Amongst this winter's multiple projects is a complete rebuild and bump in capacity of Poggiosole's photovoltaic system. Situated next to our vegetable garden, in a roughly 900 square-meter section of land bordered by our main driveway to the north, the Strada della Romita to the west, the tall hedge delimiting our pool to the east and our campo alto to the south, our matrix of 40 solar panels has served us more or less well since 2013. Other than its obvious value as a source of renewable electric power, this system is meaningful to me as the last major improvement my dad made to the property before his failing health made it impossible for him to continue to think about further upgrades. When I consider he was eighty-one years old when he ordered those panels, I'm reminded how I loved his will to do the right thing.
And... when above I write "more or less well" it's because the system, as originally configured and installed, had a few flaws.
First of all the inverter, a critical component which converts the DC current generated by the panels to AC current usable by stuff you plug in, was mounted on a south-facing exterior wall with no protection from either sun or rain. And unlike today's models that can be monitored through a mobile app and send alerts when a fault develops, when our 2013 inverter first quit working around 2016, nobody noticed. I was still working as a UX and IT consultant and awaiting the birth of a baby boy. And dad was really beginning to slide. Yeah, an LED surely glowed red (again, probably for years) on the front panel, and although the inverter may have been reset once or twice before I took the reins in 2021 really I have no idea how often it was off-line. But when, in September of 2023 our electric bill suddenly skyrocketed, I got wise to that little LED and also to the notion that this was not a device you could count on. It was also right around that time that I realized the company that had designed and installed our system had gone out of business.
Second, the photovoltaic panels were mounted on large plastic tubs filled with gravel, themselves set on a thin bed of gravel-over-fabric through which, after the first six or seven years, grass began to grow prodigiously (fact: given enough time, grass conquers all). When I'd occasionally run a mower or string trimmer in the spaces between the rows to knock down the grass shading the panels (blissfully unaware that the inverter had quit), I'd discover that the tubs and panels were a favored place for wasps to build nests. And because of the way the panels were mounted onto the tubs, it was easy for the wasps to find shaded bits to build nests on and hard to knock those nests out. Moreover, the "gravel field" the rows of panels sat on, though mostly swallowed by grass these last few years, was still present enough for my Toro mower, as I rode it near the front row of panels last summer, to launch a piece of gravel hard onto the surface of one of the panels, shattering it.
Finally, the existing system has no batteries, which means it cannot store the power it produces. Whatever wattage it generates is either used right away or wasted (yes our power company can absorb the unused energy, but due to the way the system was configured and registered back in 2013, we see no revenue from that). Given that our lodgings' air-conditioning and our swimming pool's recirculating water pump are probably our two biggest power hogs, this day-time only production never seemed too big a deal. But guests do use A/C at night. The pool pump runs 10 hours a day even on cloudy days. And, increasingly, guests are asking if they can charge their EVs overnight.
When, late last year, the inverter's "Alarm" LED lit up again for no apparent reason, I decided it was time to overhaul the whole system, rather than attempt another repair. With the cost of electric power our biggest OPEX line item year after year, our photovoltaic system is nearly as mission-critical as the pool pump and air-conditioning units it enables. In fact I've come to consider this triad Poggiosole's "solar plexus": a complex network of connections and machinery that offer respite from the sun while drawing power from it. Without a swimming pool our guest count would dwindle. Without A/C no one would come stay past mid-May (we just replaced all our A/C units, too, both lodgings, all-new this year). Without a well-functioning photovoltaic system neither of the other two are economically or environmentally viable.
So we're re-building it from the ground up, starting with a 275 square-meter surface tiled with cast cement paving bricks on which we'll mount fifty-seven 65-kg triangular concrete supports, one or two per panel, leaving plenty of clear empty space under each panel to spray wasp nests if needed. Working with a team of electricians, we've devised a way of combining the 39 surviving panels from our existing system with 11 new, higher-efficiency LONGi panels that will, all together, yield about 15kW of peak power. The new inverter, made in Austria by Fronius International, will sit, along with a bank of batteries (made in China by BYD), in an air-conditioned section of a new wooden garden shed (made in Nothern Italy by Alce), the remaining sections of which will be home to lounger cushions, tools, wheel barrows, even a repurposed laundry sink, all in service of our pool area and vegetable garden.
Work on all this started last week. Actually it started two weeks ago, with me shoveling gravel out of all 40 of those plastic tubs and wheelbarrowing that ballast into our parking area, where it will be re-used to refresh the gravel that's already there (fact: gravel wears out!). That was better than going to the gym. 😅
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