The Ultimate Guide to Solar Panels

We’ve been writing and researching for a long time about green energy for GreenMatch.co.uk and got to the point that everything looks the same. And it can get boring! We thought of this content page that presents all the information you should consider before investing in solar energy, which is easy and fun to read.

You are welcome to have a look at our solar alphabet!

Even if an installer gives you the best price and best offer, you should first make sure it is an official installer. Having your solar system installed by a non-accredited installer could mean that you are not eligible to apply for the Feed-in Tariff. If you are in the UK, you can check whether an installer is official here: microgenerationcertification.org. Also make sure that the installer is a member of RECC (Renwable Energy Consumer Code).

There are some things you should check to make sure that your building is the ideal place for a solar panel installation, such as:

• Check the size and inclination of your roof. 
• Check your roof’s orientation (S, SE, SW are ideal orientations).
• Check that nothing will block the sunlight from reaching the panels (trees, other buildings, etc.).

Some things you shouldn’t do:

• Don’t sign a deal with a sales person. Make sure an experienced surveyor visits your place and assesses all your needs and building conditions.

• Don’t clean or fix the panels yourself without checking beforehand the warranty conditions with your supplier. Sometimes the warranty won’t cover if you have touched the panels.

• Don’t accept a price over the phone, whether a non-binding estimate or a firm quote.

Efficiency is one of the most looked-at features. A solar panel in simple terms consists of a group of solar cells that are grouped next to each other on top of a backsheet and covered by glass. Solar cell efficiency refers to the amount of light that a single cell can convert into electricity and solar panel efficiency is the amount of light that one entire module can convert into electricity. Solar panels currently on the market have an efficiency between 15%- 22%. You might think this is a low percentage, but the truth is, it is enough to power your home and sell some of the remaining electricity back to the grid.

This is definitely something you should be aware of if you want to make the most out of your investment. Feed-in Tariff is a scheme by the government that will pay you for every unit of electricity you generate, either you consume it, or if you sell your surplus energy back to the grid. Most countries have some similar scheme. If you are in the UK, you can go to gov.uk/feed-in-tariffs to get all the details and requisites to be eligible for the FIT.

Despite the fact that “solar panels” is the most common term to refer to solar power, one must know that solar panels (or solar photovoltaics) are different from solar water heating systems (or solar thermal systems). While solar panels generate electricity and make it available for household use, solar thermal systems are used to heat water, which is then available for heating purposes in the house.

A solar inverter is also called “the brain“ of the solar system. This device will convert the energy captured during the day, from DC to AC, so it can be used for consumption. The inverter combines digital control technology with efficient power conversion architecture in order to make the most of the energy the panels are collecting. You can choose from grid-tie or off-grid inverters. ”Smart inverters” are being developed with forecasting algorithms, load/demand planning and so on. In addition, smart inverters can be “told” whether to use photovoltaic energy or not, send power to batteries to store it, or save you in case of a power blackout.

Are just a few brand names that manufacture solar panels. The major players in the market are competing to bring great features for the consumers such as double sided panels or anti reflective coating. A large amount of resources is invested every year in Research and Development. It is good to have an idea of the different brands in the market, and maybe read a little description of the differences and advantages of each.

Solar panels are said to be expensive. And it’s true that the initial costs are considerable (although technological development has lead to an abrupt drop in the costs of solar devices). However, like it happens with any other big investment, one should assess the costs/benefits in the long term. The cost of a solar panel installation can go from £2,500 to £8,000 depending on the type of system chosen. If you are eligible for the Feed-in Tariff, this will payback after approximately 8 years (remember that during all this time you will enjoy the free electricity).

Made from the purest form of silicone, these cells deliver the highest efficiencies. One crystal of silicon is used to make one cell. You can recognize them by the uncovered gaps at the four corners of the cells. apart from monocrystalline cells, you can also choose polycrystalline or thin-film panels.

(NOCT) are used to measure the solar panel's output under “real world” conditions. This will indicate how much power you can expect the panels to generate on any given day. Initially, the panels are tested under Standard Test Conditions (STC). This is a lab carried test, where the conditions are optimal. However, a solar system will produce lower energy when faced with changes in: weather, shading, irradiance. NOCT assumes the following: irradiance 800 W/㎡, ambient temperature 20°C, windspeed 1m/s, nominal cell temperature 45.7°C (±2°C). So when you read the data sheet of a solar panel, look for the output under NOCT.

"Photo" comes from the Greek language, and means "light"; and "voltaic", means electric, and comes from the name of the Italian physicist Volta. Often, solar panels are also called photovoltaics or solar PV’s.

Get at least a few to compare prices of different installers. Also, inquire about how long the work will take and the warranty for their work. Make sure you get binding quotations, preferably in writing. This way you will not have surprises once the work is done.

Some installers run this business model which consists of installing a free solar panel system on your roof. In this scenario, you rent your roof in exchange of free (and clean) electricity generated by the panel. The catch is that the excess electricity the panels produce will be sold to the grid and the money will be cashed in by the installer. If you decide to get the free panels you should know that you and the installer will enter a 25-year commitment contract. Also, you need to own your home and your roof must usually be 24 square meters due south, or within 35 degrees of south.

The solar cell is the main component of Photovoltaic technology and Solar PV systems use these cells to convert solar radiation into electricity. Solar cells consist of one or two layers of a semi-conductor and the most common material used in these cells is silicon, an abundant element most commonly found in sand. Watch how solar panels are made. Solar cells can be wired together to form a module (a solar panel) and these can then be connected together to form an array. More than one array connected together will form a solar system. In addition, a solar panel can weigh from 15Kg to 26Kg, and their dimensions go from 99x140cm to 105x166cm. Moreover, you should know that maximum output (expressed in Watts) is the amount of power a sun panel will generate.

The big advantage of solar energy compared with other sources of energy is that the energy of the sun is unlimited. In addition, solar energy is not only a clean and free source of energy, but also a different way to make money. Installing solar panels in your roof will therefore reduce your carbon footprint and also reduce your electricity bills since you will use less energy from your supplier. In addition, if you are eligible for the Feed-in Tariff, you can even get paid for the green electricity you produce. Here you can see a simple explanation of the carbon footprint.

Switching to solar energy is very easy once you find the right installer. Finding the right installer is not complicated either. As previously mentioned, you can get free quotes and compare the offers from different installers. You can also ask for references if you have neighbours that have already taken the lead. When you have the installer, it’s just about making the investment and enjoying for the next decades the free and green electricity from your panels.

Xavier has a 4kW Solar PV installation at his bungalow, in Bournemouth. The 16 solar panel system generates 3500 kWh per year in green energy. After the first month, he started to save £50 on his electricity bill. After 3 months, the first cheque came in with payments from the Feed-in Tariff- this time £200. Xavier now covers 80% of the electricity he consumes with the help of solar panels. The payback period for this project is 6.5 years but payments from the FIT will come for the next 20 years.

There’s not much to explain here. It is easy, it is good for the environment, and it is also good from a financial point of view.

Depending on where you live, there might be some planning permissions to consider before making any investment. You should check building permissions in your council to be sure that there are no constraints regarding solar panel installations.