40kw install

[woko]

Hello all. Just landed a 40kw install on a farm. The biggest one I've taken on so far.
160 REC 245 panels mounted on a cement board roof, netting, crawl boards etc.
2 x 17,000 TL SMA inverters.
All piped down 3 core 25mm SWA on a 100m run to a newly installed transformer.
Anyone got any useful advise on this size install.
I'm not sure about the metering import and export?
Also the SMA software says 25mm 4 core is suitable over 100m with their inverters, Or maybe install 35mm to be safe?

Any advise would be appreciated. Good or bad!!

 

[Earthstore]

I do not mean to be rude, but I feel that you should employ some professional help on this one, it would be money well spent.

On larger commercial systems, as I believe you are aware, they are more complex than a domestic, you have not mentioned G59, Structural surveys, EPC, asbestos testing, and so the list goes on.

So please employ some help, instead of trying to build a rocket ship with help from a forum.

I hope this helps.

 

[woko]

I'm quite competent to take on this size of install. I've done plenty of commercial jobs but not of this size.
I'm not asking how to do it just any advise from people who have done this size install based on their experiences. There are plenty of questions similar to mine on this forum and I don't see any of your smug answers on there.

You may not mean to be rude but you are being. You could have took the time to share any of your experiences instead of presuming I'm incompetent.

 

[sedgy34]

Have you decided on the main switch supplying the 35mm armoured cable you could post a drawing people may get involved to offer their opinions

 

[Earthstore]

Back to your original post, "any advice would be appreciated" I gave you some good advice, and apologised before hand and if it came across wrong, and then you go on to insult me.

With the attitude you have there may not be a queue of people willing to help, But may I wish you luck as I am done here.

ps Do your Vd on that cable....

 

[woko]

Earth store, I apologise if I insulted you.

Thanks for the advise on the cable, I was going off the SMA software but ill do the calcs.

As for the other things you mention, EPC, structural survey and G59, they are all in hand. It's only the roof I'm unsure of but I may contract that out.

 

[Outspoken]

Hello all. Just landed a 40kw install on a farm. The biggest one I've taken on so far.
160 REC 245 panels mounted on a cement board roof, netting, crawl boards etc.
2 x 17,000 TL SMA inverters.
All piped down 3 core 25mm SWA on a 100m run to a newly installed transformer.
Anyone got any useful advise on this size install.
I'm not sure about the metering import and export?
Also the SMA software says 25mm 4 core is suitable over 100m with their inverters, Or maybe install 35mm to be safe?

Any advise would be appreciated. Good or bad!!

Defo check your volt drop on that run...

Also the panel choice...at best 14.8% efficient is pretty poor..Have you considered Hybrid cells, they can have cell efficiencies up to 20.8% and module efficiencies exceeding 18%, far better in the long run and they work in nearer peak in a wider range of lighting conditions.

 

[woko]

I think I'll be using 35mm......

 

[BruceB]

Outspoken, It depends what you mean by 'better'. The problem with the more efficient panels is that they are more expensive for the same power output. So which you want to go for depends for instance on whether you are trying to maximise output/income for a particular surface area, if you are area limited, or whether you are trying to minimise cost per unit of output if area is not the limitation. Then tariff boundaries also come into play etc etc.

 

[woko]

I've used REC's quite a lot and they boast very good efficiency figures and are well made. I'm happy with the choice and so is my customer. I don't think there budget will stretch to hybrids.

 

[Gavin A]

Defo check your volt drop on that run...

Also the panel choice...at best 14.8% efficient is pretty poor..Have you considered Hybrid cells, they can have cell efficiencies up to 20.8% and module efficiencies exceeding 18%, far better in the long run and they work in nearer peak in a wider range of lighting conditions.

so you're going to advise using panasonic HIT panels on a 40kWp installation where there's room for 40kWp of much cheaper standard crystaline panels?

I'd be interested to know how many commercial jobs you win with that approach as you'd come in around £10k more expensive vs around a 5% output gain at most. Unless you're recommending upping the installation to 50kWp by using the HIT panels... but even then the benefits wouldn't work out IME unless the building was a very high energy user.

 

[Outspoken]

so you're going to advise using panasonic HIT panels on a 40kWp installation where there's room for 40kWp of much cheaper standard crystaline panels?

I'd be interested to know how many commercial jobs you win with that approach as you'd come in around £10k more expensive vs around a 5% output gain at most. Unless you're recommending upping the installation to 50kWp by using the HIT panels... but even then the benefits wouldn't work out IME unless the building was a very high energy user.

It's not as simple as that because the panels are more efficient at lower radiance levels they actually produce about 15-20% more electricity that the standard panels over their lifetime...I have some data somewhere and will dig out, just got in from work though so about to eat first if you don't mind...

 

[jason121]

Check out REC on PVSOL bloody good result

 

[SolarCity]

Yeah, REC panels are excellent.

I doubt very much that hybrids would exceed REC panels performance by 15-20%. Our data doesn't show this at all.

 

[Outspoken]

Yeah, REC panels are excellent.

I doubt very much that hybrids would exceed REC panels performance by 15-20%. Our data doesn't show this at all.

I am sure over the life of the panel you will see the 15-20% increase because Hybrid panels, and nearly all "high performance" (cells with efficiencies over 18%) are more reactive in low light conditions and to UV light.

Panels today are far better than several years ago, but they still lag behind other form of generation technology, and they are not free either as is often lauded because of the high cost of installation against the power generated.

If you want to see the benefits of improved manufacture techniques coupled to an ability to truly utilize the electromagnetic spectrum from nIR to eUV then you should consider these, the most efficient commercially available cell at up to 24%...