I have an area of single storey roof at 30º which faces SSE. It is 5.3m by 3.7m and is unshaded. If I installed PV myself rather than through MCS could I
a) claim FITs, I guess not!
b) export electricity and be paid for it?
c) have it signed off under Part P?
d) is DIY PV worth it?

I have a feeling that there are ways to do it, and claim FITs, but not sure how difficult is it. May have to look into it as I feel the same that the MCS is now not worth it. Mainly because the system prices are now lower, as are the payments.

The company that I worked for got their MCS by fitting a system on the bosses roof. I never checked on the price but seem to remember that it was not ridiculously expensive. James (Ingram) may know as I think he has MCS as a secondary line.
As for the electrical side, we just used third party electricians. I think there is now an SE component, but again that would be just asking someone to do the calculations. An EPC is 60 to 100 quid.

I think the high costs comes from trying to do it all and get qualified in every aspect, which is not necessary at all.

I am hoping that when smart metering comes in that this makes selling power easier. The question is how much should we get paid for it. Should we get wholesale price, retail price, somewhere in the middle, wholesale plus ROCs, retail plus ROCs, ROCs only, should we have to play a transport charge to the DNO. Quite complicated really.

At present I see PV as having few benefits in the UK, as our peak demand for electricity is on cold winter evenings. I consider the “investment” the government has made in grants for PV is a waste of money and would have been better spend on other “green” power options. (After ALL homes have been draft proofed.)

I am waiting for domestic CHP to become a sensible option, and wished that the government pushed it a lot more with at least a 10 years outlook, so that companies that see the payback from developing the systems.
(On the large scale; wave, tide and wind seems like the best options for the UK, along with as much hypo as we can do.)

The cost of PV panels would have come down anyway due to the increasing demand from countries where they do make a lot of sense.

However thinks will start to change if the cost of storing electricity comes down enough, there is a lot of research going on and progress is being made. Given than LEDs lights can run on 12v, how far are we from having DC wiring for lighting and a battery that can be charged by small PV set?

If I had a Flow battery that could provide my base load recharged on E7 every night, then I would consider PV to be a VERY good option. Once you live outside of towns, there is value from having your own dependable electricity source and people will pay for the “insurance” of not losing power for a few days every few years when the lines blow down.

There are some people on ebay offering PV kits with optional MCS. The implication is (but don't say explicitly) that you install it and then they come and approve it. Is that allowed?

There is nothing stopping a MCS approved company subcontracting some of the work (e.g. roofing), if they do the design and inspect the result. What to say the work cannot be subcontracted back to the customer?

It seems expensive, unless "Reveiw PV system and advise" is very detailed.

However could be a good option if you are going to be doing roof-work yourself.

Also what if they don't do their part after you have paid for the PV and installed it?

Given that most of the cost of the electrical work is running the cables and then making good etc, there should be a way that allow a DIYer to do that part.

However I see the real saving, being that there is no need to pay for a sales person and the same labour can be used as for other roof work that is being done at the same time.

If, and it is a big IF, the kit is MCS/OfGEM approved, and the installer is MCS/OfGEM approved, and they fill in the paperwork 'correctly', then yes...

Another thought.

What stops someone adding more panels after all the paperwork has been done?

ringi, I am planning a new build so its all being covered by the BC officer anyway, I do my own electrics when I can.

Why not roof integrated pv for a new build?

You can get trays that are designed for the job or make your own/get your own designed from GRP.

I could make my own from GRP. I dont see why the cooling is less as it still stands above the tray its over so getting plenty of air behind? My base load wont be high (two people mostly) so I will have to think hard on whether it is all worth it!!!

I feel strongly that integrated is much more aesthetically pleasing and that your avghouse buyer would feel that way too (if that interested you). So long as the roof isn't flat, any hot air under the panels rises creating a stack like effect/strong draft so integrated would not IMO suffer at any time, though as Steamy points out hardly relevant anyway. Over here in Italy your incentive is higher if the panels are integrated than if what they call semi integrated (mounted parallel with roof) and then semi pays more than the bottom rate where your panels are put on at a different angle to your roof.

Posted By: SteamyTeaAdd to that, when those conditions do occur, there is generally more more radiation than can be converted to electrical power. It is not a linear calculation.

What does that mean? PV is essentially linear, more insolation produces more energy, unless it is clipped by the inverter. At very low insolation levels the linearity drops off a bit, but power levels are so low then that it doesn't matter.

Experience shows that heating does have a significant effect on output. Look up NOCT.

I have a roof mounted 3.8 kWp system and a 4.4kWP ground mounted system, both mounted at 45 degrees. Midday on a hot sunny day the 3.8kW system shows significant power limitations, whereas the well ventilated 4.4kW system just gets clipped by the inverter. A roof integrated system will get hotter than a roof mounted system, hence will have lower output than a non integrated system in hot sunny conditions.

It's probably not particularly important overall, but it will give less output.