I am planning a new build this year and would like PV (if only to help the SAP) as we have no mains gas. SWMBO and I dont want panels on the roof as we are designing a sweet looking cottage (hopefully). I could mount them on the workshop roof (due South) but the angle will be low. Alternatively I could mount them on the ground in the field we have next to the build. The advantage here is I could construct adjustable frames as the optimum angle for PV panels over the year changes from 16 to 64 degrees (from the vertical) this would allow me to optimise the lecky generated. I have found that the FIT payment is nearly half for "stand alone", would panels mounted in the field be classed as stand alone?

Ta

The actual angles of the panels doesn't make that much difference over the year and moving the panels up and down doesn't add a huge amount. Steeper panels help quite a lot in winter which is important if you're off-grid but if you're on-grid then the extra production, though nice to have, will not make much difference in comparison with your summer generation.

In other words, it's not worth spending a lot of time or money on making the panels adjustable and definitely not worth compromising the robustness of the installation for it.

Posted By: joe90II have found that the FIT payment is nearly half for "stand alone", would panels mounted in the field be classed as stand alone?

No. Standalone means not connected to a building, and I assume that you are intending to use some of the energy generated

Ed's right, it's not worth adjusting the panel angle. A two-axis tracker might add 30% to the output, but the extra expense could just as well be spent in extra fixed panels.

Probably not as the G83 generally allows connection. There may be an issue with the local transformer if whoever else shares it has an installation. You can always phone up Western Power, it wont prejudice your connection. They are pretty good down here.

Just make sure your roof can get the modules on with the necessary 'border' around them. Better still, design them into the roof structure so they look better. I like the technology but think they look dreadful when retrofitted.

Posted By: joe90will I be limited on production as its a shared feed overhead in the middle of no-where?

The standard connection allows you to draw up to 100 amps from the grid or put 16 amps in. If your connection won't support you feeding in 16 amps (i.e., the capacity is such the voltage goes over the upper limit of 230 V + 10% = 253 V) then the electricity company can ask you to disconnect your panels temporarily while they fix the local network but they have to do so at their expense. If you want to feed in more than 16 amps you have to get their prior permission and they'll charge you for any engineering changes needed to support it.

16 amps at 230 V allows 3.68 kW so, in practice, that's the limit you have to work to.

Something the DNO will bear in mind is that your neighbours might get PV, or whatever, in the future and they'll have to allow them to put in 16 amps each. So if there are three houses on a transformer which can take 50 amps (a shade over 16 A per house) and you're the first house, wanting to put in 6 kW (about the capacity of your 44 m² extension and 26 amps at 230 V), then you'll likely either get charged to upgrade the transformer despite it not being needed yet or refused permission to put in more than 16 amps.

Is it possible to have quite a bit more than 4kWp of panels if you could limit the output of the inverter to 16A? I suspect that the panels will spend relatively little of their time producing even close to their rated output, so little would be lost by lopping off the peaks of generation. Also, your output to grid will not decline so much as the panels age.

Sorry slightly miss read your post. you could limit export via dumping.
You can limit inverter via setting or selection.
Recently FITS/MCS have clarified banding to mean 4kWP rate total power of panels installed. (TIC)
was a bit vague prior to this. FITS/MCS only asking for DNC ( declared net capacity ) which was defined output of inverter.
FITs Banding unfortunately confuses optimum system design.

Posted By: SteamyTea. Then claim that it has been extra sunny since the earthquake.

"It's that global warming stuff mate "

Posted By: mike7Is it possible to have quite a bit more than 4kWp of panels if you could limit the output of the inverter to 16A? I suspect that the panels will spend relatively little of their time producing even close to their rated output, so little would be lost by lopping off the peaks of generation. Also, your output to grid will not decline so much as the panels age.

What is the excepted rate of decline for a PV panel with age?

Also I see the advantage of more panels but would MCS not accept this?.

Posted By: mike7Is it possible to have quite a bit more than 4kWp of panels if you could limit the output of the inverter to 16A?

Yes, though (somewhat controversially) you'll finish up on the lower FiT band.

You can either limit the power output in the inverter as you suggest or you can use a diversion to an immersion or other heater if you use the approved equipment (believe there's only one device approved so far - forgotten which one).

In theory you should limit to 16 A as you say. In practice I think most inverters will only limit to a set amount of power. Apparently the DNOs accept 3.68 kW (16 A at the nominal 230 V) even though this power level will result in a higher current if the voltage is below nominal. At the minimum (which I think is 230 V - 5% = 218.5 V) that power would give 16.84 A which is obviously over the limit but would presumably actually be welcome as it's helping to hold the voltage up.

Posted By: Ed DaviesYou can either limit the power output in the inverter as you suggest or you can use a diversion to an immersion or other heater if you use the approved equipment (believe there's only one device approved so far - forgotten which one).

It's called 'EMMA' & produced by Coolpower Products (I've no connection with them & I don't have one).

Posted By: stonesSome info on arrays >All I would bear in mind is that regardless of what diversion devices are fitted to reduce export, the DNO will insist on a G53 relay if you go above 4kwp.

My understanding, which could be wrong, is that the EMMA provides such a thing or is at least a DNO acceptable alternative?

http://www.coolpowerproducts.com/uk/emma-with-ec-works.php

Here's a system which is described in the first post as '30kW, on 7 Samil 4400 inverters.... only allowed to feed 3.68kW into the grid. They use the EMMA (several of them?), and lots of storage heaters to soak up the excess.

http://www.navitron.org.uk/forum/index.php/topic,20537.0.html

Thanks again all for your input, I have to speak to them regarding other things so will add these questions.

John

There's just been a very interesting "experience so far" addition to the Navitron topic where someone has 30kWp of PV on a single phase supply with ASHP & storage heaters in a 300 year old property...

http://www.navitron.org.uk/forum/index.php?topic=20537.msg258291;topicseen#msg258291