By my rough calculations that's how many miles they'd need to cover to generate 1.21 Gigawatts.
California is ready to try out something that could help it save water and generate electricity at the same time: solar panels over irrigation canals. For this proof-of-concept experiment, some 8,500 feet of photovoltaic panels will be installed over waterways just north of Turlock, central California, generating electricity …
How about one step further, use ocean water and solar panels. Quick web search:
“The theoretical absolute minimum amount of energy required by natural osmosis to desalinate average seawater is approximately 1 kilowatt-hour per cubic meter (kwh/m3) of water produced, or 3.8 kilowatt-hours per thousand gallons (kwh/kgal). The actual SWRO energy requirement in the 1970’s was 7.0 to 9.0 kwh/m3 (26-34 kwh/kgal). With recent technological advancements and innovations in high efficiency pumps, energy recovery systems and overall higher efficiency plants, the actual expected consumed energy has reduced to 2.5 to 3.5 kwh/ m3 (10-13 kwh/kgal)”
Pick a unit system and be a dick about it. That kwh/kgal figure is an abomination!
Many years ago, I worked on fire-control software for a US Navy project. It had a bunch of different input devices: INS (3D heading/velocity, location), Sonar (for ground speed), Wind speed/direction, Odometer ticks (also for ground speed), Temperature, and so on) as well as a bunch of data input by the operator (starting lat/long/elev, barometric pressure, and whatnot). Absolutely everything was in metric except for one internal value that was calculated based on various inputs: air density was in slugs/m^3. I asked why, and was told that's just the way it's done in the US Navy.
The solar photovoltaic (PV) system, developed by Israeli startup Xfloat, is designed to move and track the sun while floating on reservoir water. The project is being carried out in cooperation with Mekorot, Israel’s national water company,
Brings up a good point. This will impact waterfowl, whether anyone likes it or not. This in turn means that this project will be held up for 10-15 years by Environmental Impact Statements, attempts to create exemptions, and related lawsuits on all sides. Cost magnitude will be 10-25X by the time it is all settled. The budget allocation will be enough for a 100-foot section after legal fees are paid.
That's an actually useful amount of power.
It's one of those "So obvious why didn't anyone think of it before?" ideas.
But yes in principle max sunlight --> max risk of evaporation so there's a nice sens of tracking.
Now the notion is out there let's hope more organisations roll it out.
2010 was the only time I have been in that area of the world and I mentioned the idea to everyone I met who might pass it on (mainly large land and business owners, and park rangers rather than government officials as I was there on vacation) - the idea originally formed to retain water by covering the canals, but it was obvious to gain electricity by using solar panels to do the shading.
Also panels on stilts on the sides of storm drains to gain electricity from underused land.
Good question. I have 24 solar panels on the roof of my house as well as two solar geysers. We have had no breakages yet (still holding thumbs). I live in Joburg, an area with regular hail storms in the summer months. The nice thing about the storms is they wash all the dust off the panels... it helps improve the efficiency of the cells. In the dry months we have to manually clean the dust off.
Solar hot water is brilliant... we had this in the eighties a couple of thousand kilometres north west of you ;-)
The panels designed at the time were heavy as hell because they actually used glass and steel plating, but it provided some seriously hot water even in winter (although there we still had to backfill with an electric tank heater once the sun set).
Sounds like a great idea. I want to propose the same idea to our local airports. I had a look at the Google Earth images of the Perpignan airport in southern France, but I don't see any solar panels on images that are dated 2022. Am I looking at the wrong airport?
"Over car parks!"
that is actually done a LOT. The local Walmart has several rows of covered parking with solar panels on top. Not the entire lot, but a significant portion of it. It has to make cost sense though.
Even without the panels, covering the canals with "something" has been discussed for DECADES.
There are many other issues outside of the scope of the article and related discussion, though, that could actually make a MUCH BIGGER difference in water usage and availability... related to the Sacramento river and a certain kind of fish. And maybe better drip irrigation systems for farmers, too.
That IS actually both a useful amount of power, and a good use of a space that otherwise can't really be utilised. Clever.
But.... not sure that the protection from evaporation will help so much with drought. All that evaporated water eventually would have fallen as rain (even though probably somewhere else). So you're only 'exporting' the drought to some other place. Depending on prevailing winds and weather patterns this could be disastrous for some other adjacent area that would get an even more severe drought.
OR it could reduce rainfall in an adjacent area tat is otherwise prone to flooding.
If good enough models can be constructed to anticipate the latter and only cover the canals in those areas it would really be a giant win.
I suppose the evaporation rain cycle also helps purify the water... I've never got why solar evaporators aren't used more to alleviate water shortages during a drought. Data centre... sea water... I mean CDNs are best placed near to undersea cable heads, aren't they? And they're putting power plants near the sea...
Now I have limited understanding of the science on this but:
How does covering water with solar panels reduced evaporation by that much?
The ambient temperature is pretty much the same.
The panels have reduced the direct sunlight but on water, it is not sunlight that causes most of the loss, it is wind.
Now I can see that the panels should reduce wind speed to some extent but they may also increase it with a tunnel effect.
In terms of a useful place to put the panels, then I can see that is worthwhile but I am not sure how much of a saving in water loss there will be.
>How does covering water with solar panels reduced evaporation by that much? The ambient temperature is pretty much the same.
The water temperature is a factor in the evaporation loss. And evaporation cools the water. So direct sunlight will keep the water warmer than it otherwise would be (that sunlight energy doesn't just disappear).
One would expect the ground through which the canal flows to keep the average water temperature cooler than it otherwise would be... but complex fluid dynamics are complex, duh, so I wouldn't be shocked if there was a warmer surface layer, warmed by the sun.
After all the downvotes I researched this some more rather than relying on the experience of what I see in my pond!
Wind & temperature are both critical:
The higher the temperature, as one would expect, the higher the evaporation.
The higher the wind speed the higher the evaporation.
The reason for this is that the in still conditions the air above the water will contain more water molecules as they evaporate, reducing the rate of evaporation (high humidity). If the wind is constantly blowing the water molecules away from the surface, humidity is lower so there is greater evaporation.
I would assume that California is both hot and has some wind, even if it is just a few mph that gives you the worst case.
So, yes covering the water will reduce the temperature (shaded) and reduce evaporation. Crucially in this scheme, the panels are not on the surface but are on a framework over the waterway.
What is rather more interesting is that increasing the depth to reduce the temperature of the water may have a greater effect.
This probably provides the most concise summary without spending hours:
I have been wondering how much the shade thrown by solar panels if mounted as a sort of second roof would contribute to keeping the house underneath more cool.
If I'm not mistaken a double roof (i.e. one to throw shade on the other and an air gap to vent any heat buildup) is already in use in countries far warmer than ours and I even found links that seem to confirm this. The disadvantage is that you need an extra construction and that it needs to be far more gust proof (due to the airgap), but it strikes me that we could take more advantage of those basic physics in play
Sadly it's not going to work on my own house as it's listed, solar panels are apparently not deemed a period feature :). But hey, I also have a
man cave shed :).
Been contacting local companies and brokers since February this year. So far I have had one vague quote for 23Q2 installation (i.e. full of caveats that the price may change) and another company planned to visit in a week. It's almost as though a 5 bed, south facing house is too small a deal for them!
As far I can see my solar panels are an inch or two above the roof tiles fixed to the joists through the roof proper, I know this cos pigeons get in there to make nests sometimes (yes must be a squeeze), so do I have a double roof? Its been there for 10 yrs so far no problems - except for the WIFI montoring which wont connect to my (sob) eero6 network
Sadly it's not going to work on my own house as it's listed
Two solutions spring to mind. Firstly, solar panels don't have to be on the house roof. Build a verandah or gazebo or something out of them. Put 'em on the shed roof (I realise this isn't doing the "shade the house to keep it cooler" thing). Even a greenhouse - not all panels block all sunlight, and thin-film flexible PV materials are now apparently available which while not as efficient as traditional panels have the potential to be significantly cheaper and can be applied to glass instead of the sorts of security and shading films often fitted.
Secondly, if the problem is aesthetic, there are such things as solar slates which can look very much like natural slate (not cheap mind), though I realise listed buildings can have a range of roofing materials which are not slate!
Disclosure - a friend works for the company I linked.
That was very helpful - I didn't know there were more companies out there making solar slates. I was not inclined to buy anything Musk has his hands in as warranty doesn't seem to be part of his business ideas so good that there's a 'local', so to speak although I my have to see how expensive and troublesome Brexit has made this..
I my have to see how expensive and troublesome Brexit has made this
Assuming you are in the UK, there are some prices on that site, for example:
The standard 500x250 PV Slate unit has a peak output of 28W and an ex-works price of £59.50. Each 500x250 unit replaces four natural 500x250 slates, covering an area of 0.2sqm. That gives PV Slate an overall roof kit price of £294/sqm or £8,449.00 for a 4kW system.
which I believe to be fairly up-to-date. Brexit has affected some prices, but this company does a lot of its own manufacturing. Their biggest problem at the moment (my friend tells me) is sourcing inverters, particularly for larger systems. This isn't a brexit issue, it's the current semiconductor supply problems.
a) It's relatively easy to build structures either on the canal sides to support panels over the canal if the canal is a few metres wide. It's not gonna happen for a glacier that's a few hundred metres wide.
b) on water you can make the panels floating, over ice they have to be supported, so you run into problem (a). Building the supports directly into the glacier wouldn't work since the glacier moves and will break the supports
c) It would be a lot of awful-looking massive infrastructure introduced into pristine mountain areas
If the intention is to cover the glaciers, it's already done with white tarp-like material that combines high reflectivity with looking rather similair to the ice, protecting it without ruining the landscape. Although for space reasons I think it's done only on glacier tongue where there is most melt rather than the entire glacier (covering which would be prohibitive eg Rhone glacier is 16 km2)
I wondered the same, I watched a video a few months back of physicist Helen Czerski visiting the worlds largest wind turbine, and that was 13MW, but it's a prototype off-shore unit, mounted on shore for testing, so not yet commercially deployed.
I did a quick look up, it's the Haliade-X in Rotterdam port. 260m tall, each blade is 107m long! Seems they expect these to hit 14MW for the production versions.
Looks like they plan to install 100s of these at the Dogger Bank Wind Farm project (along with other similar sized units from different manufacturers), for a total generating capacity of 4.8 GW.
So not even half of the 13GW, and that's going to be the largest offshore windfarm ever built (till the next one of course) :-)
"Still, the costs to construct canal-top solar systems can become much more expensive. Among the costs that Indian officials have run into is the need to galvanize panel supports with zinc due to increased risk of corrosion, and finding canals that are not too narrow, which would be inefficient, or too wide, making construction costs too high."
California could instead eliminate its "sanctuary cities" and repatriate its millions of illegal aliens, which would reap promptly greater returns, including profoundly reduced water usage.
I suspect this hasn't happened because when it comes to repatriating Aliens, typically either their engines have broken or no-one get through to anyone that can offer them a lift home.
Although you're certainly right about the water - that Alien that looked just like David Bowie turned up a few years ago, he was definitely after the water.
The term illegal alien, as defined by U.S. law, is dispassionate. Its context is well understood.
Its deliberate rewording by agenda-driven activists and the media is flagrant propaganda and should be called out as such.
Regarding Bowie's character: The extraterrestrial was not an economic refugee. The United States would likely bend over backward, as much as practicable, to help such an alien and his people, assuming, of course, that they were not the predatory lizards from "V" or the like. The last unhingeable jaw that anyone here wanted to see was Linda Lovelace's.
Good movie (his, not hers)!
A typical domestic solar panel is 1.85m2 with 370W output (peak).
Using those figures, your 13GW (peak) will be 35.1 million panels, with an area of 65 million m2, or 6500 hectares.
We don't know the width of the canals, but if we're talking 4000 miles ~= 6400km, that means roughly a 10 metre span on average.
What nobody seems to have mentioned is the cost. 35 million panels, even at $100 each, is $3.5 billion. That's without 4,000 miles of supporting structure, or the inverters, or the electrical interconnections.
Still - a lot cheaper than HS2, and probably more benefit. (Thinks: train tracks are uncovered most of the time. You could lay solar panels on the sleepers?!)
Irrigation in California, especially Central Valley, is an example of abuse of a scarce resource: water. If there is less irrigation, you need fewer canals for the water and will thus lose less to evaporation.
In the meantime by all means cover the canals. Also, install panels over the fruit trees in the above mentioned Central Valley and elsewhere. This will provide power for the warms and protect the trees
"Because the microclimate adjacent to irrigation canals is somewhat cooler than the surrounding air, TID said the project will also keep solar panels cool, fighting heat-based efficiency losses. "
Not to rain on their parade, but the reason for the cooler microclimate is due to the evaporative cooling effect of the water.
Assuming the cover results in a greatly reduced amount of evaporation, the microclimates will be greatly reduced in size and delta temp.
On the other hand, having slowly moving water somewhat close to the back sides of the PV arrays does create an opportunity: a network of tubing on the backsides, and the occasional PV powered pump, can circulate water from the cooler canal water, chill down the PVs, and deposit the warmer water back into the canal.
Tests would need to be done to see whether the cooling is worth the extra $ - maybe just have the little pumps run in the summer?