So now I have a solar PV system how do I make the most of it???

Helen18

Hi all, thanks for all the suggestions. Still working through some of them. Hope this might be of interest to others as well as helping me to sort through all the options...

Just spoken to someone from a company in thirsk so bit more local to me. He suggested that the higher performing panels are really only justifiable cost wise if you've got very limited amount of roof space (we have plenty of space but all at diff angles and irientations).

He suggested using micro inverters. As I understand it these are solid state so less to go wrong (come with a 25yr warranty) and attach to each panel. This gets round the problem of having roof at diff pitch, maybe a panel or two subject to a bit of shade from next doors roof. Also benefits in snow as snow melts off one it will start up (relatively minor benefit I know).

Apparently on 4kwp system with string inverters vs one with micro inverters, last Jan on best day they out performed by 15% and on worst day by 30%. (I guess jan showed them off particularly well!)

Anyway, he's coming to survey on tues so that's another whole different thing to look at. Apologies if someone has suggested this already and I hadn't quite grasped it. Can't really remember micro inverters mentioned much before put perhaps my brain is malfunctioning...highly likely.

Oh and his cost prediction (subject to survey) was just short of £7k so getting better. (For 16 panels) and he thought we'd get as good yield from that. Any one think that's all nonsense?

Presumably at some point I will have explored all the options!!!???
Hx

Helen18

tunnel wrote: »

Helen,

I only gave that link as an idea. I'd guess that the companies advertising on ebay are only doing so as its a very cheap form of advertising, probably costing a few quid compared to an ad in the papers costing hundreds. Most have links to their own websites.

Most companies that are still around will also probably still stay around not like the hundreds that popped up for the goldrush a couple of years ago when the FIT was offered at its maximum rate(just over 43p). Quite a few have fallen by the side, my installer included(luckily he's a damn good electrician so I know if there's any probs I can still call on him)

Take your time, as Mart says, if the rate drops in January, it won't be by a great deal!

Thanks, that's all reassuring. Def not rushing anything and will explore all (well most) options. Hx

Helen18

zeupater wrote: »

Hi

Depending on how you use your AGA (seasonal/temperature etc) chances are that you'll have such a high base-load that there will be no/very little extra generation to be used elsewhere in the home on all but the sunniest days ... one of my neighbours has an electric AGA and it keeps the kitchen pretty toasty all year long ...

Anyway, the increased efficiency of the Sunpower modules you are looking at really only give the advantage of placing more generating capacity on the same area of roof. A 4kWp Sunpower system will therefore provide similar annual levels of generation to any other 4kWp system using decent quality panels, so they certainly will not provide the equivalent of 5kWp ... it's just that having a 330W panel which is the same footprint as a 250W alternative will provide ~32%(330/245) more power, so 4kWp + 32% = 5.3kW is incorrect if you can't physically fit 16 panels of either type on the roof. Hopefully, you'll understand that what I've tried to explain is that you simply cannot account for the efficiency gain twice ...

Regarding the performance of the panels, you'll find that the main element affecting long-term performance (other than shade & weather ) is grime on the panels. If you have a reputable manufacturer's panel with self-cleaning glass the impact will be reduced, but beyond that, every silicon wafer will degrade by some extent, it's just that some makes define this in various step forms, whilst others do so as a straight line ... You'll probably find that in the real world there'll be a pronounced reduction early on as a normal level of grime builds on the pristine (ex factory) panels, followed by a gradual loss over time.

HTH
Z

Thanks Z,

We have the aga on most of the time as it's our only way of cooking until we've done more renovating and also because we keep the house warm for our disabled daughter. It's right in the middle of an open plan house so does contribute a reasonable amount to the heating. I think (if I understand correctly) the most the aga will use at any one time is 2kw. I think it uses about 1 unit per hour. It's into a standard 13A fused spur. Anyway, I suppose I am just hoping that on a good sunny day I'd be able to think 'ooh I can put the washing machine on for free, or nearly free today'. If all the panels ever do is contribute towards the running costs of the aga then that's still great but I think I'll feel a bit disappointed. I do realise in bad weather the aga will still be costing a fortune, but that's when I love it most so it's forgiven!

I think it's hard when a clever sale man makes something sound like the bees knees. I think my initial excitement about the Sunpower type panels is now more in proportion. At the moment the micro inverters sound good but again they might not be worth it if something else comes up. Hopefully I'll eventually be able to find the best fit solution for our situation! I wonder if others spend as much time on these decisions.... Hx

EricMears

Helen18 wrote: »

Just spoken to someone from a company in Thirsk so bit more local to me. He suggested that the higher performing panels are really only justifiable cost wise if you've got very limited amount of roof space (we have plenty of space but all at diff angles and orientations).

That's pretty much what Z said in posting just above this

Helen18 wrote: »

Can't really remember micro inverters mentioned much before put perhaps my brain is malfunctioning...highly likely.

Apparently on 4kwp system with string inverters vs one with micro inverters, last Jan on best day they out performed by 15% and on worst day by 30%. (I guess Jan showed them off particularly well!)

Micro-inverters have been mentioned several times. As Martyn said at 8am today, if panels are to be set at more than two different angles they're pretty well essential.

BTW, although FIT rates drop off when you install more than 4kWhP, if you have plenty of room on your roof and want to go higher you could start with a 4kWhP installation at the highest possible FIT rate then after a decent interval to get first system registered add a second installation at a lower FIT rate which shouldn't affect your existing higher rate contract. You would of course need to seek approval to export at more than 16A but it's not usually hard to get.

In the example given, if there was no shading and no partially melted snow etc the micro inverters would offer no advantage at all over a more conventional system

Martyn1981

Helen18 wrote: »

I'm thinking maybe leave the immersun type devise for now and monitor how much, if any, useful spare generation we get and hope the prices come down too.

Hx

Hiya Helen. In the back of my head a little voice was nagging me that I'd missed something earlier. This is it.

Perfectly reasonable to wait and watch regarding an Immersun, or other type of diversionary switch, but it might be cheaper to have it done at the same time. So should you?

Well you said you don't have mains gas, so I'm guessing that means DHW comes from either the pellet boiler or leccy. In the winter (as Zeupater says) there won't be any spare leccy with the Aga on, but in the summer (when it's not) and you have lots of spare leccy generation, a diversionary switch might be ideal for you.

It all depends on how you heat DHW at the moment and how much it costs. If heating by leccy (in the summer months) then the savings might make it worthwhile. Also, I assume if you have to run the pellet boiler just for hot water(?)

Just a thought, don't completely dismiss yet, but check prices, I think the SolarImmersion is a bit cheaper.

Mart.

Helen18

Eric, sorry for missing the bits about micro inverters. Are optimisers the same thing? If not, what is the difference? There are such a lot of new technologies for me to get my head round. I'm doing my best in amongst getting 3 children in 3 different directions! Also I made that post before I'd seen the replies above as they didn't refresh till after so sorry about that too. I'll make time to read back through all the posts now I've got a bit more understanding to help.

Re the micro inverters... You seem to suggest the performance won't be any better than any other inverter unless there's snow or shade, the guy I spoke to today definitely said that they performed better at lower light levels. I didn't think he meant shade by this as we talked about this being an advantage with the aga as even a little generation for as long as possible is beneficial. Isn't this the case? Am I being spun a load of sales guff again or have I misunderstood what you or he meant?

Thanks
Hx

Helen18

Oh, and I like the idea of adding more panels later if we want to increase generation. Will def keep that in mind as an option

Hx

Helen18

Mart,
Funny you should go back to the immersion issue again as we were just thinking about this again. The hot water is fuelled by the pellet stove over the summer. I was asking hubby how many pellets we'd used and since May about a tonne which is £220 and that's pretty much all on hot water as the heating hasn't been on much if at all in that time. So actually, the payback time would be pretty quick so this could be a good plan after all. We do have a 3kw electric immersion but have hardly ever turned it on as never needed it and petrified I'll forget to turn it off!
Hx

EricMears

Helen18 wrote: »

Eric, sorry for missing the bits about micro inverters. Are optimisers the same thing? If not, what is the difference?

Don't worry about it - there's no exam at the end

Helen18 wrote: »

Re the micro inverters... You seem to suggest the performance won't be any better than any other inverter unless there's snow or shade, the guy I spoke to today definitely said that they performed better at lower light levels. I didn't think he meant shade by this as we talked about this being an advantage with the aga as even a little generation for as long as possible is beneficial. Isn't this the case? Am I being spun a load of sales guff again or have I misunderstood what you or he meant?

I really don't know. However, I can't see why the things should perform better unless there's a factor that would make them better. Surely how the system behaves at low levels would be affected by how efficient the actual panels are rather than how you convert their output to 230V. Although having said that, I suspect that every system will have some differential shading from time to time - even if it's only a bird perched on the bracket.

Estwing

Hi Helen, I got the sunpowers installed in August. So far so good, exceeding each months estimated output by over 10% :T

Like what's been discussed earlier I only went for the higher power panels as I can only fit 12 panels on my roof so wanted to maximise what I had but had to pay the extra for it.

If you want a quote for sunpowers to compare with evo energy, try ucs renewables in Middlesbrough as they are also authorised installers of sunpower panels.

Waiting to see what they perform like over the winter months, but by the end of my first quarter (6th nov) I'll be reaching 900kwh so on course to reach the surveyors annual estimation of 3500kwh.