for the consumer.
Feasibility of rooftops for generating power
For home solar rooftop systems, the nature of the roof is very important to determine its feasibility. The factors that need to be considered are as follows:
- The availability of sunlight throughout the year and the area available on the rooftop is important to calculate the power that can be generated. A typical home solar panel can produce about 290 watts by harnessing one hour of direct sunlight.
- If sunlight falls for 8 hours then the solar panel can produce 2320 watts electric power.
- The orientation of the rooftop towards the sun is important. Exposure towards the south is the ideal orientation for the panel. If the roof is naturally sloping and facing south then it is very ideal for installing rooftop solar panels. This is because India is situated in the northern hemisphere and south facing rooftops receive the maximum amount of sunlight as the earth rotates on its own
- axis at an inclination. However, if the roof is flat solar panels will need to be placed at an angle facing south to receive the maximum possible sunlight. Further, high rise buildings should not hinder the exposure of the solar panels to sunlight.
- The decision on choosing a suitable type of rooftop solar system impacts the cost of the system. Each type involves different components and the costs could vary depending on them
How much rooftop to use
Based on the availability of sunlight and the space available on the rooftop the maximum power that can be generated can be determined. Further, based on the type of system – on-grid, off-grid or hybrid – the homeowner can decide on the space to be allocated on the rooftop for producing electric power.Cost-benefit
The homeowner can make a cost analysis and decide on the quantum of electricity to be produced so as to be ..
- Rooftop solar systems are becoming a popular source of electric power because it is a renewable energy source and it is abundantly available during the day. With careful planning, implementing an appropriate rooftop solar system can translate into never-ending electric power supply at minimal recurring expenses.