A tiny little scoop on solar

Note: The information contained in this post concerns the solar industry in Bulgaria. I doubt the picture is much different elsewhere but it was a note that had to be made.

Did you know that it matters which way your roof points for the effectiveness of your solar power installation?

Did you know that it matters — a lot — in which part of the world you live for your solar installation to work properly?

Did you know that, unless you have battery backup, your solar installations will not work during a blackout?

I know many of you did. I didn’t, until recently, when I had the opportunity to get a glimpse into small-scale solar installations thanks to a source from the industry. And what I learned was quite enlightening. A bit shocking, too.

First the good news. There has been a lot of mockery of solar because of its low conversion factor. Ha-ha, we evil deniers laugh, it says it’s a 100 MW farm but it only produces 27 MW because of its conversion factor.

Well, I’m happy (and a bit embarrassed) to report that a 100-MW farm is called a 100-MW farm because that’s what it actually produces. At optimal conditions, of course. This is its maximum capacity at the 27% or whatever conversion factor the panels have.

With these optimum conditions, the farm will produce 100 MW, or rather, it will produce 100 MW at peak production, meaning maximum sunlight, hence the MWp designation for solar capacity.

Now, about that maximum capacity. It gets complicated fast. Because the maximum capacity, as noted, is only available at optimal conditions. And these optimal conditions depend on the position of the house/building/plot. And its location on the global map.

They also depend on the angle of the panels, although that’s something technicians are trained to calculate and plan in such a way as to maximise output so it’s not really a problem. If they’re good at their job, that is. You never know. But assuming they’re good, the position of the place where you’ll be putting the panels is the tricky, complicated bit.

Take our roof, for example. It’s close to perfect for solar, I thought. It’s essentially a four-wall pyramid that has exposure to the East, the West, the South and the North. The northern side is shaded by trees but who cares when we’ve got the other three and this is where the sun shines from.

I was wrong, though not entirely. Because there is only one direction that is best for solar panels and ensures their maximum capacity gets utilised. That direction is true south. Nothing else gets output to the maximum.

Apparently, some slight deviation from true south is admissible and southwest is second best but in case you have an eastern or a western exposure, better forget about peak production. The system will work, it just won’t work at 100%. Here’s one website with detailed instructions from another source, not mine.

But, my thinking went, with our roof facing east, west, and south, we could put up a solar array and be getting energy for most of the day. Indeed, we would, in sunny weather, that is. Only this energy would not be coming in a constant volume. It would be — let’s say it together — variable.