Solar PV Quote seems excessive

Martyn1981

New post:

Your options, firstly don't get bogged down with the 'N' word. Option 1 - If you're happy with the triangles (and squares, T&S from now on) and can get a better price, then problem sorted. Will require a SolarEdge system, as 4 factors in play, 2 orientations and 2 different panel outputs.

Alternatively, option 2 - higher efficiency panels, used when space is limited may be an option, such as Sunpower or BenQ. This will all be a matter of how they fit, as their extra power will gain some Wp, but missing out the triangles will lose some Wp. Plus you have to decide if the easthetics of the T&S is worth the money.

No need for SolarEdge, as only two factors in play (orientation) so just a dual MPPT inverter, saving on PO's.

There are also Panasonic panels which are similar higher efficiency and price, but physically smaller (and proportionally lower Wp). They are roughly 1.6m by 0.8m v's 1.6m by 1m. This may (or may not) be an issue when trying to match to your dodgy hips

Last option, regular power panels, again 1.6m by 1m, less Wp, but then install on the WNW roof too with the cost savings. Depending on size and fit (not FiT) maybe 4.5 to 5kWp for the same price, hopefully making up the generation shortfall, and drop in FiT income as 4to10kWp gets a 10% FiT reduction.

Will require SolarEdge again, as 3 factors in play (orientation).

Last, last option. Option 2, but with a SolarEdge system, allowing an extension onto the WNW roof at a later date by piggy backing onto the existing inverter and other AC side kit. But this would cost more long term due to duplication of scaffolding costs, and some additional labour costs.

What would I do? I'm really taken by those T&S panels, but end of the day, I'd go for cheaper panels, on 3 rooves. But I've got a sneaky feeling that the hipped shape will screw that idea up, with panels 'just not' fitting.

Phew!

Mart.

Ageing_Stick_Insect

Martin,

What can I say? Excellent post and requiring several reads for it all to sink in. These hipped roofs create a real quandry regarding fitting of panels. You need a degree in quantum physics to work out what's best!

I'm more aware now of what's possible and what's not so when an installer visits on Wednesday am I should be in a better position to ask relevant questions.

One other question. Another panel user (not here) has suggested each panel have a micro-inverter rather than one for the whole array. What are your thoughts on that?

Eric, thanks for your post on scaffolding costs too.

silverwhistle

There are times when having a basic, simple ex-council terrace house (with a S facing roof able to take 4kw) is quite an advantage!

Actually posting on the scaffolding aspect: it's labour and transport that cost, judging how long they left up my scaffolding after the job was complete.. Plus they left me some scaffold boards to make some raised beds after I mentioned it nicely. :-)

Martyn1981

Ageing_Stick_Insect wrote: »

One other question. Another panel user (not here) has suggested each panel have a micro-inverter rather than one for the whole array. What are your thoughts on that?

Morning Ray. Don't know much about micro's, but would be an option for you. I think they can be doubled up, so two panels to each inverter (in some cases).

Same concern as PO's, more kit where it is harder to get at, if it fails. Not sure how the reliability/lifespan of PO's and micro's compare. PO's are relatively simple, whilst inverters (of all types) wear out eventually. Have read of at least one person with the micro's fitted inside the roof - but you'd need to make sure that this is done very carefully, and no leaks from the multiple holes, but then easy access to any units that fail.

The same shop site has micro's, go to the inverter page and check out, Enphase and Enecsys.

Mart.

Ageing_Stick_Insect

Hi Martin,

I had a look at those micro-inverters and if they have to be fitted inside the loft then I'm concerned about how many holes would be made. Lot more units that require eventual replacement and unless they give obvious benefits over a single inverter I'm not sure I'd go down that route. They made sense for my friend in Crewe as he has only 16 panels.

The more I look at the trienergia panels the more I'm taken with them. Apart from a the superior aesthetics (how does a rectangle fit inside a triangle efficiently?) I can simply get more power generated on the 3 sides of my roof.

Rectangular panels on 3 sides would look ugly and be inefficient. The Trienergia would look stylish and generate more power.

I have money sitting in an account paying 1.2% interest. Even with the higher cost of Trienergia it makes more sense to go with these. If I can get 3 quotes for those panels one is bound to be lower than the others. My mind is slowly being made up. And the timing of the release of these panels is almost like they were made for me.

Ageing_Stick_Insect

A question about how FIT payments are made. Do they base it on the theoretical power output of your system or the actual?

For example, if I had a 4kWh system but some of the panels on a north facing roof output very little would that affect the FIT payment?

Or do they just pay out the appropriate sum for a 4kWh system irrespective of the direction the panels face?

groovyf

I believe it's actual output, as that will dictate what the generation meter readings are that you have to give them.

Ageing_Stick_Insect

Thanks groovy. Makes sense.

I went around to a house that has had rectangular panels fitted and I have to say that on a hipped roof they look very unattractive. They had 3 on the E roof and 6 on the south making an output around 2.25kWh.

On rectangular roofs rectangular panels look fine. On hipped you need different shaped ones to 1) maximise output and 2) make the property look reasonably attractive especially if everything else about it is okay.

groovyf

I only managed 6 rectangular on my devilishly awkward SW-facing roof - however, due to where the house is, you can't see those panels from really anywhere other than a dual-carriage a few hundred meters away and even then you'd have to be keen-eyed. The 10 on the NE side look great.
Having said that... I really didn't know about triangular panels, as they would most definitely have worked better for me aesthetically. A quick calculation and I think instead of 1.5kWp on SW, I may have been able to get 1.8kWp - unsure whether the probable extra cost worth it in my case.

Ageing_Stick_Insect

Thanks groovy. Of course you never had the opportunity to get triangular panels as they have only just appeared. In your case the power benefits would have been marginal. With a max of perhaps 5 on the front and SSW sides it would make a total of 10for me making 2.5kWh max. I can get close to 50% more with the trienergia ones.

Any chance you (and others) could post photos of your installs please? I use dropbox.com which is free.