Solar Panels

An Introduction To Solar Panels For The Uninitiated

Most people have heard about solar panels but most people do not really understand the technology or how it works. Moreover there is even less understanding of how solar power relates to the typical household in the UK. It is true that solar, particularly solar photovoltaic technology, has been relegated to the confines of the DIY solar panel enthusiast and big business.

Up until very recently you probably would not have seen a solar PV system installed on any of the houses in your area. You may have seen the odd solar thermal system but photovoltaic technology has been too expensive for all but the most ardent Greenie with deep pockets.

Now this has all changed. Since the government launched the feed-in tariff system thousands of domestic solar PV installations have been completed. You may have noticed the large panels neatly lined up on someone's roof and wondered what they actually do.

What are solar panels and what do they do?

Solar is an embryonic industry in the UK and we are far behind the rest of Europe. At this point we are unlikely to catch up with countries such as Germany who now have a large solar industry employing tens of thousands of people and they actually have German companies making their own panels.

Solar panels are a technology that turns the energy from the Sun into useable energy for the home. There are essentially two types of solar panel, one that produces electrical energy from the light from the Sun and the other that generates domestic hot water from the heat given off by the Sun.

The different types of solar panel

Today there are 3 groups of commercially available solar panel that you can have installed on your roof to produce electricity and hot water. Thermal solar panels make your hot water for heating and washing, photovoltaic solar panels create electricity and hybrid PV-T panels that do both from a single panel.

Photovoltaic solar panels

The solar panel that has had most impact recently is the photovoltaic solar panel or PV for short. This type of panel is commercially available today due to the developments made by NASA although this technology was known about long before then.

Solar PV is based on silicon wafer that has special properties that allow it to generate a current when exposed to light. Silicon is used in different ways to produce solar cells which are then grouped together in a rectangular solar panel.

For those interested there are types of technology used which are mono-crystalline, poly-crystalline and thin film. You can see what the different types of panel look like on this page about the different types of solar panel. Today there are many different combinations and variations of these technologies which have gradually lead to the increased efficiency of the panels that you can buy today.

Photovoltaic solar panels are usually installed on a south facing roof in an array or group of panels. The more panels you have installed the more electricity the array will be able to produce. As they rely on light to generate electricity they will only work during the day. However most modern panels are able to generate electricity even if there is no direct sunlight, albeit less than if they were exposed to direct sunlight.

Thermal solar panels

Until recently these would have been the most common type of panel that you would have seen on peoples roofs. Usually there would be one or two panels that sit on a south facing roof providing hot water for the homeowner.

Thermal panels are designed to absorb heat from direct sunlight and then use that heat to heat up your hot water. There are two type of water heating thermal panels, flat plate collectors that look very similar to solar PV panels and evacuated tube collectors that look similar to the tube lighting often found in offices except they appear black rather than white.

Thermal solar works by absorbing the heat from the Sun, much like any dark surface left out in the summer Sun heat up so do the panels. The panels are usually insulated in order to retain the heat they have collected. This heat is then used to pre-heat or fully heat your domestic hot water supply. Generally they will be able to supply most of your hot water requirements during the summer, some of your hot water during spring and autumn and a negligible amount during winter. This is why some sort of back up system is still used such as a gas boiler so that you can still heat water during the colder months.

Hybrid PV-T solar panels

Solar PVT (PV-T or PV/T) panels are a hybrid system that incorporates both technologies. The benefit of having both a panel that produces hot water and electricity is that you reduce the total amount of roof area needed. There are also benefits of increased PV efficiency as the electricity producing part of the panel is kept cooler. As solar photovoltaic panels get hotter they become less efficient so using the excess heat for hot water reduces the heat effect on the panel.

At the time of writing the only MCS certified photovoltaic thermal system available in the UK is the Volther Hybrid PV-T panels manufactured by the Turkish company Solimpeks and distributed in the UK by Newform Energy. The following video gives a good demonstration of what hybrid PV-T solar panels do.

The cost of solar panels

It is important to understand that a solar panel by itself isn't going to be much use to most people. A typical solar PV panel installation consists of a number of different components, one of which is the panels themselves. You can buy an individual panel from as little as £150 but a complete installation which includes many panels and various other pieces of equipment normally starts from around £4,000. You can find out more about typical solar panel installation costs and find out more about how much solar panels cost.

Suffice to say that the cost of a photovoltaic installation is a big investment akin to buying a new car. However with the current government incentives it is currently one of the best investments you can have. Typically from a standard domestic installation you can expect to be able to generate your own electricity for at least 25 years and the panels will probably continue to work for up to 40 years.

Under the feed-in tariff scheme you will be paid for all of the electricity that you produce for a guaranteed 25 years. These payments are index linked and so will increase year on year. Typically you can expect to earn your initial investment back in as little as 7 years although it could take up to 11 years depending on your installation.

DIY solar panels - can I build and install panels myself?

There are a lot of information products on the internet that claim to show you how to build your own solar panels or get them for next to nothing. This may sound like a tempting and cheaper shortcut to getting free electricity by building your own solar installation.

It is however not practically possible to build your own home solar system. Other than the obvious practicalities even if you did manage to build your own system you would not be eligible for the solar panel grants available from the government.

Every solar photovoltaic installation on the UK needs to be registered and installed by a certified installer. The equipment that is used for the installation also needs to be certified under the microgeneration certification scheme. Without this certification you will not qualify for the feed-in tariff payments.

Solar Panel installers

The option for most people considering solar is to get a quote from a solar panel installation firm. They will be able to advise you on the suitability of your roof and what size array you could install. The size of the installation, measured in kilowatt hours, will only be limited by the size of your roof. In the UK most homes will be able to house a moderate sized installation.

I would advise anyone considering paying for a photovoltaic solar installation to get a variety of quotes. There is quite a lot of variation between companies for similar sized systems with differences in prices of up to eighty percent.

Free solar panels

There are now a number of firms that can provide free solar panels and supply and fit them at no cost to you. The scheme works where by you agree for the system to be installed for 25 years. In return you will get to use all of the electricity the panels produce. In return the company will claim the feed in tariff payments that will more than cover their initial costs.