Solar is one of the most accessible renewable energy that you can install on your home. All you need is a suitable roof and a mains electrical supply (even that’s not necessarily needed if you’re looking at being off grid). Installing solar panels is like turning your home into your own mini power station.
The benefits of solar
The reasons why people install solar can be numerous. For many the reason will likely be to produce their own renewable ‘green’ energy. For others it seen as kind of an investment due the potential savings by using the ‘free’ solar electricity generated in your home or being paid to export excess electricity to others via the national grid. The recent energy crisis has also pushed many towards considering solar due to the huge increases in the cost of electricity. For many it’s likely to be a combination of all three. Even if your reasons are solely to help the environment you may still have a niggling feeling that you want to know installing solar will pay for itself within its life time, and not be an expensive drain on your finances.
Savings via your electricity bill
Savings made by self consumption is a great way to make cost savings. It’s likely to be the first saving you will think of when considering solar. The size of self consumption savings will be dependant on whether you’re at home to use the electricity generated by your solar. The more you are home and can use the generated solar energy, the higher the self consumption savings can be. If you’re not at home during the day another option would be to install a home battery. The idea being you would be able to save the solar energy generated during the day in the battery and use that stored energy in the evening when you’re in.
Exporting your excess solar energy
If your solar system has been installed by a certified installer you have the potential to sell your excess solar energy back to the national grid via the Smart Export Guarantee (SEG). The size of SEG savings will be dependant on the amount of energy you export and the amount you’re paid per kWh for it. SEG payments can differ greatly between suppliers so it’s worth researching what’s on offer from all energy supplier as you’re not limited to only your import electricity supplier. You can have one supplier for imported energy and another for exported energy, although many suppliers offer a better SEG rate to their own customers than export only customers. One thing to note is that you will need a smart meter to be paid for your exported excess solar energy.
Understanding your potential solar production
There are many factors that can affect the how much energy you can generate from solar. The most obvious is the size of solar system you install. This is often limited by the amount of roof space you have available. The good news is solar technology has improved greatly in the last decade. The same roof space can now potentially generate two or three times more energy than what was possible a decade ago.
Solar Generation throughout the UK
Solar generation differs throughout the UK. A similar sized solar system located on the south coast of England will generate more energy than a location in northern Scotland.
Solar generation potential throughout the UK
Whilst location in the UK has an effect on generation potential it doesn’t mean solar isn’t worth the installing, it just means you may not generate as much as others can in a different location.
Roof slope and direction
The first thing to understand is the angle of your roof and direction you face. The angle of roof slope and direction can affect how much solar power you can generate.
The direction your roof faces can be found using a compass if you have one (or a compass app on your phone for younger generations), or by checking Google maps.
Calculating your roof angle needs some physical measurements of your roof. There are a few ways to do this. Either measure the length of the roof truss from the end to the centre, then measure its vertical height. Once you have those measurements you could either revisit GCSE maths (you remember how you thought you’d never have a future use for trigonometry, well now the time it’s actually useful!). There are trigonometry calculators available on the internet so you won’t need to breakout the scientific calculator. The other way is to use a measurement app on your smart phone to measure the angle of the roof beam in your loft..
Generally for solar south facing roofs are best, followed by south east and south west facing roofs. East and west facing roofs are generally the worst but solar installers can specific split roof system.
If like us your roof slope is between 30 to 40 digress and faces south, you’ve got a perfect roof for solar.
Shading
Shading on your roof can be a huge factor in deciding whether solar is worth installing or not. If you have a roof that’s in shade all day due to nearby buildings or trees the less energy solar can generate. The best roof would have no or little shading over the course of the day.
How to calculate your potential solar generation
The Energy Saving Trust solar calculator is a great way to get an idea of what a solar system could generate in your location and the potential savings that may be possible. You need to enter some basic information such as your location, the direction you face (Azimuth) and angle of roof slope.
For a better more refined calculation the European Commission’s Photovoltaic Geographical Information System is a fantastic tool that gives a more accurate picture of the likely performance of solar at your location. It’s a bit more complicated than the Energy Saving Trust’s calculator, but it’s a great way to understand what solar generation could be like at my home.
The monthly average solar generation graph is a great way to understand how solar generation shall change on a monthly basis. Solar can generate more energy in the summer months than winter months. What surprised me most was that during winter solar generation could be higher than our current monthly electricity use. Summer generation would be nearly 4 times our monthly electricity use. It really opened my eyes to how your roof can be your own mini power station.
Monthly solar generation for a 3.69kWp system at our home location
Further information on the web
The Internet has a huge wealth of information available to help you research solar before you contact an installer. I find it always helps to have an understanding of a technology before contacting an installer. Sadly the growth in solar means that there some companies that aren’t as good as they should be and it can be a minefield choosing an installer. There are also others that act as ‘middle agents’ between you and the actual installer, charging you for the privilege of doing so. The more you know the easier it is to understand which sales people don’t know what they are talking about.
Two of the best sources of information I found were Greenmatch.co.uk and the Which solar guide. Both are great to help you understand more.
Is Solar right for you?
Having now read up about solar and checked your home to see if it’s suitable for solar the next step is to contact a certified installer who can work out the best system for you. They can also give you a good idea of the potential savings that could be generated by your own solar system. One key point is to make sure your installer is MCS certified as a MCS certificate is currently required by your energy supplier for you to be paid for export solar energy.