Floating solar panels show promise, but environmental impacts vary by location, study finds:
Floating solar panels are emerging as a promising clean energy solution with environmental benefits, but a new study finds those effects vary significantly depending on where the systems are deployed.
Researchers from Oregon State University and the U.S. Geological Survey modeled the impact of floating solar photovoltaic systems on 11 reservoirs across six states. Their simulations showed that the systems consistently cooled surface waters and altered water temperatures at different layers within the reservoirs. However, the panels also introduced increased variability in habitat suitability for aquatic species.
"Different reservoirs are going to respond differently based on factors like depth, circulation dynamics and the fish species that are important for management," said Evan Bredeweg, lead author of the study and a former postdoctoral scholar at Oregon State. "There's no one-size-fits-all formula for designing these systems. It's ecology - it's messy."
While the floating solar panel market is established and growing in Asia, it remains limited in the United States, mostly to small pilot projects. However, a study released earlier this year by the U.S. Department of Energy's National Renewable Energy Laboratory estimated that U.S. reservoirs could host enough floating solar panel systems to generate up to 1,476 terawatt-hours annually, enough to power approximately 100 million homes.
Floating solar panels offer several advantages. The cooling effect of the water can boost panel efficiency by an estimated 5 to 15%. The systems can also be integrated with existing hydroelectric and transmission infrastructure. They may also help reduce evaporation, which is especially valuable in warmer, drier climates.
However, these benefits come with questions about potential impacts on aquatic ecosystems, an area that has received limited scientific attention.
[...] They found that changes in temperature and oxygen dynamics caused by floating solar panels can influence habitat availability for both warm-water and cold-water fish species. For instance, cooler water temperatures in summer generally benefit cold-water species, though this effect is most pronounced when panel coverage exceeds 50%.
The researchers note the need for continued research and long-term monitoring to ensure floating photovoltaic systems support clean energy goals without compromising aquatic ecosystems.
"History has shown that large-scale modifications to freshwater ecosystems, such as hydroelectric dams, can have unforeseen and lasting consequences," Bredeweg said.
Journal Reference: https://doi.org/10.1016/j.limno.2025.126293
(Score: 5, Insightful) by JoeMerchant on Thursday November 20, @12:23PM (3 children)
Just like hydro power, the answer to "is this construction doing more good than harm" depends on your perspective.
Are you a rainbow trout that wouldn't have sufficient habitat without the new lake? Or are you a salmon which cannot breed without a fish ladder that was left out of the project plans? Not all hydro projects are compatible with fish ladders.
Are you the world bank, looking to advance your global agenda, or are you a local resident who will see your 6 generation family farm and homes submerged?
There will be places where floating solar is clearly net good from most people's perspectives, other places where it is clearly net bad, but most places will depend on the values of those making the call.
🌻🌻🌻🌻 [google.com]
(Score: 2) by gawdonblue on Friday November 21, @03:56AM (2 children)
This is talking about floating solar, not hydro. i.e. putting solar panels on existing water, not flooding places.
I cannot think of a situation where floating solar is "clearly net bad". Not saying that there isn't, but can you give an example?
(Score: 3, Insightful) by JoeMerchant on Friday November 21, @02:23PM
>I cannot think of a situation where floating solar is "clearly net bad"
Try one where the lack of solar heating in the water causes additional freezing and cracking of the rocks in the impoundment leading to catastrophic failure and flood. Unlikely, but clearly bad.
Try one where the lack of solar heating in the water decimates the ecosystem underneath - I believe this is what TFA is getting to... this can have significant impacts not only on the area under the panels but also ecosystems downstream, potentially including the ocean.
Try one where the constant maintenance required on the floating panels and associated systems leads to excessive traffic through what was formerly a quiet and peaceful area. Sure, they eat at the truckstop and "bring money into the local economy" - not everyone is looking for additional truckstop revenue in their town.
Try one where the hydro power that the solar panels are going to float on is already bad enough for the ecology, but putting the panels on the impoundment pond raises the economic value sufficiently to cancel the dam removal project that would have otherwise been approved.
All in all, solar is less invasive than hydro, but it's also shorter life cycle - the parts wear out faster and create more recycling work ... in theory, in practice they fill the landfills, get dumped in third world countries that still accept electronic waste, and highly likely: a lot of that junk is going to end up at the bottom of the lake it used to float on - which is all kinds of bad that most people will deny happens, but anybody with any experience with the real world knows: it's gonna happen, a lot.
🌻🌻🌻🌻 [google.com]
(Score: 1) by khallow on Saturday November 22, @05:32PM
Hydro was used as a similar example: "large-scale modifications to freshwater ecosystems, such as hydroelectric dams, can have unforeseen and lasting consequences".
We have JoeMerchant's example of creating and displacing habitat, depending on the organism. Underwater plants have to compete for sunlight and depending on the setup, it can provide habitat for small marine animals and birds. It also competes with other human uses of the lake - such as recreational boating and fishing. And you can have flooding spaces as a possibility, if a marginal hydroelectric project becomes much more feasible through floating solar.
(Score: 4, Insightful) by datapharmer on Thursday November 20, @01:26PM (5 children)
I hope they study the maintenance requirements and compare to other installation locations/methods before widely implementing this... I suspect failures do to moisture will be non-trivial.
(Score: 2) by JoeMerchant on Thursday November 20, @02:04PM (2 children)
Our neighbor's rooftop install has a major dust and pollen problem, how much that costs depends on your perspective. Are you hiring contractors to clean your solar panels? Minimum $300 per year for that, probably closer to $1000 in today's labor market. Are you instead getting your own gear (probably $300 in ladders, pole brushes, etc. which have to be stored somewhere...) and doing your own labor (probably 5-10 hours per year if you're going to keep the panels' efficiency less than 10% degraded by dust and pollen) and dealing with the potential for accident / injury in the process of your weekend-warrior ladder-top escapades?
Our neighbors' experience: 1) finally get the solar panels installed and working after 10+ months of project delay, 2) six months later watch the net power generation drop approximately 30% after pollen dusting (turning the projected break-even in 15-20 years vs install cost into break-even never), 3) get the $1000 quotes from multiple contractors, 4) spend the $300 on equipment, 5) two months later start the pollen cleaning project, 6) do a smashingly wonderful cleaning job on about 10% of the panels in about 2 hours of labor, 7) leave the ladder and pole brushes standing there for the next 5 months... we'll see what happens from here. Pollen season is right around the corner.
🌻🌻🌻🌻 [google.com]
(Score: 3, Interesting) by VLM on Thursday November 20, @04:23PM (1 child)
I've been thinking about putting up some solar in my infinite spare time and the more I learn the more I want ground mount.
I have plenty of land and I already own two patio umbrellas so the idea of a solar pergola or similar replacing my actual umbrellas that generates a KW or so "for free" is appealing. I mean, I want an umbrella or pergola or similar anyway, so may as well have one that makes watts.
Maintaining stuff while standing on the ground is SO much easier than maintaining stuff on a roof.
I get that if you don't have the land, you want to use the roof, like retail, commercial, industrial. But I don't have that constraint. I can build right off the back of the garage. Not sure if its good or bad that I can't see that land from the house windows...
Also all the solar farms I've seen use ground mount. I don't see them putting up 10K tool sheds to hang 10K panels on the roofs.
Solar on a roof is kind of like having a goat as livestock, if you meet a farmer who doesn't have enough problems in his life, buy him a goat. Likewise my roof is enough of an expensive PITA to keep the heat on the correct side and the water out as it is, last thing I need is panels up there to make it even more complicated and difficult.
In my geography an average acre of solar farm makes like 300+ MWh/year which is a lot, even at our latitude and insane annual rainfall (we literally don't know what to do with 3 to 4 FEET of rain per year). I'm not going to cover my entire back yard with panels and I don't know what to do with 300 MWh/year if I did. I could build my own ammonia or nitric acid production plant, or I could refine deuterium the hard way, or run a very small local AI farm for the LOLs...
Funny engineering rule of thumb: It takes about a gigawatt-hour to boil an acre-foot of water. So if we get four feet of rain some years thats 4 gigawatt-hours of solar thermal required to evaporate all the rain that falls on my back yard. But we don't get that much solar ... so where I live, long term, rainwater runoff is simply inevitable. Its "interesting" to look at maps showing where rain mostly evaporates vs where rain mostly runs into the ocean. Where I live, at least some of the rain has to end up in the gulf of mexico (err, Gulf of America I guess) it can't soak in and evaporate. So I'm not very concerned about the effects of covering my back yard with panels, there's gonna be runoff anyway and most of the water will soak into the ground anyway.
(Score: 2) by JoeMerchant on Thursday November 20, @10:16PM
Ground mount is great, if you don't use your ground for anything (including looking at it...)
I really tried to make a solar carport work for us, but it just didn't make any economic sense. The 2 vehicle slab to park on was $10K, the hurricane rated steel structure (with 2 side walls) was $7K installed ($500 of that being an infinitely annoying permit, local installers would have "handled the permit for us", and also charged $12K to put up the same structure.) Every solar thing I looked at started around $35K for the structure with panels and inverters, not counting the slab, and the permit would have been PITA^3. I tried the idea of having a standing seam metal roof on the structure that I might DIY install a few panels on and build up as I got practical uses for the solar power established (not trying to grid-tie.) - but just switching to that style roof (the only kind you can mount panels to without additional roof penetrations), was jumping up my structure cost from $7K to more like $20K+.
There are various carport solutions that use the solar panels as the roof - none under $40K installed. In the end, we just wanted the new truck and old car out of the sun and the rain, so simple and cheap won the day.
🌻🌻🌻🌻 [google.com]
(Score: 3, Interesting) by Username on Thursday November 20, @02:41PM (1 child)
They would be filled with algae by the end of the year. I hope they make them spherical or turtles and brids will wreck them.
(Score: 2) by JoeMerchant on Thursday November 20, @10:29PM
Seagulls defecating on your solar panels? Better have a regular washing system to get that off before it etches the surface of the panels. Lucky there's a water source nearby, and power to pump it, but that's a whole extra layer of complexity and expense that the rose tinted eyeshade financial analysts tend to overlook.
🌻🌻🌻🌻 [google.com]
(Score: 2) by VLM on Thursday November 20, @04:42PM (2 children)
I live in a "famous outdoor recreation state" and there is WAY too much money wrapped up in tourism and boating and fishing and skiing and swimming to ever consider taking all of that away for solar panels.
I imagine in a way it would be even worse in a non-outdoor recreation state because of supply and demand.
Ah I was about to ponder how they handle ice fishing season which is rapidly nearing, but I see this is just for victims of the "war of northern aggression".
I have an uncle who ice fishes, has an ice shanty and everything (for you southerners, us yankees drag a small toolshed out on the ice, traditionally somewhat well insulated with a small woodburner although just keeping out of the wind helps enough). Anyway I ran the numbers on him for a solar panel on the roof vs predicted use and its not bad. Then I thought about the battery and I know lead acid will not survive deep discharging outside and the new fangled LiFePO4 batteries will not work in the winter where I live.
I've been thinking, if its not safe to store LiFePO4 batteries outdoors in my climate during BOTH the summer and winter, how do they ship those without damage? My guess is, they don't? I did not like that answer, not at all. If you don't believe me you can literally look at battery labels online. How does that work with EV car batteries? Norsk sells a marine battery with a built in electric heater, OK then. Fully charged legacy lead acid batteries will not crack outdoors at even at record low temps. Discharged ones surely will, but just ship them charged and its safe.
Anyway yeah rough guess if lakeshore home lots cost at LEAST $1M more than non-lakeshore, and there's hundreds of houses per lake ,and hundreds of lakes in my state, thats a good fraction of a trillion reasons in just my state alone to not do floating solar. Real estate is big money....
Not unrealistic thought experiment: We may be at the nadir for family farmers. Its almost at the point where a poor corn farmer would make more money selling KWh to AI data centers than selling harvested corn to big food. This will also have some fascinating effects on food store prices. Imagine blueberries staying the same price because thats still going to be more profitable than solar farming, but wheat moving up to cost as much as blueberries per volume. Hmm.
(Score: 2) by Username on Thursday November 20, @05:49PM (1 child)
Sounds like you just need more batteries. A fully charged 14.5v flooded auto battery freezes at something like -75f, and a 11v depleted one freezes at something like 20f. So if we get more than it will drain, or put in some kind of voltage detection/shut off, it won't freeze and we can charge it via panels the next day.
(Score: 2) by VLM on Friday November 21, @02:48PM
Unfortunately thats well above the high temp for a couple days every January.
In my climate it should, in theory, even during a long dark night, be safe to discharge down to 50%, lets say 60% for safety. So now you have minimal sunlight during the day to charge what little capacity you have, and only 40% of battery capacity ugh.
And even that's not as bad as the official specs for storage, discharge, and charge for Lithium iron phosphate batteries... Those have to be used in my climate controlled basement and can't be safely shipped to me during the depths of winter or summer. Ugh.
And I don't even live THAT far north, sure I could drive to Canada, but it would be a long day. Its not like I have penguins in my back yard, I got mosquitoes just like the southerners.
(Score: 5, Insightful) by Thexalon on Thursday November 20, @06:26PM (2 children)
The problems with solar panels have little to do with where you can put them. There's tons of viable places to put them that would work just fine: rooftops, on structures over parking lots and pedestrian plazas (added bonus: shade and rain protection), over roads, backyards, fields that would otherwise just be doing nothing because the agriculture market is so bad, in deserts, etc.
The problems have everything to do with the fact that the sun isn't always shining. And while you can make adjustments to deal with that, using batteries and grid distribution and such, you have to deal with it somehow. But none of that has anything to do with the idea that there's not enough places to put them.
"Think of how stupid the average person is. Then realize half of 'em are stupider than that." - George Carlin
(Score: 2) by JoeMerchant on Thursday November 20, @10:32PM (1 child)
While stuck in traffic for an hour each evening in the Miami summers, I often thought that they should "double deck" US1 south of downtown, like that highway on Oahu did... if you're going the long haul, get up on the limited access upper level in the sun, but moving. If you're on the local section, at least you're in the shade while you wait for the traffic lights to cycle.
Double decker highways are expensive, but a solar power generating shade system 20' up over the street? Sounds like a winner to me.
🌻🌻🌻🌻 [google.com]
(Score: 2) by Thexalon on Thursday November 20, @11:48PM
Double-decker highways also have the drawback of being ugly as all get-out, as I remember from many many times in pre-Big-Dig Boston. But solar panels could definitely be raised on something more attractive than that, because they don't have to hold up trucks.
"Think of how stupid the average person is. Then realize half of 'em are stupider than that." - George Carlin
(Score: 2) by jman on Friday November 21, @02:04PM
Arthur Clarke's 1980 novel Fountains of Paradise reworked Tsiolkovsky's vision of the space elevator.
What would make most sense would be to put the collectors outside the gravity well - their extra mass would only help in keeping it aloft - let the juice come down inside the tower, and and disseminate from there.
Get some 22nd century hotshot version of Tesla (Nikola, not the current fake trillionaire we all seem to be saddled with) and we just might figure out ground, eliminating the need for wires everywhere.
Of course, the keen observer will note that having the tower itself would mean "putting something in the atmosphere". Let's worry about that after it's built. If there's one thing Man is good at, it's building things. If there's another, it's improving on previous work.