There are at least a couple of outfits claiming a nano coating or a nano glass surface for solar panels that are so smooth as to not collect dusts. Their other claim is greatly improved angular photon capture since the panel is just that flat. The two companies I've seen claim ~20% improvement - and less maintenance.
I would generalise this a little: The problem with buying a complex item is information inequality. The seller knows more about it than the potential buyer. When inspecting the item, the buyer therefore looks for signs of hidden defects or for evidence that the item is in good condition overall. In this way, cleanliness becomes a proxy for the general condition of the object. Similar mechanisms are at work elsewhere too. Take job applications, for example. A sloppy application is a red flag, even if the applicant’s references are excellent.
Exactly the same reason you should probably clean the rest of the house when you're selling it.
Theoretically, the price of the house before cleaning should be equal to the value if the house after cleaning, minus whatever the cleaning costs. In reality, you'll get much less for your house without cleaning it, because human emotions.
We had a contractor doing repairs before we sold our house. Without being asked he took an orbital sander to the wooden hand railings along the stairs to the front door and said "people really notice this".
A family came for the tour and before walking in the father put his hand on the rail, looked up at the house, and said "this place seems well maintained". Then they bought the house after a small pleasant (for us) bidding war.
The contractor earned his high rate and then some.
If I tour a house with pet urine stains all over the carpet, it's only logical to conclude that the owner is likely not maintaining the rest of the house to a very high standard.
It’s not just emotions, it’s a sign that, when presented with something annoying that you should do but not strictly required, it shows that you pushed through and did it anyway.
It doesn’t prove that you’ve been generally on top of things for the lifetime of the house but the inverse situation where you couldn’t clean one time for guests sure doesn’t.
Having recently bought a house, I love thinking about things that increase perceived value relative to cost (more so because they're nice to have, not because we plan to sell any time soon).
A few things we changed right away:
- new mailbox (replacing a rusted 30+ year old one)
- lots of landscaping work (the majority of which I can do myself)
- installed a wine fridge (I always felt it gave the sense that the kitchen was upgraded when we were touring places)
- replaced old door knobs with modern matte black levers; ~$50 each
The house was built in 1968, so it's been interesting to think about all of the small things that make it feel dated that can be changed for not much money.
To add a few more: it's similarly easy to swap cabinet handles, vent covers, outlet wall plates. Fresh caulk is nice too, even if it's a bit sloppy, still beats stained or cracked caulk.
It's not just emotions, it's also a matter of time and uncertainty.
I was in a buying situation where my old lease was expiring soon, I had a second kid on the way, and the last thing I'd have wanted is to buy a place where I'd have contractors milling around for weeks or months to make various repairs. I was willing to pay a hefty premium for a place that's in a move-in condition.
I don't think this extends to "you'll get $10k less if you don't vacuum", but it's a common courtesy on a million-dollar transaction to maybe not leave a mess.
> In reality, you'll get much less for your house without cleaning it, because human emotions.
It's trust, because if the previous owners can't even bother cleaning it up, what else might their neglect have done to the house? Do you need to change the house wiring, maybe verify if any new paint job is hiding mold or infiltration... All that is the cost of uncertainty and uncertainty grows with distrust.
It's perfectly rational to assume someone who didn't bother to clean the house before selling probably didn't take good care of the house in other, less visible ways.
See also why houses are often painted when being staged for selling just so that the new purchaser can paint immediately after with their preferred colour. Wasteful but it works.
I agree. Doesn't matter what you sell, you will get a higher price if it is cleaned and tidy when presented to the market - because the kinds of people who pay higher prices are looking for clean and tidy things.
Exactly. "Is it clean and tidy right now" is a decent proxy for "Has this been properly taken care of in the past"
Obviously it's not infallible. But even if the owner only cleaned their stuff now that they are selling it that still tells you they are the type of person to take action where it's beneficial
I think it's more of a negative indicator. It's like turning up to a job interview wearing dirty clothes - unless you're a savant it's probably indicative that you don't give a shit or have some sort of other problems in life. But wearing clean clothes doesn't give you points because it's assumed to be the norm in that setting.
> "Is it clean and tidy right now" is a decent proxy for "Has this been properly taken care of in the past"
I don't think so, esp at selling time, I definitely expect that the owner has just made it look pristine. But the opposite is definitely true: if you can't even bother making it look clean and tidy when trying to sell, I'm pretty sure you've not taken care of it in the past!
Definitely. On the other side, if you can't even bother to clean it before you sell it, I have no reason to believe you've put any effort in maintaining it.
Cleaning in general is also usually a core part of maintaining something. Dirt and grime lead to wear and tear.
Wikipedia is written by various people, but likely someone with interest in a given topic. One or more realtors probably wrote or edited this post.
Actually, the history of edits shows that this is contested territory where people regularly remove what they term as spam links. So, while a disinterested editor might remove a link to a listicle about how to stage your home, they might leave in the breathless tone as harmless. The drive by editors probably feel that they have no more time to rewrite it than we do, given that they watch over many articles, not just this one.
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.
Re: the slightly strange shape of the curve. The drop at the beginning could be due to the matching between the panels getting worse. Solar panels in a bank don't like being in different conditions. As a rule of thumb they will all perform at about the same level as the worst in the bank but at the finer levels you could get less straightforward interactions.
The drop off after cleaning could well be because some of the initial boost could come from the water cooling off the panels: solar panels become less efficient at higher temperatures so the drop of after they're all cleaned could be them warming up again after the water has evaporated.
Was just watching a video about a guy who has a boat that runs on solar power that he drove all the way from Finland to the Mediterranean in Winter. Obviously in the winter he was charging his batteries using shore power. But since spring he's been running on solar power doing long journeys and maxing out at 5-8 knots. He just cleaned his panels. Lots of salt, dust and sea gull shit. Also a few kids dropped a rock on one of his panels. Cleaning them improved performance by about 10%. Not nothing. But they were really dirty.
Question for people here: my local power company charges a fee if solar is attached to the grid and is high enough to make installing residential solar impractical.
I'm thinking the best thing to do would be put a large battery in between the grid and my home and selectively recharge the battery with the solar. I believe that setup circumvents the fee since the only thing using energy is the battery, as though it were an off grid setup. I might consider not putting the entire home behind the battery but just the largest energy hogs, like the HVAC or others.
Does this make sense, are there existing setups like this and what are thoughts about something like this?
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.
Eh, compared to what though? Compared to speaking to licensed electrician, definitely. But compared to doing a raw web search and trying to put the information in the right order for the application you’re currently working on, I think it’s at worst a wash.
There are many different ways to connect solar panels to the inverter. Usually the exposed metallic parts will be “grounded” (bonded to the ground / protective earth / equipment grounding conductor / whatever your jurisdiction calls it at the inverter).
But this is an array that looks a bit remote from any structure, and even if the electronics themselves are utterly, perfectly safe, the bonding wire will cause the panel frames to be at the potential of the inverter’s ground, and the soil will be at whatever its local potential is, and this may be different, resulting in a “touch potential”. You can mitigate this with a supplemental ground (or whatever your jurisdiction calls it) closer to the panels. There are fancy ways to do this particularly well to improve safety in the event of a fault.
If you are contacting the actual power wiring of the solar array, something is wrong. If you are feeling capacitive coupled current from the power wiring of the array, then I imagine this means your inverter has crappy filtering, and again the only way you would feel it is if the panel frame isn’t at the same potential as the local soil.
Oh, and if you live somewhere prone to lightning, you probably want to give a possible lightning strike to the panel a better route to a high quality ground than through the bonding wire to your house.
(In fact, in many parts of the world, including IIRC 48 US states, the power utilities may operate their distribution networks with a current carrying wire (combined neutral and ground) that is grounded at multiple points along its route, which will generate substantial leakage current through the ground. The exceptions are IIRC California and Wisconsin, and IIRC those states have their rules to help protect cattle from becoming part of an undesirable circuit while being milked. In CA at least, all the distribution transformers on the poles have at least two bushings on the primary side, and this is why. I believe this is California General Order 95, rule 33 [0].)
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?
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.
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.
Solar panels are increasingly being oriented east or west instead of south, as while it reduces overall yield, it maximises power when it's needed the most - during morning and evening peaks.
I don't have numbers, but I suspect it alleviates issues with dust buildup and temperature.
The most interesting trackers to me, for DIY install in my yard, is a 2-axis tracker. Especially in summer, sunrise and sunset are quite a bit north of east and west, meaning a true south facing fixed set of panels wouldn't even see the sun yet.
Sadly, my investigations a few years back indicated that a suitably strong and robust 2-axis tracker that would withstand our local winds and snow loads is significantly more expensive than just buying more panels and facing some of them east/south/west to accomplish the same thing. Doing this on an existing shed also avoids some local zoning rules vs a dedicated ground mounted system.
I get the impression they are getting less viable because the extra cost and maintenance outweighs just putting more panels down. There are some calculations that suggest even mounting them on angled frames might not be worth the cost, depending on how dirty they get when you just lie them flat on the ground.
(This assumes that you have enough space, but for grid-scale solar this is not the limiting factor. The costs are roughly in order from most to least: the cost of the inverters and grid connection, the cost of installing the panels, the cost of the panels themselves, then the cost of the land to put them on)
I can speak to this somewhat. My panels are on adjustable frames. Typically I switch from flat (summer) to tilted (winter).
As always ymmv and depends somewhat on your location. I'm around 30 degrees from the equator.
During summer, lying flat gets a lot more power. And more importantly the start and end of the generating period is longer. Ie the panels get more sun in the morning and evening thankfully they were tilted.
In winter the sun is more "from one direction" and obviously is lower on the horizon.
The upcoming "balcony solar" legislations will allow up to a limit (iirc 1200W in Virginia) of solar to be directly be connected to the electricity outlets of a house to make our electricity costs lower without having to pay for a battery from what I understand.
Yes, I meant I can get on board with automatically (periodically or based on some trigger or sensor) spraying the panels with water but I was hoping it isn't necessary to use Windex® or even dish soap on the panels themselves.
Of course washing them makes sense, physics-wise. As others have pointed out, you are almost certainly seeing a rise due to cooling off the panels (this would not make economic sense to do all of the time). Temperature has a pretty dramatic effect on solar panel output. Cooling a panel can boost production by 10% or more. Do not polish them. Solar panels are designed to be anti-reflective. You don't want a shiny surface.
But, the real factor in all of this is how valuable the time required to clean the panel is.
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.
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.
It's not 10%, it's much more than that. I'm obviously comparing the peak values, which tend to be days when we don't consume much, which might mean a background 100W vs a couple of kW peak generation. I can dig deeper into the per hour generation and it's similar.
There’s this viral video on X of a guy at an Alex Hormozi talk saying he makes money cleaning solar panels… and it’ll probably turn into a whole market. If he’s getting 2% to 5% gains, I can already see marketing blowing that way out of proportion
Appreciate the attempts to quantify it. I haven't tried to quantify washing, but I do look at mine regularly. I doubt anything accumulates that rain doesn't handle well enough.
Messing around with ground panels is lower risk and safer than roof panels where tool extenders and ladders start to become involved. If you have roof panels, you are the biggest danger to your panels (and yourself.) Don't try to clean them, spray them, knock snow off of them. I was told this multiple times by my installer. :)
As another anecdata-point, when we did this for a now already fairly old roof installation of about 15kWp, it was more than “just about worthwhile”, since the panel area is contiguous: cost seemed to scale up less quickly than the wattage/theoretical maximum output, and the cleaning guy (solo company, IIRC) even told us it wasn’t necessary to do this every year (we hadn’t had it done even once the first decade+ of the installation’s lifetime).
In many countries it is actually illegal to use tall ladder etc. owners would have to erect a scaffolding to make access for work people to clean it safely.
There are definitely some wacky nanny state rules out there… but I’m a little skeptical of “In many countries it is actually illegal to use tall ladder”
However if you are using a string inverter you will want to wash all the ones on the same string in one go if you can, you don't really want them generating different voltage or you will miss out on a lot of power.
So if it's a 2-5% increase, barely break even, it more than breaks even during an extended power failure if you live somewhere this is likely. There are a lot of things I choose to do to avoid future timelines where 'sus appliances break at the worst possible moment. This would be along the same lines to me. Your mindset may vary YMMV.
Nobody can answer this. It simple depends on each setup. Some panels will get incredibly dirty quick like those in the south west where there may be a lack of rain and lots of dust but in other regions you may never need to.
> 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!
> 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).
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.
> 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.
That's not true. You can upgrade to the same capacity on the previous feed-in tariff and keep what you had. It makes sense to upgrade as you can then fill the extra space with additional panels (which will not be on the old tariff, but can be a separate system).
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.
Given the angle of a panel should match its latitude and average sun angle, the panels might generate noticeably more by being pitched steeper at over 30 degrees. Eyeballing this, it appears closer to 25 degrees right now which doesn't even make sense for the summer sun in the UK. I could be wrong as it also appears these are on a slope!
On Mars, the wind storms and dust devils are so fearsome that some of the robots there could rely on dust being blown clean off all the solar panels on a regular basis. Spirit and Opportunity benefited the most from these effects.
InSight was stationary and not so fortunate. But, the ground team got quite creative with its robotic arm to try and manipulate the sand that had accumulated on the solar panel, and gained a little bit more power.
Rain usually just cakes the dirt. Unless it's a downpour, it doesn't move with enough velocity or volume to remove the dirt. So the dirt just gets damp, maybe moves a few cm with gravity, then dries as a mud cake.
I haven't noticed too much of a power increase in my backyard solar farm after cleaning, but I do notice a very significant increase by weeding the surrounding stuff. Even a pretty small amount of shade will very significantly reduce your yield, like seriously 20-30%.
Oh, also, I've noticed that at least with my panels, bird poop seems to be particularly bad. The dust that accrues doesn't seem to do much, but even a relatively small bit of bird poop will be almost as bad as weeds. Fortunately it's not terribly difficult to clean once it's dried.
There are at least a couple of outfits claiming a nano coating or a nano glass surface for solar panels that are so smooth as to not collect dusts. Their other claim is greatly improved angular photon capture since the panel is just that flat. The two companies I've seen claim ~20% improvement - and less maintenance.
> why would you clean them when you're about to sell the house?
So they look good and the potential buyer sees something that looks to be in good condition and working well.
I would generalise this a little: The problem with buying a complex item is information inequality. The seller knows more about it than the potential buyer. When inspecting the item, the buyer therefore looks for signs of hidden defects or for evidence that the item is in good condition overall. In this way, cleanliness becomes a proxy for the general condition of the object. Similar mechanisms are at work elsewhere too. Take job applications, for example. A sloppy application is a red flag, even if the applicant’s references are excellent.
Exactly the same reason you should probably clean the rest of the house when you're selling it.
Theoretically, the price of the house before cleaning should be equal to the value if the house after cleaning, minus whatever the cleaning costs. In reality, you'll get much less for your house without cleaning it, because human emotions.
We had a contractor doing repairs before we sold our house. Without being asked he took an orbital sander to the wooden hand railings along the stairs to the front door and said "people really notice this".
A family came for the tour and before walking in the father put his hand on the rail, looked up at the house, and said "this place seems well maintained". Then they bought the house after a small pleasant (for us) bidding war.
The contractor earned his high rate and then some.
> because human emotions.
If I tour a house with pet urine stains all over the carpet, it's only logical to conclude that the owner is likely not maintaining the rest of the house to a very high standard.
It’s not just emotions, it’s a sign that, when presented with something annoying that you should do but not strictly required, it shows that you pushed through and did it anyway.
It doesn’t prove that you’ve been generally on top of things for the lifetime of the house but the inverse situation where you couldn’t clean one time for guests sure doesn’t.
Having recently bought a house, I love thinking about things that increase perceived value relative to cost (more so because they're nice to have, not because we plan to sell any time soon).
A few things we changed right away: - new mailbox (replacing a rusted 30+ year old one) - lots of landscaping work (the majority of which I can do myself) - installed a wine fridge (I always felt it gave the sense that the kitchen was upgraded when we were touring places) - replaced old door knobs with modern matte black levers; ~$50 each
The house was built in 1968, so it's been interesting to think about all of the small things that make it feel dated that can be changed for not much money.
To add a few more: it's similarly easy to swap cabinet handles, vent covers, outlet wall plates. Fresh caulk is nice too, even if it's a bit sloppy, still beats stained or cracked caulk.
It's not just emotions, it's also a matter of time and uncertainty.
I was in a buying situation where my old lease was expiring soon, I had a second kid on the way, and the last thing I'd have wanted is to buy a place where I'd have contractors milling around for weeks or months to make various repairs. I was willing to pay a hefty premium for a place that's in a move-in condition.
I don't think this extends to "you'll get $10k less if you don't vacuum", but it's a common courtesy on a million-dollar transaction to maybe not leave a mess.
> In reality, you'll get much less for your house without cleaning it, because human emotions.
It's trust, because if the previous owners can't even bother cleaning it up, what else might their neglect have done to the house? Do you need to change the house wiring, maybe verify if any new paint job is hiding mold or infiltration... All that is the cost of uncertainty and uncertainty grows with distrust.
This simple procedure increases the selling price of everything. Just a fact.
It's perfectly rational to assume someone who didn't bother to clean the house before selling probably didn't take good care of the house in other, less visible ways.
People often confuse "irrational" with "rational on inference given incomplete information"
This is the latter.
See also: stereotype accuracy
See also why houses are often painted when being staged for selling just so that the new purchaser can paint immediately after with their preferred colour. Wasteful but it works.
Also you don't need anything fancy when washing them, their surface is just glass.
I agree. Doesn't matter what you sell, you will get a higher price if it is cleaned and tidy when presented to the market - because the kinds of people who pay higher prices are looking for clean and tidy things.
> because the kinds of people who pay higher prices are looking for clean and tidy things.
I'd say it's also "because the kind of people who clean and tidy things also maintain them"
Exactly. "Is it clean and tidy right now" is a decent proxy for "Has this been properly taken care of in the past"
Obviously it's not infallible. But even if the owner only cleaned their stuff now that they are selling it that still tells you they are the type of person to take action where it's beneficial
I think it's more of a negative indicator. It's like turning up to a job interview wearing dirty clothes - unless you're a savant it's probably indicative that you don't give a shit or have some sort of other problems in life. But wearing clean clothes doesn't give you points because it's assumed to be the norm in that setting.
Right. Clean house on the market means almost nothing.
Gross house means almost certainly not maintained.
> "Is it clean and tidy right now" is a decent proxy for "Has this been properly taken care of in the past"
I don't think so, esp at selling time, I definitely expect that the owner has just made it look pristine. But the opposite is definitely true: if you can't even bother making it look clean and tidy when trying to sell, I'm pretty sure you've not taken care of it in the past!
Definitely. On the other side, if you can't even bother to clean it before you sell it, I have no reason to believe you've put any effort in maintaining it.
Cleaning in general is also usually a core part of maintaining something. Dirt and grime lead to wear and tear.
See also "staging":
* https://en.wikipedia.org/wiki/Home_staging
Why is it written like that lmao
Wikipedia is written by various people, but likely someone with interest in a given topic. One or more realtors probably wrote or edited this post.
Actually, the history of edits shows that this is contested territory where people regularly remove what they term as spam links. So, while a disinterested editor might remove a link to a listicle about how to stage your home, they might leave in the breathless tone as harmless. The drive by editors probably feel that they have no more time to rewrite it than we do, given that they watch over many articles, not just this one.
Its been "staged"
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.
Re: the slightly strange shape of the curve. The drop at the beginning could be due to the matching between the panels getting worse. Solar panels in a bank don't like being in different conditions. As a rule of thumb they will all perform at about the same level as the worst in the bank but at the finer levels you could get less straightforward interactions.
The drop off after cleaning could well be because some of the initial boost could come from the water cooling off the panels: solar panels become less efficient at higher temperatures so the drop of after they're all cleaned could be them warming up again after the water has evaporated.
Was just watching a video about a guy who has a boat that runs on solar power that he drove all the way from Finland to the Mediterranean in Winter. Obviously in the winter he was charging his batteries using shore power. But since spring he's been running on solar power doing long journeys and maxing out at 5-8 knots. He just cleaned his panels. Lots of salt, dust and sea gull shit. Also a few kids dropped a rock on one of his panels. Cleaning them improved performance by about 10%. Not nothing. But they were really dirty.
https://www.youtube.com/watch?v=FhBBUFuTwR4
Question for people here: my local power company charges a fee if solar is attached to the grid and is high enough to make installing residential solar impractical.
I'm thinking the best thing to do would be put a large battery in between the grid and my home and selectively recharge the battery with the solar. I believe that setup circumvents the fee since the only thing using energy is the battery, as though it were an off grid setup. I might consider not putting the entire home behind the battery but just the largest energy hogs, like the HVAC or others.
Does this make sense, are there existing setups like this and what are thoughts about something like this?
Thanks
Ask a lawyer about the law.
Why would I ask a lawyer for advice about whole home battery solar setups with a grid backup?
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.
Eh, compared to what though? Compared to speaking to licensed electrician, definitely. But compared to doing a raw web search and trying to put the information in the right order for the application you’re currently working on, I think it’s at worst a wash.
The system in question does not have a transformer so a grounding rod is not required as it is not a separately derived system.
The equipment grounds should be tied together to prevent any difference in potential though.
There are many different ways to connect solar panels to the inverter. Usually the exposed metallic parts will be “grounded” (bonded to the ground / protective earth / equipment grounding conductor / whatever your jurisdiction calls it at the inverter).
But this is an array that looks a bit remote from any structure, and even if the electronics themselves are utterly, perfectly safe, the bonding wire will cause the panel frames to be at the potential of the inverter’s ground, and the soil will be at whatever its local potential is, and this may be different, resulting in a “touch potential”. You can mitigate this with a supplemental ground (or whatever your jurisdiction calls it) closer to the panels. There are fancy ways to do this particularly well to improve safety in the event of a fault.
If you are contacting the actual power wiring of the solar array, something is wrong. If you are feeling capacitive coupled current from the power wiring of the array, then I imagine this means your inverter has crappy filtering, and again the only way you would feel it is if the panel frame isn’t at the same potential as the local soil.
Oh, and if you live somewhere prone to lightning, you probably want to give a possible lightning strike to the panel a better route to a high quality ground than through the bonding wire to your house.
(In fact, in many parts of the world, including IIRC 48 US states, the power utilities may operate their distribution networks with a current carrying wire (combined neutral and ground) that is grounded at multiple points along its route, which will generate substantial leakage current through the ground. The exceptions are IIRC California and Wisconsin, and IIRC those states have their rules to help protect cattle from becoming part of an undesirable circuit while being milked. In CA at least, all the distribution transformers on the poles have at least two bushings on the primary side, and this is why. I believe this is California General Order 95, rule 33 [0].)
[0] https://ia.cpuc.ca.gov/gos/go95/go_95_rule_33.html
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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?
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.
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.
Solar panels are increasingly being oriented east or west instead of south, as while it reduces overall yield, it maximises power when it's needed the most - during morning and evening peaks.
I don't have numbers, but I suspect it alleviates issues with dust buildup and temperature.
Tracking systems are also becoming more popular. You spend a little more up front but get a lot more usable power.
The most interesting trackers to me, for DIY install in my yard, is a 2-axis tracker. Especially in summer, sunrise and sunset are quite a bit north of east and west, meaning a true south facing fixed set of panels wouldn't even see the sun yet.
Sadly, my investigations a few years back indicated that a suitably strong and robust 2-axis tracker that would withstand our local winds and snow loads is significantly more expensive than just buying more panels and facing some of them east/south/west to accomplish the same thing. Doing this on an existing shed also avoids some local zoning rules vs a dedicated ground mounted system.
I get the impression they are getting less viable because the extra cost and maintenance outweighs just putting more panels down. There are some calculations that suggest even mounting them on angled frames might not be worth the cost, depending on how dirty they get when you just lie them flat on the ground.
(This assumes that you have enough space, but for grid-scale solar this is not the limiting factor. The costs are roughly in order from most to least: the cost of the inverters and grid connection, the cost of installing the panels, the cost of the panels themselves, then the cost of the land to put them on)
I can speak to this somewhat. My panels are on adjustable frames. Typically I switch from flat (summer) to tilted (winter).
As always ymmv and depends somewhat on your location. I'm around 30 degrees from the equator.
During summer, lying flat gets a lot more power. And more importantly the start and end of the generating period is longer. Ie the panels get more sun in the morning and evening thankfully they were tilted.
In winter the sun is more "from one direction" and obviously is lower on the horizon.
Panels are so cheap now you're better off just installing twice as many without tracking.
isn't that more of a storage issue, which a home battery would solve?
A battery would solve it, but it can be cheaper to have additional panels oriented east and west than to add the equivalent battery capacity
The upcoming "balcony solar" legislations will allow up to a limit (iirc 1200W in Virginia) of solar to be directly be connected to the electricity outlets of a house to make our electricity costs lower without having to pay for a battery from what I understand.
Yes, I meant I can get on board with automatically (periodically or based on some trigger or sensor) spraying the panels with water but I was hoping it isn't necessary to use Windex® or even dish soap on the panels themselves.
Some places don't get much rain (and these are the places that tend to get even more dust - e.g. deserts).
Look at any outside surface in a rainy climate.
The dirt may not be piling up, but it's far from clean.
Of course washing them makes sense, physics-wise. As others have pointed out, you are almost certainly seeing a rise due to cooling off the panels (this would not make economic sense to do all of the time). Temperature has a pretty dramatic effect on solar panel output. Cooling a panel can boost production by 10% or more. Do not polish them. Solar panels are designed to be anti-reflective. You don't want a shiny surface.
But, the real factor in all of this is how valuable the time required to clean the panel is.
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.
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.
It's not 10%, it's much more than that. I'm obviously comparing the peak values, which tend to be days when we don't consume much, which might mean a background 100W vs a couple of kW peak generation. I can dig deeper into the per hour generation and it's similar.
There’s this viral video on X of a guy at an Alex Hormozi talk saying he makes money cleaning solar panels… and it’ll probably turn into a whole market. If he’s getting 2% to 5% gains, I can already see marketing blowing that way out of proportion
Appreciate the attempts to quantify it. I haven't tried to quantify washing, but I do look at mine regularly. I doubt anything accumulates that rain doesn't handle well enough.
Messing around with ground panels is lower risk and safer than roof panels where tool extenders and ladders start to become involved. If you have roof panels, you are the biggest danger to your panels (and yourself.) Don't try to clean them, spray them, knock snow off of them. I was told this multiple times by my installer. :)
As another anecdata-point, when we did this for a now already fairly old roof installation of about 15kWp, it was more than “just about worthwhile”, since the panel area is contiguous: cost seemed to scale up less quickly than the wattage/theoretical maximum output, and the cleaning guy (solo company, IIRC) even told us it wasn’t necessary to do this every year (we hadn’t had it done even once the first decade+ of the installation’s lifetime).
So, at least in our case, definitely worth it.
Interesting; what was on the panels? What was the ROI on paying the guy?
In many countries it is actually illegal to use tall ladder etc. owners would have to erect a scaffolding to make access for work people to clean it safely.
There are definitely some wacky nanny state rules out there… but I’m a little skeptical of “In many countries it is actually illegal to use tall ladder”
Definitely wash the panels.
However if you are using a string inverter you will want to wash all the ones on the same string in one go if you can, you don't really want them generating different voltage or you will miss out on a lot of power.
So if it's a 2-5% increase, barely break even, it more than breaks even during an extended power failure if you live somewhere this is likely. There are a lot of things I choose to do to avoid future timelines where 'sus appliances break at the worst possible moment. This would be along the same lines to me. Your mindset may vary YMMV.
But if cash is tight, yeah, not so much.
Nobody can answer this. It simple depends on each setup. Some panels will get incredibly dirty quick like those in the south west where there may be a lack of rain and lots of dust but in other regions you may never need to.
> 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!
> 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).
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.
> 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.
That's not true. You can upgrade to the same capacity on the previous feed-in tariff and keep what you had. It makes sense to upgrade as you can then fill the extra space with additional panels (which will not be on the old tariff, but can be a separate system).
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.
Given the angle of a panel should match its latitude and average sun angle, the panels might generate noticeably more by being pitched steeper at over 30 degrees. Eyeballing this, it appears closer to 25 degrees right now which doesn't even make sense for the summer sun in the UK. I could be wrong as it also appears these are on a slope!
It totally depends on your area. In the PNW I get sap and conifer tree pollen all over my panels and have to wash them at least twice a year.
I know that dust on the panels is one of the reasons that one of the Mars rovers eventually croaked.
On Mars, the wind storms and dust devils are so fearsome that some of the robots there could rely on dust being blown clean off all the solar panels on a regular basis. Spirit and Opportunity benefited the most from these effects.
InSight was stationary and not so fortunate. But, the ground team got quite creative with its robotic arm to try and manipulate the sand that had accumulated on the solar panel, and gained a little bit more power.
https://en.wikipedia.org/wiki/InSight#Surface_operations
https://en.wikipedia.org/wiki/Martian_regolith
I imagine rain will clean them. In most places it rains every so often.
Rain usually just cakes the dirt. Unless it's a downpour, it doesn't move with enough velocity or volume to remove the dirt. So the dirt just gets damp, maybe moves a few cm with gravity, then dries as a mud cake.
my experience is that unless you get some really torrential rain, it's not enough to clean the sand/dust/grime
Can confirm, my car doesn’t get cleaner unless there’s a downpour
I haven't noticed too much of a power increase in my backyard solar farm after cleaning, but I do notice a very significant increase by weeding the surrounding stuff. Even a pretty small amount of shade will very significantly reduce your yield, like seriously 20-30%.
Oh, also, I've noticed that at least with my panels, bird poop seems to be particularly bad. The dust that accrues doesn't seem to do much, but even a relatively small bit of bird poop will be almost as bad as weeds. Fortunately it's not terribly difficult to clean once it's dried.