It’s easy to think that, because we’ve seen something done a certain way, this is the only right way to do that particular thing. Confused? OK, think about all the homes you’ve seen that have solar power. Is there anything that strikes you as apparent? Something they all have in common?
Of course, almost all home solar installation put the solar panels on the roof of the house! Why is that? Is there some reason this is the preferred place to put the panels? Unlike with home wind turbines, it doesn’t matter how high you mount your solar panels. Being a few meters closer to the sun really does nothing unless you have a giant fog machine covering everything below the roofline. So why put them on the roof?
Raise the Roof
The main reasons are all pretty pragmatic ones. Not everyone has space outside for PV panels anywhere other than their roof. It’s also easy to do the wiring from PV panels down into your home electrical system.
Roof-mounted installation is also quite a bit cheaper than ground-mounted solutions, because the roof provides the foundation for the panels. It takes less time, you don’t usually need special permission, and when you do, the requirements are not onerous. It’s also space efficient, since you weren’t using that roof space anyway, right?
Overall, it might be a more elegant to put your PVs on the roof, but putting them on the ground comes with its own set of sweet, sweet advantages.
The Power of Being Grounded
By putting your solar panels on the ground, the most obvious first advantage is that you don’t have to climb up onto a roof to maintain or repair them. If there’s dirt or debris on your panels and they are on the ground, you can sort the problem out in minutes. If there is anything wrong with the performance of your panels, it’s much easier to troubleshoot if the panels are on the ground.
Mount the panels on the roof and someone has to risk their neck every time. Don’t forget that roofs also need to be repaired periodically. When that happens you’ll have to remove the solar installation in order to do the job.
Solar panels need to stay in a relatively narrow temperature range to work at their best. Heat tends to be more of an issue for roof-mounted system. The roof bakes in the sun all day and raises the operating environment temperature. On the ground this isn’t a problem, especially since ground mounts tend to be quite a bit off the ground and have good natural airflow. With roof installations, the tendency is to lay them flat against the roof.
The main major advantage of ground-mounting your panels is that you can install them along any angle you want. With roof installation some directions are not possible, which sucks if one of those directions is the best one for power capture.
When installing ground-mounted solar panels, you have a choice between two popular mount types. The stock standard mounting is just a frame bolted into the ground. This means that the direction of the panel is permanently set, but you can tilt it and make other small manual adjustments to the panel as needed.
Pole-mounts, on the other hand, often have active solar tracking systems, which means your panels are always angled to get the most sun all day. There are also two types of pole mount – single axis mounts can track the sun during the day; dual-axis mounts can do that and adjust for seasonal changes in the sun’s path.
Making the Balanced Choice
Personally, I think that in the long run ground-mounted solar panels work out better for the reasons we dealt with above. The main problem is that they are much more of a pain to install upfront.
First of all, you have to get more stringent permits, because you are essentially erecting a structure. That could mean quite a lot of time filling out forms for your local municipality. Then, once you have permission, there’s the actual labor and cost involved in building the support structure. The wiring is also more complicated and could involve digging a trench in your yard. You should also know that certain types hard soil can make it much more expensive to build the installation. So get a professional builder to assess the type of soil you have and factor that additional cost in. If you belong to a body corporate or homeowners association, you’ll also have to check with their rules to establish if and where you can install solar equipment.
Neither of your installation options are intrinsically better and they have to match your personal needs. The pros and cons of the two choices have different weights for different people. What’s really important is that you know there are other places to stick solar panels than on your roof!