The cost-effectiveness of solar panels

[felstedrider]

If the goal is more solar, is subsidising small scale domestic installations really the best way to achieve that?

One of the few benefits of the exceedingly high power prices is that unsubsidised solar build now makes sense.  If it's sustained then there should be a load of new build assets on the ground in the next 18 months.

[Cudzoziemiec]

Meanwhile I receive a letter from an anonymous-sounding agency offering me a subsidy of up to £10,000 for energy-related property improvements that are unspecified, with only a phone number to ring for further details. It's rather like a cold call with the twist that I get to make the call myself, so on that basis I'll pass.

"I'm calling about the solar panel accident you were involved in... "

[Morat]

If the goal is more solar, is subsidising small scale domestic installations really the best way to achieve that?

I would imagine that it could be quite efficient if domestic installations could power the building they're attached to. I get that you don't achieve the same economies of scale as you do with thousands of acres of solar arrays in big farms, but at least you don't need quite so many thousands of acres changing from food to solar production.
If there's a way to provide local storage too (be that batteries or H2) then we could, I would hope, bring a decent proportion the required production to the premises where it is consumed. Whether that's a goal for the power companies I'm not sure - but it would help out with reducing the cost of domestic electricity which would provide quite a nice incentive for going green.

I'm getting keen on H2 energy storage as a principle. Batteries are fine but gas cylinders can store energy for years which allows true seasonal storage (assuming you can get enough juice off the roof during the summer of course).

Teslas can already be used to store energy for domestic solar, alongside the Tesla power wall - but I just don't think that lithium cells are a great long term solution for storing energy compared to gas cylinders. I could be dead wrong, but it's hard to find comparison data on the efficiency of Solar -> Li-Ion -> work vs Solar -> H2 -> Fuel Cell -> work

[Polar Bear]

There has been a project running in Orkney for years which test underwater turbines.  The project is based off the west side of the island of Eday.   They now use the surplus energy produced there to power the ferries overnight in Kirkwall Harbour.  The electricity is turned into hydrogen and comes from Eday to Orkney mainland in bottles on the regular ferry service.  It is turned back into electricity to power the ferries overnight.

Of course there is some energy loss but it means that the ferries are not powered by diesel with ferries running their engines overnight. 

Underwater turbines are superb because they run in both directions so only have minimal periods when the blades are not turning.  I can see in the future that an offshore wind turbine farm could have underwater turbines Installed alongside the wind turbines providing an even more reliable and very predictable base load.  Add in hydrogen storage and we have the makings of a genuine reliable energy source requiring neither the burning of coal of splitting of the atom.

[mrcharly-YHT]

There are some assumptions here that are really far off the mark.

"gas can be stored in cylinders" Actually that is really difficult with h2, it leaks past seals.

"only have minimal periods when the blades are not turning" Apart from a few, very rare, places in the world, there are hours of slack tide every day.

" it could be quite efficient if domestic installations could power the building they're attached to"  Every installation needs a complex, expensive inverter system. It is relatively easy to link panels into the grid. Really quite difficult to use that power only locally. Not impossible, just difficult and expensive.

Most of these things can be done at scale, with major engineering installations. Try doing it in every home and gets expensive, unjustifiably so.

[Morat]

Interesting stuff, thanks.

There are quite a few H2 storage systems out there, or at least listed on the web which might not be quite the same thing
I notice the prices are not listed!
GKN have a system that uses metal hydride pellets instead of plain old gas to store the energy, it has reached the first full size trial stage. Maybe that will be worth it when it comes to avoiding leaking seals.
edit: Some info here https://www.gknpm.com/en/innovation/hydrogen-technology/

[mrcharly-YHT]

Interesting stuff, thanks.

There are quite a few H2 storage systems out there, or at least listed on the web which might not be quite the same thing
I notice the prices are not listed!
GKN have a system that uses metal hydride pellets instead of plain old gas to store the energy, it has reached the first full size trial stage. Maybe that will be worth it when it comes to avoiding leaking seals.
edit: Some info here https://www.gknpm.com/en/innovation/hydrogen-technology/

You still have to pipe the gas to the fuel cell.

These aren't insurmountable problems, but we are a bit of a way-away from sorting them on a commercial scale, for common everyday use.

[grams]

GKN have a system that uses metal hydride pellets instead of plain old gas to store the energy, it has reached the first full size trial stage. Maybe that will be worth it when it comes to avoiding leaking seals.

Metal hydride pellets for storing electricity you say?
https://youtu.be/y48wCuC3KcA

[Morat]

That is indeed a pointless product

[FifeingEejit]

Set the controls for the heart of the sun...

Speaking of which, the sun will have turned into a small dark cold chunk of coal before I have PV at F towers.

The electromagnetic noise generated by the inverters is an act of environmental vandalism like streetlights that spew light upwards into the dark skies.
I operate a VLF observation station here, and PV inverters within a few hundred metres totally blat out the entire VLF spectrum.

Make the inverters electromagnetically quiet then I'll think about it again!

As someone who was kept awake by the squeeking of the control unit on an electric heater in a Travelodge the other night (yet can't separate a conversation from the rest of the noise in a pub, or for that matter hear much mid-range, noticeable dip when doing hearing tests at roughly the sound frequencies of a Nicholson tuned Cosworth DFV being hammered off the line...)
I find this interesting, my neighbours have 18 panels on their roof, and the only annoying noise I ever hear is my refrigerator.  Maybe I make too much noise during the day when it's operating.

I reckon there's room for 24.

Major line fault?

Some eejit cut the cable.

Navy were conducting exercises in the area at the time, no other vessels present. Wasn't us, no sir, couldn't be. Cable must have spontaneously snapped.

New cable has been in place for about a month now. However, the cost of replacement used up the budget that would have gone to a second, much higher capacity, cable.

Aye... they have previous for such like.
Nope, there wasn't a sub there... nope couldn't be... what's that? Everyone saw it going up the Kyles of Lochalsh? What do you mean it ran aground on the way back...

Solar energy is free and abundant. IMO no new house should be built without them. The problem at the moment is that it is only generated during daylight hours and it is clear that storage technology needs to continue to develop. However I have no doubts that it will. Added to that is the fact that all cars will be electric in the not too distant future which will create a lot of storage capacity which could be tapped when demand is high. If the government is serious about renewable energy they should be incentivising home owners to install solar panels by buying production at rates which make it an attractive investment. In the meantime with a domestic installation any production surplus to immediate demand can be used to heat water thus storing energy.

The problem is, is that if the government continue to push the "everyone back to the office, starbucks needs you and your local shop doesn't", all those electric cars will be sitting in the wrong place when its sunny rendering their storage capacity useless, unless we're going to use solar, to pump hydro, to load it up into cars overnight incase it's excessivley overcast in the morning.

I'm getting keen on H2 energy storage as a principle. Batteries are fine but gas cylinders can store energy for years which allows true seasonal storage (assuming you can get enough juice off the roof during the summer of course).

Teslas can already be used to store energy for domestic solar, alongside the Tesla power wall - but I just don't think that lithium cells are a great long term solution for storing energy compared to gas cylinders. I could be dead wrong, but it's hard to find comparison data on the efficiency of Solar -> Li-Ion -> work vs Solar -> H2 -> Fuel Cell -> work

I am now wondering how the age of the average calor gas bottle compares, I've got one at the parents which I reckon is about as old as me. Well it's been in the shed for as long as I can remember, and I have no idea why because we're as committed to the orange bottles as Hank Hill, so that Blue one's a bit of an oddity.

[Wowbagger]

I was under the impression that hydrogen in cylinders gradually found its way out through seals as the molecules are so tiny compare to big lumbering gases like CH4.

Warning: I am not a scientist therefore I reserve the right to spout bollox about science.

[Morat]

Well, this is what the Yanks think about it: https://www.energy.gov/eere/fuelcells/hydrogen-storage
Plenty of diagrams and arrows

[Feanor]

The electromagnetic noise generated by the inverters is an act of environmental vandalism like streetlights that spew light upwards into the dark skies.
I operate a VLF observation station here, and PV inverters within a few hundred metres totally blat out the entire VLF spectrum.

I find this interesting, my neighbours have 18 panels on their roof, and the only annoying noise I ever hear is my refrigerator.

The noise is not audible, it's electromagnetic.

The VLF spectrum is between 3 and 30 kHz, which includes the audio frequency range.
But you lugs can't hear electromagnetic energy.

Think of it like audio frequency energy in a loudspeaker cable.
You can't hear it as an electrical signal.
You would need to connect the wires to a loudsqueaker to convert the electromagnetic energy to pressure waves in the air wot your lugs can detect.

Oh, that reminds me.
SAQ are due to do a transmission at the end of the month on 17.2kHz.

[Kim]

Think of it like audio frequency energy in a loudspeaker cable.
You can't hear it as an electrical signal.
You would need to connect the wires to a loudsqueaker to convert the electromagnetic energy to pressure waves in the air wot your lugs can detect.

That said, it's common for some components (usually those involving coils of wire, like inductors and transformers) to act like extremely inefficient loudspeakers when they're not supposed to, which can result in audible whistling sounds when they're being switched at audio frequencies.  Hence the audible^[1] whistling noises from switched-mode power supplies and CRT displays^[2].

I expect many solar inverters *do* make audible noise, but at the sort of levels where you'd have to be in a quiet room with the inverter to notice.  The EM noise, on the other hand, propagates much further - helped by the wiring acting as a aerial.  (There's a similar problem with those Ethernet-over-mains-wiring wossnames, which - by design - radiate prolifically and obliterate some amateur radio bands.)


_{[1] For values of audible that mostly apply to people under the age of 30.
[2] We can't be far off the point where everyone who remembers CRT displays is too old to hear it.}

[Feanor]

Think of it like audio frequency energy in a loudspeaker cable.
You can't hear it as an electrical signal.
You would need to connect the wires to a loudsqueaker to convert the electromagnetic energy to pressure waves in the air wot your lugs can detect.

That said, it's common for some components (usually those involving coils of wire, like inductors and transformers) to act like extremely inefficient loudspeakers when they're not supposed to, which can result in audible whistling sounds when they're being switched at audio frequencies.  Hence the audible whistling noises from switched-mode power supplies and CRT displays.

I expect many solar inverters *do* make audible noise, but at the sort of levels where you'd have to be in a quiet room with the inverter to notice.  The EM noise, on the other hand, propagates much further - helped by the wiring acting as a aerial.  (There's a similar problem with those Ethernet-over-mains-wiring wossnames, which - by design - radiate prolifically and obliterate some amateur radio bands.)

I am on the verge of being old enough to be able to tell what channel was on the TV by being able to tell the difference between 405 and 626 line frequencies from the LOPT!
I've not snuggled up close enough to a PV inverter to hear it's soft breathing, but I expect my ears are not up to it.

But the gain you need to apply to the active antenna to pick up things like Schumann Resonances means that local EM interference is a real problem.

I see it like the Victorian era: "Pah! Accept the coal smoke and smog, it's all for the greater good!"
My view is more "you are welcome to create pollution in your own space, but please don't allow it to propagate to my space."
I'm defining pollution to include EM, as astronomers include light.
Either design the inverters to produce cleaner sine-waves, or screen the fuck out of them and filter their noisy switching spoor out of their mains feed.

[SoreTween]

[The EM noise, on the other hand, propagates much further - helped by the wiring acting as a aerial.  (There's a similar problem with those Ethernet-over-mains-wiring wossnames, which - by design - radiate prolifically and obliterate some amateur radio bands.)

Yeah, about that... Enphase controllers communicate with their microinverters¹ over the top of mains, quite likely IEEE 1901.  There's no direct comms or mains connetion, so long as the controller and microinverters are off the same fuseboard they can chat to one another.  One of these days I'll plug a scope into a mains socket and see if I can confirm that suspicion.

I makes me cringe now but a project of mine back when I was a PSO pre university was a pair of serial over mains interfaces.  Not much more than a bistable oscillator at each end linked to the mains wires by capacitors.  Can you imagine the Defcon 9 fit Elfin Safety would have over that today?  Thinking back I can't decide if Feanor equivs in the Reigate area curse my unknown name to this day or if my crude design wouldn't have had the oomph to bother someone more than half an electronics lab away.

¹ By convention the term microinverters means one inverter per panel instead of one per string of panels.  On the up side this means a bit of shading on one panel knackers that panel's production whereas with a string inverter shading one panel can nobble the entire string.  It also means very simple installation as HVDC is eliminated leaving only mains risks which are well understood.  On the down side this means xx inverters on your roof instead of one on your garage wall.  All merrily singing away in harmony.

[fd3]

If the goal is more solar, is subsidising small scale domestic installations really the best way to achieve that?

IF you subsidise by buying in bulk and giving the savings to the small scale owners you basically pay nothing to have the large amount of solar built.  really it would make much more sense to give big piles of money to the governments' friends to build a large bridge made out of solar panels.