Advantages of Solar Electricity | Disadvantages of Solar Electricity

This page covers advantages and disadvantages of Solar Powered Electricity at home. It mentions benefits or advantages of Solar Electricity and drawbacks or disadvantages of Solar Electricity.

What is Solar Electricity ?

The conversion of sunlight into electrical energy is known as solar electricity. There are two ways sunlight is converted into electrical energy viz. Photo-Voltaic (PV) system and Concentrating solar thermal power (CSP) system.

At home, PV based solar electricity is used. In PV system, sunlight is absorbed by PV cells in solar panel. The solar energy moves electric charges which is proportional to E-field in the cell. This causes electricity to flow. As shown in the figure, solar powered electricity system houses inverter which charges battery using solar power. When power goes, inverter converts DC from battery unit into proportional AC to power the electrical appliances.

CSP system uses mirrors which reflect the sunlight and concentrate the same on receivers. These receivers collect the solar energy and convert it into heat which can be used to generate electricity. CSP based solar powered technology is used in large power plants.

The block diagram of solar electricity system is shown in the figure. Following components are used in a typical solar power electric system.
Solar panel : Solar cells in the panel absorb sublight. Due to these electrons start moving in the solar cells and consecutively generate DC voltage. This DC voltage is sent to solar inverter. Solar panels are available in various nominal voltage ratings such as 12V, 20V and 24V. A 12V panel can be used with 12V charge controller, 12V inverter and 12V battery. The solar panels can be connected either in series or parallel to achieve different powers as desired by the consumers based on usage.
Batteries : The batteries are available with different ratings with nominal operating voltage of 12V. Battery is also available with 24 V and 48 V. Based on backup time requirements, user can select appropriate battery with 120 Ah, 150 Ah or 200 Ah.
Solar charge controller : The controller is used to regulate amount of current flow in and out of the battery. It handles both over-charge and deep discharge of the battery by controlling DC voltage or current going to the battery. There are two types of charge controllers viz. PWM (Pulse Width Modulation) based and MPPT (Maximum Power Point Tracking) based. Charge controllers are available as separate modules or housed in the inverter itself. PWM controller functions as switch between solar panels and battery. When battery is fully charged, it cuts off solar PV panel power going into the battery. Usually during battery charging mode it allows connections between solar panels and the battery. MPPT controller functions as DC to DC converter. MPPT controller is used when solar panel output is considerably higher than the battery voltage. Refer difference between PWM and MPPT >> solar charge controllers.
UPS or Inverter : It converts DC energy into AC energy which is used by appliances in the home. Now-a-days inverter comes along with built-in charge controller (PWM or MPPT).
Load : The electrical home appliances which utilizes AC electrical power is known as load. It includes essential devices such as bulbs, table fans, ceiling fans etc.

Following are the types of solar electric systems based on three different kinds of solar inverters.
1. Off-grid or independant system : It works similar to normal inverter system. In this system, DC voltage generated by solar PV system is used to charge the solar battery. During power cuts, inverter takes DC input from solar battery and convert it into AC energy to run home appliances. It is used in the areas where there is frequent power cuts.
2. Grid-connected system : In this system, inverter must be integrated with utility grid power station. Un-utilized power generated by solar inverter is injected into power grid using bi-directional meter. There is no battery in this system. Hence during power cuts inverter stops its functioning and consumer will not have access to power. It is used in the areas where there is rare power cuts.
3. Hybrid system : It is the combination of off grid and grid systems. This system is connected with both power grid and battery. During normal operation it supplies AC power to the home and charge the battery as well. Moroever excess un-utilized power is fed to the grid. During power cut conditions, the inverter is switch over to the battery supply and delivers AC supply independent of the grid.

Benefits or advantages of Solar Electricity

Following are the benefits or advantages of Solar Electricity:
➨It saves money by reducing mains power usage from grid.
➨It is easy to install and maintain.
➨Consumers will have comfort as they can use electrical appliances all the time.
➨It reduces carbon footprint which helps in reducing global warming.
➨It is renewable and pollution free technique.
➨Solar cells used here do not make noise.
➨Solar energy does not have any harmful emissions. Hence solar electricity is beneficial to human being as it reduces health risks and health related expenditure also.
➨Solar electricity does not depend on fossil fuels for its generation.

Drawbacks or disadvantages of Solar Electricity

Following are the drawbacks or disadvantages of Solar Electricity:
➨Solar energy can not be harnessed in certain conditions such as stormy weather, during winter season, during cloudy day or at night. Hence solar electricity is not available during these period.
➨Initial investment to install solar powered electric system is expensive.
➨Solar electric system requires more space to install.
➨It is not suitable for home where high usage of electricity is required. Moreover it is not ideal for home having more children requiring use of electric powered toys or electric gadgets.