Solar PV Panels

Cardew

malch wrote: »

i have a quote for 12 Sharp panels with an inverter kicking in at 125V ( many don't kick in untill you start producing 200V ) giving a peak output of 2.16 Kw
my SAP Calculations are

number of panels 12

panel output 180 watts

peak system output 2.6 Kw (number of panels X panel output = watts divided by 1000 to = Kw)

solar input factor 1200

KWh/year 2592 ( system output X input factor)

orientation factor 93%

shading 1

SAP calculation 2410

i have other quotes ( upto £14,700 for same/simular system :shocked:) but the they all seem to come up with different figures for the solar input why the discrepancies? on this quote i will have paid for the system in 7.08 years.:beer: on other sites using the same installation but their solar input figures it will be 7.5 years.:j

To have an generated output of 2,592kWh pa from a 2.16kWp system, I assume you live in Southern Spain?;)

Most people in UK will get 1,600kW to 1,800 kWh per year from that size system.

malch

that's what i mean where would he have gotten these figures if it is to goverment tables?

zeupater

malch wrote: »

i have a quote for 12 Sharp panels with an inverter kicking in at 125V ( many don't kick in untill you start producing 200V ) giving a peak output of 2.16 Kw
my SAP Calculations are

number of panels 12

panel output 180 watts

peak system output 2.6 Kw (number of panels X panel output = watts divided by 1000 to = Kw)

solar input factor 1200

KWh/year 2592 ( system output X input factor)

orientation factor 93%

shading 1

SAP calculation 2410

i have other quotes ( upto £14,700 for same/simular system :shocked:) but the they all seem to come up with different figures for the solar input why the discrepancies? on this quote i will have paid for the system in 7.08 years.:beer: on other sites using the same installation but their solar input figures it will be 7.5 years.:j

Hi

12 Sharp NU180 panels with a matched sma inverter on my SW roof would produce around 1620kWh/annum according to the sma modelling software ...... (It looks like your roof is 'off-South' too)

I suggest that you download the software and compare the panels on your various quotes against what sma would expect the production to be .... http://www.sma.de/en/service/downloads.html in order to get a feel for the accuracy of the data provided .....

Download the full package (it's free), you can choose to install the Northern Europe met data only if you want to save installation space on the disk.

And there was me thinking that the MCS process was supposed to prevent sharp, double glazing type, sales practices ..... let us know if you want to complain to to the relevant body, I'm sure that someone on the forum will be able to provide contact details, especially the MCS registered members who would want to protect the reputation of the MCS process .....

HTH
Z

ps ... you'll probably find that the problem is that the annual solar input factor is likely to be below 800kWh/kWp, not 1200kWh/kWp as stated ....

malch

hi zeupater
i have downloaded the software and the solar input does appear wrong on my quote, it comes out at 916 kWh/KWp which i think will be 1972 KWh/year, about a fith short which means i should be looking at £817 for generation, £120 saved from my useage and £36 sold to leccy company. which would take 8.7 years to pay off the capital.all amounts are approx.
incidently my roof is 15 degrees off due south, so not to far.

zeupater

malch wrote: »

hi zeupater
i have downloaded the software and the solar input does appear wrong on my quote, it comes out at 916 kWh/KWp which i think will be 1972 KWh/year, about a fith short which means i should be looking at £817 for generation, £120 saved from my useage and £36 sold to leccy company. which would take 8.7 years to pay off the capital.all amounts are approx.
incidently my roof is 15 degrees off due south, so not to far.

Hi

You'll probably find it hard to save £120 on your electricity bill, but not impossible if you really work hard at it ... might be an idea to trim that down a little if your not going to be obsessive over every single watt consumed ..... also, for payback calculation the primary investment should really be treated as if invested, so the value of the investment should be increased by an long term annual rate, probably 4.5%APR at the moment, but remember that rates are particularly low at the moment .... also factor in the tax liability on the invested sum appropriate to your circumstances ...... also, the 50% assumed export to the electricity company should be reduced to £30pa to reflect the 916kWh/kWp ......

You could go further and factor in the expected panel efficiency loss over time, inflation etc .... but if you fire your new figures into a readymade calculator such as that on the reuk site you'll get an idea of where the real breakeven point is likely to be ......

Anyway, I guess that with 916kWh/kWp you're about as far south as you can get in the UK .... that's far better than what I get from the sma software, or my panels

HTH
Z

malch

well i think i had better get on and cancel this order today as all does not seem as it should be looks like i have been miss sold, proper minefield out there in the solar PV world. incidently i am near Bournemouth

zeupater

malch wrote: »

well i think i had better get on and cancel this order today as all does not seem as it should be looks like i have been miss sold, proper minefield out there in the solar PV world. incidently i am near Bournemouth

Hi

The MCS scheme is supposed to prevent sharp practice .... having said that, there's always the possibility that the misleading figures are as a result of a genuine error ......

As an aside, when I was looking at systems I had a flyer from a pv company so I gave them a bell on their freephone number. Turns out that they were from somewhere around Bournmouth ..... If I had used them I would have been generating somewhere in the region of 30% more than using any other supplier and would be able to produce electricity in moonlight, this being due to the 'special' high efficiency panels which they had especially selected and carefully matched to the very best inverters ..... they also attempted to convince me of the technical benefits of mounting the pv panels by drilling straight through the (fired clay) roof tiles :eek: .... of course, over the phone I couldn't tell whether the guy was wearing a stetson, but I quickly assumed he was so didn't bother asking them to survey & provide a full quotation !!

Good luck
Z

margin

zeupater wrote: »

To anyone reading this post who believes, or has been told, that a system at current UK price levels will breakeven within 7 years or even 9 years, please query the assumptions and do a little research .... payback has been discussed in detail on this forum, please take time to review the relevant threads .....

HTH
Z

Maybe I should have made it clear that I was talking about an actual installation that is generating payments in line with the calculator. A double-check against the Energy Savings Trust calculator confirms that the system should pay for itself in just over 7 years.

As regards cleaning the panels, I see no reason why I shouldn't be able to do that myself!

keith_r59

margin wrote: »

Maybe I should have made it clear that I was talking about an actual installation that is generating payments in line with the calculator. A double-check against the Energy Savings Trust calculator confirms that the system should pay for itself in just over 7 years.

As regards cleaning the panels, I see no reason why I shouldn't be able to do that myself!

You will probably have to provide actual details of your installation, including costs, for the majority on this forum to believe your payback claims.

Cardew

margin wrote: »

Maybe I should have made it clear that I was talking about an actual installation that is generating payments in line with the calculator. A double-check against the Energy Savings Trust calculator confirms that the system should pay for itself in just over 7 years.

As regards cleaning the panels, I see no reason why I shouldn't be able to do that myself!

As said above, none of the calculators confirm anything.

They calculate payback times based on several estimated factors (see post#10) that you input.

You obviously know the price you paid.

However if you are getting FITs you only have the predicted annual output.

You have to estimate, Interest rates, inflation rate, fuel inflation rate, how much electricity you use in the house and presumably have faith no repairs will be required.

Why not post your price paid and all assumptions?