Yingli v's Sunpower PV

A question about : Yingli v's Sunpower PV

My parents have been getting quotes and are now in need of some advice. Ikea quoted Ј4,200 for 1.8kw so they have been discarded. Another company refused to quote because it would not be aesthetically pleasing on their cottage - would be the only house on the street with panels. Third company have given two quotes - one for Yingli and one for Sunpower panels. Hopefully they have given me all the details needed to help them make an informed decision as to which to go for.

Yingli - 14 x 275w =Ј4,700 +VAT

First year - Income from feed in generation tariff @ 13.88p kw/h Ј 487.33
Income from exporting @ 4.77p kw/h Ј 83.74
Electricity saving @ 13p kw/h Ј 228.22
Total benefit Ј 799.29
Pay back times 6 Years 2 Months
Total profit over 20 years Ј 16, 569.82
( 11.25 % per year )

10 year limited product warranty
Limited power warranty - 1 year 98% of minimal rated power output.
10 years at 92%
25 years at 82%

Sunpower - 12 x 327w = Ј6,800 +VAT

First year – Income from feed in generation tariff @ 13.88p kw/h Ј 496.22
Income from exporting @ 4.77p kw/h Ј 85.27
Electricity saving @ 13p kw/h Ј 232.38
Total benefit Ј 813.87
Pay back times 7 Years 7 Months
Total profit over 20 years Ј 14, 807.57
( 11.27 % per year )

25 year product warranty
Power warranty - 95% for first five years then -0.4%/year to year 25

Materials needed are the same for both -
1 x Solis 3.6 Inverters
 8 x PV rails and accessories
 36 x Inter clamps
 8 x End clamps
 4 x MC3 clamps
 2 x 16A DC isolators
 2 x 20A AC isolator
 30m of Pv cable
 1 x generation meter – Ofgem
 1 x Safety labels
 1 x MCB
 Ionisation smoke detector (If any electrical equipment is located in the loft)

There are also optional extras some of which are no use to them because they don't have a water tank but the others I have no clue about so couldn't help them. They are-

Voltage optimiser - from Ј320 - Voltage optimisation reduces excess supply voltage to match the ideal operating level, enabling appliances to run more efficiently, reducing wasted energy and saving money.

Wattson solar monitoring - from Ј180 - The energy monitor showing electricity generation, usage and net usage. It maximises returns on your solar PV.

Passiv heating control - from Ј1000 - PassivEnergy learns the thermal properties of your home and monitors the temperature outside to keep your home comfortable and cut energy waste. The Passiv energy app gives you control wherever you are in the world.

So advice please. I have heard Yingli manufacture to the bare minimum requirements so would they be better paying the extra for the better quality and hopefully reliability of the sunpower even though the estimated benefits are not as great due to the initial costs? Would they benefit getting any of the optional extras?

All advice greatfully recieved. If it makes a difference they are in Fife and their roof is 30 degrees from south towards west.

Best answers:

• Hiya.
  First off, I've done a quick check of the generation figure on PVGIS and that looks good. Great start. Though I'd question the leccy savings figure. Maybe base estimates on half that but hope for more.
  Nothing wrong with Sunpowers, but what they offer is a more efficient panel, allowing you to squeeze more Wp into a given space. Since your parents are able to get very close to the 4kWp FiT tariff band with regular panels, then there seems little point in paying the extra for them.
  Comparing generation, you can see that the quotes only vary by the difference in system sizes, which is minimal. Certainly not worth Ј2,100 + VAT. In fact, Ј2,100+VAT would buy 14 replacement panels (@Ј150 each) if they ever needed too - I just found them retail at Ј148.70+VAT.
  Nothing wrong with YingLi, they are probably the largest supplier and very popular all over the world.
  That first quote at Ј4,935 (inc VAT) looks very attractive.
  Some folk on here have Wattson systems and can advise, but the other options look like a waste of money to me.
  Mart.
• Thank you Martyn. I think the electricity saving is what the company quoted based on an average but I know they are on the same tariff I am which is only 10.8p/kwh so that will definitely be less. I have had a look online and the wattson monitor can be bought for much less than the Ј180 quoted so I'll tell them if they want it to get it themselves.
  I didn't realise the panels themselves were that cheap. I think in that case they will go for the Yingli. They have only just retired so that extra Ј2k could give them a nice holiday instead.
• Not had any issues with them "touch wood" and been installed for 3.5 years
• I would agree with Mart. I was attracted to the Sunpower when I was getting quotes but unless you don't have room on your roof to get your 4kWp with lower efficiency panels, or you are going to bust through the 4kWp barrier and max out on production for the available roof space, I don't think the extra expense would ever repay itself.
  With the benefit of hindsight and seeing as I have now gone to 5.25kWp by putting in a second system to add an extra 1.75kWp, I would probably have gone with Sundowner had I made that decision originally as I could have squeezed 50% more production out of my usable roof space.
  What is more important in my view is to spend the extra money and split your system over two roofs if you have a large west-facing roof and small south-facing like me (this is why I put the second system in). For a 50/50 split you will get about 5% more production overall but, more importantly, you get a far more even spread of generation over the day - my west-facing roof produces very little (few hundred watts at any given time) until about noon when it comes into direct sunlight and then quickly rises to max production. Putting the second system in means I now get worthwhile production in the morning too for self-consumption.
  This was the only mistake I made when planning my investment and having learned what I did "wrong" within a few weeks of going live, what annoyed me about the industry and every bidder was that they all focussed only on annual production v installation cost (split config costs more in scaffolding and install time for a few % increase in FiT returns) and didn't mention the daily spread of usable generation - it is no good generating 4kW in the afternoon if you only use say 2kW at any given time to make tea or whatever, and virtually nothing in the morning when you still need your 2kW. Better to max out at, say 2kW over most of the day and to therefore import less from the grid...
  Gary