First, the ground screws.
To start, here’s Denise carrying one of the shorter ones we use to put the size of these things in perspective.
The reason we typically use ground screws is for time savings. We have tried a number of different ground mount anchor methods, and in most cases, even with the challenges we typically face with less than ideal soil conditions, the ground screws save us time and money. They also free us up from having to schedule with a concrete company to deliver mud to us-we’ve had jobs where concrete was a month or more lead time, which totally wrecks our entire program.
When soil conditions are right, we can sink a screw about every ten minutes once we are set up.
We use one of the highest torque output mini auger drives out there-it’s capable of 3350 ft-lbs, and we have often stalled it with screws or augers. 🙄
Once the screws are in, we don’t have to wait for concrete to cure-we can jump right into the array structure assembly. This allows not only speed, but flexibility on these remote jobs.
Now, truth be told, we unfortunately almost NEVER encounter ideal soil for installing these screws. However, we have developed a number of work-arounds that still make them viable. Usually we end up pre drilling the holes with a rock auger, then repacking the hole with native fill before finally installing the screw. This puts our install time at closer to an hour per screw unfortunately, but even with that extended installation time, we feel we are still ahead of what it takes to do concrete anchors.
Now, as to why we are fighting freezing weather at almost 9000 feet elevation and risking having all our equipment snowed in and stranded in December?
It’s a long story that I will try to keep short.
This customer contracted with us many months ago to install a small but powerful solar system on his summer vacation cabin. As usual, I recommended he permit the installation as it adds resale value to a property, and often helps when the owner goes to insure the solar system ( which I STRONGLY recommend).
So we had permit submittals drawn up and put in for a permit with the county.
Easy-peazy.
Except it wasn’t.
Turns out flagstaff had a once-every-hundred-years record snowstorm a few years back that ended up damaging a lot of older structures. The county then commissioned NAU to do a snow load study, and based on that study, the county implemented new snow load requirements for any structure built above 7,500 feet in elevation.
It turns out the new snow load requirements are off the charts high as a result.
And require an engineered system.
Even for something as small as 8 solar panels in such a remote area. 🙄
I pleaded with the county for an exemption ; asked if we could just fence it off to keep people safely away from the array in the extremely unlikely event it failed; asked for a defeated snow load due to the tiny size of the array and it’s low impact as a hazard-all to no avail, although the plans people thought all of those ideas were good with sound reasoning, in the end they wouldn’t budge.
And so, we then had to find an engineer who would be willing and able to design for a 177 pounds per square foot snow load rating.
Ridiculous.
Particularly when no known solar panels themselves are rated that high.
Eventually, we found a solar engineering firm that was familiar with the concept and had done this before and expressed confidence that they could take our off-the-shelf ground mount system and ground screws, add some more bracing and we’d be good to go.
The reality of the deal ended up being months of frustration as they then changed their minds on how much they wanted to add to the structure, tripled their fees, and just generally were a pain in the ass.
Once that was straightened out, we had to have the plans redrawn, and that seemingly simple task ended up being far more work and took far longer than it had any right to.
Then, with only a couple weeks left before our permit application process would have to be completely started over due to almost six months passing since our initial application, we finally had engineered plans to submit. 🙄
In our defense, this was the first time we had run into this issue, as it only affects one of the many counties we work in, and there are not many properties that fall into that snow load category.
The upshot of all this is:the customer-who had already paid tens of thousands of dollars in deposit money- had patiently waited half a year and had been forced to use his cabin with only an annoying little generator for power.
We wanted to do everything we could to get his system installed as soon as possible so that he could at least use it next season. So, despite the fact that it costs us considerably more in time and expense to work in these conditions, we are up here doing our best to make things right for him.
And it hasn’t been easy-yesterday morning saw a low of 6 degrees, and both the water and sewer plumbing froze up and we spent several hours of our work day thawing that all out. The excavator takes a long time to warm up to do work at these temperatures-I’ve learned the folly of pushing cold hydraulic equipment into hard work before it’s warmed up in the past with blown seals, lines and filters. All these extra clothes slow down our work. We’ve already burned through 15 gallons of propane trying to keep things warm…. There’s a lot of reasons we avoid working in this type of weather, and they are all coming home to roost here now.
Additionally, the forest service closes the road in and out of this place for the season with the first significant snow fall, so we are keeping a wary eye on the weather for fear of our entire work Fleet being stranded and us out of business for six months. 😬