Is PV becoming a chocolate teapot ?

[needasparks]

Putting this out to the people at the sharp edge as i don't get involved in it but get asked about it all the time by my clients and it would be good to get better info so i can answer the questions given to me.
My overall knowledge is very small so, OK i know how it all works etc I've been sparking for years, I'm no new boy but all i can go by is stories i hear but from what i see with only a few systems out there networks are already having problems with over voltage and people having systems shut down due to it and and will there be a time when we hit a satuation point that the grid can't take anymore as during the day is low use on most housing only transformers as it seems a lot of money to shell for the possible chance of earning the export or nill in the future.
As already mentioned during the day when you are all at work and no home use is happening other than the fridge means not much self use is gained either.

This coupled with poor installs and cheap gear fitted does not paint a great picture of things to come as replacement kit when it breaks or goes wrong after a few years will not make someone planning a twenty year nest egg very happy.

So what say you all ?

I'm not after the sales pitch as you can't kid a kidder. just what you think.

 

[Gavin A]

there obviously will be limits to sensible levels, which judging from the few approvals for significant sized schemes I've seen, seems to boil down to around 1.5-2kWp per house without the transformer needing upgrading.

I also thing that we really need to encourage more east / west facing systems, not just south, because that would get us the better spread of generation both through the day, and particularly in the morning and late afternoon peak domestic consumption periods.

Germany has around 24GWp of solar installed vs around 1GWp now installed here, and have had to use some clever techniques to make this work, including having inverters set up so that the grid operator can actively reduce their output remotely when needed instead of the situation here where they're all set to cut out at the same frequency, which is a recipee for cascade failure if we don't sort it out and follow the german model (not hard seeing as we're mostly using their inverters which already have the functionality).

Mostly overvoltage issues are minor teething problems that get resolved by the DNO reducing the tapping on the inverter, or the installers haven't set the inverter up correctly to UK settings, other than a very few isolated incidents, which mostly seem to get resolved one way or another - usually the customer would just have to accept occasionally the inverter will cut out for brief periods, but even this can be solved via circuits that automatically switch a 1kW immersion heater on etc to increase the load and reduce the voltage.

So yes there are some issues, but there are also technical solutions to overcome most of them, and the Germans have already implemented most of them, it's just a question of whether the muppets in charge in the UK will get their act together on this before it becomes a serious issue... which I'm thinking seems a little unlikely on current form.

 

[babba]

What was the question as you seemed to answer them as you typed them.

 

[Darkwood]

Large amounts of money are been invested into into increasing the conversion % of light to electricity, at moment the theoretical limit is 33% will the technology on the market but only realistically giving 25%max. A new paint has already been devoloped that could be used to coat PV panels that shows a promising increase to 40% and other scientific routes are also developing better gains from redesigning from scratch... so in my mind at present its only going to show good investment in well designed systems especially considering the new goverment tarriffs. Having said this within 5 to 10 yrs the panels will be expected to convert 50% plus which is double what we have acheived to date so i do see it holding its ground if not going through a little dip at first.

 

[Gavin A]

I'll bet you a fiver there's no panels on the market in 10 years time that convert 50% of light to electricity or anything close.

The 33% limit you mention at the start of your post would give a good indication why not, particularly when you consider that this is cell efficiency, not module, and modules need space around the cells, frame etc so the module efficiency will always be lower than the celll efficiency.

My estimate would be that at best the top end of the basic range will be close to the Sunpower efficiency now, but I doubt it. Module efficiencies in the 90s were mainly in the 13-14% bracket, now they're mostly around 15-16% at the top end, and I'd expect something like 17-18% for most mono-crystaline panel manufacturers top end in 10 years time would be about right.

I don't see the 16amp limit getting lifted anyway, so for most it's a bit of a moot point unless they couldn't originally fit 4kW on the roof.

 

[Darkwood]

Increasing Solar Cell Efficiency with Graphene | SciTechDaily , Photochemical Upconversion Adds “Turbo” to Solar Cell Efficiency | SciTechDaily

A couple of pages to browse for you, and although the graphene is still theoretical it has proven workable through calculation, but the second link is alot further on with regards upconversion which dosn't alter the solar cells efficiency but actually boosts the usable light given by converting what isn't normally usable, this is a 2months old report and they already have a product given close to 35% although lab only, if the product can be cost effective in which case its plausable then this could see the market within 5-10 yrs thus makes my predictions not so out there.
Although i will re-write to 15% efficient o the market as my error was to remember the Lab results and not the market results, my own prediction is going to see a few of these technologies teaming up to produce a £multi-billion industry but the above links are only a fraction of what is been invested and lab achieved as the world wide industry is seeing one of the largest investments ever (billions).

 

[needasparks]

Some interesting scales and tech that mean it can work, only downside that stands out like the elephant in the room is Investment, and all hinges on Gov/supply companies making it work. I guess for the foreseeable the cheap installs and common problems will remain whilst high charges are still being made by supply companies for use with their heads in the sand and ear plugs in (I'm reading between the lines here).

Some good in-depth info there guys, I'm sure the powers at be are fully aware of these issues but I think It will take a brave person in gov to actually start to address them rather than let everyone just moan about FIT's.

Yes babba, your sort of correct. It was not a direct question but more a which way now as you can see from the answers given.
We all think we know more than we do at times and this was my void

 

[Darkwood]

Teaming Up to Slash Solar Cell Cost | SciTechDaily check this link out as this could be the company that rocks the market by knocking 2thirds off the cost of the price you pay for a panel, alot of nervous eyes are watching these boys as it could undercut all solar cell manufacturers out there leaving them in a one man race, its a well designed company merger and may just send a few shockwaves through the market, but will be good for the installers and end of line users.

You'd think with all this heads up that id be an installer but seriously never touched it in my life lol.... im more a geek when it comes to new tech and science

 

[Earthstore]

PV does work and is still a good investment, the returns are around the same as they were 2 years ago, it is just the capital outlay is less, so really it is better now than it was then.

The problem is the Government, they have made things so complex, and if you ask any questions to the governing bodies (OFGEM, DECC) they will not give you an answer they just send you to a file or document and tell you the answer is in there, even though you have told them it is not.

As to the overvoltage, this in the main, is a fault that customers have come up on their Inverters, and it is usually in install problem, not always, but usually.
Think about it, if you are generating say 3KW, that is not a huge amount of power is it, hardly enough to up the voltage to over 261V for the whole street, if that were the case and all the houses switched the kettle on at the same time it would turn all the lights out, if you see what I mean.

 

[needasparks]

You'd think with all this heads up that id be an installer but seriously never touched it in my life lol.... im more a geek when it comes to new tech and science

I was going to say something but you beat me to it

 

[needasparks]

Earthstore, I see what your saying but just like the photo that went on here a while back where the whole street of council houses had PV would surely give a different result. In saying that, with Jeremy kyle on during the day on 50inch plasma's to each house would bring it down a bit.

 

[Earthstore]

Earthstore, I see what your saying but just like the photo that went on here a while back where the whole street of council houses had PV would surely give a different result. In saying that, with Jeremy kyle on during the day on 50inch plasma's to each house would bring it down a bit.

Yes of course it would, you never know these folk may all get a job and not be at home in the daytime, doubtful I know.

I have a friend who works for a DNO, and now most of his time is spent sorting over voltage issues because of PV, and it is nearly always the PV that is at fault, and not the grid.

Inverters shut down with a code that normally says "system overvoltage" or "grid voltage too high", but if you check it at the incoming supply it is normally within tolerance IE less than 253V, so for the system to go overvoltage it has to be an install fault.

 

[Gavin A]

Yes of course it would, you never know these folk may all get a job and not be at home in the daytime, doubtful I know.

I have a friend who works for a DNO, and now most of his time is spent sorting over voltage issues because of PV, and it is nearly always the PV that is at fault, and not the grid.

Inverters shut down with a code that normally says "system overvoltage" or "grid voltage too high", but if you check it at the incoming supply it is normally within tolerance IE less than 253V, so for the system to go overvoltage it has to be an install fault.

but they'll only know that if they actually put the tested on for 2 weeks to check it, rather than just via an instantaneous check of the voltage at any particular time, and they do love to try to not have to install the tester to do it properly.

my experience is the other way round, as in every time we've had an issue it's been at the DNO end. Obviously it appears it's pv that's the problem, but it's mostly just that the DNO has been going outside the limit for years, but it only gets picked up when someone sticks an inverter on the system that actually tells the owner there's a problem.

 

[FB.]

I have a friend who works for a DNO, and now most of his time is spent sorting over voltage issues because of PV, and it is nearly always the PV that is at fault, and not the grid

There are a dozen PV arrays within several hundred yards of me.

Normal grid voltage around here is high-230's.
When the sun comes out, it quickly ramps up into the high-240's as all the inverters start a bidding war to export their power to the grid.

 

[Earthstore]

There are a dozen PV arrays within several hundred yards of me.

Normal grid voltage around here is high-230's.
When the sun comes out, it quickly ramps up into the high-240's as all the inverters start a bidding war to export their power to the grid.

This may be in answer to your other post,
In theory, the is why you should have DNO approval, but I am sure you are aware of that.