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- Hacker News
- In the southeast states in the US, we experience "the pollening" each Spring, which can leave 1/8" or more of thick crusted pollen on solar panels. I wash ours at least monthly March through May. They're at least 15-20% more efficient, if not more, without the pollen crusted on them.by nrjames
- I clean my solar panels, 7kwh, every monmth or two.
When I check on the VRM portal it makes a difference, and since I am so dependent on them all year round, I have no problem giving them some attention from time to time. Ten mins well spent.
by CrzyLngPwd - > I clean my solar panels, 7kwh, every monmth or two.
This honestly sounds like a non-trivial strike against installing solar panels, especially if they’re installed on tall roofs.
I definitely wouldn’t want to have to clean them that often, or pay to have them cleaned that often.
If you’re spending only 10 minutes on them, then maybe you don’t have that many, and they’re not up high.
by jader201 - I am curious how much of a difference it makes.
I have 4kw of panels and 15kwh of storage. I only get down to about 80% most nights (I heat with wood and propane).
But my system will charge completely in about 2 hours of full sun. If it took 3 hours it wouldn't make a difference. So I generally don't clean them (well, the rain and snow do that work).
I do remove snow, because that has a very noticeable impact.
Is the difference that you are pushing back to a grid (I am not), so the power all gets used regardless of you being the one to use it?
by scarecrowbob - Our peak daily export energy jumped by about 35%-40% when we had our panels cleaned for the first time in 8 years. They _look_ much cleaner, and the measured export shows it.by hgomersall
- If export energy is 10% of your total output, and it jumped 35% then you got a ~3.5 - 4% gain in total output, not far from the author's experience.
Of course, you can math that any way you like to make the numbers bigger or smaller, depending on whether you're representing the buyer or the seller of the system.
- > If I increase the power output of the system then the additional capacity will not be eligible for the feed-in tariff and will revert to present-day prevailing tariff which is about 4x worse before you even consider that I currently get to use electricity and still get paid for generating it.
> This is the yin and yang of market-distorting incentives. Today's incentive to install solar becomes tomorrow's disincentive to upgrading it.
I am not sure what author is trying to hint. But solar does not need artificial subsidies, and can pay for itself!
There are no subsidies in UK! Homeowners get so much money, because of all that sunshine and wind energy, their house generates! UK goverment just run out of money, when energy got expensive!
UK goverment needs to step up, to replace gaz with renewables!
You can not expect homeowners to sell energy bellow market price!
by bebe8393jrir - when it first started it was basically 450GBP/MWh (In 2010 GBP). and that was paid for every kWh generated (whether exported or not). And the PPA lasts for 20-25 years.by peter_stokes
- > I am not sure what author is trying to hint. But solar does not need artificial subsidies, and can pay for itself!
At grid scale, yes.
For the house, not so much.
The feed in tariff was at one point 41 pence per kwhr which is probably £10 a day in summer.
but at 12p a kwhr it drops to £3.6
However, 10kwp of panels is ~£1800, but the micro inverters needed to drive them are >£3k (as its outside you can probably use two larger inverters.) Then mounting system is probably a good 800 quid too.
by KaiserPro - > I am not sure what author is trying to hint. But solar does not need artificial subsidies, and can pay for itself!
I think he is describing a subside that some governments gave years ago: you installed for example 5K, and get paid for whatever they generate at 300% market price, for a long time (25 years?). Today you find out that upgrading panels would made perfect financial sense, if you were selling at 100% and are going to sell electricity at 100% (you will be doubling the output for a tenth of the inversion 15 years ago), but as the subsides of 300% no longer exist, you will be actually losing money by upgrading.
by otherme123 - Solar gets lots of subsidies in the UK. Homeowners who installed it 10 years ago get a ridiculous payment for generating excess, even if the grid doesn't use it.
- > solar does not need artificial subsidies, and can pay for itself
That's true now, but wasn't true when those panels were installed. There were subsidies available to get the market kick-started.
They consist of an extra payment for every kwh you generate on top of the payment for delivering the power to the grid. The amount varied depending on when you signed up to the scheme, but at certain points it was as much as 50p/kwh (+ inflation, so more than that now).
by rjmunro - Maybe the thing to do is to NOT upgrade existing working panels but rather set up a different/separate entity with completely different accounts and new panels?
And about the washing, I wonder if it would be worth it to automate the process with a spray of water periodically? You can still wash the panels but I suspect it won't be necessary if there isn't too much dust accumulation? Isn't rain supposed to wash away the dust? What am I missing here?
by collabs - Some places don't get much rain (and these are the places that tend to get even more dust - e.g. deserts).by ido
- Look at any outside surface in a rainy climate.
The dirt may not be piling up, but it's far from clean.
by BurningFrog - The author had ground level access. In that case, A microfiber covered sponge on a pole with a 5 gallon bucket of soapy water is probably the easiest thing. Especially if you do it annually, the dust wouldn’t be completely caked on requiring scraping and excessive elbow grease.
I do a similar procedure for my house windows. I use a squeegee on those but probably not necessary for panels.
by conductr - > You can still wash the panels but I suspect it won't be necessary if there isn't too much dust accumulation? Isn't rain supposed to wash away the dust? What am I missing here?
In places where solar panels are used the most, like the Southwest US, there isn't much rain to speak of. Panels get a lot of dust accumulation from Feb-Nov typically, just when they're needed the most.
by fckgw - It may also be worth spraying them with water when they are too hot. As they get hotter the efficiency drops a little. It's only a few percent, and usually it happens at the time you need the efficiency the least because it's sunny, but if you can combine cleaning and cooling and get a few extra w out if it, why not.by rjmunro
- Horses for courses. My system is off grid, so any extra power is just not used, and its designed in a way that a 2-5% change doesn't do anything. That might be a more meaningful change if I were selling power to other folks.
Kind of off topic, but I see a lot of folks proximate to me have built systems to turn panels so they face the sun more closely. I can see the use in that if you don't have much space or if you have a large commercial operation, but this area is very rural.
My array (4kw) which I built myself has 10 400W panels. The panels cost me $1200 because the minimum order is 12 and the supplier suggested buying extras; shipping large panels one at a time isn't cheap. In fact, the shipping for the entire system (about $5000 worth of equipment) was almost $1000.
But my feeling is that for the cost of a moving array that tracks the sun / time of year would have cost quite a lot more and have involved construction that I personally wasn't comfortable with. The conclusion I came to is that it would cost about the same to build a second array, angle it for "summer" (mine is angled to be most efficient in winter), and hook it to the other MPPT on my controller.
That would take up a lot of space, but a) I am 40 acres and b) then I could run a mig welder with impunity during the day...
by scarecrowbob - Are these older systems? The panels are cheap now but they used to be quite expensive, which would’ve changed the economics a bit.by rsynnott
- It does no longer pay to be clever with solar panels; they're too cheap. Angle not quite right? Add a couple extra. Summer vs. Winter? Add a couple extra.
- A lot of these designs are an artifact of a time when the panels themselves would have been far and away the most expensive component in the system. The place I'm in originally had 10 125W panels that probably cost north of $8k when installed, and they were mounted on a rotating, tilt-adjustable post. Also the entire house was wired to run off DC as much as possible, with three different wiring schemes throughout and rare & expensive appliances. It reminded me strongly of RV power schemes, and maintenance was probably a huge headache.
I replaced it all with 9kW worth of panels (about $3k, shipped) on 4 simple 60° ground mounts, normal wiring and appliances. Angle is optimized for early spring / late fall - there's effectively no sun in winter, and the rest of the year I have excess power even with fixed, sub-optimal angles.
The diminished cost of panels alone over the past 20 years has transformed "off-grid" from a pastime for wealthy hippies into a reasonable solution for remote living.
by Shog9 - Washing solar panels is one of the current popular business ideas on social media. It’s an easy pivot for anyone who already has some experience with much harder home repair handiwork involving a ladder.
The reason it’s popular is because most people don’t understand the economics at all. Someone can go door-to-door in a neighborhood offering to clean solar panels and making huge claims about improving efficiency so much that you can’t afford not to do it.
Homeowners who invested $30K in solar panels think of a $300-600 charge as an easy choice to keep their investment producing money.
My parents had someone going around their neighborhood trying to charge $50/panel for cleaning. They didn’t even climb a ladder. They sprayed washing solution from the ground. Most neighbors declined, but you could see the guy spraying down a couple roofs.
Easy way to clear $1000+ per day for knocking on some doors and pointing a hose at a couple rooftops, at least until the public figures out the scam.
by Aurornis - Are window cleaners not a thing in your neck of the woods?by benj111
- Its an easy value add for a pressure-wash / soft-wash businessby JamesSwift
- I asked a friend with a window cleaning business and they charge about $10 a panel. At that rate I'm tempted to try it but I'm not sure if it's even worth that.by jhot
- Funnily enough, there was a thread a while ago here where people were fixated on the idea that you had to wash solar panels, and thus proponents are underestimating maintenance costs. I had wondered where that idea had come from, as I thought it was fairly well understood that even quite dirty panels once much of an efficiency drop…by rsynnott
- Where I live we don't get much rain, have a lot of dust, and I have a pine tree next to my house that sheds sap onto the panels. That means they get pretty filthy over a year. I pay a guy $150 once a year to come clean them off.
The gains are marginal, I'd have to do more research than I feel like doing to get hard numbers weighted against weather conditions, but I'd guesstimate around 300-400kWh more output per month.
SDGE gives me $0.3-0.5 per kWh during solar peak, so I'm breaking even after one month, and it makes the house look nicer, so I'd call that a win.
by ChiperSoft - Many years ago (and possibly still today) there were firms offering refrigerator-cleaning services. Brushing off the condenser (external) coils.
Yes, that may save you a bit of energy. No, not that much, and overall the financial savings are a small fraction of the service's charge.
A friend worked in energy conservation at the time and actually studied the impact of cleaning coils on refrigerators as part of a recycling programme (so: measuring pre- and post-cleaning power consumption on units which had been in use, most for quite some time). The net results, over hundreds (if not more) units: to little difference to detect statistically.
If you're doing the work yourself or don't have to pay for it: possibly worthwhile for peace of mind if nothing else. Paying someone else? No.
I suspect a similar situation for solar panels.
by dredmorbius - It's a bit worrying the author is asking chatgpt about the tingle rather than making sure there's a grounding lug on all the panels and they're all bonded to a grounding rod.
The rudimentary nature of the setup makes me think there isn't something like a single conductor 12awg (or euro equivalent) copper wire that bonds to all panels and a basic $30 rod.
by walrus01