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What are photovoltaic systems?

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Photovoltaic technology works by converting the sun’s energy into electricity. A photovoltaic cell, also referred to as a solar cell, uses semiconducting materials such as silicon to convert light into electricity – this is what’s known as the photovoltaic effect. 

In our jargon-free guide to photovoltaic systems, our experts delve into how the technology works and the system’s components and compare different types of solar panels and their benefits.

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What is a photovoltaic system?

A photovoltaic system is a system that generates renewable energy via photovoltaic cells and then converts it into usable electricity. Photovoltaic systems consist of one or more solar PV panel along with an inverter.

Step-by-step guide to how photovoltaic systems work: 

  1. Solar cells use a semiconductor material – usually silicon – to collect solar energy from the sun’s rays. 
  2. The collected energy produces an electrical charge, which releases an electric current known as direct current (DC). 
  3. DC electricity is converted into alternating current (AC) via the photovoltaic system’s inverter. 
  4. AC electricity can be used to power home appliances or stored in a solar battery for later use.  

Two forms of energy can be generated via solar panels – electricity and heat. Solar PV systems work as described above. Solar thermal systems, meanwhile, convert sunlight into heat, and hybrid systems use PV materials, with electricity routed to a hybrid inverter and solar battery. 

What is the difference between solar panels and photovoltaic systems?

This is where solar panel terminology can become confusing. Solar panel is a general term that often refers to photovoltaic systems and solar panels – but you should know that while all PV systems are solar panels, not all solar panels use PV technology. Here’s the difference: 

Solar PV panels: use the photovoltaic effect. Electricity is generated when a photon makes contact with its semiconductor surface to release an electrical charge known as direct current (DC).  

Solar thermal panels: also known as solar thermal collectors, these are roof-mounted just like solar PV panels. This type of panel turns solar energy into heat instead of power. They collect sunlight to heat a liquid running through the panels – usually a mixture of water and antifreeze. The heated water is sent to the heat exchanger inside your water tank, and the exchanger then heats the water. The heat is then released for space and water heating. The water flows back to the thermal collectors for reheating.

What are the components of a photovoltaic system?

Photovoltaic system components
Photovoltaic systems rely on several key components to power your home (Adobe)

Photovoltaic systems typically consist of several components, some of which are crucial to the inner workings of the system, while others are optional. 

Solar array

A photovoltaic system consists of multiple solar panels, which are connected to form a solar array. PV systems are typically mounted to your roof using brackets that are secured via bolts. Your solar array must be mounted at an optimal angle to maximise sunlight exposure – 30 to 35 degrees is the desired angle. 

Your solar panel’s photovoltaic cells collect sunlight, which is then converted into DC electricity.   

Inverter

An inverter is a crucial component within a photovoltaic system. As previously mentioned, solar panels collect sunlight and convert this into DC. An inverter’s role is to convert electricity from DC to AC, which is needed to power your home’s electrical appliances.    

Battery bank

A battery bank stores unused energy generated from your solar panels. This optional component allows homeowners to save more money on their energy bills. Also known as solar batteries, a battery bank can store excess electricity to power your home during the evening or on cloudy days when your panels are generating less or no electricity. Though its money-saving capabilities are desirable, battery banks are costly. 

Charge controller

This component is only necessary if you have installed a solar battery. For those who have, it’s what controls the DC from your solar panels, ensuring your batteries don’t overcharge – which can cause permanent damage – by stopping the flow of current. Charge controllers can regulate and monitor energy. .  

Utility meter

All households have a utility meter. Its purpose is to measure your energy consumption. Your utility meter will be connected to your photovoltaic system at the point of installation and measure your energy consumption as well as your system’s energy generation – if you have not installed a battery, the surplus is fed back to the electric grid, and you’re usually paid for this through the Smart Export Guarantee (SEG) scheme. 

Electric grid 

Most UK homes are connected to the electric grid. Living off-grid means you’ll rely solely on the renewable energy generated by your solar panels – which isn’t a reality for most. To do this, you’d need to store enough electricity in your solar batteries to power your home 24/7. 

For those not off-grid, your surplus electricity is fed back to the grid. Similarly, if your battery is full, the excess electricity will also feed back to the electric grid.

Are photovoltaic solar panel systems worth it?

Photovoltaic systems solar panels and thermal collectors
Photovoltaic systems can feature both solar panels and solar thermal collectors to provide electricity and heating or hot water (Adobe)

Installing a solar panel array can reduce your carbon footprint and lower your energy bills. While these are both desired outcomes, the benefits you receive will depend on the type of solar panels you choose. 

Solar panels vs solar tiles

Both solar panels and solar tiles work in the same way – collecting the sun’s energy via photovoltaic cells for it to be converted into usable electricity. The differences between the two are mostly to do with panel efficiency, which can drastically affect the overall performance of your solar array. 

Solar panels vs thermal collectors 

Solar PV panels work by collecting the sun’s rays and converting them into electricity to power your home. Thermal collectors are used to generate heat, rather than power, that can be used to heat homes and water.  

Types of solar systems compared

Key factors Solar panels Solar tiles Thermal collectors
Efficiency Have an average efficiency of 20 per cent and up to 22 per cent or higher Have an average efficiency of 10 to 20 per cent Are 60 to 80 per cent efficient
Lifespan Average lifespan of 25 to 30 years Average lifespan of 25 to 30 years Average lifespan of 25 years
Average Warranty 15 years 10 years Five to 10 years

How to maximise a photovoltaic system

Photovoltaic systems generate electricity to power homes and commercial buildings. With technological advancements, some solar panels now have an efficiency surpassing 20 per cent. This means the solar panel can convert 20 per cent of the sun’s energy into usable electricity. 

However, regardless of efficiency, roof pitch, orientation and cell type will also affect your solar array’s performance. 

Roof pitch 

For your solar panels to maximise sunlight hours, they should be pitched between 30 and 40 degrees. Research suggests this is the optimal angle to maximise sunlight exposure. As a general rule of thumb, the more sunlight your panels receive, the more electricity they can generate. 

Orientation

Though there is little you can do to change this, the orientation of your roof directly affects system performance. It has been proven that solar panels in the UK that are south facing collect the most sunlight. 

Solar panel type 

There are three main types of solar panels – monocrystalline, polycrystalline and thin-film solar panels.

  • Monocrystalline: cells are made from a single silicon crystal – the highest grade – and the most efficient type of the three panels at around 20 per cent or more    
  • Polycrystalline: cells are formed from multiple silicon fragments melted together. While not as efficient as monocrystalline, with just a 13 per cent efficiency rating, they are cheaper to make and therefore cheaper to purchase 
  • Thin-film:  made from a thin film of silicon transferred onto glass – their efficiency is around 7 per cent. They’re the cheapest of the three types of panels. They’re not recommended for homes where space is limited due to their low efficiency 

Although generally speaking the best angle for solar panels is between 30 and 40 degrees, there is a slight variation between seasons and locations within the UK. According to Solarific’s data, these are the most efficient angles for different UK locations, whether you can change your solar panels’ tilt each season or have to choose a fixed position.

City Fixed tilt Winter Spring and autumn Summer
London 47.9 degrees 69.8 degrees 48.2 degrees 23.1 degrees
Manchester 49.6 degrees 71.6 degrees 50.1 degrees 24.9 degrees
Edinburgh 51.8 degrees 73.8 degrees 52.5 degrees 27.2 degrees
Birmingham 48.8 degrees 70.7 degrees 49.1 degrees 24 degrees
Somerset 47.6 degrees 69.5 degrees 47.8 degrees 22.8 degrees
Norfolk 49.1 degrees 71.1 degrees 49.6 degrees 24.4 degrees

Frequently asked questions about photovoltaic systems

To install a photovoltaic system, your solar installer will most likely begin by switching off your home’s power and erecting scaffolding on your roof for safety. Solar panels are then secured to your roof at the optimal angle, and then your solar panels are fixed to them. Your PV system will be wired into your home and connected to an inverter, which converts the collected sunlight into electricity. A solar battery can also be installed at the same time if you have chosen to include one. Your PV system will also be connected to the generation meter to monitor how much electricity is generated and your energy consumption – finally, the system is tested by switching the power back on.

Yes, photovoltaic systems can work on rainy days. However, the electricity generated from your PV system will be less on rainy days due to the lack of direct sunlight. Rain can also help to keep your solar panels clean and free of debris, which is beneficial for maximising electricity generated on sunny days.

rachel

Rachel Sadler

Home Tech Writer

Rachel is a seasoned writer who has been producing online and print content for seven years. 

As a home tech expert for Independent Advisor, Rachel researches and writes buying guides and reviews, helping consumers navigate the realms of broadband and home security gadgets. She also covers home tech for The Federation of Master Builders, where she reviews and tests home security devices. 

She started as a news and lifestyle journalist in Hong Kong reporting on island-wide news stories, food and drink and the city’s events. She’s written for editorial platforms Sassy Hong Kong, Localiiz and Bay Media. While in Hong Kong she attended PR events, interviewed local talent and project-managed photoshoots. 

Rachel holds a BA in English Language and Creative Writing and is committed to simplifying tech jargon and producing unbiased reviews.

Molly Dyson

Editor

After growing up with a passion for writing, Molly studied journalism and creative writing at university in her home country of the United States.

She has written for a variety of print and online publications, from small town newspapers to international magazines. Most of her 10-year career since relocating to the UK has been spent in business journalism, writing and editing for admin professionals at PA Life magazine and business travel managers at Business Travel News Europe and representing those titles at conferences around the world.

Now an Editor at the Independent Advisor, Molly is an expert in a broad range of consumer topics, that include solar panels and renewables, home improvements and home insurance, and consumer technology such as home security and VPNs.

In her free time, Molly can usually be found exploring the outdoors with her husband and their young son or gardening.