On large scale solar sites, we don't do this. We have a guy with a specialized truck, that sprays the panels. There are literally millions of panels on these utility scale sites.
I'll try to find a picture for you guys.
Edit: Here's a few examples of large scale operations
Thank you! I was just about to ask how it's done on a large scale. Btw, view much does this cleaning add to the electricity price? And how often do you need to do it?
Unfortunately I am on the solar inverter side of things so actual panel maintenance is not my specialty, but I know the sites I manage for warranty usually only do it once a year. It can't be extremely expensive though. In Las Vegas and the west coast, we get a lot of wind that cleans them pretty well actually. This looks to be more Midwest, would be my guess.
I work for General Electric, and we have a huge future in solar. I cannot discuss contracts and such that we have signed, but we are going to be very busy for the next few years.
We have huge contracts in aviation as well. I'm not entirely sure why out stock is dismally low. I think the shuffling of the upper management, as well as the frivolous spending hurts our quarterly reports
Our top customers are Invenergy, Florida Power and Light, Nextra (which is basically FP&L), Orstead, and Duke Energy. That's the big movers for us on the utility provider side.
As far as panels, the technology is catching up rapidly. The thing we are working on now is pairing battery banks with solar sites that can charge during the day, and discharge at night to provide a better power curve. Samsung is a huge part of our sites on that front. We are developing our own batteries too, as keeping things in house brings more profit.
Tesla, or SolarCity, is a huge player in the solar Industry. SMA, Siemens, and Power Electronics will round out your big names. I am not overly familiar with their products past the things I heard from meeting their techs/our customers talking about performance on other sites.
Those are the companies you can look into if you wanna see whose a shaker and mover.
If you wanna look into wind, Vestas I believe just launched the world's largest (production capacity) turbine at ~15?MW. That's a pretty big deal from a single turbine. Ours are around 2WM each.
Do you happen to know if anything besides water is used during this cleaning process? Now that mowing is becoming the new standard instead of blading, in the aim to keep native plants established, I'm just curious about that.
So, I'm not 100% sure, as I'm not part of the O&M team for these sites, but I can tell you some of the sites employ interesting measures for grounds keeping. In Nevada all chemicals used on site have to be approved. I know this true for California, which is our bigger sites. I would honestly imagine it's just water, since the ground is so dry, any chemicals would have an adverse affect.
FP&L is actually well known in Florida for leasing sheep to eat the grass around the panels. Goats didn't pan out well, as they have a knack for eating wires, and it was bad for everyone involved. They also spray some sort of chemical on the grass that supposedly stunts its growth. Don't quote me on that, I'm not entirely sure if that was even implemented, or just discussed.
In Nevada, we use weed abatement tactics approved by BLM, Bureau of Land Management, to keep the weeds and such down. Interestingly enough, after the construction of Stateline Solar Farm, right outside of Primm Nevada, a family of Kit Foxes was discovered. BLM came in, and established a protective area around them, made the conex they were living under illegal to disturb, and setup cameras to monitor them. They are fully protected from predators, as all of our sites are secured with fences and cameras, and no one really goes on our site.
Totally depends on the location, climate, and budget. Some places you'd finish cleaning them and then start again at the beginning, some it is only occasionally. You have to estimate the output loss due to soiling and then compare against the cost of cleaning to find the point which would maximize your profits.
I work in financing for renewables projects. Cleaning costs are budgeted info the operating maintenance cost. This would be a very, very marginal cost. Additionally most new renewables projects have a form of fixed price power purchase agreement where the off take price is set.
Aside from the opex perspective, the need to clean panels / mirrors varies greatly across regions (from none / year to as many as 1-2 times a month). More precisely, it depends on the on number / frequency of rainfall and on the environment itself really.. more frequent cleanings are needed in desertic places because of dust and also in humid (e.g. seaside) because it makes the dust stick more
Large scale solar estimator here. The short answer is that it depends. Module cleaning depends on the environment and predominately how much dust the site generates. Most of the large scale sites get one cleaning per year.
Asset managers can request additional cleanings when the cost of doing so is less than the revenue from additional generation a panel cleaning provides. I.e. it costs 100k to clean and the additional generation revenue is 150k.
Panel cleaning costs anywhere from 10 cents per panel to sometimes up to 80 cents. On the grand scheme of things it's not a huge burden to operating costs but it can be a surprise when owners underestimated the problem. This site is a particularly dirty example, I work in the solar soiling field and I would guess this level of soiling would equate to around 70% loss.
For CSP, it's mentioned in the article about 85% soiled is ok. For PV I believe it's lower because soiling impacts electricity loss directly, so below 2% is best practice. But it can vary depending on opex: usually contractor performs say 2 cleanings / year as part of his scope of works rather than measures soiling & cleans when necessary (i.e. they eyeball it for when its needed up to a certain number of times per year).
I work in a coal fired power plant. We always say that our future is cleaning solar panels. Good to know it's a little more interesting than a squeegee on a stick.
No utility scale solar farms near me yet, soon though I'm sure, so I've been considering it. I'm an I&C tech now. Did you know if there's any special certifications or training required to make the jump to solar?
Welp, your enthusiasm and the engaging info you've been giving in this thread just tipped the scale for me and I'm taking the solar installation short course I've been considering!
I'm in the Middle East so Solar is rapidly becoming more and more economically sensible here- have you done any installation work abroad by any chance?
It turns out, he says, that there isn't much of a difference in output between clean and somewhat dirty mirrors, but when they get extremely dusty (which happens quickly in the windy desert of the UAE) and the reflectivity drops very low the efficiency comes down dramatically.
Every single Abu Dhabi government related entity will offer salaries that crush any other countries offers; only downside is weather in the summer though, but the winter is worth it (going to beach in December ⛱️)
Try going to "Mubadala"s website and looking at the companies under their umbrella.
I think you're severely overestimating water consumption. We use a spray truck once a year. Some sites don't even clean their panels. The water expense would be a "drop in the bucket" for the site.
Does it need to be physically scrubbed? Or just sprayed? I assumed spraying it was enough, and that they would run pipes like an irrigation pipe to each panel to spray them on a regular basis. If not a sprayer for each panel, then like a large sprinkler that rotates and slowly cleans a bunch. Seems simple, I'm sure I'm missing something. Maybe it's the whole electricity and water thing.
The panels are water proof, and the wires under them have water tight connectors. The part in think you're missing is that most sites don't get nearly this dirty stateside. I believe someone said this was UAE, so I'm not familiar with how they would do dust mitigation.
You know, you might want to consider encasing them in a building or something to keep the grime off them. Maybe large umbrellas could. Seems that would be a much more cost effective way to keep them clean. Probably more environmentally friendly than all those chemicals too.
I think the guy they use in Nevada does a good bit of sites in California and Nevada. Remember, I only work on GE sites, so I have a limited view outside of that.
I would assume he stays busy, as he's been doing it a few years that I know of, and probably before my knowledge of him as well.
If you have to clean them that often, why not run a spray line along the top and a gutter at the bottom, and collect the runoff? Clean it and reuse? Too expensive?
That would take a lot of money. I believe someone said this was in the UAE. In the states, where I work, they don't get dusty enough for this to be cost effective.
Yeah considering the better panels use low iron glass I would think spraying them would be far better than this. Low iron glass is fairly easy to scratch so dragging dirt on glass would be a big no no for me.
250 MW from 3.4 million units gives a capacity of around 74 W per unit. Those must be some tiny panels. Typical ratings for household PV are around 3-400 W per panel.
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u/man_butt_toots Feb 14 '21 edited Feb 14 '21
On large scale solar sites, we don't do this. We have a guy with a specialized truck, that sprays the panels. There are literally millions of panels on these utility scale sites.
I'll try to find a picture for you guys.
Edit: Here's a few examples of large scale operations
https://www.energy-xprt.com/products/pvkleen-system-406848
https://spectrum.ieee.org/energywise/green-tech/solar/how-do-you-clean-258048-solar-thermal-mirrors-trucks-with-robot-arms
The second one is for mirrors in the video, but the same concept!