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Scientific paper here

Abstract

Growing global energy use and the adoption of sustainability goals to limit carbon emissions from fossil fuel burning are increasing the demand for clean energy, including solar. Floating photovoltaic (FPV) systems on reservoirs are advantageous over traditional ground-mounted solar systems in terms of land conservation, efficiency improvement and water loss reduction. Here, based on multiple reservoir databases and a realistic climate-driven photovoltaic system simulation, we estimate the practical potential electricity generation for FPV systems with a 30% coverage on 114,555 global reservoirs is 9,434 ± 29 TWh yr−1. Considering the proximity of most reservoirs to population centres and the potential to develop dedicated local power systems, we find that 6,256 communities and/or cities in 124 countries, including 154 metropolises, could be self-sufficient with local FPV plants. Also beneficial to FPV worldwide is that the reduced annual evaporation could conserve 106 ± 1 km3 of water. Our analysis points to the huge potential of FPV systems on reservoirs, but additional studies are needed to assess the potential long-term consequences of large systems.

> The cost of solar power has dropped dramatically over the past decade, making it the cheapest source of electricity in much of the world. Clearly, that can mean cheaper power. But it also means that we can potentially install panels in places that would otherwise be too expensive and still produce power profitably.
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> One of the more intriguing options is to place the panels above artificial bodies of water, either floating or suspended on cables. While more expensive than land-based installs, this creates a win-win: the panels limit the evaporation of water, and the water cools the panels, allowing them to operate more efficiently in warm climates.
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> While the potential of floating solar has been examined in a number of places, a group of researchers has now done a global analysis and find that it's huge. Even if we limit installs to a fraction of the surface of existing reservoirs, floating panels could generate nearly 10,000 TeraWatt-hours per year, while keeping over 100 cubic kilometers of water from evaporating.
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> Obviously, that potential is not evenly distributed, with countries like Canada and the Nordics getting less sun exposure to benefit from. The biggest winner in floating solar would be the US, which has the potential for 1,900 TWh under the 30/30 limitations. The US is using about 3,900 TWh a year, so that works out to be just under half its electricity consumption.

im not sure blocking sunlight for underwater life is all that good tho

as amore amore. amore. amore. amore. to amore. amore. amore. This article is talking about installing solar panels over artificial bodies of water (like reservoirs), not covering our oceans with solar farms, which is interesting considering the extent to which we trash our oceans on a daily basis for reasons far worse than clean energy.

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It would only matter if the panels were placed over shallows, reefs, and other places with high densities of living things. But this technique still makes no sense unless we somehow ran out of land space. Which just isn't happening.

Proposal is for on top of man-made water reservoirs, slowing evaporation. No fishies harmed.

Cooling is my guess.

Read more than just the title

It can prevent water loss due to evaporation when placed over things like aqueducts.

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You vastly over estimate how much surface area it would take to generate the power we need.

That being said, we should be adding solar to all kinds of places. Roof tops, above parking lots, deserts...and so on.

Could be super effective if they’re designed with multiple benefits in mind. I feel like I’ve read about mussels farmed from dangling ropes on fixed and floating infrastructure somewhere…

water quality could decrease. light is important for a bunch of stuff. but a balance could be found.

Parking lots for damn sure. The others come with some complications.

Most houses are still not required to be built solar-ready. Solar installations add thousands of pounds a typical roof isn’t engineered to carry on top of the snow load. Deserts seem like a good place aside from the weathering they’d probably see from all the bloody sand.

Main take away is that we aren’t doing enough.

Just some considerations for conversation -

1. Applications to increase waters reflectivity and prevent the penetration of some wavelengths have been considered to reduce solar absorbance, to reduce heating.
2. The square footage at hand here is vanishingly small compared to the square footage of the ocean. You could easily just put these out to sea over deadzones, where ecosystems aren't reliant on light anyway.

I am not saying every roof needs it, but many roofs can add it, as well as city buildings, big box stores...etc

Changing water’s reflectivity would be suicide - a suicide that we’re already attempting by bathing with oily UV-reflective sun tan lotion all over ourselves, that then blocks the needed UV light from underwater plants, eliminating entire habitats.

https://www.bbc.com/future/article/20200923-could-geoengineering-save-the-arctic-sea-ice

Similar to this, though I've also read of proposals to release dyes in the polar gyre to reduce reflectivity.

Light isn't a limiting factor for most marine biomes that rely on photosynthesis.

Even if they are solar ready a lot of HOAs are against them because they think they are ugly.

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I doubt that there is enough man-made water reservoirs to make a third of power needed.

I know some places have had good luck with covering metro canals with solar panel roofs. Hot places can also benefit from reduced evaporation in reservoirs.

A city in the US covered their reserve in black floating balls for a different reason. Imagine if they used Solar Panels for the same purpose, but got the benefit of electricity generation as well.

Sandy deserts are the exception, not the rule. Most deserts are rocky and dry, with patches of sand that move around a usually somewhat geographically confined area.

Sandy deserts as movies and media portray them are called ergs.

Haha good point. Imagine if we replaced the great pacific garbage patch with solar panels. I'm sure somebody would say it was terrible.

Many of these already in use on smaller reservoirs. They prevent a lot of evaporation, very helpful in the sunbelt states where everybody lives.

A pilot program over a major California aqueduct is in progress right now.

Nah. They currently use half-submerged black plastic spheres to block sunlight from reservoirs. It prevents radical bromine creation as a result of electromagnetic stimulation.

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There is a federal law that doesn't allow HOA to stop them from being installed.

If society would buy in to solar in general then larger grid scale installations make much more sense than distributed panels on housing. There are a lot of roofs to put solar panels on, but there is a whole lot more open land.

Grid scale installations are significantly cheaper to maintain/install, can actually be installed in optimized geometries and stop people getting all pissy about curb appeal.

I would be great if people could buy a few hundred square feet of solar panels in a solar farm rather than putting solar on a roof.

This is definitely not to say that adding solar to a roof is bad, it is just suboptimal.

If society would buy in to solar in general then larger grid scale installations like these would make much more sense than distributed panels on housing. There are a lot of roofs to put solar panels on, but there are a lot more efficient implementations.

Grid scale installations are significantly cheaper to maintain/install, can actually be installed in optimized geometries and stop people getting all pissy about curb appeal.

I would be great if people could buy a few hundred square feet of solar panels in a floating solar farm rather than putting solar on a roof.

This is definitely not to say that adding solar to a roof is bad, it is just suboptimal.

Is there a way to make solar panel components renewable though? I’m under the impression that panels are currently built using finite metals.

Someone only read the title

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It can provide all of it, too. It's "just" a matter of cost, as always.

> While more expensive than land-based installs

Yeah.

Producing a large fraction of the electricity with photovoltaics is already expensive even without making the installation more complex. You either need an alternative in winter or you need a massive overproduction in summer.

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Depends how big they are and I doubt they will place them on the whole oceans. Also, if you keep a little bit space enough sunlight should be there

Yep, so dam lakes that are used as gravity batteries could be refilled via the solar panels which then pump eater back in.

No wait, it’s better to cover the vaporized ponds with plastic balls

I mean that depends on where you live. Over here in Germany we do not have open land.

The only way you are putting solar on open land is by removing farming areas or by cutting down forest.

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Recyclable is the word your looking for. It depends on the solar panel as there are many types now but it is something researchers have been working on.

Utility scale solar (putting all the panels in one place) has enormous advantages over distributed solar (putting panels in random places all over). With the costs averaged out, energy from distributed panels can easily be 10x more than solar energy that comes from utility scale locations. Higher energy prices are regressive, meaning they hurt the poor more than they hurt the rich, and imo should not be encouraged when a cheaper option exists that is environmentally similar.

Also research the duck curve. Until we solve storage, there are certain places that shouldn’t have more solar installed.

I was curious (and didn't have a prior), but the answer appears to be yes. I found the largest man-made reservoirs on Wikipedia: the largest 100 manmade reservoirs in the US have about 8500 sq mi of surface area. Assuming 15% efficiency you'd need something like 20,000 square miles of solar installation to power the US based on this Dept of Energy document: Link.

More interestingly, the largest 25 reservoirs in the US have just under 5000 sq mi of surface area.

Many of these reservoirs are in places that don't receive full sun of course. But I think people underestimate just how large some bodies of water are. An area the size of, say, Lake Erie would be sufficient to provide solar power for almost all of the US with full sun - less than 1% of land area in the contiguous US. The federal government owns about 40 times that much land already, much of it in places that are ideal for solar.

So panels on reservoirs alone would provide up to 42% of the entire US power requirement. Obviously the real number would be much lower but that’s still astoundingly good.

Going to Google but do you have any links on the subject?

I live near a large man made reservoir (lake) with a dam and hydroelectric power generating. It is full of fish. It’s not a big concrete lined swimming pool. It absolutely would suffer if a large percentage of lake had light blocked out.

By the time this materializes there will be no underwater life.

What we can float so far are cruise ships, tankers, oil rigs and garbage. I’m not gonna hold my breath for this.

Things can be recycled. The difference with solar to fossil fuels, is onelce the thing is made, it just works for many years before needing to recycle. Fossil fuels are vaporized the moment we need them. No getting those back.

Some types of solar arrays are just mirrors that red-light and boil liquid to spin turbines. And I am sure we will come up with many other types of panels as well.

Well, obviously, utility scale is the main focus, but as technology improves and costs curves keep coming down, I see no reason why we won't come up with cost effective thin films that can line all kind of things.

As for storage, I agree, that is the biggest hurdle, but there are many ideas being researched for that. Solar is still a relatively small % of electricity, so storage can be figured out as we scale up.

But they can reduce oxygen production by 1/3

Yeap. The development of civilization leads to destruction.

It’s not just a matter of creating energy but of managing the grid. The power on the lines needs to be balanced with the load in real time second by second. Generation sources need to be shut off and turned on to make that happen but solar panels are difficult to impossible to shut off. More or less they need to be covered physically which can’t be done on distributed solar.

During much of the day real time electricity prices are actually negative. We don’t need radically more day time electricity from slapping thin film in every place we can think of. The priority needs to be on the ability to manage the grid or else we force more stable, lower or no carbon sources of energy offline & need to rely on natural gas peakers for the dark hours when we have most energy demand. The combo of just solar & natural gas is potentially worse for the environment than no solar but better managed non-renewable plants.

Don’t confuse this with me being against sustainable energy. The grid management aspect of solar is just really poorly understood and leads to a lot of pressure for things that don’t align with the real goals.

If the reservoir was made by damming a river, then the harn has already been done.

Yes, our grid also needs upgrading. This is very true and not well understood. But local solar would first power local stuff, and then runoff would be sent to storage facilities, which could also be local, with the next step being municipal. Those could be battery, chemical, mechanical, hydrolic...etc

Of course, all of this has to be done at cost, or else it is useless. But again, as solar scales up, these other things are being worked on, too. Solar is still only like 3-4% of total electricity, so this will all take many years.

I actually work at a public power company, and I hear them talk about the challenges that need to be worked out with the grid and rooftop solar...etc. But this stuff is hardly the biggest challenge humans have tackled.

We have built out massive infrastructure for oil, coal, and gas extraction and refining. Pipelines, gas station networks, and war machines to secure energy sources around the world. We can certainly figure out a well managed solar power network. It just takes time.

That does seem better than subjecting them to the oceans varying conditions

And probably kill marine life

I’m surprised to hear you say you work at a public power company while also imagining that local solar could power local things and “runoff” could be sent elsewhere. That isn’t how electricity works at all. You can’t control where an electron goes once released into the grid and the frequency needs to be maintained within a very narrow range so the load needs to exist at the same time the energy is created. Having solar on your roof doesn’t mean you get “your” electrons powering your house.

I’m not really sure we can continue this when you’re going to say “yes but storage” .. electricity going to storage is also a load — i.e. we can have more solar when we’re prepared at utility scale to need it .. why would we build utility’s scale batteries and also not build the utility’s scale solar to go with it but still have any need to put thin film everywhere. Regardless of progress, distributed solar will never be cheaper than utility because distributed has unique installations that don’t benefit from scale or learning.

You are assuming some weird scenario where we build out local solar, with none of the other components in place. Obviously, anywhere that local solar would be installed would be accompanied with bi-direction meters, micro-inveters, and possibly even local storage.

As for grid vs. local, decisions would be made based on cost, land availability, the grid itself. This will take years and more innovation. You keep glossing over that point where I say this is not a today thing, but something that could happen over decades. Please explain how you k ow what technology will be available 1-2 decades from now?

I am just a web developer, and my point about the company I work at, is not that I am some electricitiy expert, but that I hear the challenges brought up frequently in conversation and company meetings. These are main issues being worked on as we speak, but it is a slow-moving process. And again, solar is only 3-4% of electricity, so all the other stuff that is needed, will be worked on as we scale.

I’m sorry you don’t fundamentally understand the grid.. bidirectional meters don’t help with management of the power, only payment. And they generally are associated with net metering which increases the price of electricity enormously for everyone without panels. It’s an extremely regressive policy.

Take a listen to The economics of rooftop solar if you want to understand more on this particular issue.

Otherwise I hope you have a great day. I’m stepping out of this discussion here.

I understand Germany is dense, but you definitely have some open land. The threshold to make rooftop solar the most efficient approach is incredibly dense, pretty much constant dense urban sprawl for an entire nation. Solar installations can replace a field, but a single field can replace entire neighborhoods worth of rooftop solar.

The point I am making is that the distributed infrastructure required, awkward installation geometry and therefore overall inefficiency means that rooftop solar is about 50% less “useful” compared to the equivalent panels in a grid scale facility.

Uhh man made reservoirs are made by damming natural rivers or lakes. There are not many man made reservoirs that don't contain some kind of aquatic life.

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If you’re aiming for full replacement, perhaps. But as a partial replacement solution it works. A third of power coming from the sun is a significant transition.

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There are lots of commercial developments that have storm water reservoirs to prevent flooding and prevent the water treatment system from being overloaded.

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The thing is, I don't really feel like the main issue holding back solar power production is a lack of physical space where we can put the panels.

Look at Nevada. We could probably cover 75% of the land area of the state in solar panels before having to put a single panel within sight of anyone's house! We've got absolute fucktons of basically unused space right here on land, which is going to be way cheaper to build on and way easier to maintain.