Solar Photovoltaic power generation is expected to reach a new high of 156 TWh in 2020, representing a 23 % increase over 2019. After overtaking biofuel in 2019, solar Photovoltaic accounted for 3.1 % of worldwide electricity output, and it remains the third-largest renewable electricity technology behind hydropower and onshore wind. The electricity generated by the conversion of solar energy, which is most typically done using photovoltaic cells, is known as photovoltaic electricity. Solar panels contain a large number of photovoltaic cells that use the Sun's incoming light to generate power. As a result, the energy currency derived from solar energy is photovoltaic electricity. The flow of electrons in a semiconductor, which are pushed out of their atomic orbit by incoming photons, generates electricity. As technology improves and the demand for sustainable energy grows more prominent, photovoltaic electricity is becoming more popular. This article will explain to you about the Photovoltaic Electricity which will be helpful in preparing the Environment syllabus for the UPSC Civil Service exam.

What are Photovoltaic (Solar) Cells?

• A solar cell, also known as a photovoltaic cell, is an electrical device that uses the photovoltaic effect, physical and chemical phenomena, to convert light energy directly into electricity.
• It's a type of photoelectric cell, which is described as a device with electrical characteristics that change when exposed to light, such as current, voltage, or resistance.
• Individual solar cell devices are frequently used as the electrical components of photovoltaic modules, also known as solar panels.

Photovoltaic (Solar) Cells - Working

• Photovoltaic cells are made up of two or more layers of semiconductors, one of which is positive and the other is negative, lined up next to each other.
• Sunlight, which is made up of small energy packets known as photons, strikes the cell and is either reflected, transmitted, or absorbed.
• When photons are absorbed by the photovoltaic cell's negative layer, their energy is converted to an electron in one of the cell's atoms.
• The electron departs the atom's outer shell as its energy increases. The released electron naturally migrates to the positive layer, resulting in a potential difference between the two layers.
• The electron flows through the circuit when the two layers are coupled to an external circuit, providing a current.

Photovoltaic Cell - History

• Bell Telephone researchers invented the first practical PV cell in 1954.
• PV cells have been used to power US space missions since the late 1950s.
• PV panels were producing electricity in remote, or off-grid, regions without electric power lines by the late 1970s.
• Since 2004, the majority of PV systems in the United States have been grid-connected—that is, they have been connected to the electric power grid—and have been put on/or near residences and buildings, as well as at utility-scale power plants.
• Since the mid-1990s, technological advancements decreased PV system costs, and various financial incentives and government policies have enabled substantially spread PV use to other countries.
• The majority of small-scale PV systems are found on rooftops and are referred to as rooftop PV systems.

Photovoltaic Plants - Types

Photovoltaic plants are divided into three categories: those that are connected to the grid, those that are not, and the hybrid types. There are two sub-classes within the former:

Off-Grid Systems

• As the name implies, this system is decoupled from utility grids (discomms) and saves all excess energy in battery banks.
• It's widely used in places where there are a lot of power outages or there's not a lot of sunlight.
• During these hours, the battery banks supply backup power.

On-Grid Systems

• This is the most common Solar PV system, which is mostly used in residential, industrial, and commercial settings.
• On-Grid Systems receive regular power from the utility grid.
• Excess energy is transmitted to the utility system, where it is either credited to the consumer’s bill or paid, depending on state legislation.

Hybrid Systems

• This type of system, as the name implies, is a hybrid of on-grid and off-grid systems.
• This system is also connected to the grid and has a battery backup.
• It is installed in places where residents are unable to rely on their electrical providers and require a backup during power outages.

Photovoltaic Plants - Challenges and Future Perspectives

Several factors have a considerable impact on the PV system's performance.

• Data Handling: To begin with, data handling may be a challenge in the PV system's implementation. Traditional technology is unable to manage the massive amounts of data created as the number of solar power plants grows. As a result, a strong system that can monitor a significant amount of data in real time must be constructed.
• Security: Second, the security of a wireless monitoring system is critical. System functioning can be threatened by a lack of security. Protection, privacy, and confidentiality, as well as adherence to security rules, should all be ensured.
• Signal Interference: Third, there may be signal interference issues. This can make monitoring the data from the solar PV installation difficult. Slow data transfer, poor module operation, poor signal strength, and disconnection can all be caused by signal interference. All of this lowers the quality of service and increases revenue loss.
• The lifespan of the Node Battery: Fourth, the lifespan of the node battery affects the energy efficiency of a PV system. The PV system, in particular, is made up of many transmitter nodes. The PV-lifespan network is shortened with each node battery failure.
• Not An User-Friendly Option: The fifth need is that the operating system and programming language be user-friendly.
• Range of Inappropriate Data Transmission: Sixth, the data transfer range must be appropriate for the PV system in question. This is critical in systems where the distance between the two farthest PV panels can be measured in kilometers.
• Environmental Effects: Seventh, the effects of the environment on the PV system (such as dust, temperature, radiation, and humidity) are critical to the system's proper operation. Deposition of dust, for example, limits the amount of sunlight captured by solar cells on a PV panel.
• Accuracy of Transmission: Eighth, differing electromagnetic and radio waves can alter the transmission module's accuracy. As a result, compatible shield modules should be built and coupled with data transmission boards.
• The efficiency of Solar Cell Technology: Ninth, the effectiveness of various solar cell methods varies substantially depending on the material used to make them (e.g. mono-crystalline silicon, poly-crystalline silicon, amorphous silicon, thin-film copper indium disulfide, heterojunction incorporating thin film). As a result, the most appropriate solar cell technology should be used to attain maximum efficiency.

Photovoltaic Cell - Advantages

• Environmental Sustainability: Photovoltaic cells produce clean and green energy because no hazardous gases such as COx, NOx, and other pollutants are emitted. They also don't pollute the environment, making them perfect for use in residential settings.
• Economically Viable: The cost of operating and maintaining cells is very cheap. The cost of a solar panel is merely the upfront cost, which includes the purchase and installation.
• Accessible: Solar panels are simple to install and can be made available in rural locations or sparsely populated areas at a lower cost than traditional transmission lines. They are simple to install and do not interfere with daily living in the home.
• Renewable: As it is renewable energy, it is free and abundant in nature.
• Cost: Except for some highly complex sunlight tracking mechanical bases, solar panels have no mechanically moving parts. As a result, the cost of solar panel maintenance and repair is minimal.

Photovoltaic Cell - Disadvantages

• Low Efficiency: Solar panels have low efficiency when compared to other renewable energy sources.
• Uncertain Availability: The sun's energy is sporadic and unpredictable, and it can only be used in the presence of sunlight. In addition, when the weather is cloudy, the power generated is diminished.
• Difficult for Long Distance Transmission: Solar energy transmission over long distances is inefficient and difficult.
• Requirement of Extra Equipment: The current generated is DC, which necessitates the installation of extra equipment such as inverters to convert the DC power to AC current.
• Easily Destroyable: Photovoltaic panels are delicate and can be easily damaged.
• Additional Insurance: Additional insurance payments are required to ensure that the investments are protected.

Conclusion

With an 80 percent capacity, the PV system can last up to 25 years, or 10 years with a 90 percent capacity. The ability to modify the PV panel's displacement in response to the solars motion results in an increase in efficiency. In order to obtain consistent energy for consumption, the PV system can be combined with other renewable (e.g. wind) or nonrenewable (e.g. diesel) sources.

FAQs 

Question: What is Photovoltaic (PV) electricity?

Question: How do photovoltaic cells work?

Question: What are the main components of a PV system?

Question: What are the advantages of using PV electricity?

Question: What challenges are associated with photovoltaic electricity?

MCQs 

1. Photovoltaic electricity is generated by:

A) Burning fossil fuels

B) Nuclear reactions

C) Converting sunlight into electricity

D) Using hydropower

2. Which material is commonly used in photovoltaic cells?

A) Gold

B) Iron

C) Silicon

D) Copper

3. The device that converts direct current (DC) produced by PV cells into alternating current (AC) is called a:

A) Transformer

B) Inverter

C) Generator

D) Rectifier

4. Which of the following is a major advantage of photovoltaic electricity?

A) High greenhouse gas emissions

B) Low operating and maintenance costs

C) Limited to non-renewable sources

D) High dependence on fossil fuels

5. The efficiency of a photovoltaic system can be affected by:

A) The amount of sunlight

B) Temperature and shading

C) The angle of installation

D) All of the above

GS Mains Questions and Model Answers

Q1: Explain the working principle of photovoltaic cells and their role in renewable energy generation.

Answer: Photovoltaic (PV) cells convert sunlight into electricity through the photovoltaic effect. When sunlight strikes a PV cell, made of semiconductor materials like silicon, it excites electrons, creating a flow of electric current. This process generates direct current (DC) electricity, which is then converted into alternating current (AC) using an inverter for practical use. PV cells play a crucial role in renewable energy generation by providing a clean, sustainable source of power that reduces reliance on fossil fuels and lowers greenhouse gas emissions. Their modularity allows for a range of applications, from small-scale installations on rooftops to large solar farms.

Q2: Discuss the advantages and challenges of using photovoltaic electricity in the context of sustainable development.

Answer: Photovoltaic (PV) electricity offers numerous advantages, including renewable energy generation with minimal environmental impact, reduction of greenhouse gas emissions, and energy independence. PV systems have low operating and maintenance costs and can be deployed in remote or off-grid areas. However, challenges include high initial installation costs, the intermittent nature of solar energy, and land-use requirements for large-scale installations. Technological advancements, such as improved efficiency, energy storage solutions, and government incentives, are helping overcome these challenges, making PV electricity a key component of sustainable development.

Q3: Evaluate the role of government policies and incentives in promoting the adoption of photovoltaic electricity.

Answer: Government policies and incentives play a critical role in promoting the adoption of photovoltaic (PV) electricity. Subsidies, tax incentives, feed-in tariffs, and net metering policies encourage individuals and businesses to invest in solar energy systems. Research and development grants further drive innovation, making PV technology more efficient and affordable. Government programs for solar energy deployment in rural areas improve energy access and reduce reliance on non-renewable sources. By supporting regulatory frameworks and financing mechanisms, governments can accelerate the transition to renewable energy, contributing to climate change mitigation and sustainable economic growth.

Previous Year Questions on Photovoltaic Electricity

1. UPSC CSE - 2020

Question: "Discuss the role of solar energy in achieving energy security and reducing carbon emissions."

Answer: Solar energy plays a crucial role in achieving energy security and reducing carbon emissions by providing a clean, renewable source of power. Photovoltaic (PV) systems harness sunlight to generate electricity, reducing dependence on fossil fuels and lowering greenhouse gas emissions. Solar energy is widely available, scalable, and can be deployed in both grid-connected and off-grid settings. By diversifying the energy mix, it enhances energy security and mitigates the impact of fluctuating fossil fuel prices. Government policies, technological advancements, and investment in solar infrastructure are key to maximizing the potential of solar energy for a sustainable and secure energy future.

2. UPSC CSE - 2019

Question: "Analyze the challenges faced in large-scale adoption of photovoltaic (PV) systems in India."

Answer: Large-scale adoption of photovoltaic (PV) systems in India faces challenges such as high initial installation costs, intermittency of solar power due to weather and daylight variability, and the need for large land areas for utility-scale projects. Infrastructure constraints, such as inadequate grid integration and energy storage solutions, further complicate large-scale deployment. Additionally, financing and access to technology can be barriers, particularly for rural and economically weaker sections. Addressing these challenges requires government incentives, investments in research and development, policies to support decentralized solar energy, and enhanced energy storage technologies to ensure reliable and efficient solar power generation.