As electricity costs rise, so does the interest in solar panels as a way of generating your own free, clean electricity. But, if your roof isn't suitable for solar PV panels, are ground mounted solar panels worth installing instead?
While not as common as roof mounted panels, solar PV generation is all about sunshine, so if it's not possible to mount panels on the roof of the home, then it may be best to look at a ground mounted system located away from the home – but in an optimum position.
Renewables energy expert, David Hilton is here to explain everything you need to know about ground mounted solar panels, ranging from the reasons why you might need to consider them, through to how they work and their pros and cons.
When to consider ground mounted solar panels
Solar PV panels need to ideally face south at a pitch of around 30° to 40° depending on where you are in the country. If your roof faces in the right direction and is big enough to accommodate around 10 panels on unshaded roof space, then this is usually the ideal location for the solar panel installation, for a number of reasons.
Firstly, in most instances, you usually do not need solar panel planning permission as they are covered under permitted development guidelines. And secondly, it is the most common installation method, so is well understood by installers and homeowners alike.
However, there are many reasons why the roof is not always the ideal location for solar panel installation. If the roof is covered in thatch, brittle tiles or has an undulating contour then it is probably not suitable for solar PV panels.
Likewise, if it faces the wrong way, is shaded, the property is listed or in a restricted area, or the architecture or vernacular will be blighted by the solar panels, then an alternative solution will often be required. And this is where ground mounted solar panels may be a viable alternative form of renewable energy.
What are ground mounted solar panels?
Ground mounted solar arrays are simply a solar panel system that has been fitted to a frame or structure that is fixed to the ground, or to a building other than your home.
If you have a garden building, such as a robust log building, then this can be a great solution to use as a frame, as it also adds a useable space in the garden. The solar panel inverter equipment can be fitted in the building with a separate sub distribution board, and then a standard 230v supply wired back to the main supply in the home, usually via an appropriate armoured cable.
If however a garden building isn't available, then there are two main options for ground mounted solar panels.
Option one is when the panels are physically mounted on a sturdy framework. Most frames will be made of steel or aluminium, but they do need to be anchored to the ground. The structures will often need to be deemed as non-permanent structures, which means that concrete foundations should not be used. Screw pile anchors can be used instead.
Option two is when solar PV panels are mounted onto a pole based system, with the added advantage of many of them including solar tracking functionality that tracks the path of the sun. These are known as solar tracking frames.
There is usually a single central pole anchored firmly in the ground, that has a frame and motor mounted on the top of it. The panels are clamped to the frame and the motor moves it so that it starts facing east in the morning, and then moves towards the west as the sun moves during the day.
They are not as big as most static frames and can usually have around 4 to 8 panels on each frame. They can of course be higher, but this can potentially be a downside, as we'll cover in the next section on the pros and cons of ground mounted solar panels.
Ground mounted solar panels and planning permission
Because they are not installed on a home the new footprint of a ground mounted solar array is likely to require planning permission. According to the Renewable Energy Hub, only the smallest systems will fall under permitted development,
Therefore if your ground mounted solar panel system meets any of the following criteria, you will need to apply for planning permission:
- It is over 4m in height
- It has a footprint greater than 9m2
- It is closer to the road than the nearest part of house
- It is within 5m of the property boundary
- It is in the curtilage of a listed building, an AONB or conservation area
And, you might also find your Local Authority requesting additional conditions relating to height and frame colour to further reduce the visual impact.
Pros and cons of ground mounted solar panels
Although in general, ground mounted solar panels can have the same, if not improved benefits as roof mounted solar panels, there are still some distinct pros and cons to be taken into account if you are considering them as part of your renewable energy plans.
Cons of ground mounted solar panels
As well as the fact ground mounted solar panels will usually need planning permission and incur the necessary fees, whatever frame the panels are fixed to will need to be robust enough to withstand wind loads and wind lift, as well as any other weather events.
So, even though there is no scaffolding required to install ground mounted solar panels, the frames themselves and the anchor systems they require add a lot more cost than the equivalent scaffolding charges.
Plus, the further the panels are away from the home, the more expensive the electrical connection will be too, as the cable needs to be fully protected and often buried in a trench at least 750mm deep. Add to this the fact that the longer the cable is, the thicker it needs to be, and it's easy to understand why costs for ground mounted solar panels can soon start to escalate.
If you also don't have a huge amount of land, you may find yourself losing more of your garden than you hoped, or having to justify the removal of trees and plants to install them. Something which could prove problematic if you have Tree Preservation Orders in place, or bats in trees.
Pros of ground mounted solar panels
That said, costs and the need to apply for planning aside, there are some definite positives to ground mounted solar panels that are worth taking into consideration.
Opting for a ground mounted system gives you greater scope to have more panels, (land and space permitting). As you aren't restricted to the direction your roof faces, they can also be located to face directly south and at the optimal angle to catch maximum light.
The fact they aren't located on a roof also reaps rewards. No structural alterations or work is required to your roof or home, and the low level access makes them much easier to maintain. Even snow for example can be more easily removed, meaning they will perform better, even during the winter.
They can also be mounted on land that perhaps could not be used for other purposes due to slopes, drains or other limitations turning wasted space into something with a financial and ecological benefit.
And, on the subject of money, while they may cost more to buy and install, because they can be installed in the best possible location, ground mounted solar panels can often generate at least 20% more yield than their roof mounted counterparts. This is even more likely with a solar tracking system, that can show an increase of up to 45%.
Although my answer to are solar panels worth it is yes, my final advice before you make your decision regarding ground mounted solar panels is that you need to be fully aware of the conditions that need to be in place.
Firstly, make sure you have sufficient land and space to install them so they are facing in the most optimum direction. This is a system more suited to properties with land, space and fewer neighbouring properties.
Check whether you need planning permission and that all costs have been considered including any ground work, trenching (for cables), additional cable costs and potential maintenance requirements vs the potential return on investment. I'd also recommend you compare the costs and benefits of a tracking system vs a static frame system, as the longer term gains may be worth the additional cost.
Also ensure you avoid one of the most common solar panel problems which results in reduced performance, by checking your ground mounted solar panels won't be shaded in any way not just now, but also in the future.
Good positioning and regular maintenance will also help to ensure they generate as much energy as possible, and be sure to consider a solar power battery to help store the energy your ground mounted solar panels will create.
