A ground-mounted solar PV system is supported by posts and racking. The posts stick out of the ground like piers supporting a deck, and the racking is installed on and across the posts to support the panels, like the background of this photo:
The posts are driven into the ground with a mini-excavator. The mini-excavator vibrates the posts so quickly that the soil under the post is effectively liquidated, allowing the post to slide into the ground, like a toothpick into a stick of butter.
Check it out – the post vibrates faster than the frame rate of the video, so it’s hard to capture exactly how neat this looks in person.
In our region, we must drive the posts at least 6′ deep, well below the frost line and deep enough to support the weight of the array. All of our ground-mounted projects include a subgrade condition evaluation, as it’s very possible to hit bedrock in the rolling hills of the Finger Lakes. (Ask us how we know.)
In this video, you can see how quickly the post sinks into the ground – watch the black ground-level line – and the length of the post to start – 12.5 feet!
These videos were taken on a 27.36 kW project in the autumn of 2021. The homeowners were frustrated with their high utility bills, so they decided to “pre-pay” for the next decade of electricity by investing in solar. With our guidance, they chose a premium LG panel, with a 25-year production warranty of 90.1%, which will give them many years of satisfaction from their project.
Even though the homeowners were paying a small fortune in utility bills, they still had occasional outages – one lasting over four days! Unfortunately, with a standard, non-battery-backed solar PV system, when the grid goes down, the solar cannot power the house directly.
However, the SunnyBoy string inverter includes a Secure Power Supply module that can power a couple of outlets directly, even when the grid is down. This can supply power to phone chargers, batteries, flashlights, small appliances, etc. We installed a Secure Power Supply at the array to give the homeowners peace of mind that they would be able to access some power during a grid outage.
On a personal note, we loved this job because of the beautiful serenity of the site. The homeowner lives up a quiet mountain road on the side of a steep hill behind a nature preserve. It was a pleasure to work here!
