Advantages and Disadvantages of Solar Electricity

This article explores the pros and cons of using solar-powered electricity in your home.

What is Solar Electricity?

Solar electricity refers to the process of converting sunlight into electrical energy. There are two main methods for achieving this:

• Photovoltaic (PV) System: This system directly converts sunlight into electricity using solar panels.
• Concentrating Solar Thermal Power (CSP) System: This system uses mirrors to focus sunlight onto a receiver, which then converts the solar energy into heat to generate electricity.

For home use, PV-based solar electricity is the more common approach.

In a PV system, the solar panel’s PV cells absorb sunlight. This absorbed energy causes electric charges to move, generating electricity. As illustrated in the figure, a solar-powered electricity system includes an inverter, which uses solar power to charge a battery. When the main power grid fails, the inverter converts the DC power from the battery into AC power to run your appliances.

CSP systems, on the other hand, utilize mirrors to reflect and concentrate sunlight onto receivers. These receivers collect the solar energy and convert it into heat, which is then used to generate electricity. CSP technology is typically used in large power plants.

Solar Electricity Block Diagram

The block diagram illustrates the components of a typical solar power electric system:

• Solar Panel: Solar cells within the panel absorb sunlight. This causes electrons to move, generating DC voltage, which is then sent to the solar inverter. Solar panels are available in various voltage ratings, such as 12V, 20V, and 24V. A 12V panel can be used with a 12V charge controller, a 12V inverter, and a 12V battery. Solar panels can be connected in series or parallel to achieve different power outputs based on the consumer’s needs.
• Batteries: Batteries are available with different ratings and nominal operating voltages, such as 12V, 24V, and 48V. Based on backup time requirements, users can select appropriate batteries with capacities like 120 Ah, 150 Ah, or 200 Ah.
• Solar Charge Controller: This device regulates the current flow into and out of the battery. It prevents overcharging and deep discharging by controlling the DC voltage or current going to the battery. There are two main types of charge controllers:
  • PWM (Pulse Width Modulation) based: Functions as a switch between the solar panels and the battery. When the battery is fully charged, it cuts off the solar PV panel power.
  • MPPT (Maximum Power Point Tracking) based: Functions as a DC-to-DC converter. It’s used when the solar panel output voltage is considerably higher than the battery voltage.
• UPS or Inverter: This converts DC energy into AC energy, which is used by appliances in the home. Modern inverters often come with a built-in charge controller (PWM or MPPT).
• Load: This refers to the electrical home appliances that use AC electrical power, such as bulbs and fans.

There are three main types of solar electric systems, classified by the type of solar inverter used:

1. Off-Grid or Independent System: This system operates similarly to a normal inverter system. The DC voltage generated by the solar PV system charges the solar battery. During power outages, the inverter uses DC input from the solar battery and converts it into AC energy to power home appliances. It’s commonly used in areas with frequent power cuts.
2. Grid-Connected System: This system must be integrated with the utility grid power station. Excess power generated by the solar inverter is fed back into the power grid using a bi-directional meter. There’s no battery in this system, so during power outages, the inverter stops functioning, and the consumer doesn’t have access to power. This is used in areas with rare power cuts.
3. Hybrid System: This is a combination of off-grid and grid systems. It’s connected to both the power grid and a battery. During normal operation, it supplies AC power to the home and charges the battery. Any excess power is fed back into the grid. During power outages, the inverter switches over to the battery supply and delivers AC power independently of the grid.

Benefits or Advantages of Solar Electricity

Here are the main benefits of using solar electricity:

• Cost Savings: Reduces reliance on the main power grid, saving money on electricity bills.
• Easy Installation and Maintenance: Solar systems are relatively easy to install and maintain.
• Continuous Power Supply: Provides a reliable power source, ensuring continuous operation of electrical appliances.
• Reduced Carbon Footprint: Contributes to reducing carbon emissions and mitigating global warming.
• Renewable and Pollution-Free: A renewable energy source that doesn’t produce pollution.
• Quiet Operation: Solar cells operate silently, without generating noise.
• No Harmful Emissions: Solar energy doesn’t produce any harmful emissions, reducing health risks and healthcare costs.
• Independence from Fossil Fuels: Solar electricity doesn’t rely on fossil fuels for generation.

Drawbacks or Disadvantages of Solar Electricity

Here are the main drawbacks of using solar electricity:

• Weather Dependency: Solar energy can’t be harnessed in certain conditions, such as during storms, winter, cloudy days, or at night.
• High Initial Investment: The initial cost of installing a solar-powered electric system can be expensive.
• Space Requirements: Solar electric systems require a significant amount of space for installation.
• Not Suitable for High Electricity Usage: It might not be suitable for homes with high electricity demands or those with many children who use electric-powered toys or gadgets.