3 ms·

There are few issues about floating p.v.: sometimes the water is calm and flat so p.v. works. Sometimes not. Did you imaging what happen not just in mere struct

by kkfx 4y ago

There are few issues about floating p.v.: sometimes the water is calm and flat so p.v. works. Sometimes not. Did you imaging what happen not just in mere structural terms but ALSO in string output? 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.

pencilguin 4y ago
It should be obvious that it would be foolish to expect to meet all your power needs, including EV charging, with a small rooftop installation. Rooftop solar is to cut down on your power bill. "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.
- kkfx 4y ago
  I think you are dreaming on some propaganda instead of seeing the actual tech. We have effective storage with pumped hydro, where we can, witch is "somewhere" but far from being enough. All the rest is experimental and NOT promising at all beside propaganda. 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.
  - pencilguin 4y ago
    The operators of the many GW of floating PV in use seem to have solved your string problem, assuming there was any. My guess, not. 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.

by kkfx 4y ago

pencilguin 4y ago

It should be obvious that it would be foolish to expect to meet all your power needs, including EV charging, with a small rooftop installation. Rooftop solar is to cut down on your power bill. "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.

kkfx 4y ago
I think you are dreaming on some propaganda instead of seeing the actual tech. We have effective storage with pumped hydro, where we can, witch is "somewhere" but far from being enough. All the rest is experimental and NOT promising at all beside propaganda. 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.
- pencilguin 4y ago
  The operators of the many GW of floating PV in use seem to have solved your string problem, assuming there was any. My guess, not. 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.