Types of solar panels. Which are worth choosing?

Choosing the right type of solar panel is a pivotal decision when making the leap to renewable energy. With various technologies available, understanding their nuances is essential for making an informed choice. This article delves into the world of solar panels, exploring their diverse types, technologies, advantages, disadvantages, power capacities, and cost considerations.

What is a solar panel?

A solar panel, also known as a photovoltaic (PV) panel, is a device designed to harness the energy from sunlight and convert it into usable electricity. It consists of multiple solar cells made from semiconductor materials, usually silicon. These solar cells are interconnected and encased in protective materials to form a solar module, collectively creating a solar panel.

Solar panels operate based on the photovoltaic effect. When sunlight strikes the solar cells' surface, photons from the sunlight energise electrons within the semiconductor material. This energy can be harnessed for different purposes, most often to generate electricity.

Photovoltaic Panels

Photovoltaic (PV) panels are the most commonly used type of solar panels that immediately come to mind.

These panels consist of semiconductor materials, usually silicon, which generate an electric current when exposed to sunlight. The interconnected solar cells generate a flow of DC electricity, which is then converted into alternating current (AC) through an inverter for household or commercial use. 

There are also different types of PV panels, depending on the type of solar cell technology used, which we’ll discuss below.

Advantages: 

• High efficiency
  
  
• Low maintenance
  
  
• Versatile applications

Disadvantages: 

• Affected by low light conditions
  
  
• Higher initial cost

Thermal Panels

Thermal solar panels, also known as solar thermal collectors, focus on capturing sunlight to generate heat for various applications. Unlike photovoltaic panels, thermal panels are designed to absorb sunlight's heat energy and transfer it to a heat-transfer fluid or directly to water, which can then be used for space heating, water heating, or even electricity generation. 

These panels are highly efficient at converting sunlight into heat energy but are limited in their ability to generate electricity. There are three main types of thermal collectors:

• Flat Plate Collectors: These appear similar to PV solar panels as a solid plate of solar glass with liquid-conducting tubes running beneath it in an insulated chamber.
  
  
• Evacuated Tube Collectors: These consist of exposed tubes running in parallel, commonly with a white storage tank connecting them.
  
  
• Concentrating Collectors: These rely on a concave surface that reflects sunlight toward a suspended tube carrying the liquid.

Advantages: 

• High heat efficiency
  
  
• Compatible with heating systems.

Disadvantages: 

• Doesn’t produce electricity for general use
  
  
• Complex installation.
  
  
  
  

Hybrid Solar Panels

Hybrid solar panels combine both photovoltaic and thermal technologies in a single unit, allowing for the simultaneous generation of electricity and heat. By harnessing sunlight for both power and heat, these panels maximize energy production and utilization. 

They are particularly suitable for applications requiring both electricity and thermal energy, such as residential and commercial heating systems.

Advantages: 

• Optimised energy utilisation
  
  
• Space efficiency
  
  

Disadvantages: 

• Higher costs
  
  
• Increased design complexity
  
  
  

The main types of solar panels, according to their technology

As technology has advanced, various types of solar panels have emerged, each utilising unique materials and designs to harness solar energy. While they work in mainly the same fashion, these panels offer distinct advantages and disadvantages based on their technological approach.

Monocrystalline

Monocrystalline solar panels are crafted from single-crystal silicon, resulting in high energy conversion efficiency. Their dark appearance and rounded edges are recognisable features. Typically, monocrystalline panels have an efficiency of 15% to 23% but cost around £0.80 - £1.20 per watt. In other words, a single 450W panel would cost between £360 and £540.

Advantages: 

• High efficiency/energy output
  
  
• Space-saving
  
  
• Highly durable

Disadvantages: 

• Higher cost.
  
  
  

Polycrystalline

Polycrystalline solar panels use multiple silicon fragments to generate electricity. They boast cost-effectiveness but offer slightly lower efficiency compared to monocrystalline panels. Polycrystalline panels have a lower range of efficiency of between 13% and 17%, with top-of-the-range models reaching 19%. They cost around £0.70 - £0.80 per watt (£280-£320 for 400W).

Advantages:

• Cost-effective.
  
  
  

Disadvantages: 

• Sensitive to high temperatures
  
  
• Lower lifespan.
  
  
  
  

Passivated Emitter and Rear Cell (PERC)

PERC solar panels enhance efficiency by adding a rear-side passivation layer. This technology reflects unused light back across the n-type and p-type junctions, minimising energy loss and improving power output. PERC panels excel in efficiency and performance, making them a favourable choice for various applications. They have similar efficiency to monocrystalline panels, ranging between 18% to 23%.

Advantages: 

• Enhanced efficiency
  
  
• Improved power output
  
  
  

Disadvantages: 

• Expensive.
  
  
  
  

Thin-film

Thin-film solar panels are lightweight and flexible, making them suitable for diverse installations. They utilise various materials, such as cadmium telluride (CdTe), amorphous silicon (a-Si), and copper indium gallium selenide (CIGS), to capture sunlight and convert it into energy. 

While mono and polycrystalline panels are most often used in toin commercial or residential applications, thin film is used in more unorthodox situations. 

Advantages:

• Lightweight and flexible
  
  
• Good low-light performance
  
  
• Cheaper

Disadvantages:

• Lower efficiency
  
  
• Faster degradation
  
  
  
  

Cadmium telluride (CdTe)

CdTe thin-film solar panels offer cost-effectiveness and good efficiency. They require less material for production, making them environmentally friendly. However, concerns arise due to the toxic nature of cadmium.

Amorphous silicon (a-Si)

Amorphous silicon thin-film panels are characterised by flexibility and ease of production. They are less efficient than their crystalline counterparts but have lower production costs. Their versatility suits specific applications like portable devices.

Copper indium gallium selenide (CIGS)

CIGS thin-film panels offer high-efficiency potential and better performance in low-light conditions. Their thin and lightweight structure makes them suitable for various settings. However, they can be relatively costly for thin-film panels.

The cost of each type of solar panels

Different types of solar panels have different price points owing to their level of demand, performance, technological advancement, and how complex they are to produce. Typically, you can expect to pay the following for different types of solar panels:

• Monocrystalline: £0.30 to £0.50 per watt OR £200 to £350 for a 450W panel.
  
  
• Polycrystalline: £0.30 to £0.40 per watt OR £160 to £250 for a 400W panel.
  
  
• PERC: £0.30 to £0.45 per watt OR £200 to £350 for a 400W panel.
  
  
• Thin film: £0.20 to £0.30 per watt OR £100 to £200 for a 400W panel.

However, it’s important to note that there are many more factors to consider than just the initial cost of each type of solar panel. Especially if you want to take a long-term financial view, you have to consider the following:

• Efficiency and payback: Solar panels that are more efficient are generally more expensive. However, they also yield more energy, which means you can save more on your utility bills and reach a full return on your investment sooner.

• Degradation: All solar panels lose efficiency with time. More expensive panels, like monocrystalline and PERC, tend to degrade at the slowest rate. However, monocrystalline, polycrystalline, and PERC panels only degrade at about 0.75-1% per year, so the difference is negligible. Thin film, on the other hand, degrades at around 1-2% per year.

• Maintenance: Most solar panels require minimal maintenance throughout their lifespan - only £100 per year on average. However, the more expensive panels generally require the least maintenance, while thin film requires the most.
  
  
  

Power capacity of each type of panel

The power capacity of solar panels is a crucial factor to consider when choosing the right type for your installation. Different types of panels offer varying levels of power output, which directly impacts their efficiency and ability to generate electricity. 

Here is a breakdown of the typical power capacity of each major type of solar panel:

• Monocrystalline: Monocrystalline solar panels typically have higher power capacity compared to other types. Modern monocrystalline panels often offer power capacities ranging from 300W to over 400W per panel, with some premium models even exceeding 450W.

• Polycrystalline: Polycrystalline solar panels generally have slightly lower power capacities compared to monocrystalline panels. Their power capacities typically range from 250W to 350W per panel.

• Passivated Emitter and Rear Cell (PERC): PERC panels, which are an advanced version of monocrystalline panels, offer improved power capacity. These panels often range from 320W to 400W per panel. 

• Thin Film: Thin-film solar panels generally have lower power capacities compared to crystalline panels. Cadmium Telluride (CdTe) thin-film panels typically range from 100W to 350W per panel. Amorphous silicon (a-Si) and Copper Indium Gallium Selenide (CIGS) panels have even lower power capacities, ranging from 50W to 200W per panel.

Keep in mind that the specific power capacity of a solar panel depends on factors such as the manufacturer, technology advancements, and the panel's dimensions. 

The obvious implication is that solar panels with higher output can cater to higher electricity demands.

However, it also influences your ideal systems in other ways. For example, the higher the output capacity per panel, the fewer you will need, possibly simplifying your installation and resulting in less space needed. Despite being roughly the same size, that’s why monocrystalline panels tend to be more efficient than polycrystalline, for example.

What type of solar panels works best?

The best type of solar panel depends on various factors such as your energy goals, available space, budget, and location. However, these are the most typical applications for each type of panel:

            Monocrystalline panels are known for their high efficiency and space efficiency, making them suitable for installations with limited space. They are most              commonly used in residential and commercial settings. 

            Polycrystalline panels offer a cost-effective option with slightly lower efficiency. They are also most commonly used in residential and commercial                      settings. Passivated Emitter and Rear Cell panels combine high efficiency with improved performance under certain conditions. They are suitable for  
            residential, commercial, or industrial settings. 

            Thin-film panels, including CdTe, a-Si, and CIGS, are flxible and generally best suited for unconventional or niche applications. For example, on atypical              roofs or as a portable solution for solar backpacks, camping gear, RVs, and boats.

The choice ultimately depends on balancing efficiency, cost, and specific project requirements to maximise energy production and financial benefits.

What do the different types of panels look like?

             Monocrystalline, polycrystalline, and PERC PV panels are most likely what comes to mind when you picture solar panels. However, even between them,

there are subtle differences the keen-eyed can spot.

Monocrystalline panels are typically uniformly black with rounded-edge cells. They have a sleek appearance that many would consider aesthetic.

Polycrystalline panels feature blueish, square cells with textured surfaces. This is the quintessential mental picture we have of a rooftop solar panel.

True to their name, thin film panels look like a large film that can bend and warp at will. They have a sleek, low-profile design and come in various sizes.

Summary

           Understanding the diverse types of solar panels is crucial in making an informed choice. Monocrystalline panels excel in efficiency and space savings, while polycrystalline panels offer a cost-effective solution. PERC panels combine efficiency and performance, while thin-film panels provide flexibility for unconventional settings. 

Other factors you need to balance when planning a solar power installation are power capacity, design, available space, and cost. With each type of solar panel having its unique place in the landscape, it’s up to you to determine the ideal one for your requirements.