April 20, 2018: Why you MUST monitor your solar system.

Lots to get through this week so I’ll try to be brief.

Firstly just a quick reminder that we’re having our 4th Earth Day Party at the Greeny Flat on Sunday from 4-7pm. Everyone’s welcome… more info in last week’s Newsletter here.

Should you monitor the output from your solar panels?

The answer is an emphatic YES! In fact I would go so far as to say you MUST monitor your solar power system and here’s why…

Our solar power monitor at noon on a good sunny day last week.

Our solar power monitor at noon on a good sunny day last week.

We’ve been monitoring our solar power system since it was installed four years ago. It’s rated as a 3kW solar system but you’ll never get the full rated production from your solar panels. When it was first installed we found that it could produce 2.7kW on a good, cool, sunny day. (Cool is important because solar panels produce less when they get hot). But lately I had been noticing that our power production seemed to have dropped off a bit. So earlier this week I took a closer look and, sure enough, the photo above shows that we were only getting less that 2kW out of the panels on a cool, sunny day at noon.

So I went out and had a look at the panels and this is what I saw…

The culprit... or so I thought.

The culprit… or so I thought.

Yep, there was a gorgeous big bird turd right in the middle of one of the panels and I thought, ‘Ah Ha! That must be shading one of the cells and taking down the production of the whole string’. (FYI – our solar panels are attached to what’s called a ‘string’ inverter which means that, if one of the cells of one of the panels is shaded, it reduces the production of the whole string – the way to avoid that is with ‘optimisers’ or microinverters but that’s a whole other discussion). Anyway, I jumped up a ladder, carefully removed the offending excrement and ran back inside to find…

Not the culprit apparently.

Not the culprit apparently.

… it made bugger all difference. So I jumped back up the ladder and had another look.

These solar panels look clean to me.

These solar panels look clean to me.

The panels looked pretty clean and it took me a while to spot the problem…

The new culprit!

The new culprit!

Along the bottom of each panel (this photo was taken from the top of the roof) was a little row of lichen growing. The aluminium frame around the edge of the panel creates a little lip that catches enough dirt to provide a place for lichen to take hold. And, as you can see, these little bits of lichen are starting to cover a little bit of the edge of the solar cells. A little bit of lichen shading a little bit of a few cells of each panels… could this be enough to reduce our total production so dramatically? There was only one way to find out…. clean the panels!

Pressure washing to worst of the dirt and lichen off the panels.

Pressure washing to worst of the dirt and lichen off the panels.

The important thing when cleaning solar panels is not to scratch the surface of the glass because that would also reduce the production. A pressure washer is a good tool to get most of the dirt and lichen off the panels without risking any scratches (although this article from Solar Choice says not to use a pressure washer because you risk cracking the glass). I definitely do not recommend that you do this yourself unless you have a lot of experience working on roofs and some good safety equipment. The water from the pressure washing gets everywhere, including the roof that you’re standing on, and makes everything very slippery. Anyway, I managed to get it done but I noticed that there were still some spots and bits of lichen root clinging to the glass.

Gently scrubbing with a very soft broom so as not to scratch the glass.

Gently scrubbing the solar panels with a very soft broom so as not to scratch the glass.

So I found a very soft, clean broom (so as not to scratch the glass) and gently scrubbed the remaining spots off with a mixture of sugar soap and bleach. This was even more dangerous because the soap made the roof I was standing on even more slippery. Once again, I do not recommend doing this yourself.

After a thorough rinsing to remove any soap residue I was eager to see what the monitor had to say…

That's more like it!

That’s more like it!

…and lo and behold, our solar production had shot back up to 2.6kW. So, by cleaning the panels we were able to get about 700 more watts out of the panels. At a guess that will add up to about an extra 2.8kWh per day or 1000kWh per year. That’s worth at least $100 (up to $250 depending on how we use our solar power). So cleaning the panels was definitely worth the effort.

But the main point I’m trying to make is that, if we hadn’t been monitoring the production of electricity from our solar power system we would not have known that we had a problem. The panels looked fine from the ground but, because the monitor told us they were not producing properly, we were motivated to look more closely and to find the lichen problem and fix it.

So, getting back to the original question… should you monitor the output of your solar panels… the answer is ABSOLUTELY!

14% of Solar System may not be working at all

According to this article from Solar Analytics,  ‘more than half of Australia’s residential solar systems perform below the standard they’re supposed to. And even worse, about 14% of the country’s solar systems develop a major fault every year and stop working altogether.’

Unless you have a monitoring device, how would you know if your solar system is working at all? One way is to look closely at your electricity bills. Another is to look at the digital display screen on your inverter or at the reading on your electricity export meter. But the best way is to install a monitoring device. I have a Wattson meter but they have gone out of business. Friends of mine have various different monitoring systems including ‘Efergy‘, ‘Smappee‘ and ‘Solar Analytics‘. There are plenty of others but my advice is, it doesn’t matter which system you choose, just get one and pay attention to it. You’ll be glad you did.

Solar for Pensioners

In our Newsletter on March 30th we talked about how it’s a great time to install solar due to the excellent financial returns. One of our readers (and neighbours), Phil, sent the following response outlining how solar can be even more beneficial for pensioners…

‘…people on part pensions currently have their pensions increased (or decreased) with every $1000 movement in their deemable assets. What this means is that if a pensioner spends, say $6000 on a system, their assets go down by $6000 which increases their pension by $468 per year (6 x $78), so after about 13 years the Govt has paid them $6000+ ie paid for the solar. Plus they have an asset which increases the value of their home. They will of course lose the earning capacity of the $6000 but even if it could have returned 4%, they are still ahead by 3.8%.’
So there’s another hidden benefit of rooftop solar… thanks Phil.

Exhibition Success

Finally, thanks to everyone who came along to our ‘Celebrating Clay’ exhibition. The exhibition as a whole was beautifully presented and Cintia’s ceramics and my photos were very warmly received. We really appreciate the support.

Some of the exhibitors at the 'Celebrating Clay' exhibition last week.

Some of the 10 exhibitors at the ‘Celebrating Clay’ exhibition last week.

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