Photovoltaic Panels: Harnessing the Power of the Sun

Introduction

Do you want to learn the way to change sunlight into electricity? If yes, you are interested in photovoltaic panels, which means a solar panel is the best option. Photovoltaic panels capture the energy from tiny parts of the light known as photons. After capturing photos, photovoltaic cells convert them into direct current electricity that we use to power our houses, use in our devices, and later store in batteries. 

Nowadays, Photovoltaic panels are in high demand because of their easy accessibility,  affordability, and as a renewable source of energy for our homes, communities, and offices. They produce clean energy and reduce dependence on fossil fuels, decreasing environmental pollution. They cut off your electricity bills as well as lower your carbon footprint. But the question is how these panels work. Let’s explore the working process of photovoltaic panels, their types and models, their benefits and challenges,  and how to install them. 

Types of Photovoltaic Panels

The most common types of photovoltaic panels are monocrystalline, polycrystalline, and thin film. Each type has its specifications, features,  benefits, and drawbacks. Each has different efficiency, performance, cost, and appearance. 

Monocrystalline silicon

their cells are made of single-crystal silicon wafers with a uniform black colour. These cells have round edges. Their efficiency is 15-22%, the highest of all crystalline cells. As they have high-quality performance and are long-lasting in terms of durability. They can withstand temperature and can resist degradation. 

But unfortunately, they are the most expensive photovoltaic panels. The reason is that they require a high amount of energy and material to produce them. 

Examples:

• LG NeON 2
• SunPower Maxeon 3
• Canadian Solar HiKu7

Polycrystalline silicon

The cells of polycrystalline silicon are made of multiple silicon pieces. These silicon pieces are blended that make a wafer. Wafer has a blue or speckled colour. Polycrystalline silicon is lower in efficiency than monocrystalline as its efficiency rate is 15%-17%. They are more prone to degradation and heat loss but are cheaper and readily available. Their ready availability is because they consume less energy and need fewer materials to produce them than monocrystalline silicon. 

Examples 

• Trina Solar Honey M Plus
• Jinko Solar Eagle G2
• LONGi Solar Hi-MO 4

Thin film

They are made by depositing one or more thin layers of PV material on a supporting material. This supporting material could be glass, plastic, or metal. Thin film photovoltaic semiconductors are present in two major types in the market. The first is cadmium telluride (CdTe), and the second is copper indium gallium diselenide (CIGS). 

Their efficiency rate is 10% to 13%, which is lower than polycrystalline but much lower than monocrystalline. The performance rate of the thin film is also lower, with a vulnerability to degradation, temperature, humidity, etc. Still, on the other hand, they have the lowest price out of all three PV. They are more flexible, easily accessible, readily available, and produced in large quantities. 

Examples 

• First Solar Series 6 (CdTe)
• Solar Frontier SF170-S (CIGS)
• MiaSolé FLEX Series (CIGS)

Factors affecting the efficiency and performance of photovoltaic panels

Solar irradiance

solar irradiance means the amount of sunlight that reaches the earth’s surface. It varies by location, season, weather, and time of day. If the solar irradiance increases, the PV panels get more solar energy to convert to electricity.

Temperature

Here temperature means the temperature of the PV cells and modules. Higher temperatures decrease the voltage output and elevate the resistance of photovoltaic cells, ultimately leading to lower efficiency and performance. It also affects the photovoltaic panel’s degradation rate and lifespan. 

Shading

Shading means any object that presents is between the sunlight and the Photovoltaic panel, such as trees, buildings, clouds, dust, dirt, snow, etc., that reduces or blocks the sunlight. It directly affects the current flow in PV cells and causes a decrease in power output, creating hotspots. 

Orientation 

Another factor is orientation means the angle and direction that the PV panels face relative to the sun, and it depends upon the latitude, longitude, tilt angle, and azimuth angle of the photovoltaic panel. An optimal orientation means maximising the exposure of the PV panels to direct sunlight throughout the day. 

Inverter efficiency

Inverter efficiency is the device’s efficiency that converts direct current (DC) electricity generated by the PV panels into alternating current (AC) electricity that can be used by appliances or fed into the grid. To achieve higher inverter efficiency, it’s necessary to ensure lesser power loss during the conversion process between direct and alternating current. The average range of inverter efficiency is  90% to 98%.

Mounting Structures and Building-Integrated Photo Voltaic Panels

These devices support and secure PV modules to the roof, ground, or other surfaces. Building-integrated PV (BIPV) is the system that incorporates PV modules into the building envelope, such as the roof, windows, or façades.

Different ways of installing photovoltaic panels

Depending upon the size, type, and location of a PV module, they are installed in multiple ways. Let’s explore the most common ways:

i. Rack mounting

Rack mounting is a common, prevalent, and dominant way to install PV panels on roofs and grounds involving metal frames or racks to hold and tilt the module at a fixed angle. The local latitude, orientation, and electrical load requirements can determine this fixed angle. The rack mounting method is straightforward to install but needs additional wiring and grounding as it adds wind resistance to the roof. 

ii. Tracking

Tracking is a method of mounting PV modules on the ground, allowing them to follow the sun across the sky throughout the day. 

It enhances the energy output and increases the exposure to the direct sunlight of photovoltaic panels. Majorly two types of tracking are common. The first is one-axis tracking, and the second is two-axis tracking. One-axis tracking moves the photovoltaic module from east to west, while two-axis tracking moves the photovoltaic modules in horizontal and vertical directions. Tracking has limitations and challenges, such as needing more upfront and maintenance costs. It is also not fit for every location and climate. 

iii. Building-integrated PV

As represented by its name, its integration of PV modules into the building material. The building material may include roofing tiles, skylights, shingles, windows, and façades. BIPV is beneficial in several ways:

• Provide savings in materials and electricity costs
• Reduce fossil fuel consumption and greenhouse gas emissions
• Add architectural interest to the building

But, BIPV also faces technical and commercial barriers such as: 

• Higher costs
• Lower efficiency
• Complex installation
• Limited design options
• Regulatory issues

Examples of innovative and aesthetic applications of building-integrated PV

BIPV systems provide innovative and aesthetic solutions for the production of solar energy. You can easily incorporate them into your buildings, giving your home an excellent aesthetic. BIPVs are present in different categories. Let’s explore:

Roofing

BIPV roofing products replace conventional roofing materials such as tiles, shingles, or metal sheets. You can also integrate roofings into skylights or atriums. Some examples are: 

• Tesla Solar Roof (USA)
• SunTegra Solar Shingles (USA)
• Onyx Solar Photovoltaic Glass (Spain)
• Hanergy Thin Film Solar Tiles (China)

Windows

Windows are a suitable replacement for conventional glass windows or curtain walls, and you can easily integrate them into blinds and shutters. Their examples are:

• Physee PowerWindows (Netherlands)
• SolarGaps Smart Blinds (USA)
• Heliatek Organic Solar Film (Germany)
• ClearVue Transparent Solar Glass (Australia)

Façades

BIPV façades are the best replacement for conventional cladding materials such as bricks, stones, or metal panels, and you can also integrate them into balconies or railings. Facades examples are:

• Swisspearl Solar Façade (Switzerland)
• Solstex Solar Facade System (USA)
• Issol Luminescent Solar Concentrator (Belgium)
• Solar Squared Glass Bricks (UK)

Inverters and Batteries Of Photovoltaic Panels

Inverters and batteries are two core pillars of a photovoltaic system. Both play critical roles in energy production and storage. Inverters convert the direct current (DC) produced by photovoltaic modules from sn power into alternating current (AC) that we use for different purposes in our homes and offices to run our devices and power the grids. On the other hand, batteries store energy for later use. They store energy when PV modules generate an excessive amount of electricity. Then that energy could be used when the sun is not shining, like at night or when the electricity demand is high. So both inverter and batteries have their specific roles. Let us explore some other roles of them.

Role Of Inverter And Batteries

i. Inverters 

• Inverters are essential for grid-connected PV systems because they enable the synchronisation and integration of solar electricity with the utility grid. 
• They also provide functions such as maximum power point tracking (MPPT), voltage regulation, anti-islanding protection, data monitoring, and communication. 
• Inverters can also be used for off-grid PV systems, as they allow AC appliances and devices that are more common and efficient than DC ones.

ii. Batteries

• Batteries are optional for grid-connected PV systems because they provide backup power in case of grid outages or peak shaving to reduce electricity bills. 
• They also enable the self-consumption of solar electricity and participation in demand response or grid services programs. 
• Batteries are essential for off-grid PV systems, as they provide power during the night or periods of low solar irradiance. 
• They also help stabilise the voltage and frequency of the system.

Different types and models of inverters and batteries

i. Inverters

Majorly three types of inverters for PV systems are standard string inverters, microinverters, and hybrid inverters. 

Standard string inverters 

• Have one input for solar panels and one output for AC electricity. 
• They suit large-scale or uniform PV systems with minimal shading or orientation issues. 

Examples:

• SMA Sunny Boy
• Fronius Primo
• SolarEdge HD-Wave

Microinverters 

• They have one input and one output for each module. 
• They suit small-scale or complex PV systems with shading or orientation issues. 

Examples:

• Enphase IQ7+
• APsystems QS1
• Chilicon CP-250E

Hybrid inverters 

• They have one input for solar panels, one input for batteries, and one output for AC electricity. 
• They are suitable for grid-connected or off-grid PV systems with battery storage. 

Examples:

• Tesla Powerwall 2 + Gateway 2
• LG Chem RESU + SolarEdge StorEdge
• Sonnen ecoLinx + sonnenGateway

ii. Batteries

The two main types of batteries for PV systems are lead-acid batteries and lithium-ion batteries. 

Lead-acid batteries 

• These batteries are the oldest and most widely used for off-grid PV systems. 
• They have low upfront costs, high availability, and long lifespan if properly maintained but they also have some challenges like low energy density, low efficiency, high maintenance requirements, and environmental concerns. 

Examples:

• Trojan T-105RE
• Rolls S6 L16-HC
• Crown CR430

Lithium-ion batteries 

• These are the newest and most advanced types of batteries for grid-connected or off-grid PV systems. 
• They have a high energy density, high efficiency, low maintenance requirements, and long lifespan if properly managed, but they need high upfront costs and have limited availability and safety issues. 

Examples:

• Tesla Powerwall 2 + Gateway 2
• LG Chem RESU + SolarEdge StorEdge
• Sonnen ecoLinx + sonnenGateway

FAQs

Final Analysis

Photovoltaic (PV) panels can be used for various applications, such as residential, commercial, industrial, or utility-scale power generation, and also be integrated with other components, such as inverters, batteries, or mounting structures, to form a complete photovoltaic system. Choosing and using PV panels can have various benefits and challenges for the system’s performance, cost, reliability, and environmental impact. Therefore, it is vital to consider certain factors when selecting and installing PV panels, such as type and size of PV panels, Location and orientation of PV panels,  Type and configuration of PV system, and Maintenance and monitoring of PV system. PV panels are a promising technology for providing clean and renewable electricity generation. However, they also face technical and commercial barriers that must be overcome to achieve widespread adoption and integration. Therefore, further research and development are needed to improve PV panels and systems’ efficiency, performance, durability, and affordability.