Help and guidance please on solar energy

hethmar

Have received a quotation for 14 seraphim 285w panels with a solis inverter and solar i boost (for hot water) ad BMC (whatever that is?)

We are in norfolk and the panels would go on two different roof aspects, one is SW and one is S.

The estimated output given is 3363 Kwh.

The quote is for £7195

The costings given show over 20years a total benefit of £36312 and profit as £29117 - this says it is a yearly return of 14.39%

The salesman said that once the panels are fitted the subsidy is fixed for 20 years - is that correct please?

So could anyone who is savvy about these things comment on these figures please? And possibly recommend other firms for a quotation?

pw22

My first thoughts are as follows -

Annual generation figures look right but the returns over 20 years look very inflated.

The cost of the system is also high and posters have been getting similar systems for about 5500 recently.

The salesman is correct in that the FIT is for 20 years.

Hope this helps.

tunnel

Can you be more specific? How many panels to each roof and which solis inverter?
Getting the wrong inverter could cost you thousands in lost generation and if the salesmans (inflated)figures were to be believed I wouldn't trust they'd get it right. Basically it would need to be a dual MPPT(2 string) inverter so both rooves work independently.


Does your roof also suffer from ANY shading, ie..chimney, aerial or tree or neighbours roof? Again...important.


The subsidy is not fixed for 20 years, it is indexed linked to the RPI, thus a slight increase for the next 20 years


Price, wow...£2k too much


The only good thing I see in your quote is the iboost, a good way to use up excess generation for hot water.


Firstly answer the important questions I asked and then get plenty of quotes, preferably starting with a 4 or 5.

Love_Solar

Hi
can you answer a few questions
How much electric do you use per year in KW
What price are you paying for your electric per kW

tunnel

Love_Solar wrote: »

Hi
can you answer a few questions
How much electric do you use per year in KW
What price are you paying for your electric per kW

Who is that directed at...the OP?
What is the relevance of the question?
Care to expand?, possibly by starting your own thread so any help given to the OP doesn't get muddled in a tranche of posts about usage and electric costs

hethmar

Thanks everyone.

The panels were to be placed equally 7 on each aspect.

I dont have a yearly electric costing as we tend to swop companies and Ive been with first utility since Jan. We pay £111 per month at mo for gas and electric dual fuel. It was £135 until this month when first utility said we were two months payments in advance (well, its been hot). We also use a wood burner.

Its a 4 bed detached 1940s house.

The quote just says "solis" inverter, no other indication.

I am also a bit concerned now, having read up a bit more on various installers sites that the house must have an EPC Cert of D and above. Not sure if we meet that - we have lived here 25 years so never needed a cert.

tunnel

Do you have cavity wall insulation or loft insulation, double glazed and LED lightbulbs? Doing just these few brings the EPC down considerably!


As a comparison my gas and electric are down to £70 a month and I'm in credit


Shading?

Love_Solar

Hi
The very first question a solar PV installer should ask the customer is how much electric do they use per year. It can vary from below 2000 kWh per year to over 10 thousand kWh per year, and this makes a difference to profit from the Solar PV system. The more you use per year the greater the return.

From the monthly costs of £110.00 and registered with First Utility Jan 2015, I expect price break down your usage to be as follows.
£110.00 per month x 12 = £1320 per year
First Utility prices Standing charge £74.64 per fuel and you have dual fuel this equals £149.28
Price per kWh electric 10.735p
Price per kW gas 2.72p
£1320 less standing charge = £1170.72 this split 40% electric 60% gas as an assumption
£468.28 for electric and £702.43 for gas
£468.28 / by 10.735p = 4362 kWh per year for electric.(please confirm from your electric bill this figure is correct)

Your 3.99kW solar PV system (14 x 285 watt panel) will generate 3363KWh per year and this sound’s about right for your area and the way the solar panels are pointing.

Now down to savings and FITs payments, the total profit is well over the mark at £36312.00 over twenty years. Let’s break this down on electric savings in the home for the generated power from the panels and then the FITs and export payments.

In house savings, from your 4362 kWh per year you will save between 26% to 34% of this amount, so lets say you save 30% in the middle, 30% of your 4362 is 1308 kWh per year, in money terms 1308 x 10.735p = £140.47 per year with the price of electric increasing by 6% per year the total savings over twenty five years would be £7703.00 approx.
Fits payments year 1
3363 kwh x £0.1292 per kw = £434.49
With assumed RPI per year of 1.5% the total would be =£9373.70 over twenty years

Export 3363kwh / 2 x 0.0485 = £81.55 with the same 1.5% RPI increase would be £1759.86 approx

Total FIT over twenty years = £11133.56
Total savings in house over twenty five years £7703.00
Total benefit = £18,836.56

From installing the Iboost unit this will save you 600 kwh per year.
600 kw x £0.10735p = £64.41 per year.

I would recommend the following a 3 kW system with using the solar edge inverter and optimisation units, this will give you full monitoring online and better warranty as this is twelve years as standard and can be extended to twenty years for £156.00
You will still make the same saving in house as the 3.99 kw system. Use the standard 250 or 260 watt solar panels and this system should cost you no more than £5000.00 I If you can’t find an installer to do that for you I’m in Lincolnshire and would gladly come over and install it for you.

If you are uncertain about my answers just ask the same question on the heat my home” forum.

And that is why the question about price of electric and consumption is an important question to ask.

tunnel

Love_Solar wrote: »

Hi
The very first question a solar PV installer should ask the customer is how much electric do they use per year. It can vary from below 2000 kWh per year to over 10 thousand kWh per year, and this makes a difference to profit from the Solar PV system. The more you use per year the greater the return.

From the monthly costs of £110.00 and registered with First Utility Jan 2015, I expect price break down your usage to be as follows.
£110.00 per month x 12 = £1320 per year
First Utility prices Standing charge £74.64 per fuel and you have dual fuel this equals £149.28
Price per kWh electric 10.735p
Price per kW gas 2.72p
£1320 less standing charge = £1170.72 this split 40% electric 60% gas as an assumption
£468.28 for electric and £702.43 for gas
£468.28 / by 10.735p = 4362 kWh per year for electric.(please confirm from your electric bill this figure is correct)

Your 3.99kW solar PV system (14 x 285 watt panel) will generate 3363KWh per year and this sound’s about right for your area and the way the solar panels are pointing.

Now down to savings and FITs payments, the total profit is well over the mark at £36312.00 over twenty years. Let’s break this down on electric savings in the home for the generated power from the panels and then the FITs and export payments.

In house savings, from your 4362 kWh per year you will save between 26% to 34% of this amount, so lets say you save 30% in the middle, 30% of your 4362 is 1308 kWh per year, in money terms 1308 x 10.735p = £140.47 per year with the price of electric increasing by 6% per year the total savings over twenty five years would be £7703.00 approx.
Fits payments year 1
3363 kwh x £0.1292 per kw = £434.49
With assumed RPI per year of 1.5% the total would be =£9373.70 over twenty years

Export 3363kwh / 2 x 0.0485 = £81.55 with the same 1.5% RPI increase would be £1759.86 approx

Total FIT over twenty years = £11133.56
Total savings in house over twenty five years £7703.00
Total benefit = £18,836.56

From installing the Iboost unit this will save you 600 kwh per year.
600 kw x £0.10735p = £64.41 per year.

I would recommend the following a 3 kW system with using the solar edge inverter and optimisation units, this will give you full monitoring online and better warranty as this is twelve years as standard and can be extended to twenty years for £156.00
You will still make the same saving in house as the 3.99 kw system. Use the standard 250 or 260 watt solar panels and this system should cost you no more than £5000.00 I If you can’t find an installer to do that for you I’m in Lincolnshire and would gladly come over and install it for you.

If you are uncertain about my answers just ask the same question on the heat my home” forum.

And that is why the question about price of electric and consumption is an important question to ask.

Why are you quoting electric savings over a 25 year period when the FiT is only 20 years?
Why are you quoting 6% annual increase when electric prices have come down and inflation is currently zero?
Why oh why would you recommend the OP buy a 3kWp system when a 3.99kWp will fit just as well AND only for a difference of £40 more for the panels
See here for a list of prices, note retail prices and not trade http://www.swithenbanks.co.uk/shop.php?action=index


I'm pleased to have the perspective of an installer but I find your recommendations slightly odd and one which could cost the OP more money for less of a system, at no point has the OP stated they have any shade issues so a standard dual MPPT inverter would suffice for a dual aspect roof, fitting solaredge with PO's adds another 14 pieces of kit on the roof that could go wrong...with or without any extra warranty.


£5k for a 3kWp system, are you having a laugh? So not only is it too expensive but they'd only get 3/4 of the FiTs of a 3.99kWp system, something you fail to mention in your recommendation


Now if you'd like to explain your reasoning I'm all ears?

tunnel

I might add that the estimated generation for Norfolk is probably 10% higher than the OP has been quoted, we enthusiasts use this site http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php
A quick pin of Norwich(2kWp S, 2kWp SW) gives an estimate of around 3700 to 3800kWh produced. You will find that it is extremely accurate and used by many posters on these forums as a standard.

hethmar

Grateful for all input, Im slowly getting this into my old head.

BTW, got our annual electric usage figure today which is surprisingly 5607 Kw.

We have decided to get a local firm which has good reviews on solar forums in for another quote.

Grateful for everyones kind assistance in this