Floating solar panels that track the Sun
bbc.com
bbc.com
Consider things like battery storage for the grid etc. and you might think it is a dead horse. However, what if every house had solar panels and a relatively small number of cells with a grid-tie unit. I no longer need to store an enormous amount of energy, just enough for perhaps a few hours of demand for my house. You get to soak up most of the high-sun days into batteries, you can also feed each other a little if someone is using a fair bit more energy along existing small cables.
You can then feed in a much smaller number of larger power plants who can make up any remaining peaks and troughs. Don't need to store 1TW of power into a grid-scale plant, just 20M 10KW systems distributed round the entire country.
Don't need to point the panels at the sun all day then!
To reduce the number of power plants in the area, we'd need to import electricity from elsewhere, at which point you need to overprovision some geographies and run significant amounts of HVDC lines across the country. Neither of these are free or without their own impacts. Whether that would be better than fission or waiting for fusion or continuing with natural gas is debatable- steel and aluminum are not entirely coal free yet either, nor is the concrete or any of the construction work.
OTOH, very sunny areas like the southwest could do quite well here.
from the article:
> Locations must be chosen carefully to avoid tidal forces and stormy weather from destroying the panels as well as their mooring and anchoring systems.
That sort of removes anywhere we have hurricanes, tropical cyclones, typhoons and such; mostly where we have ample sun.
That said, it does look interesting. Maybe if they have some more built-in self protection from weather?
I imagine that hurricanes would also rule out much of the east coast and gulf of mexico, leaving... California and Hawaii?
So as far as being location-dependent, indeed it is, though that doesn't preclude other renewable solutions.
If we littered the landscape of Iowa with enough windmills to fill chemical or mechanical batteries, though, that might cut down on the distance we need to import energy at least.
BTW I have p.v. at home, a NEW home so well insulated and all-electrical equipped, while I'm in the French southern Alps (at 1030m) so in a VERY GOOD place for p.v. y-o-y I hardly reach 50% self consumption. Now with an EV I need at minimum 18kWp p.v. to just charge A BIT my EV from Sun while WFH... That's because in winter, just today, I have had plenty of Sun from 9:30 to 13:30 so in just 4 hours I need to recharge a car (let's say it's not that empty, let's say 40kWh), heat water for house heating and sanitary hot water, plus all other home appliances I can concentrate in 4 hours in the morning. Imaging what can do those who not WFH and who live in less p.v. friendly areas...
EVs are the formally untold way to have a THEORETICALLY stable smart grid (who do not exists in the real world so far) witch significant renewable productions with their pick loads. The EVs are mostly connected in big numbers across a country all the time and they tend to be in large number not fully charged not fully discharged so they can theoretically quickly start charging full-power and the slow down or quickly discharge to the grid full-power and then slow down allowing classic large power plants we need anyway to have time to regulate their production keeping the grid operation at the right frequency. A way to offload enormous short-life storage costs to the people instead to the large utilities.
But no, as a small domestic p.v. "user" and an engineer I see NO WAY for a society to run on p.v. on scale with the actual tech. We can do MUCH more, like creating en masse new homes to lower enormously heating and cooling energy needs, we can subsidize EVs on scale and spread bi-directional service in pure DC to use them like any stationary p.v. lithium storage (they are already 400V DC anyway on both sides for 99% of the available gears on sale) to allow a stable grid while pushing p.v. up but without something else we have no option to keep a modern society operational on scale.
"For a society to run on PV on scale" you of course rely on municipal, commercial, and regional "actual tech" solar and wind installations, storage, transmission lines and backup peaker plants to make up the difference. Some storage might involve lithium batteries, or other chemistries, or non-chemical methods such as pumped hydro or other gravitational methods, compressed or liquified air, or synthetic fuels such as hydrogen and ammonia; and commonly a mix of the above.
Floating PV is sited at places where the water is habitually calm; calm water is always flat. Reservoirs and canals are favored sites, as noted in the article. Nobody talks about floating PV on breaking shore waves. It is hard to guess what could be meant by "string output", if anything, unique to floating PV. Solar panel output is the same, terrestrial or floating, and is handled the same way.
We are fortunate that planning for regional renewable power does not depend on people who cannot see how they would deploy it. Others, including other engineers, can and do.
Floating solar will be sited throughout most of the world. Ice on a solar panel does not reduce its output much, but being embedded in ice that, finally, breaks up could be damaging. Engineers are good at designing for local conditions.
The article makes a big deal of imaginary shortfalls of available land for solar, but there is in fact very far from any such shortage. So, solar will always be sited wherever it is cheapest. Some places, it will be floated. Other places, it will share pasturage or crop land. Others, commercial warehouses. In France it will be, by statute, on all big parking lots.
So, with my small p.v., witch I can double and I will do, but remaining far from autonomous I simply relay on nuclear and fossil power plant. Because that's the reality at scale.
My power needs are far less than industry needs, hospitals needs etc.
Specifically on string output: floating p.v. means panels who can move even if only a bit, witch means if not used on micro-inverter systems, their DC current output going crazy.
Any competent engineer can design a perfectly workable utility-scale energy storage system. All that is uncertain is which designs will be cheapest, or otherwise most practical. (There are many kinds of cost.) Experience will identify the best. We have lots of pumped hydro storage because we have lots of hydro generation easily retrofitted with a pump.
Other utility storage is not being built out much yet because it would be stupid to build storage there is not renewable generation to charge from, and utility operators are not generally stupid. Small battery arrays that shift just a small excess of energy from midday to early evening, and otherwise stabilize grid fluctuations, have been massively successful.
Where does the power come from? Home installations generally won't cover it. Centralized installations may (hopefully will), but the power is needed even more overnight than during the day.
I still think you're going to need pretty substantial central storage facilities.
There is little value in central storage, except in methods where economy of scale rules. Storage can otherwise be distributed as widely as convenience suggests, and the power moved around on wiring.
Of course you don't build out storage until you have enough spare renewable generating capacity to charge it from. In the meantime you fill shortfalls from peaker plants, the usual way. As synthetic fuels like hydrogen and ammonia become cheaper than NG, peakers will be fired with them, either synthesized locally or imported, when cheaper storage runs low.
And what about the blockage of the light? That will inhibit growth of algae and plants underwater.
I can see how this might be super useful for man-made bodies of water (for drinking, runoff, etc) but it seems it might be a bit impactful on natural bodies of water.
Veritasium video about Los Angeles' reservoir black spheres project. They used black because
- The goal was light-blocking more than anything else; black worked best
- The black pigment held up to the environment (especially UV degradation) better than anything else they tried
I expect the second point was the most important thing. Black plastic is very stable.
Note, most aquatic wildlife benefits from shade, even where they depend on an algae-rooted food chain.
The extreme for preferring absurd complication seems especially to show up in attempts at extracting wave energy. So, wave energy startups almost always fail; not because the energy is insufficient or hard to extract, but just because they seem compelled to field doomed, overpriced, expensive, and fragile designs.
I sometimes wonder if you need to have foolishly complicated tech to impress investors, who would be disinclined to fund what they feel like they could understand.
Generally, if you are putting stuff out in the water, apparatus that might need servicing should be onshore, with the simplest possible connection out to stuff in the water. For wave energy collection, make your collectors suck air out of a big, shared pipe from shore, with a turbine in the inlet onshore. You don't want your expensive, fragile turbine attacked by salt water and crashing waves, and you don't want lots of little ones where one big, shared one does better.
Apparatus to collect wave energy should be always under the surface, away from crashing surface waves.
You could mount each panel on a swivel that has a spring on one side and a screw drive on the other side. At night when no power is being generated, the spring causes the panel to automatically move so it is pointing at a slight angle (e.g. 15 degrees) to the east. When the sun comes up in the morning and the panel starts generating power, it also activates a very small motor that turns the screw every few minutes to begin a slow tilt toward the west. This continues all day until the sun goes down and the process resets.
It's much, much, much cheaper to just plonk down a few extra square meters of panels instead.